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2016 Volume Issue 4
2016, (4): 399-401
doi: 10.11777/j.issn1000-3304.2016.16111
Abstract:
Fullerene-free polymer solar cells have received increasing attention, because the non-fullerene acceptors offer a great chance to achieve complementary absorption and appropriate molecular orbitals to the polymer donor materials, which may result in much improved performance of the resulting devices.Recently, a new record of power conversion efficiency of 11.2% has been set based on a non-fullerene electron-accepting material and a medium-bandgap conjugated polymer.This result indicates that the development of new non-fullerene electron-accepting materials and their applications in polymer solar cells would be a next hot spot of the research field, which may be the breakthrough point of this technology.
Fullerene-free polymer solar cells have received increasing attention, because the non-fullerene acceptors offer a great chance to achieve complementary absorption and appropriate molecular orbitals to the polymer donor materials, which may result in much improved performance of the resulting devices.Recently, a new record of power conversion efficiency of 11.2% has been set based on a non-fullerene electron-accepting material and a medium-bandgap conjugated polymer.This result indicates that the development of new non-fullerene electron-accepting materials and their applications in polymer solar cells would be a next hot spot of the research field, which may be the breakthrough point of this technology.
2016, (4): 402-408
doi: 10.11777/j.issn1000-3304.2016.15341
Abstract:
In this work, the waste polyurethane foams were recycled and used as precursors to fabricate magnetically carbonized foams which exhibited effectively oil absorption and magnetic responsive preporties through a facile approach.Polyurethane foams were firstly dipped into acrylic acid (AA) aqueous solution to be modified with PAA on the surface of their pores by using solution polymerization.Then the foams were immersed into FeCl3 aqueous solution for soaking Fe3+ until saturation.Subsequently, the composite materials were heated to 230℃ and kept at that temperatue under the protection of nitrogen for 4 h to form magnetically carbonized foams.The effects of concentrations of AA and FeCl3, and heat temperature on the performances of magnetically carbonized foams were investigated in detail.The results of optical microscopy show that the as-fabaricated foams are porous.The data of Fourier transform infrared spectroscopy depict that the foams are modified by PAA and Fe3+.X-ray diffraction patterns demonstrate that Fe3+ changes to Fe3O4 after heating.The contact angles of water on the foams increased from 80.8 to 115.4.Optimized magnetically carbonized foams can absorb oil more than 10 times of their own weight and can quickly absorb oil within 5 min.Importantly, the density of the foams are low so that they can float on the surface of water for treating oil spills.And the foams absorbing oil can be easily seperated by a magnet.The magnetically carbonized foams synthesized in this work are good candidates for oil spill absorption and oil-water seperation.
In this work, the waste polyurethane foams were recycled and used as precursors to fabricate magnetically carbonized foams which exhibited effectively oil absorption and magnetic responsive preporties through a facile approach.Polyurethane foams were firstly dipped into acrylic acid (AA) aqueous solution to be modified with PAA on the surface of their pores by using solution polymerization.Then the foams were immersed into FeCl3 aqueous solution for soaking Fe3+ until saturation.Subsequently, the composite materials were heated to 230℃ and kept at that temperatue under the protection of nitrogen for 4 h to form magnetically carbonized foams.The effects of concentrations of AA and FeCl3, and heat temperature on the performances of magnetically carbonized foams were investigated in detail.The results of optical microscopy show that the as-fabaricated foams are porous.The data of Fourier transform infrared spectroscopy depict that the foams are modified by PAA and Fe3+.X-ray diffraction patterns demonstrate that Fe3+ changes to Fe3O4 after heating.The contact angles of water on the foams increased from 80.8 to 115.4.Optimized magnetically carbonized foams can absorb oil more than 10 times of their own weight and can quickly absorb oil within 5 min.Importantly, the density of the foams are low so that they can float on the surface of water for treating oil spills.And the foams absorbing oil can be easily seperated by a magnet.The magnetically carbonized foams synthesized in this work are good candidates for oil spill absorption and oil-water seperation.
2016, (4): 409-421
doi: 10.11777/j.issn1000-3304.2016.16037
Abstract:
Design and synthesis of novel optically active helical polymers are active subjects and frontiers in the field of polymer science.Optically active helical vinylterphenyl polymers are physically and chemically stable and are of potential applications in chiral recognition and asymmetric catalysis.In this review, the helix-sense-selective radical polymerization of vinylterphenyl monomers, chiral teleinduction in radical copolymerization, and self-assembly of amphiphilic block copolymers consisting of helical chains as rigid segments in solution and at the air/water interface are comprehensively introduced.The results obtained up to now are summarized and a short outlook on the development of optically active vinylaromatic polymers is provided.
Design and synthesis of novel optically active helical polymers are active subjects and frontiers in the field of polymer science.Optically active helical vinylterphenyl polymers are physically and chemically stable and are of potential applications in chiral recognition and asymmetric catalysis.In this review, the helix-sense-selective radical polymerization of vinylterphenyl monomers, chiral teleinduction in radical copolymerization, and self-assembly of amphiphilic block copolymers consisting of helical chains as rigid segments in solution and at the air/water interface are comprehensively introduced.The results obtained up to now are summarized and a short outlook on the development of optically active vinylaromatic polymers is provided.
2016, (4): 422-427
doi: 10.11777/j.issn1000-3304.2016.15222
Abstract:
PMMA stretched chains was prepared successfully by dropping dilute PS-b-PMMA toluene solution, and the morphology and the conformation transition of PMMA stretched chains under acetone and water vapour annealing were characterized by using AFM.The results showed the PMMA stretched chains with height of 0.2 nm and length of 100 nm~300 nm can be formed on the mica substrate by dropping dilute PS-b-PMMA toluene solution with concentration of 110-6; this method can be used for PS-b-PMMA materials with different molecular weights, the highly stretched PMMA chains can be prepared easily when the molecular weight of PMMA segment was larger than that of PS segment.The PMMA stretched chains will be contracted rapidly and fused with PS core to form spherical structure when the surface micelles were annealed by acetone vapour; the conformation transition depended on the initial concentration of preparing surface micelles during annealing with water vapour, the surface micelles prepared by dilute solution of 110-6 can be changed into spherical structure only; the micelles having much more PMMA stretched chains prepared with a concentration of 510-6 can be assembled into flower like micelles and rod micelles with step-like PMMA molecular layers.
