Login In
1964 Volume 6 Issue 3
1964, 6(3): 171-177
Abstract:
In the polymerization of caprolactam in presence of 6一amino—caproic acid and benzoic acid．experimental results indicated that the r61e played by the benzoic acid in-cluded：the formation of polymer chains by“induction”，the acid—splitting reaction of the macromolecular chains and the acylation reaction of the amino-group of the macro-molecules．During the beginning stage of the reaction，benzoic acid exerted a catalytic action on the monomer molecules causing them to unite to macromolecular chains and did not add to the monomer．As the reaction was going on，when the number of macromole-cules gradually increased，acid splitting reaction became more and more pronounced；and，after 3—4 hours’ reaction， it surpassed p01ycondensation and made the molecular weight of the polymer decreased and the carboxyl．content increased．The acylation reaction was clearly indicated after 7—8 hours’reaction when the quantity of the polymer formed and the molecular weight of the polymer have already reached constant values，while the consumption of the benzoic acid was still going on．At the end of the reaction．when the ultimate equilibrium has been established，there was still found free benzoic acid and free carboxyl-groups；this indicated that acid-splitting， acylation and polycondensation are all reversible reactions．In the experiments on the polymerization of caprolactam in presense of water but in absense of carboxylic acid，the polymers obtained was heated'at 250°。270°or at 300°under ordinary pressure while a stream of nitrogen was passed through．The molecular weight of the polymer did not increase after heated for 6 hours (and in case of 250°，for 15 hours)．The reason for no further condensation might be that the reaction medium became highly viscous which prevented the escape of water molecules and made the dif-fusion and collision of the macromolecules difficult． At the sametime，the steric hinde-rance of the macromolecular chain exerted on the functional groups became more and more pronounced when the chain reached certain definite 1ength．These all made the polycondensation stopped at a certain stage．
In the polymerization of caprolactam in presence of 6一amino—caproic acid and benzoic acid．experimental results indicated that the r61e played by the benzoic acid in-cluded：the formation of polymer chains by“induction”，the acid—splitting reaction of the macromolecular chains and the acylation reaction of the amino-group of the macro-molecules．During the beginning stage of the reaction，benzoic acid exerted a catalytic action on the monomer molecules causing them to unite to macromolecular chains and did not add to the monomer．As the reaction was going on，when the number of macromole-cules gradually increased，acid splitting reaction became more and more pronounced；and，after 3—4 hours’ reaction， it surpassed p01ycondensation and made the molecular weight of the polymer decreased and the carboxyl．content increased．The acylation reaction was clearly indicated after 7—8 hours’reaction when the quantity of the polymer formed and the molecular weight of the polymer have already reached constant values，while the consumption of the benzoic acid was still going on．At the end of the reaction．when the ultimate equilibrium has been established，there was still found free benzoic acid and free carboxyl-groups；this indicated that acid-splitting， acylation and polycondensation are all reversible reactions．In the experiments on the polymerization of caprolactam in presense of water but in absense of carboxylic acid，the polymers obtained was heated'at 250°。270°or at 300°under ordinary pressure while a stream of nitrogen was passed through．The molecular weight of the polymer did not increase after heated for 6 hours (and in case of 250°，for 15 hours)．The reason for no further condensation might be that the reaction medium became highly viscous which prevented the escape of water molecules and made the dif-fusion and collision of the macromolecules difficult． At the sametime，the steric hinde-rance of the macromolecular chain exerted on the functional groups became more and more pronounced when the chain reached certain definite 1ength．These all made the polycondensation stopped at a certain stage．
1964, 6(3): 178-185
Abstract:
Under different conditions，such as different solvents，temperature，．reaction time，the amount of reactants and order of addition，the chloromethylated polystyrene were reacted with butyl lithium；the products without cross—linking were selected for the preparation of graft copolymers．Besides，the chloromethylated polystyrene was allowed to react with methyl methacrylate in the presence of lithium．Neither polymethyl methacrylate nor polymethyl methacrylate-grafted copolymer could be isolated by the reaction of polystyrene methylene lithium prepared in ether soluti6n with methyl methacrylate．However，the polymethyl methacrylate-grafted copolymer was isolated by the reaction of methyl methacrylate with polystyrene methylene lithium pre-pared in toluene solution．The graft copolymer was identified by the quantitative analysis of carbon，hydrogen，and chlorine，the determination of exchange capacity of the hydrolyzing product，the turbidimetric titration，and infra-red absorption spectra．The percentage by weight of polymethyl methacrylate in the graft copolymer was about firty as estimated by the first tWO methods mentioned above．Graft copolymers were isolated by the reactions of chloromethylated polystyrene with methyl methacrylate in the presence of metallic lithium．The percentage of polymethyl methacrylate in the graft copolymers was about three to three and half．The graft copoly-mers were identified by the determination of exchange capacities of the hydrolyzing pro-ducts．the turbidimetric titration and thermo—mechanical properties．
