Login In
2020 Volume 51 Issue 1
2020, 51(1):
Abstract:
下载PDF文件可查看本期的封面、目录和图文摘要。
下载PDF文件可查看本期的封面、目录和图文摘要。
2020, 51(1): 1-11
doi: 10.11777/j.issn1000-3304.2020.19165
Abstract:
As a special species of polyamide, long chain polyamide (LCPA) provides combined performances of polyolefin and polyamide due to its chemical structure with long methylene chains segments between two neighbor polar amide groups. During the processing or application, strain-induced crystallization (SIC) has a significant effect on the mechanical strength and elasticity of LCPA and LCPA based its copolymers. It is of great importance to further study the microstructural evolution mechanism for the design and production of LCPA and its copolymers under the external field. With a focus on the SIC, this feature article mainly summarizes our group’s work on SIC of LCPA since 2010 and some related studies of other researchers, including the phenomenon of SIC observed in LCPA and its copolymer, the influencing factors of SIC and the corresponding rules, the correlation between SIC and the mechanical properties, and the characterization technics as well.
As a special species of polyamide, long chain polyamide (LCPA) provides combined performances of polyolefin and polyamide due to its chemical structure with long methylene chains segments between two neighbor polar amide groups. During the processing or application, strain-induced crystallization (SIC) has a significant effect on the mechanical strength and elasticity of LCPA and LCPA based its copolymers. It is of great importance to further study the microstructural evolution mechanism for the design and production of LCPA and its copolymers under the external field. With a focus on the SIC, this feature article mainly summarizes our group’s work on SIC of LCPA since 2010 and some related studies of other researchers, including the phenomenon of SIC observed in LCPA and its copolymer, the influencing factors of SIC and the corresponding rules, the correlation between SIC and the mechanical properties, and the characterization technics as well.
2020, 51(1): 12-29
doi: 10.11777/j.issn1000-3304.2020.19142
Abstract:
The homo- and co-polymerizations of polar and non-polar monomers, since they can remain the stereo-regularity of the non-polyolefin precursors and meanwhile introduce polar groups into the non-polar polyolefins to improve their surface properties or bring unpredicted new functionalities, have attracted great attention of both academia and industries. However, polar groups are Lewis-basic while the catalysts employed in the polymerizations are usually Lewis acidic, which are prone to interact with the catalytic metal center to poison the catalysts, thus the study on homo- and co-polymerizations has been a challenging project. To date, many achievements have been obtained, and the following research should focus on realizing the homopolymerizations of polar monomers, increasing the activity and insertion ratio of the polar monomer in the copolymers, regulating the polar monomer composition and distribution along the copolymer macromolecular chains and isolating high molecular weight and practically available products. In this review, we summarized the recent developments of our group on the homo- and co-polymerizations of polar monomers, in particular polar styrenes and conjugated dienes with styrene, ethylene, butadien, isoprene and other popular nonpolar olefins, aiming to provide the readers novel strategies for designing new catalysts and polar monomers, as well as the unprecedented mechanisms.
The homo- and co-polymerizations of polar and non-polar monomers, since they can remain the stereo-regularity of the non-polyolefin precursors and meanwhile introduce polar groups into the non-polar polyolefins to improve their surface properties or bring unpredicted new functionalities, have attracted great attention of both academia and industries. However, polar groups are Lewis-basic while the catalysts employed in the polymerizations are usually Lewis acidic, which are prone to interact with the catalytic metal center to poison the catalysts, thus the study on homo- and co-polymerizations has been a challenging project. To date, many achievements have been obtained, and the following research should focus on realizing the homopolymerizations of polar monomers, increasing the activity and insertion ratio of the polar monomer in the copolymers, regulating the polar monomer composition and distribution along the copolymer macromolecular chains and isolating high molecular weight and practically available products. In this review, we summarized the recent developments of our group on the homo- and co-polymerizations of polar monomers, in particular polar styrenes and conjugated dienes with styrene, ethylene, butadien, isoprene and other popular nonpolar olefins, aiming to provide the readers novel strategies for designing new catalysts and polar monomers, as well as the unprecedented mechanisms.
2020, 51(1): 30-38
doi: 10.11777/j.issn1000-3304.2020.19144
Abstract:
Self-healing hydrogel is a new generation smart material that has drawn great attention among researchers from multiple cutting edge areas. Self-healing hydrogels are continuously enriching our knowledge in developing new materials and changing our lives. In the recent decades, thanks to numerous dedicated researchers, series of self-healing hydrogels have been explored through dynamic chemistry and supramolecular interactions, which have been applied in interdisciplinary areas for controlled release of drugs, 3D cell culture, and scaffolds of tissue engineering, etc. Self-healing hydrogels can be injected as solid gels instead of liquid precursor, then self-heal in situ. Thus, self-healing hydrogels have been utilized as a new type of injectable carrier to deliver drugs. This method effectively avoids unwanted cargo loss throughout the cycling and dramatically improves the delivery efficiency of drugs. Thus, self-healing hydrogels have been studied in recent research as great therapeutic carrier for tumour therapy and wound-healing. This review aims to summarize some recent research progresses in the preparation of self-healing hydrogels based on different dynamic covalent bonds. The bio-medical applications of self-healing hydrogels including tumour therapy and wound-healing have also been introduced. The future development and challenges of dynamic chemistry based on self-healing hydrogels have also been discussed.
Self-healing hydrogel is a new generation smart material that has drawn great attention among researchers from multiple cutting edge areas. Self-healing hydrogels are continuously enriching our knowledge in developing new materials and changing our lives. In the recent decades, thanks to numerous dedicated researchers, series of self-healing hydrogels have been explored through dynamic chemistry and supramolecular interactions, which have been applied in interdisciplinary areas for controlled release of drugs, 3D cell culture, and scaffolds of tissue engineering, etc. Self-healing hydrogels can be injected as solid gels instead of liquid precursor, then self-heal in situ. Thus, self-healing hydrogels have been utilized as a new type of injectable carrier to deliver drugs. This method effectively avoids unwanted cargo loss throughout the cycling and dramatically improves the delivery efficiency of drugs. Thus, self-healing hydrogels have been studied in recent research as great therapeutic carrier for tumour therapy and wound-healing. This review aims to summarize some recent research progresses in the preparation of self-healing hydrogels based on different dynamic covalent bonds. The bio-medical applications of self-healing hydrogels including tumour therapy and wound-healing have also been introduced. The future development and challenges of dynamic chemistry based on self-healing hydrogels have also been discussed.
2020, 51(1): 39-54
doi: 10.11777/j.issn1000-3304.2020.19148
Abstract:
High molecular material (or abbreviated as polymer) is the substantial foundation of human survival and development, which is regarded as the important symbol of social civilization. Polymer materials usually can be divided into plastic, fiber and rubber according to the application fields and molecular weight. Among them, polymer fibers are defined as the thin strip shaped materials with the length-diameter ratio larger than 1000 (usually a nanoscale or micron-scale diameter) and certain tensile strength and toughness. With the development of society and the progress of science and technology, the application fields of polymer fibers are gradually expanded from traditional home textile and clothing to advanced fields such as aerospace, biomedicine, environment, energy and so on. Therefore, the product connotations and applications of polymer fiber materials are expanding continually, which are the basic materials of national economy, the strategic materials of national defence, the frontier materials of emerging industries. In this work, we briefly introduced the development history of polymer fiber materials firstly, which have experienced the natural fiber, artificial fiber, synthetic fiber, functional fiber and high-performance fiber stages in turn. Then, the present situation of several representative polymer fiber materials (such as common fiber-poly(ethylene terephthalate) fiber, high performance fiber-poly(phenylene sulphide) fiber, biomass fiber-poly(lactic acid) fiber) were introduced systematically based on our group’s research work, including the development history, fabrication methods, chemical and physical structures and properties, modification technologies and application fields. In the end, we put forward the future prospect of polymer fiber materials combined with the social development demand. Based on the interdisciplinary integration and technological breakthroughs of materials, information, biology, machinery and other disciplines, the polymer fiber material (called Next Generation Fiber) with multiple components, multiple structures and multiple functions will become future development trend, which are characterized by green, super performance and intelligence.