PMMA stretched chains was prepared successfully by dropping dilute PS-b-PMMA toluene solution, and the morphology and the conformation transition of PMMA stretched chains under acetone and water vapour annealing were characterized by using AFM.The results showed the PMMA stretched chains with height of 0.2 nm and length of 100 nm~300 nm can be formed on the mica substrate by dropping dilute PS-b-PMMA toluene solution with concentration of 110-6; this method can be used for PS-b-PMMA materials with different molecular weights, the highly stretched PMMA chains can be prepared easily when the molecular weight of PMMA segment was larger than that of PS segment.The PMMA stretched chains will be contracted rapidly and fused with PS core to form spherical structure when the surface micelles were annealed by acetone vapour; the conformation transition depended on the initial concentration of preparing surface micelles during annealing with water vapour, the surface micelles prepared by dilute solution of 110-6 can be changed into spherical structure only; the micelles having much more PMMA stretched chains prepared with a concentration of 510-6 can be assembled into flower like micelles and rod micelles with step-like PMMA molecular layers.
2016, (4): 428-435
doi: 10.11777/j.issn1000-3304.2016.15223
Abstract:
The aromatic poly(m-phenylene isophthalamide)(PMIA) hollow fiber membranes with polyethylene glycol (PEG), LiCl and CaCl2 as additives were fabricated by dry-wet spinning technology. The effects of adding amount of PEG in the casting solution during membrane fabrication on the performance of the PMIA hollow fiber membranes were investigated. Membrane characterization was conducted through pure water flux, porosity, contact angle, mechanical strength, thermogravimetric analysis (TGA), rejection rate and the flux of hot water. The SEM results indicated that the cross section of the hollow fiber membrane had an asymmetrical structure that consisted of a dense outer surface acting as a selectively layer, a spongy-like transition layer, and finger-like microvoids close to the inner and outer surface. The addition of PEG in casting solution can significantly improve the water flux of PMIA hollow fiber membranes, however when the adding amount of PEG increased to a certain degree, the water flux of the PMIA membranes showed a downward trend; PMIA hollow fiber membranes showed good rejection performance for BSA solution, the rejection rate can reach 92%; the addition of PEG can improve the PMIA membranes' hydrophilicity, the contact angle decreased from 51 to 44; the maximum number of tensile strength can reach to 5.8 MPa. Finally the resistance performance of PMIA membranes to heat water and alkali solution was investigated. The results showed that the PMIA hollow fiber membranes have a good resistance of hot water and alkali solution.
The aromatic poly(m-phenylene isophthalamide)(PMIA) hollow fiber membranes with polyethylene glycol (PEG), LiCl and CaCl2 as additives were fabricated by dry-wet spinning technology. The effects of adding amount of PEG in the casting solution during membrane fabrication on the performance of the PMIA hollow fiber membranes were investigated. Membrane characterization was conducted through pure water flux, porosity, contact angle, mechanical strength, thermogravimetric analysis (TGA), rejection rate and the flux of hot water. The SEM results indicated that the cross section of the hollow fiber membrane had an asymmetrical structure that consisted of a dense outer surface acting as a selectively layer, a spongy-like transition layer, and finger-like microvoids close to the inner and outer surface. The addition of PEG in casting solution can significantly improve the water flux of PMIA hollow fiber membranes, however when the adding amount of PEG increased to a certain degree, the water flux of the PMIA membranes showed a downward trend; PMIA hollow fiber membranes showed good rejection performance for BSA solution, the rejection rate can reach 92%; the addition of PEG can improve the PMIA membranes' hydrophilicity, the contact angle decreased from 51 to 44; the maximum number of tensile strength can reach to 5.8 MPa. Finally the resistance performance of PMIA membranes to heat water and alkali solution was investigated. The results showed that the PMIA hollow fiber membranes have a good resistance of hot water and alkali solution.
2016, (4): 436-442
doi: 10.11777/j.issn1000-3304.2016.15225
Abstract:
In order to improve the ion conductivity and alkaline stability of the anion exchange membranes derived from quaternary ammonium poly(ether sulfone)s, a series of new self-crosslinked membranes (CQPES) were successfully prepared from three kinds of aliphatic di-tertiary amines, namely, N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl-1, 3-propanediamine (TMPDA) and N,N,N',N'-tetramethyl-1, 6-hexanediamine (TMHDA), by solution casting.For the CQPES membranes, their properties such as solvent resistance, dimensional stability, mechanical stability, hydrolytic stability as well as alkaline stability were enhanced significantly, while the high ion conductivity was maintained.For example, the membrane of CQPES-H-0.5 (1.45 mmol/g, TMHDA as the cross-linker) showed 43% of water uptake, lower than 10% of size change in in-plane direction at 30℃, and 17 mS/cm and 64 mS/cm of ionic conductivity in water at 30℃ and 90℃, respectively.During the evaluation of stability, 21% loss in ionic conductivity after treatment in 4 mol/L NaOH solution for 168 h and 3.8% loss in weight after treatment in 100℃ water for 24 h were found for CQPES-H-0.5 membrane, while 12% and 40% losses were for the uncrosslinked membrane (QPES), respectively.The excellent performance of CQPES-H-0.5 suggests its potential application in the fuel cell system.
In order to improve the ion conductivity and alkaline stability of the anion exchange membranes derived from quaternary ammonium poly(ether sulfone)s, a series of new self-crosslinked membranes (CQPES) were successfully prepared from three kinds of aliphatic di-tertiary amines, namely, N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl-1, 3-propanediamine (TMPDA) and N,N,N',N'-tetramethyl-1, 6-hexanediamine (TMHDA), by solution casting.For the CQPES membranes, their properties such as solvent resistance, dimensional stability, mechanical stability, hydrolytic stability as well as alkaline stability were enhanced significantly, while the high ion conductivity was maintained.For example, the membrane of CQPES-H-0.5 (1.45 mmol/g, TMHDA as the cross-linker) showed 43% of water uptake, lower than 10% of size change in in-plane direction at 30℃, and 17 mS/cm and 64 mS/cm of ionic conductivity in water at 30℃ and 90℃, respectively.During the evaluation of stability, 21% loss in ionic conductivity after treatment in 4 mol/L NaOH solution for 168 h and 3.8% loss in weight after treatment in 100℃ water for 24 h were found for CQPES-H-0.5 membrane, while 12% and 40% losses were for the uncrosslinked membrane (QPES), respectively.The excellent performance of CQPES-H-0.5 suggests its potential application in the fuel cell system.