Under different conditions，such as different solvents，temperature，．reaction time，the amount of reactants and order of addition，the chloromethylated polystyrene were reacted with butyl lithium；the products without cross—linking were selected for the preparation of graft copolymers．Besides，the chloromethylated polystyrene was allowed to react with methyl methacrylate in the presence of lithium．Neither polymethyl methacrylate nor polymethyl methacrylate-grafted copolymer could be isolated by the reaction of polystyrene methylene lithium prepared in ether soluti6n with methyl methacrylate．However，the polymethyl methacrylate-grafted copolymer was isolated by the reaction of methyl methacrylate with polystyrene methylene lithium pre-pared in toluene solution．The graft copolymer was identified by the quantitative analysis of carbon，hydrogen，and chlorine，the determination of exchange capacity of the hydrolyzing product，the turbidimetric titration，and infra-red absorption spectra．The percentage by weight of polymethyl methacrylate in the graft copolymer was about firty as estimated by the first tWO methods mentioned above．Graft copolymers were isolated by the reactions of chloromethylated polystyrene with methyl methacrylate in the presence of metallic lithium．The percentage of polymethyl methacrylate in the graft copolymers was about three to three and half．The graft copoly-mers were identified by the determination of exchange capacities of the hydrolyzing pro-ducts．the turbidimetric titration and thermo—mechanical properties．
1964, 6(3): 186-192
Abstract:
The graft copolymerization of acrylonitrile onto cotton yarn and viscose rayon with ceric。ammonium nitrate as initiator has been studied． It was shown that the grafting occured readily．and the homopolymerization could be inhibited under proper experimental conditions．The grafting is believed to take place principally through the active centers which are formed on the cellulose substract by the action of ceric ion．It was also shown that the grafting was controlled by the diffusion of the solution tO cellulose．The graf-ting proceeded very rapidly at the begining and then leveled off tO a limiting value，depending on the fine structure of the cellulosic material，as a result of the retar- dation of diffusion by the formation of polyacrylonitrile on the surface of the cellulose．A preliminary estimation was made on the properties of the grafted products．
The graft copolymerization of acrylonitrile onto cotton yarn and viscose rayon with ceric。ammonium nitrate as initiator has been studied． It was shown that the grafting occured readily．and the homopolymerization could be inhibited under proper experimental conditions．The grafting is believed to take place principally through the active centers which are formed on the cellulose substract by the action of ceric ion．It was also shown that the grafting was controlled by the diffusion of the solution tO cellulose．The graf-ting proceeded very rapidly at the begining and then leveled off tO a limiting value，depending on the fine structure of the cellulosic material，as a result of the retar- dation of diffusion by the formation of polyacrylonitrile on the surface of the cellulose．A preliminary estimation was made on the properties of the grafted products．
1964, 6(3): 193-205
Abstract:
The rate equation of the ionic solution polymerization may be expressed in．general by r=—dM—dθ=kMmCn where M and C denote the concentrations of the monomer and the catalyst in the solu-tion respectively．m and n are kinetic parameters characterizing the polymerization sys-tem．In order to control the polymerization process or to design an adequate reactor system，it is required to regulate the reaction rate to conform with the heat transfer capacity of the system．Various operating schemes were postulated and their rate behavior during the reaction obtained by integrating the fundamental rate equation for these schemes．The results obtained for batch polymerization under control at isothermal conditions are as follows.
The rate equation of the ionic solution polymerization may be expressed in．general by r=—dM—dθ=kMmCn where M and C denote the concentrations of the monomer and the catalyst in the solu-tion respectively．m and n are kinetic parameters characterizing the polymerization sys-tem．In order to control the polymerization process or to design an adequate reactor system，it is required to regulate the reaction rate to conform with the heat transfer capacity of the system．Various operating schemes were postulated and their rate behavior during the reaction obtained by integrating the fundamental rate equation for these schemes．The results obtained for batch polymerization under control at isothermal conditions are as follows.