High molecular material (or abbreviated as polymer) is the substantial foundation of human survival and development, which is regarded as the important symbol of social civilization. Polymer materials usually can be divided into plastic, fiber and rubber according to the application fields and molecular weight. Among them, polymer fibers are defined as the thin strip shaped materials with the length-diameter ratio larger than 1000 (usually a nanoscale or micron-scale diameter) and certain tensile strength and toughness. With the development of society and the progress of science and technology, the application fields of polymer fibers are gradually expanded from traditional home textile and clothing to advanced fields such as aerospace, biomedicine, environment, energy and so on. Therefore, the product connotations and applications of polymer fiber materials are expanding continually, which are the basic materials of national economy, the strategic materials of national defence, the frontier materials of emerging industries. In this work, we briefly introduced the development history of polymer fiber materials firstly, which have experienced the natural fiber, artificial fiber, synthetic fiber, functional fiber and high-performance fiber stages in turn. Then, the present situation of several representative polymer fiber materials (such as common fiber-poly(ethylene terephthalate) fiber, high performance fiber-poly(phenylene sulphide) fiber, biomass fiber-poly(lactic acid) fiber) were introduced systematically based on our group’s research work, including the development history, fabrication methods, chemical and physical structures and properties, modification technologies and application fields. In the end, we put forward the future prospect of polymer fiber materials combined with the social development demand. Based on the interdisciplinary integration and technological breakthroughs of materials, information, biology, machinery and other disciplines, the polymer fiber material (called Next Generation Fiber) with multiple components, multiple structures and multiple functions will become future development trend, which are characterized by green, super performance and intelligence.
2020, 51(1): 55-65
doi: 10.11777/j.issn1000-3304.2020.19152
Abstract:
It is a practical method to control the property of polymer material by incorporating nanoparticles. Recently polymer/nanoparticle composites have drawn increasing attention in the polymer field. Although researchers have made apparent progresses in the property regulation of polymeric materials by incorporating nanoparticles, progress in the development of the corresponding theory is, however, greatly inhibited, due to the lack of proper characterization approach, especially on the interaction mechanism between various nanoparticles and matrix polymers mainly at their interface area. This mini review summarizes recent simulation results of our research group, especially on a polymer/nanoparticle composite system where nanoparticles are single-chain crosslinked polymer nanoparticles with the same chemical composition as matrix polymers. In particular, after a thorough discussion of the structure and dynamic properties at nanoparticle/polymer interface region, it is clear that the interface in this system, where nanoparticle and matrix polymer interact effectively, has approximately the same size as nanoparticle itself. This interface size has no dependence of matrix polymer chain length. We hope that this conclusion can be helpful for the further development of relevant theory for polymer/nanocomposite systems.
It is a practical method to control the property of polymer material by incorporating nanoparticles. Recently polymer/nanoparticle composites have drawn increasing attention in the polymer field. Although researchers have made apparent progresses in the property regulation of polymeric materials by incorporating nanoparticles, progress in the development of the corresponding theory is, however, greatly inhibited, due to the lack of proper characterization approach, especially on the interaction mechanism between various nanoparticles and matrix polymers mainly at their interface area. This mini review summarizes recent simulation results of our research group, especially on a polymer/nanoparticle composite system where nanoparticles are single-chain crosslinked polymer nanoparticles with the same chemical composition as matrix polymers. In particular, after a thorough discussion of the structure and dynamic properties at nanoparticle/polymer interface region, it is clear that the interface in this system, where nanoparticle and matrix polymer interact effectively, has approximately the same size as nanoparticle itself. This interface size has no dependence of matrix polymer chain length. We hope that this conclusion can be helpful for the further development of relevant theory for polymer/nanocomposite systems.
2020, 51(1): 66-86
doi: 10.11777/j.issn1000-3304.2020.19160
Abstract:
The “Green Chemistry” has become the strategy direction of research and development of the world in the 21th century. Cellulose, as the most abundant natural polymers, is a very important renewable resource and the main industrial raw material. The cellulose shows many great advances including biocompatibility, biodegradability, high structure stability. However, due to the large amounts of inter- and intra-hydrogen bonding among the cellulose molecules, the cellulose has a dense structure and is very hard to be processed through dissolution or melt, which limit the further exploitation of the cellulose resource. The traditional organic solution of the cellulose often has the problem of high cost and pollution. In recent decades, with the development of the “Green” solvent (alkaline/urea, ionic liquid, etc.) and the cellulose nanotechnology, the researchers have greatly expanded the cellulose application in biomedical, energy storage, optical fields in addition to the traditional spinning and papermaking industry. This review mainly introduces the new methods (“bottom to up” and “up to down”) for the exploitation of cellulose based materials in recent years through the following four sections: (1) the regenerated cellulose based materials from the “green” solution-alkaline/urea aqueous and ionic liquid; (2) the preparation and self-assembly of the nanocellulose; (3) the development and utilization of the wood nanotechnology; (4) bacterial cellulose based functional materials.
The “Green Chemistry” has become the strategy direction of research and development of the world in the 21th century. Cellulose, as the most abundant natural polymers, is a very important renewable resource and the main industrial raw material. The cellulose shows many great advances including biocompatibility, biodegradability, high structure stability. However, due to the large amounts of inter- and intra-hydrogen bonding among the cellulose molecules, the cellulose has a dense structure and is very hard to be processed through dissolution or melt, which limit the further exploitation of the cellulose resource. The traditional organic solution of the cellulose often has the problem of high cost and pollution. In recent decades, with the development of the “Green” solvent (alkaline/urea, ionic liquid, etc.) and the cellulose nanotechnology, the researchers have greatly expanded the cellulose application in biomedical, energy storage, optical fields in addition to the traditional spinning and papermaking industry. This review mainly introduces the new methods (“bottom to up” and “up to down”) for the exploitation of cellulose based materials in recent years through the following four sections: (1) the regenerated cellulose based materials from the “green” solution-alkaline/urea aqueous and ionic liquid; (2) the preparation and self-assembly of the nanocellulose; (3) the development and utilization of the wood nanotechnology; (4) bacterial cellulose based functional materials.
2020, 51(1): 87-90
doi: 10.11777/j.issn1000-3304.2020.19162
Abstract:
In this paper, we briefly review the origins and growth of polymer physics from our perspective. It is proposed that the theory of rubber elasticity can be regarded as a starting point of polymer physics. It reveals why many mainstream theories can work and play key roles in the history of polymer science. We hope researchers may take their impetus from the achievement of classic and modern polymer physics.
In this paper, we briefly review the origins and growth of polymer physics from our perspective. It is proposed that the theory of rubber elasticity can be regarded as a starting point of polymer physics. It reveals why many mainstream theories can work and play key roles in the history of polymer science. We hope researchers may take their impetus from the achievement of classic and modern polymer physics.
2020, 51(1): 91-97
doi: 10.11777/j.issn1000-3304.2020.19145
Abstract:
Regioselective polymerization of α-methylene β-butyrolactone (MβBL) to afford polyesters with various topological structures was achieved by the use of different catalysts or initiators. With azodiisobutyronitrile (AIBN) as initiator, polymerization selectively occurred at the C＝C bond to produce linear poly(α-methylene-β-butyrolactone) (PMβBL) with the remain of β-butyrolactone unit. Achiral Salen aluminum complexes afforded linear syndiotactic-enriched polyesters with controllable molecular weight and a narrow polydispersity, in which ring-opening polymerization selectively occurred at the acyl C―O bond of MβBL and the C＝C bond was remained. Strong organic bases, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), exhibited high activity for ring-opening polymerization of MβBL under mild condition, affording linear polyesters. Simple sodium iodide mediated MβBL polymerization predominately produced crystalline cyclic polyesters with a melting point of 145.4 °C, in which the ring-opening mainly concerned the alkyl Cβ―O bond cleavage. This study demonstrates that the synthesis of various topological materials with different properties can be achieved by regioselective polymerization of functional monomers with the exquisite choice of catalyst or initiator.
Regioselective polymerization of α-methylene β-butyrolactone (MβBL) to afford polyesters with various topological structures was achieved by the use of different catalysts or initiators. With azodiisobutyronitrile (AIBN) as initiator, polymerization selectively occurred at the C＝C bond to produce linear poly(α-methylene-β-butyrolactone) (PMβBL) with the remain of β-butyrolactone unit. Achiral Salen aluminum complexes afforded linear syndiotactic-enriched polyesters with controllable molecular weight and a narrow polydispersity, in which ring-opening polymerization selectively occurred at the acyl C―O bond of MβBL and the C＝C bond was remained. Strong organic bases, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), exhibited high activity for ring-opening polymerization of MβBL under mild condition, affording linear polyesters. Simple sodium iodide mediated MβBL polymerization predominately produced crystalline cyclic polyesters with a melting point of 145.4 °C, in which the ring-opening mainly concerned the alkyl Cβ―O bond cleavage. This study demonstrates that the synthesis of various topological materials with different properties can be achieved by regioselective polymerization of functional monomers with the exquisite choice of catalyst or initiator.
2020, 51(1): 98-116
doi: 10.11777/j.issn1000-3304.2020.19151
Abstract:
The functionalized polyisobutylenes (PIBs) carrying allyl-Br or allyl-NH2 with different molecular weights and narrow molecular weight distribution, could be successfully synthesized via controlled/living cationic polymerization of isobutylene (IB) in n-hexane/CH2Cl2 mixed solvents at −80 °C. Controlled/Living cationic ring-opening polymerization (ROP) of tetrahydrofuran (THF) was achieved with Allyl-Br/AgClO4 initiating system at 0 °C. Two kinds of novel functionalized PTHF-b-PIB-b-PTHF triblock copolymers were designed and synthesized via combination with controlled/living cationic polymerization of IB and controlled/living cationic ROP of THF. Terminal hydroxyl functionalized HO-PTHF-b-PIB-b-PTHF-OH triblock copolymers (expressed as FIBF-OH) were successfully synthesized by using the PIBs with difunctional allyl-Br terminal groups (Br-PIB-Br) as macroinitiators to initiate living cationic ROP of THF in the presence of AgClO4 to create living PTHF+-b-PIB-b-PTHF+ chains and then terminating by H2O molecules. On the other hand, PTHF-b-HN-PIB-NH-b-PTHF triblock copolymers containing hydrogen bonds at the connection point of PTHF and PIB segments (expressed as FIBF-NH) were also successfully synthesized via efficient nucleophilic substitution reaction between living PTHF+ chains and amine groups in H2N-PIB-NH2. Due to the dynamic incompatibility between polar PTHF segments and nonpolar PIB segments and the crystallization of PTHF segments, PTHF-b-PIB-b-PTHF triblock copolymers exhibit an obvious microphase separation micromorphology. It is recognized that the chemical structure in the PTHF-b-PIB-b-PTHF triblock copolymers makes a great contribution to the formation of hydrogen bonding and thus the supramolecular network. The crystallization of PTHF segments could be improved even in FIBF-NH with relatively short PTHF segments, e.g. Mn,PTHF = 0.7 kg·mol−1. FIBF-NH could be completely self-healing at 25 °C for 10 min after cutting on its surface. However, the cutting on FIBF-OH surface was difficult to heal even at 30 °C for 3 days. Moreover, the PTHF-b-PIB-b-PTHF triblock copolymers could be used as drug carrier by interactions between PTHF segment and drug. The drug carrier microspheres exhibit pH-sensitive drug-release rate in PBS with different pH values. The novel functionalized PTHF-b-PIB-b-PTHF triblock copolymers combined the respective good properties from PIB and PTHF segments would have their potential applications as biomedical and smart-healing functional materials.
The functionalized polyisobutylenes (PIBs) carrying allyl-Br or allyl-NH2 with different molecular weights and narrow molecular weight distribution, could be successfully synthesized via controlled/living cationic polymerization of isobutylene (IB) in n-hexane/CH2Cl2 mixed solvents at −80 °C. Controlled/Living cationic ring-opening polymerization (ROP) of tetrahydrofuran (THF) was achieved with Allyl-Br/AgClO4 initiating system at 0 °C. Two kinds of novel functionalized PTHF-b-PIB-b-PTHF triblock copolymers were designed and synthesized via combination with controlled/living cationic polymerization of IB and controlled/living cationic ROP of THF. Terminal hydroxyl functionalized HO-PTHF-b-PIB-b-PTHF-OH triblock copolymers (expressed as FIBF-OH) were successfully synthesized by using the PIBs with difunctional allyl-Br terminal groups (Br-PIB-Br) as macroinitiators to initiate living cationic ROP of THF in the presence of AgClO4 to create living PTHF+-b-PIB-b-PTHF+ chains and then terminating by H2O molecules. On the other hand, PTHF-b-HN-PIB-NH-b-PTHF triblock copolymers containing hydrogen bonds at the connection point of PTHF and PIB segments (expressed as FIBF-NH) were also successfully synthesized via efficient nucleophilic substitution reaction between living PTHF+ chains and amine groups in H2N-PIB-NH2. Due to the dynamic incompatibility between polar PTHF segments and nonpolar PIB segments and the crystallization of PTHF segments, PTHF-b-PIB-b-PTHF triblock copolymers exhibit an obvious microphase separation micromorphology. It is recognized that the chemical structure in the PTHF-b-PIB-b-PTHF triblock copolymers makes a great contribution to the formation of hydrogen bonding and thus the supramolecular network. The crystallization of PTHF segments could be improved even in FIBF-NH with relatively short PTHF segments, e.g. Mn,PTHF = 0.7 kg·mol−1. FIBF-NH could be completely self-healing at 25 °C for 10 min after cutting on its surface. However, the cutting on FIBF-OH surface was difficult to heal even at 30 °C for 3 days. Moreover, the PTHF-b-PIB-b-PTHF triblock copolymers could be used as drug carrier by interactions between PTHF segment and drug. The drug carrier microspheres exhibit pH-sensitive drug-release rate in PBS with different pH values. The novel functionalized PTHF-b-PIB-b-PTHF triblock copolymers combined the respective good properties from PIB and PTHF segments would have their potential applications as biomedical and smart-healing functional materials.
2020, 51(1): 117-124
doi: 10.11777/j.issn1000-3304.2020.19159
Abstract:
Ultrahigh molecular weight polyethylene (UHMWPE) shows outstanding toughness, wear resistance and chemical inertness as a high performance polymer. However, extremely high entanglement degree results in high viscosity and processing difficulties, which greatly limits the applications. To address this issue, the new single-site Z-N catalysts have been used to regulate the growth and cohesion of molecular chains during the polymerization of ethylene in recent years, by which nascent UHMWPE with low entanglement degree and excellent processing capability can be obtained. With such UHMWPE nascent powder, different sintering temperatures (Ts) of 170, 190 and 220 °C were set, respectively, then a isothermal crystallization step with precise temperature control was added, and the effect of chain entanglement on the structures and properties of sintered UHMWPE was investigated. Through the tensile tests at 160 °C, it was confirmed that UHMWPE chains significantly reentangled when Ts = 220 °C, resulting in high degree of entanglement; while the initial low entanglement state can be sufficiently reserved when Ts = 170 °C, Me reached 12.3 kg/mol. Therefore, the samples with distinct different entanglement states can be obtained. DSC results have shown that low entanglement degree was beneficial to the formation of crystal lamellae with higher melting temperature (up to 141 °C) and high crystallinity (up to 65%) through isothermal crystallization steps, which was close to the level of nascent UHMWPE powder. Moreover, it proved that the integrated mechanical performance of the product sintered at 170 °C was significantly improved. The yield strength was increased by up to 72%, the tensile strength by 139%, the elastic modulus by 162%, and the elongation at break by 36%, realizing simultaneously strengthening and toughening of sintered UHMWPE materials. This provides a new strategy for the high performance UHMWPE sintered products from the perspective of chain entanglement regulation.
Ultrahigh molecular weight polyethylene (UHMWPE) shows outstanding toughness, wear resistance and chemical inertness as a high performance polymer. However, extremely high entanglement degree results in high viscosity and processing difficulties, which greatly limits the applications. To address this issue, the new single-site Z-N catalysts have been used to regulate the growth and cohesion of molecular chains during the polymerization of ethylene in recent years, by which nascent UHMWPE with low entanglement degree and excellent processing capability can be obtained. With such UHMWPE nascent powder, different sintering temperatures (Ts) of 170, 190 and 220 °C were set, respectively, then a isothermal crystallization step with precise temperature control was added, and the effect of chain entanglement on the structures and properties of sintered UHMWPE was investigated. Through the tensile tests at 160 °C, it was confirmed that UHMWPE chains significantly reentangled when Ts = 220 °C, resulting in high degree of entanglement; while the initial low entanglement state can be sufficiently reserved when Ts = 170 °C, Me reached 12.3 kg/mol. Therefore, the samples with distinct different entanglement states can be obtained. DSC results have shown that low entanglement degree was beneficial to the formation of crystal lamellae with higher melting temperature (up to 141 °C) and high crystallinity (up to 65%) through isothermal crystallization steps, which was close to the level of nascent UHMWPE powder. Moreover, it proved that the integrated mechanical performance of the product sintered at 170 °C was significantly improved. The yield strength was increased by up to 72%, the tensile strength by 139%, the elastic modulus by 162%, and the elongation at break by 36%, realizing simultaneously strengthening and toughening of sintered UHMWPE materials. This provides a new strategy for the high performance UHMWPE sintered products from the perspective of chain entanglement regulation.