2016, (4): 443-448
doi: 10.11777/j.issn1000-3304.2016.15228
Abstract:
Poly(vinylidene chloride-methyl acrylate)-b-poly(acrylic acid) (PVDC-b-PAA) block copolymers with different compositions were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, and their micellization behavior was investigated by dynamic light scattering, surface tension measurement and transmission electron microscope analysis.It was found that PVDC-b-PAA copolymers could be self-assembled to form transparent micelle aqueous solutions by dissolving of the copolymer in N,N-dimethylformamide and dialysis by water.The critical micelle concentrations of PVDC-b-PAA copolymers were ranged from 9.9 to 19.6 mg/L, and increased with increasing PAA content in the copolymer.The micelles were almost in spherical morphology with a size range of 70.9~110.9 nm and with narrow size distributions.The pH value of aqueous phase affected the zeta potential and aggregation of micelles.When pH value was decreased from 3 to 1, the zeta potential of micelles was changed from a negative value to a positive value, the aggregation degree and the average size of micelle aggregates were rapidly increased, and the size distribution became wider.
Poly(vinylidene chloride-methyl acrylate)-b-poly(acrylic acid) (PVDC-b-PAA) block copolymers with different compositions were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, and their micellization behavior was investigated by dynamic light scattering, surface tension measurement and transmission electron microscope analysis.It was found that PVDC-b-PAA copolymers could be self-assembled to form transparent micelle aqueous solutions by dissolving of the copolymer in N,N-dimethylformamide and dialysis by water.The critical micelle concentrations of PVDC-b-PAA copolymers were ranged from 9.9 to 19.6 mg/L, and increased with increasing PAA content in the copolymer.The micelles were almost in spherical morphology with a size range of 70.9~110.9 nm and with narrow size distributions.The pH value of aqueous phase affected the zeta potential and aggregation of micelles.When pH value was decreased from 3 to 1, the zeta potential of micelles was changed from a negative value to a positive value, the aggregation degree and the average size of micelle aggregates were rapidly increased, and the size distribution became wider.
2016, (4): 449-456
doi: 10.11777/j.issn1000-3304.2016.15234
Abstract:
A series of phosphorus-containing poly(arylene ether)/poly(arylene ether ketone) copolymers were synthesized by the nucleophilic substitution through changing the molar ratio of bis(4-chlorophenyl) phenyl phosphine oxide (BFPPO) and 4, 4'-difluoro diphenylmethanone (DFK).The copolymers with large side groups, twisted and noncoplanar conformation were readily soluble in a variety of organic solvents, such as DMF, DMSO and so on.The structure of the copolymers was confirmed by FTIR, 31P-NMR, 1H-NMR and 13C-NMR.The molecular weight and its distribution of copolymers were also investigated by GPC.Furthermore, the DSC test revealed that the glass transition temperature of the copolymers increased linearly with the BFPPO content increasing and the maximum can reach 270℃.Experimental results indicated that the polymers had good thermal stability, with the temperature at 5% weight loss of 494~498℃ and CR800 of 5.3%~11.8% at air atmosphere.Moreover, the copolymer films showed good mechanical properties with tensile strength of 74~95 MPa, tensile modulus of 2.3~2.6 GPa and elongation at break of 6.1%~9.0%.It was concluded that the polymers which kept good thermodynamic properties exhibited outstanding flame retardance due to the existence of triphenylphosphine-oxide moieties in the main chain.The UL94 of the copolymer films reached VTM-0 grade and the LOI values were up to 50% significantly.
A series of phosphorus-containing poly(arylene ether)/poly(arylene ether ketone) copolymers were synthesized by the nucleophilic substitution through changing the molar ratio of bis(4-chlorophenyl) phenyl phosphine oxide (BFPPO) and 4, 4'-difluoro diphenylmethanone (DFK).The copolymers with large side groups, twisted and noncoplanar conformation were readily soluble in a variety of organic solvents, such as DMF, DMSO and so on.The structure of the copolymers was confirmed by FTIR, 31P-NMR, 1H-NMR and 13C-NMR.The molecular weight and its distribution of copolymers were also investigated by GPC.Furthermore, the DSC test revealed that the glass transition temperature of the copolymers increased linearly with the BFPPO content increasing and the maximum can reach 270℃.Experimental results indicated that the polymers had good thermal stability, with the temperature at 5% weight loss of 494~498℃ and CR800 of 5.3%~11.8% at air atmosphere.Moreover, the copolymer films showed good mechanical properties with tensile strength of 74~95 MPa, tensile modulus of 2.3~2.6 GPa and elongation at break of 6.1%~9.0%.It was concluded that the polymers which kept good thermodynamic properties exhibited outstanding flame retardance due to the existence of triphenylphosphine-oxide moieties in the main chain.The UL94 of the copolymer films reached VTM-0 grade and the LOI values were up to 50% significantly.
2016, (4): 457-463
doi: 10.11777/j.issn1000-3304.2016.15227
Abstract:
The crystallization behavior of long chain branched polypropylene (LCBPP) and linear isotactic polypropylene (PP) was studied by DSC, WAXD and POM.The results of WXAD and DSC showed that the LCB structure was conductive to -crystal crystallization, a little of -crystal appeared in LCBPP samples.The results of POM and DSC verified that the LCB structure can perform the function of promoting heterogeneous nucleation and decreasing crystal size.Compared with pure PP, the crystallization temperature and crystallization rate of LCBPP increased.The crystal size of LCBPP decreased with the increased branching content.The higher crystallization temperature and faster crystallization rate of LCBPP were in favor of bubble curing and increased the maximum foaming temperature.In addition, because of the higher melt strength of LCBPP, the LCBPP showed bigger expanding ratio than linear PP at the same foaming condition.The results of batch foaming with supercritical CO2 as blowing agent at 18 MPa showed that the LCBPP displayed a better foamability than linear PP.The LCBPP exhibited a wide foaming temperature window (about 5 K) while linear PP exhibited a very narrow foaming temperature window (about 2 K) and the maximum expantion ratio of LCBPP was 25.8 while the maximum expantion ratio of linear PP was only 18.6.
The crystallization behavior of long chain branched polypropylene (LCBPP) and linear isotactic polypropylene (PP) was studied by DSC, WAXD and POM.The results of WXAD and DSC showed that the LCB structure was conductive to -crystal crystallization, a little of -crystal appeared in LCBPP samples.The results of POM and DSC verified that the LCB structure can perform the function of promoting heterogeneous nucleation and decreasing crystal size.Compared with pure PP, the crystallization temperature and crystallization rate of LCBPP increased.The crystal size of LCBPP decreased with the increased branching content.The higher crystallization temperature and faster crystallization rate of LCBPP were in favor of bubble curing and increased the maximum foaming temperature.In addition, because of the higher melt strength of LCBPP, the LCBPP showed bigger expanding ratio than linear PP at the same foaming condition.The results of batch foaming with supercritical CO2 as blowing agent at 18 MPa showed that the LCBPP displayed a better foamability than linear PP.The LCBPP exhibited a wide foaming temperature window (about 5 K) while linear PP exhibited a very narrow foaming temperature window (about 2 K) and the maximum expantion ratio of LCBPP was 25.8 while the maximum expantion ratio of linear PP was only 18.6.
2016, (4): 464-470
doi: 10.11777/j.issn1000-3304.2016.15232
Abstract:
To improve the network structure of glycidyl azide polymer (GAP) binder system, the effects of the prepolymerization of GAP with difunctional isocyanates (TDI or IPDI), the ratio of N-100 and different curing agent on the mechanical properties, network parameters, integrity of the network, and the morphology of tensile fracture surfaces of elastomers were studied.The experimental results showed that the integrity of the network was improved by the prepolymerization of GAP with TDI, the tensile strength and elongation were improved accordingly.Defined amount of difunctional isocyanate in system can also improve the integrity of the network.By the reason of the difference of structure and reactivity between TDI and IPDI, for GAP/TDI/N-100 elastomers, the network structure was the most complete when the weight ratio of N-100 and TDI was 7:3, while the most complete network structure appeared when the weight ratio of N-100 and IPDI was 5:5 for GAP/IPDI/N-100 elastomers.The tensile strength of GAP/IPDI/N-100 elastomers was larger than that of GAP/TDI/N-100 elastomers at the same N-100 ratio, and the elongation was lower.With the decreasing content of N-100, the tensile strength of GAP/TDI/N-100 elastomers decreased from 0.66 MPa to 0.32 MPa, the elongation increased from 104.6% to 506.3%, while GAP/IPDI/N-100 elastomers exhibited maximum tensile strength of 0.69 MPa when the weight ratio of N-100 and IPDI was 7:3, and the elongation increased from 103.2% to 391.4% with decreasing N-100 content.SEM results showed that the morphology of tensile fracture surfaces of elastomers has a good corresponding relation with the integrity of the network and mechanical properties.
To improve the network structure of glycidyl azide polymer (GAP) binder system, the effects of the prepolymerization of GAP with difunctional isocyanates (TDI or IPDI), the ratio of N-100 and different curing agent on the mechanical properties, network parameters, integrity of the network, and the morphology of tensile fracture surfaces of elastomers were studied.The experimental results showed that the integrity of the network was improved by the prepolymerization of GAP with TDI, the tensile strength and elongation were improved accordingly.Defined amount of difunctional isocyanate in system can also improve the integrity of the network.By the reason of the difference of structure and reactivity between TDI and IPDI, for GAP/TDI/N-100 elastomers, the network structure was the most complete when the weight ratio of N-100 and TDI was 7:3, while the most complete network structure appeared when the weight ratio of N-100 and IPDI was 5:5 for GAP/IPDI/N-100 elastomers.The tensile strength of GAP/IPDI/N-100 elastomers was larger than that of GAP/TDI/N-100 elastomers at the same N-100 ratio, and the elongation was lower.With the decreasing content of N-100, the tensile strength of GAP/TDI/N-100 elastomers decreased from 0.66 MPa to 0.32 MPa, the elongation increased from 104.6% to 506.3%, while GAP/IPDI/N-100 elastomers exhibited maximum tensile strength of 0.69 MPa when the weight ratio of N-100 and IPDI was 7:3, and the elongation increased from 103.2% to 391.4% with decreasing N-100 content.SEM results showed that the morphology of tensile fracture surfaces of elastomers has a good corresponding relation with the integrity of the network and mechanical properties.
2016, (4): 471-476
doi: 10.11777/j.issn1000-3304.2016.15239
Abstract:
In order to develop environment-friendly polymer materials based on lignosulfonate calcium(HLS) and polyvinyl alcohol (PVA), the solution casting HLS/PVA films were prepared and the interaction between HLS and PVA and the effect of HLS on the thermal, crystalline and mechanical properties of PVA were carefully studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing, respectively.When the HLS content is below 35 wt%, HLS/PVA blends showed good compatibility, HLS could be uniformly distributed in PVA.The melting depression theory was adopted for calculating the interaction parameter of HLS/PVA blends.The Flory-Huggins interaction parameter of HLS/PVA was a negative value (-0.0002).It indicated that strong interaction and good compatility occured in HLS/PVA.HLS could reduce the equilibrium melting point of PVA and improve the thermal stability, thus the PVA thermoplastic processing temperature window could be broadened.As for HLS/PVA blend with 35 wt% HLS, the maximum decomposed temperature (Td) is about 16 K higher than that of pure PVA.HLS could reduce the crystallinity, that means the ordered arrangement of PVA main chains in crystalline region could be disturbed by the incorporation of HLS, owing to the specific interactions between PVA and HLS.HLS could improve the strength of PVA.As for HLS/PVA with 35 wt% content of HLS, HLS/PVA blend's tensile strength can reach 92.88 MPa (about 91.9% higher than that of pure PVA) and its Young's modulus can reach 4988.67 MPa (about 604.7% higher than that of pure PVA), but its elongation at break reduced greatly.
In order to develop environment-friendly polymer materials based on lignosulfonate calcium(HLS) and polyvinyl alcohol (PVA), the solution casting HLS/PVA films were prepared and the interaction between HLS and PVA and the effect of HLS on the thermal, crystalline and mechanical properties of PVA were carefully studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing, respectively.When the HLS content is below 35 wt%, HLS/PVA blends showed good compatibility, HLS could be uniformly distributed in PVA.The melting depression theory was adopted for calculating the interaction parameter of HLS/PVA blends.The Flory-Huggins interaction parameter of HLS/PVA was a negative value (-0.0002).It indicated that strong interaction and good compatility occured in HLS/PVA.HLS could reduce the equilibrium melting point of PVA and improve the thermal stability, thus the PVA thermoplastic processing temperature window could be broadened.As for HLS/PVA blend with 35 wt% HLS, the maximum decomposed temperature (Td) is about 16 K higher than that of pure PVA.HLS could reduce the crystallinity, that means the ordered arrangement of PVA main chains in crystalline region could be disturbed by the incorporation of HLS, owing to the specific interactions between PVA and HLS.HLS could improve the strength of PVA.As for HLS/PVA with 35 wt% content of HLS, HLS/PVA blend's tensile strength can reach 92.88 MPa (about 91.9% higher than that of pure PVA) and its Young's modulus can reach 4988.67 MPa (about 604.7% higher than that of pure PVA), but its elongation at break reduced greatly.
2016, (4): 477-485
doi: 10.11777/j.issn1000-3304.2016.15245
Abstract:
The sulfonated alkali lignin (SAL) with different sulfonic group contents and the sulfonated alkali lignin polyethenoxy ether (SAL-PEG) with different crosslinking degrees and molecular weights were prepared.The effects of the sulfonic acid group content and the PEG nonionic long chain on the behaviors of SAL and SAL-PEG in solution were studied by dynamic light scattering (DLS).The results showed that the aggregation behavior existed in 1.0 g/L SAL aqueous solutions.And the degree of aggregation decreased with increasing the sulfonic acid group content of SAL, because the more sulfonic acid groups caused the increasing molecular stretch degree of SAL.The addition of 2 mol/L NaCl made the molecular configuration of SAL become compact in solution and the aggregates of SAL were disaggregated evidently.The SAL-PEG mainly took the form of single molecule in 1.0 g/L aqueous solution, with weak aggregation behavior, and the hydrodynamic radius (Rh) of SAL-PEG was proportional to its molecular weight and the crosslinking degree.The addition of 2 mol/L NaCl made the PEG nonionic long chain of SAL-PEG become compact severely in solution, and Rh of SAL-PEG was significantly reduced.Meanwhile the degree of reduction was proportional to its molecular weight and cross-linking degree, but the degree of aggregation of SAL-PEG was still weak.
The sulfonated alkali lignin (SAL) with different sulfonic group contents and the sulfonated alkali lignin polyethenoxy ether (SAL-PEG) with different crosslinking degrees and molecular weights were prepared.The effects of the sulfonic acid group content and the PEG nonionic long chain on the behaviors of SAL and SAL-PEG in solution were studied by dynamic light scattering (DLS).The results showed that the aggregation behavior existed in 1.0 g/L SAL aqueous solutions.And the degree of aggregation decreased with increasing the sulfonic acid group content of SAL, because the more sulfonic acid groups caused the increasing molecular stretch degree of SAL.The addition of 2 mol/L NaCl made the molecular configuration of SAL become compact in solution and the aggregates of SAL were disaggregated evidently.The SAL-PEG mainly took the form of single molecule in 1.0 g/L aqueous solution, with weak aggregation behavior, and the hydrodynamic radius (Rh) of SAL-PEG was proportional to its molecular weight and the crosslinking degree.The addition of 2 mol/L NaCl made the PEG nonionic long chain of SAL-PEG become compact severely in solution, and Rh of SAL-PEG was significantly reduced.Meanwhile the degree of reduction was proportional to its molecular weight and cross-linking degree, but the degree of aggregation of SAL-PEG was still weak.
2016, (4): 486-493
doi: 10.11777/j.issn1000-3304.2016.15246
Abstract:
A novel Fe3+ loaded polyacrylamidoxime modified waste wool adsorbent (Fe3+/W-g-PAO) was prepared to eliminate fluorinion (F-) in aqueous solutions.To be specific, polyacrylonitrile (PAN) was first grafted onto the waste wool by traditional free radical polymerization, in which thiol groups on waste wool were act as active sites for chain transfer.Subsequently, cyano-groups were converted to amidoxime groups.The prepared adsorbent (W-g-PAO) could successfully load Fe3+, due to the outstanding coordination ability of amidoxime groups with Fe3+.Fe3+/W-g-PAO possessed excellent adsorption capacity for F-, and the adsorption process was rapid and efficient.The adsorption process of F- on Fe3+/W-g-PAO could be fitted well by the quasi-two dynamics model and Langmuir model.However, by this adsorption style, the adsorption capacity of F- on W-g-PAO was only 14.26 mg/g.If the formation of coordination compounds of Fe3+ and F- was first prepared, the adsorption capacity of F- on W-g-PAO could be improved significantly to 49.2 mg/g.That's because Fe3+ could be reduced into Fe2+ during the loading process of Fe3+.The results indicated that the structure of Fe(III)[F-]3[-NH2]3 was formed when F- was adsorbed on Fe3+/W-g-PAO.In conclusion, the material prepared in this work, W-g-PAO, has the advantages of low-cost, recyclable and excellent adsorption capacity, which can be used as a promising material for the application in the treatment of waste water containing fluoride ions.
A novel Fe3+ loaded polyacrylamidoxime modified waste wool adsorbent (Fe3+/W-g-PAO) was prepared to eliminate fluorinion (F-) in aqueous solutions.To be specific, polyacrylonitrile (PAN) was first grafted onto the waste wool by traditional free radical polymerization, in which thiol groups on waste wool were act as active sites for chain transfer.Subsequently, cyano-groups were converted to amidoxime groups.The prepared adsorbent (W-g-PAO) could successfully load Fe3+, due to the outstanding coordination ability of amidoxime groups with Fe3+.Fe3+/W-g-PAO possessed excellent adsorption capacity for F-, and the adsorption process was rapid and efficient.The adsorption process of F- on Fe3+/W-g-PAO could be fitted well by the quasi-two dynamics model and Langmuir model.However, by this adsorption style, the adsorption capacity of F- on W-g-PAO was only 14.26 mg/g.If the formation of coordination compounds of Fe3+ and F- was first prepared, the adsorption capacity of F- on W-g-PAO could be improved significantly to 49.2 mg/g.That's because Fe3+ could be reduced into Fe2+ during the loading process of Fe3+.The results indicated that the structure of Fe(III)[F-]3[-NH2]3 was formed when F- was adsorbed on Fe3+/W-g-PAO.In conclusion, the material prepared in this work, W-g-PAO, has the advantages of low-cost, recyclable and excellent adsorption capacity, which can be used as a promising material for the application in the treatment of waste water containing fluoride ions.
2016, (4): 494-502
doi: 10.11777/j.issn1000-3304.2016.15247
Abstract:
Liquid polysulfide rubber (LP-3) was used as a toughening modifier to improve the toughness of polybenzoxazine obtained from bisphenol A-aniline based benzoxazine (B-a).The mixing and curing processes of B-a and LP-3 were monitored by 1H-NMR, FTIR and DSC.It was found that the ring-opening addition reaction between B-a and LP-3 happened during mixing, and the resultants showed lower curing temperature and faster curing rate than the pure B-a.The thermal and mechanical properties of the cured materials with various LP-3 incorporations were measured by TGA, DMA, impacting and flexural test.The results showed that LP-3 was an effective toughener for polybenzoxazine from B-a.Materials containing LP-3 in the crosslinked network showed much better toughness than that without LP-3.With the increase of LP-3 incorporation, impacting strength increased while modulus and glass transition temperature (Tg) decreased.When 5 wt% LP-3 was added, the impacting strength of the cured material was about 3.4 times higher than that of the polybenzoxazine from pure B-a.Simultaneously, the material at this LP-3 content retained high storage modulus (E'=3.9 GPa at 30℃) and high glass transition temperature (Tg=206℃) with improved flexural properties and thermal stability (T5%=322℃, T10%=342℃).It was concluded that LP-3 was a promising modifier for the commercial B-a resin even with small addition amount.When the amount of LP-3 was 5 wt%, the cured material owned the best overall performance.
Liquid polysulfide rubber (LP-3) was used as a toughening modifier to improve the toughness of polybenzoxazine obtained from bisphenol A-aniline based benzoxazine (B-a).The mixing and curing processes of B-a and LP-3 were monitored by 1H-NMR, FTIR and DSC.It was found that the ring-opening addition reaction between B-a and LP-3 happened during mixing, and the resultants showed lower curing temperature and faster curing rate than the pure B-a.The thermal and mechanical properties of the cured materials with various LP-3 incorporations were measured by TGA, DMA, impacting and flexural test.The results showed that LP-3 was an effective toughener for polybenzoxazine from B-a.Materials containing LP-3 in the crosslinked network showed much better toughness than that without LP-3.With the increase of LP-3 incorporation, impacting strength increased while modulus and glass transition temperature (Tg) decreased.When 5 wt% LP-3 was added, the impacting strength of the cured material was about 3.4 times higher than that of the polybenzoxazine from pure B-a.Simultaneously, the material at this LP-3 content retained high storage modulus (E'=3.9 GPa at 30℃) and high glass transition temperature (Tg=206℃) with improved flexural properties and thermal stability (T5%=322℃, T10%=342℃).It was concluded that LP-3 was a promising modifier for the commercial B-a resin even with small addition amount.When the amount of LP-3 was 5 wt%, the cured material owned the best overall performance.
2016, (4): 503-510
doi: 10.11777/j.issn1000-3304.2016.15250
Abstract:
A nonfouling polypeptide(Poly(D)-K) with poly(aspartic acid) backbone and lysine side chains was developed by polycondensing a covalently bonded dimer of aspartic acid (D) and lysine (K).Gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy(XPS), circular dichroism (CD) were conducted to determine the molecular weight, structure, secondary structure of the polypeptide and compositions of self-assembling monolayers (SAMs) of the polypeptide on gold chips, respectively.The results show that the polypeptide was successfully prepared, of which the average molecular weight (Mw) is about 3.8103, polydispersity index (PDI) is 1.33, average degree of polymerization (DP) is about 12.4; and secondary conformation of the polypeptide in water solution is random coil.The polypeptide could form SAMs on gold chips by the terminal thiol groups, and the lowest relatively nonspecific protein adsorption on SAMs surface determined by Enzyme-linked Immunosorbent Assay (ELISA) for anti-IgG and Fg was (8.53.6)% and (12.54.8)%, respectively, where the protein adsorption on tissue culture polystyrene (TCPS) surface was set as 100%.The cell viability of the polypeptide determined by MTT assay was (87.64.3)% even its concentration was up to 5 mg/mL.
A nonfouling polypeptide(Poly(D)-K) with poly(aspartic acid) backbone and lysine side chains was developed by polycondensing a covalently bonded dimer of aspartic acid (D) and lysine (K).Gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy(XPS), circular dichroism (CD) were conducted to determine the molecular weight, structure, secondary structure of the polypeptide and compositions of self-assembling monolayers (SAMs) of the polypeptide on gold chips, respectively.The results show that the polypeptide was successfully prepared, of which the average molecular weight (Mw) is about 3.8103, polydispersity index (PDI) is 1.33, average degree of polymerization (DP) is about 12.4; and secondary conformation of the polypeptide in water solution is random coil.The polypeptide could form SAMs on gold chips by the terminal thiol groups, and the lowest relatively nonspecific protein adsorption on SAMs surface determined by Enzyme-linked Immunosorbent Assay (ELISA) for anti-IgG and Fg was (8.53.6)% and (12.54.8)%, respectively, where the protein adsorption on tissue culture polystyrene (TCPS) surface was set as 100%.The cell viability of the polypeptide determined by MTT assay was (87.64.3)% even its concentration was up to 5 mg/mL.
2016, (4): 511-519
doi: 10.11777/j.issn1000-3304.2016.15251
Abstract:
The polyethylene glycol 200 (PEG200) and polyethylene glycol 400 (PEG400) as the fourth monomers were introduced into succinic acid (SA), 1, 4-butanediol (BDO), ethylene glycol (EG).PEG200-PBES and PEG400-PBES copolyesters with different lengths of ether chains were synthesized by melt copolymerization, then solid composite materials were prepared by solution blending copolyesters with modified thermoplastic starch (TPS).The effects of different ether chain lengths on mechanical properties and thermal stability of composite materials were studied, the interactions between PBS, PEG-PBES and TPS in composite systems of different ether chain length were analyzed by adopting molecular dynamics.The results showed that the compatibility of composite systems increased significantly with the increase of ether chain length, the parameter and Emix values of (PEG400-PBES)/TPS composite systems were more close to 0, its cohesive energy density and solubility parameter were greater than those of PBS/TPS and (PEG200-PBES)/TPS composite systems.Therefore, (PEG400-PBES)/TPS composite system has better compatibility.Meanwhile, with the growth of ether chain length, the tensile strength of composite materials was increased from 1.86 MPa to 8.84 MPa and elongation at break was improved from 25.54% to 74.75%.In addition, the temperature of thermo-gravimetric 50% weight loss was increasedfrom 281.68℃ to 310.53℃.
The polyethylene glycol 200 (PEG200) and polyethylene glycol 400 (PEG400) as the fourth monomers were introduced into succinic acid (SA), 1, 4-butanediol (BDO), ethylene glycol (EG).PEG200-PBES and PEG400-PBES copolyesters with different lengths of ether chains were synthesized by melt copolymerization, then solid composite materials were prepared by solution blending copolyesters with modified thermoplastic starch (TPS).The effects of different ether chain lengths on mechanical properties and thermal stability of composite materials were studied, the interactions between PBS, PEG-PBES and TPS in composite systems of different ether chain length were analyzed by adopting molecular dynamics.The results showed that the compatibility of composite systems increased significantly with the increase of ether chain length, the parameter and Emix values of (PEG400-PBES)/TPS composite systems were more close to 0, its cohesive energy density and solubility parameter were greater than those of PBS/TPS and (PEG200-PBES)/TPS composite systems.Therefore, (PEG400-PBES)/TPS composite system has better compatibility.Meanwhile, with the growth of ether chain length, the tensile strength of composite materials was increased from 1.86 MPa to 8.84 MPa and elongation at break was improved from 25.54% to 74.75%.In addition, the temperature of thermo-gravimetric 50% weight loss was increasedfrom 281.68℃ to 310.53℃.
2016, (4): 520-527
doi: 10.11777/j.issn1000-3304.2016.15219
Abstract:
Benzoxazine(BOZ) with low curing shrinkage was used to modify epoxy in liquid composite molding(LCM) process.The purpose was to reduce curing shrinkage of epoxy greatly, while the heat resistance, manufacturability and mechanical property did not decrease.The curing shrinkage property, curing reactivity, LCM manufacturability and mechanical properties of modified resins with different contents of BOZ were studied.Then the composites reinforced by unidirectional carbon fiber fabric were prepared by vacuum assisted resin infusion(VARI) process, and the mechanical properties of the composites were studied.The results show that the addition of BOZ basically has no influence on the curing reactivity, LCM manufacturability and heat resistance of epoxy.The curing shrinkage of modified resin decreases with the increasing of the BOZ content, andthe curing shrinkage of modified resin with 15 wt% BOZ decreases by about 79%, compared to the unmodified resin.Simultaneously, the tensile strength of the modified resin increases by about 19%, as well as the impact strength increases by about 148%.Moreover, the tensile strength and the interlaminar shear strength(ILSS) of the modified resin based composite improve by about 23% and 9% respectively, relative to the unmodified resin based composite.Namely, the mechanical properties and the interface bonding properties of the modified resin based composite are superior.
Benzoxazine(BOZ) with low curing shrinkage was used to modify epoxy in liquid composite molding(LCM) process.The purpose was to reduce curing shrinkage of epoxy greatly, while the heat resistance, manufacturability and mechanical property did not decrease.The curing shrinkage property, curing reactivity, LCM manufacturability and mechanical properties of modified resins with different contents of BOZ were studied.Then the composites reinforced by unidirectional carbon fiber fabric were prepared by vacuum assisted resin infusion(VARI) process, and the mechanical properties of the composites were studied.The results show that the addition of BOZ basically has no influence on the curing reactivity, LCM manufacturability and heat resistance of epoxy.The curing shrinkage of modified resin decreases with the increasing of the BOZ content, andthe curing shrinkage of modified resin with 15 wt% BOZ decreases by about 79%, compared to the unmodified resin.Simultaneously, the tensile strength of the modified resin increases by about 19%, as well as the impact strength increases by about 148%.Moreover, the tensile strength and the interlaminar shear strength(ILSS) of the modified resin based composite improve by about 23% and 9% respectively, relative to the unmodified resin based composite.Namely, the mechanical properties and the interface bonding properties of the modified resin based composite are superior.
2016, (4): 528-537
doi: 10.11777/j.issn1000-3304.2016.15285
Abstract:
Nano hydroxyapatite (HA)/polypyrrole (PPy)/Ag composite coatings were prepared using pulse electrochemical deposition on biomedical titanium surfaces.The effects of Py concentration, Ag+ concentration, and salt concentration on the morphology and composition of the composite coatings were investigated.This study discussed the formation of spherical HA-NPs and Ag-NPs in the PPy polymerization process, and the biological activity, physical stability and anti-bacterial properties of the composite coating.The results showed that the concentration of Py in the electrolyte could affect the morphology of the coating;the Py concentration of 0.03 mol/L was found to be beneficial to the deposition of the composite coating.The concentration of Ag+ in the electrolyte affected the morphology and crystallization of the coating, and the optimal concentration of Ag+ in the electrolyte was determined to be 0.3 mmol/L.The morphology and crystallization of the coating were influenced by Ca2+ concentration in the electrolyte, higher concentrations led to particle size increase and Ca2+ concentration of 5.0 mmol/L was determined to be the most suitable for the electrolyte.The composite coating could induce the formation of HA, in particular, the (002) crystal plane exhibited preferred growth and demonstrated good biological activity.The addition of PPy greatly reduced the release rate of Ca2+ and Ag+ and improved the physiological stability of the composite coating.Antibacterial tests showed the composite coating demonstrated good antimicrobial properties.
Nano hydroxyapatite (HA)/polypyrrole (PPy)/Ag composite coatings were prepared using pulse electrochemical deposition on biomedical titanium surfaces.The effects of Py concentration, Ag+ concentration, and salt concentration on the morphology and composition of the composite coatings were investigated.This study discussed the formation of spherical HA-NPs and Ag-NPs in the PPy polymerization process, and the biological activity, physical stability and anti-bacterial properties of the composite coating.The results showed that the concentration of Py in the electrolyte could affect the morphology of the coating;the Py concentration of 0.03 mol/L was found to be beneficial to the deposition of the composite coating.The concentration of Ag+ in the electrolyte affected the morphology and crystallization of the coating, and the optimal concentration of Ag+ in the electrolyte was determined to be 0.3 mmol/L.The morphology and crystallization of the coating were influenced by Ca2+ concentration in the electrolyte, higher concentrations led to particle size increase and Ca2+ concentration of 5.0 mmol/L was determined to be the most suitable for the electrolyte.The composite coating could induce the formation of HA, in particular, the (002) crystal plane exhibited preferred growth and demonstrated good biological activity.The addition of PPy greatly reduced the release rate of Ca2+ and Ag+ and improved the physiological stability of the composite coating.Antibacterial tests showed the composite coating demonstrated good antimicrobial properties.
2016, (4): 538-544
doi: 10.11777/j.issn1000-3304.2016.15316
Abstract:
Uniform polymer microspheres of diameters between 1 m and 2 m were prepared through precipitation polymerization of trihydroxymethyl propane triacrylate (TMPTA) and methyl methacrylate (MMA) at 2 wt% of monomer concentration in ethanol or in its mixture with water.2, 2-Azobis-isobutyronitrile was used as the free radical initiator.Effects of polymerization conditions, including polymerization time, amount of the cross-linker monomer TMPTA and water content in the mixed solvent, on the polymerization process and the size and the uniformity of the microspheres were studied.The results indicated that, during polymerization, a large amount of polymer was present as oligomers of low molecular weight and remained dissolved in the solvent, which made the monomer conversion and the yield of the microspheres increase not at the same time:monomer conversion showed a fast increase at start of the polymerization, leading to a high amount of oligomers with quite low amount of polymer particles.At a later stage of polymerization (2 h), when the monomer conversion reached to its highest value in the polymerization and became almost constant, the yield of the microspheres was keeping to increase at a much higher rate than the monomer conversion, owing to a direct adsorption of the oligomers by the microspheres or/and the continuous polymerization of the oligomers with the double bonds on the surface of the microspheres.Monomer conversion and microsphere yield were increased with increasing the TMPTA amount and the water proportion in the binary solvent; whereas the size of microspheres was decreased on the same time.While polymer microspheres were well formed for TMPTA-MMA polymerization with TMPTA/MMA mass ratio of 6/4, providing that the water amount in the solvent was controlled at 42 vol% or lower in the mixed solvent, highly uniform microspheres (Dw/Dn1.01) were obtained only when the water amount was kept between 30 vol% and 40 vol%.With the water amount in ethanol-water fixed at 35 vol%, polymer microspheres were well formed with TMPTA kept at 40 wt% to 80 wt%, highly uniform microspheres (Dw/Dn1.01) were obtained only with TMPTA at 50 wt% to 70 wt% in the monomer mixture.Microspheres were seriously aggregated when either water amount in the solvent exceeded 42 vol% or TMPTA amount in the monomer mixture surpassed 80 wt%.
Uniform polymer microspheres of diameters between 1 m and 2 m were prepared through precipitation polymerization of trihydroxymethyl propane triacrylate (TMPTA) and methyl methacrylate (MMA) at 2 wt% of monomer concentration in ethanol or in its mixture with water.2, 2-Azobis-isobutyronitrile was used as the free radical initiator.Effects of polymerization conditions, including polymerization time, amount of the cross-linker monomer TMPTA and water content in the mixed solvent, on the polymerization process and the size and the uniformity of the microspheres were studied.The results indicated that, during polymerization, a large amount of polymer was present as oligomers of low molecular weight and remained dissolved in the solvent, which made the monomer conversion and the yield of the microspheres increase not at the same time:monomer conversion showed a fast increase at start of the polymerization, leading to a high amount of oligomers with quite low amount of polymer particles.At a later stage of polymerization (2 h), when the monomer conversion reached to its highest value in the polymerization and became almost constant, the yield of the microspheres was keeping to increase at a much higher rate than the monomer conversion, owing to a direct adsorption of the oligomers by the microspheres or/and the continuous polymerization of the oligomers with the double bonds on the surface of the microspheres.Monomer conversion and microsphere yield were increased with increasing the TMPTA amount and the water proportion in the binary solvent; whereas the size of microspheres was decreased on the same time.While polymer microspheres were well formed for TMPTA-MMA polymerization with TMPTA/MMA mass ratio of 6/4, providing that the water amount in the solvent was controlled at 42 vol% or lower in the mixed solvent, highly uniform microspheres (Dw/Dn1.01) were obtained only when the water amount was kept between 30 vol% and 40 vol%.With the water amount in ethanol-water fixed at 35 vol%, polymer microspheres were well formed with TMPTA kept at 40 wt% to 80 wt%, highly uniform microspheres (Dw/Dn1.01) were obtained only with TMPTA at 50 wt% to 70 wt% in the monomer mixture.Microspheres were seriously aggregated when either water amount in the solvent exceeded 42 vol% or TMPTA amount in the monomer mixture surpassed 80 wt%.