1964, 6(3): 206-212
Abstract:
Ten of such polyacylthioureas have been synthesized through the reactions of adipic，azelaic and terephthalic diisothiocyanates with hydrazine，ethylenediamine，hexamethylerie-diamine，p-phenylenediamine and benzidine respectively．ne structure of the polymers obtained have been confirmed by elementary analysis，degradation examination，ultra-violet as well as infra-red spectroscopy．These polymers were coloured(yellow to orange) powder，sparingly soluble in common organic solvents but readily soluble in dimethylformamide and cold conc．sulfuric acid．The x-ray diffraction patterns showed that these polymers possessed fair crystallinity．The softening points of the polymers decreased with increasing length of the aliphatic carbon—chain and increased when ben- zene nuclei were introduced into the chain． Four out of these polymers possessed sof-tening points higher than 300℃．
Ten of such polyacylthioureas have been synthesized through the reactions of adipic，azelaic and terephthalic diisothiocyanates with hydrazine，ethylenediamine，hexamethylerie-diamine，p-phenylenediamine and benzidine respectively．ne structure of the polymers obtained have been confirmed by elementary analysis，degradation examination，ultra-violet as well as infra-red spectroscopy．These polymers were coloured(yellow to orange) powder，sparingly soluble in common organic solvents but readily soluble in dimethylformamide and cold conc．sulfuric acid．The x-ray diffraction patterns showed that these polymers possessed fair crystallinity．The softening points of the polymers decreased with increasing length of the aliphatic carbon—chain and increased when ben- zene nuclei were introduced into the chain． Four out of these polymers possessed sof-tening points higher than 300℃．
1964, 6(3): 213-220
Abstract:
Neither benzyl chloride nor N，N-dimethylaniline is an initmtor for vinyl polymeriza-tion．When these compounds are used together，they will act as an'effective initiator．For studying the effects of the concentration of the initiator，temperature and the solvents the polymerization rates of methyl methacrylate have been determined．In the initiation systems CHa-xClx+ N CH3 CH3 x=1，2，3，the larger is the x，the greater is the initiation rate．The initiation rates of the binary mixture and the quaternary ammonium salt prepared from this binary sys-tom were compared．Thus a mechanism for vinyl polymerization initiated by this system is proposed and the rate equation derived as—d[m]-dt=Kp(ki-kt)1-2[DMA]1-2[BzCl]1-2[M]．The activation energy of initiation is calculated to be 13．2 kcal／mole in the temperature range from 50 to 70℃．
Neither benzyl chloride nor N，N-dimethylaniline is an initmtor for vinyl polymeriza-tion．When these compounds are used together，they will act as an'effective initiator．For studying the effects of the concentration of the initiator，temperature and the solvents the polymerization rates of methyl methacrylate have been determined．In the initiation systems CHa-xClx+ N CH3 CH3 x=1，2，3，the larger is the x，the greater is the initiation rate．The initiation rates of the binary mixture and the quaternary ammonium salt prepared from this binary sys-tom were compared．Thus a mechanism for vinyl polymerization initiated by this system is proposed and the rate equation derived as—d[m]-dt=Kp(ki-kt)1-2[DMA]1-2[BzCl]1-2[M]．The activation energy of initiation is calculated to be 13．2 kcal／mole in the temperature range from 50 to 70℃．
1964, 6(3): 221-231
Abstract:
Polystyrene of different molecular weights in emulsified solution was used for the preparation of polystyrene-hydroperoxide，the intrinsic viscosity and HPO-value (the average number of hydroperoxyl groups per 1000 monomeric units of polystyrene) of which were then determined．A wide absorption band in the region of 3200--3600 cm-1 attributed to the hydroperoxyl group was observed in the infrared absorption spectra of the polystyrene-hydroperoxide；its absorption intensity became more marked with increas-ing HPO-value．The polymeric hydropetoxide was then used for the initiation of vinyl monomers，e．g．styrene and methyl methacrylate respectively，and the final products after purification were identified as graft copolymers by the following ways： (1)turbidimetric titration， (2)determination of thermomechanical curve， (3)determination of exchange capacity of the copolymers after alkaline hydrolysis，and (4) infrared absorption spectra．
Polystyrene of different molecular weights in emulsified solution was used for the preparation of polystyrene-hydroperoxide，the intrinsic viscosity and HPO-value (the average number of hydroperoxyl groups per 1000 monomeric units of polystyrene) of which were then determined．A wide absorption band in the region of 3200--3600 cm-1 attributed to the hydroperoxyl group was observed in the infrared absorption spectra of the polystyrene-hydroperoxide；its absorption intensity became more marked with increas-ing HPO-value．The polymeric hydropetoxide was then used for the initiation of vinyl monomers，e．g．styrene and methyl methacrylate respectively，and the final products after purification were identified as graft copolymers by the following ways： (1)turbidimetric titration， (2)determination of thermomechanical curve， (3)determination of exchange capacity of the copolymers after alkaline hydrolysis，and (4) infrared absorption spectra．
1964, 6(3): 232-241
Abstract:
The fractionation, viscosity and light-scattering measurements for three types of polystyrene, i.e., atactic, isotactic and 1:1 mixture of the two, were studied. Noticeable differences in the [η]-M relationship, second virial coefficients A2 and mean square end-to-end distances were found among the three types of polystyrene samples. Conclusions about the solution properties of isotactic polystyrene suggested by Danusso and confirmed by Krigbaum were discussed.
The fractionation, viscosity and light-scattering measurements for three types of polystyrene, i.e., atactic, isotactic and 1:1 mixture of the two, were studied. Noticeable differences in the [η]-M relationship, second virial coefficients A2 and mean square end-to-end distances were found among the three types of polystyrene samples. Conclusions about the solution properties of isotactic polystyrene suggested by Danusso and confirmed by Krigbaum were discussed.
1964, 6(3): 242-243
Abstract:
Poly-(bisphenol-A terephthalate) was synthesized by interfacial polycondensation of bisphenol-A in alkali and terephthaloyl chloride in chloroform, and the optimum conditions for the reaction studied. Films made from this polymer are well crystalline with good thermal stability.
Poly-(bisphenol-A terephthalate) was synthesized by interfacial polycondensation of bisphenol-A in alkali and terephthaloyl chloride in chloroform, and the optimum conditions for the reaction studied. Films made from this polymer are well crystalline with good thermal stability.
1964, 6(3): 244-247
Abstract:
