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1983 Volume 1 Issue 1
1983, 1(1): 1-5
Abstract:
9-Amino-nonaneic acid was polycondensed in boiling paraffin hydrocarbon medium, the water formed during the reaction was immediately carried away by the vapor of the medium. By using this technique, polycondensation ran very rapidly, and within 15 min. the extent of reaction (p) reached more than 95%, and after 3 hrs., p surpassed 99%. The number average molecular weight was higher than 40,000. These have never been reached as reported in literature.Because p can be pushed to over 99%, it is possible to study the complete course of poly condensation reactions.It was found that the reaction followed second order from the beginning up to p around 99%.Beyond this,the system became so viscous that factor should be considered.This caused the reaction to be changed to third order.
9-Amino-nonaneic acid was polycondensed in boiling paraffin hydrocarbon medium, the water formed during the reaction was immediately carried away by the vapor of the medium. By using this technique, polycondensation ran very rapidly, and within 15 min. the extent of reaction (p) reached more than 95%, and after 3 hrs., p surpassed 99%. The number average molecular weight was higher than 40,000. These have never been reached as reported in literature.Because p can be pushed to over 99%, it is possible to study the complete course of poly condensation reactions.It was found that the reaction followed second order from the beginning up to p around 99%.Beyond this,the system became so viscous that factor should be considered.This caused the reaction to be changed to third order.
1983, 1(1): 6-10
Abstract:
In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6-aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%. It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids(monomers of the A-B type),and the controversial results that appeared in the literature may be cleared up by our experiments.
In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6-aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%. It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids(monomers of the A-B type),and the controversial results that appeared in the literature may be cleared up by our experiments.
STUDY ON THE EFFECT OF POLYSTYRENE SULFONIC ACID MACROMOLECULES ON THE POLYMERIZATION OF ACRYLAMIDE*
1983, 1(1): 11-16
Abstract:
The effect of polystyrene sulfonic acid (PSSA) macromolecules on the polymerization of acrylamide (AM) has been studied. It was found that the rates of polymerization of AM were greatly increased in the presence of PSSA in the polymerization system.The maximum value of the rate of polymerization of AM was obtained when the ratio of [—SO3H]: [AM] reached 3:1. When the insoluble crosslinked PSSA was used instead of the soluble one, this effect decreased considerably. The interaction between molecules of PSSA and AM was determined by infrared spectroscopy,elementary analysis and X-ray photoelectron spectroscopy.The combination form,-SO3-NH3+CO-,formed between sulfonic group and amide group was found to be existed since the infrared absorption band of -NH2 shifted from 3400cm-1 to 3150cm-1,the binding energy of electron N1s changed from 399.7eV to 401.3 eV,and the atomic ratio of N to S of the products was similar to the ratio of reagents.Based on these experimental results,the mechanism of AM polymerization in the presence of PSSA is proposed.The initial step is the combination of AM with sulfonic group to form—CONHa+,then followed by poly merization on the PSSA macromolecule.The role of PSSA on the polymerization of AM is discussed.
The effect of polystyrene sulfonic acid (PSSA) macromolecules on the polymerization of acrylamide (AM) has been studied. It was found that the rates of polymerization of AM were greatly increased in the presence of PSSA in the polymerization system.The maximum value of the rate of polymerization of AM was obtained when the ratio of [—SO3H]: [AM] reached 3:1. When the insoluble crosslinked PSSA was used instead of the soluble one, this effect decreased considerably. The interaction between molecules of PSSA and AM was determined by infrared spectroscopy,elementary analysis and X-ray photoelectron spectroscopy.The combination form,-SO3-NH3+CO-,formed between sulfonic group and amide group was found to be existed since the infrared absorption band of -NH2 shifted from 3400cm-1 to 3150cm-1,the binding energy of electron N1s changed from 399.7eV to 401.3 eV,and the atomic ratio of N to S of the products was similar to the ratio of reagents.Based on these experimental results,the mechanism of AM polymerization in the presence of PSSA is proposed.The initial step is the combination of AM with sulfonic group to form—CONHa+,then followed by poly merization on the PSSA macromolecule.The role of PSSA on the polymerization of AM is discussed.
1983, 1(1): 17-24
Abstract:
The polymerization mechanism of various vinyl monomers in the presence of aromatic tertiary amines has been studied. It was found that the mechanisms of different monomers are varied with the structures of monomers. Those monomers, such as methacrylic esters containing α-CH3 group on the double bond could be polymerized with aromatic tertiary amine in the absence of light, while the monomers without α-CH3 group, such as methyl acrylate, acrylonitrile etc. would polymerize only under light.The structural effects,both of the monomer and the amine,on the rate of photopolymerization were studied. The activities of monomers and amines may be arranged in the following order Monomer:AN>MA>VA>ST Amine:DMT>DMA>DMB>DNA It is revealed that both the electro-negative group on the double bond of monomer which acts as an acceptor and the electro-positive group on the nitrogen atom of amine which acts as a donor would effectively increase the rate of photopolymerization.
The polymerization mechanism of various vinyl monomers in the presence of aromatic tertiary amines has been studied. It was found that the mechanisms of different monomers are varied with the structures of monomers. Those monomers, such as methacrylic esters containing α-CH3 group on the double bond could be polymerized with aromatic tertiary amine in the absence of light, while the monomers without α-CH3 group, such as methyl acrylate, acrylonitrile etc. would polymerize only under light.The structural effects,both of the monomer and the amine,on the rate of photopolymerization were studied. The activities of monomers and amines may be arranged in the following order Monomer:AN>MA>VA>ST Amine:DMT>DMA>DMB>DNA It is revealed that both the electro-negative group on the double bond of monomer which acts as an acceptor and the electro-positive group on the nitrogen atom of amine which acts as a donor would effectively increase the rate of photopolymerization.
1983, 1(1): 25-31
Abstract:
The yield of copolymerization of tetrahydrofuran and propylene oxide (THF:PO=100:5—15, by wt.) using a binary catalyst of fuming sulfuric acid (21% or 28%) and perchloric acid is around 50—60%, and the loss of THF in the reaction is below 10—15%. The average molecular weight of the product can be controlled in the range of 1000—2000 by varying the binary catalyst system. The present method, which is different from the usual copolymerization initiated by BF3-diol or SbCl5-diol system, shows the pecularities i.e.the yield of copolymerization with the low PO feed is not decreased,the hydroxyl funcitonality is equal to 2,and the end-groups are predominantly primary hydroxyls(around 65-70%).
The yield of copolymerization of tetrahydrofuran and propylene oxide (THF:PO=100:5—15, by wt.) using a binary catalyst of fuming sulfuric acid (21% or 28%) and perchloric acid is around 50—60%, and the loss of THF in the reaction is below 10—15%. The average molecular weight of the product can be controlled in the range of 1000—2000 by varying the binary catalyst system. The present method, which is different from the usual copolymerization initiated by BF3-diol or SbCl5-diol system, shows the pecularities i.e.the yield of copolymerization with the low PO feed is not decreased,the hydroxyl funcitonality is equal to 2,and the end-groups are predominantly primary hydroxyls(around 65-70%).
1983, 1(1): 32-39
Abstract:
As a model of serine hydrolase, the condensation polymers of salicylic acid, formaldehyde and methyl amine, n-propyl amine, n-hexyl amine or n-lauryl amine were prepared by polycondensation catalyzed by sulfuric acid. It was confirmed by potentiometric titration and infrared spectrum that the polymers containing tertiary amino group possess the structure which resembles the internal salt of amino acid in weak basic and weak acidic solution:The catalytic reaction of the above polymers for hydrolysis of active ester,p-nitrophenyl acetate(PNPA),was studied.It was found kinetically that the most efficient catalytic effect of polymer was composed of two salicylic acid groups and one tertiary amino group in the polymer chain.The rates of hydrolysis of PNPA increase with increasing of pH values and length of the alkyl groups in the side chain of the polymers and the effect of the conformation of the polymer containing tertiary amino group in the buffer solution on the catalytic activity was also investigated.Hydrolysis of PNPA catalyzed by the polymer made of salicylic acid,formaldehyde and n-lauryl amine follows the simple Michaelis-Menten type mechanism.The kinetics parameters were determined as:Km6.7×10-5M and Vmax2.07×10-7M·min-1.
As a model of serine hydrolase, the condensation polymers of salicylic acid, formaldehyde and methyl amine, n-propyl amine, n-hexyl amine or n-lauryl amine were prepared by polycondensation catalyzed by sulfuric acid. It was confirmed by potentiometric titration and infrared spectrum that the polymers containing tertiary amino group possess the structure which resembles the internal salt of amino acid in weak basic and weak acidic solution:The catalytic reaction of the above polymers for hydrolysis of active ester,p-nitrophenyl acetate(PNPA),was studied.It was found kinetically that the most efficient catalytic effect of polymer was composed of two salicylic acid groups and one tertiary amino group in the polymer chain.The rates of hydrolysis of PNPA increase with increasing of pH values and length of the alkyl groups in the side chain of the polymers and the effect of the conformation of the polymer containing tertiary amino group in the buffer solution on the catalytic activity was also investigated.Hydrolysis of PNPA catalyzed by the polymer made of salicylic acid,formaldehyde and n-lauryl amine follows the simple Michaelis-Menten type mechanism.The kinetics parameters were determined as:Km6.7×10-5M and Vmax2.07×10-7M·min-1.
1983, 1(1): 40-52
Abstract:
In order to investigate synthetic route of polyperfluorotriazine elastomer, 2-trifluoromethyl4,6-bis(4′-iodo-2′-oxahexafluorobutyl)-1,3,5-triazine (1), a novel triazine monomer, was synthesized from 5-iodo-3-oxa-octafluoropentanesulfonyl fluoride (2) in eight-steps. 2 was reduced by potassium sulfite to the sulfinate (3), which was treated with hydriodic acid to yield 5-iodo-3oxa-hexafluoropentanoic acid (4). Compound 4 was transformed to 5-iodo-3-oxa-hexafluoropentanenitrile (7) through the corresponding ester 5 and amide 6.The desired product 1 was prepared by acylation-cyclodehydration of the imidoylamidine 9,obtained by condensation of the nitrile 7 with the amidine 8. The various methods for the esterification of perfluorocarboxylic acid were studied and a possible mechanism for the transformation of perfluorosulfinate to the corresponding perfluorocarboxylic acid by hudriodic acid was proposed.Crude 1 contained compounds6,11,13 as impurities which were removed by low temperature crystallization followed by filtration through a short alumina column.The monomer 1 was polymerized by UV-irradiation in the presence of Hg with or without solvent.Polyperfluorooxaalkyl triazine 17 thus obtained showed good thermal stability.In the main chain of the polymer there was no weak unit of the uncyclized ring.Polymer 17 had an average molecular weight of ca.1.33—2.0×104(D.P=27—42) and the temperature of 10% weight loss in nitrogen was 340℃.
In order to investigate synthetic route of polyperfluorotriazine elastomer, 2-trifluoromethyl4,6-bis(4′-iodo-2′-oxahexafluorobutyl)-1,3,5-triazine (1), a novel triazine monomer, was synthesized from 5-iodo-3-oxa-octafluoropentanesulfonyl fluoride (2) in eight-steps. 2 was reduced by potassium sulfite to the sulfinate (3), which was treated with hydriodic acid to yield 5-iodo-3oxa-hexafluoropentanoic acid (4). Compound 4 was transformed to 5-iodo-3-oxa-hexafluoropentanenitrile (7) through the corresponding ester 5 and amide 6.The desired product 1 was prepared by acylation-cyclodehydration of the imidoylamidine 9,obtained by condensation of the nitrile 7 with the amidine 8. The various methods for the esterification of perfluorocarboxylic acid were studied and a possible mechanism for the transformation of perfluorosulfinate to the corresponding perfluorocarboxylic acid by hudriodic acid was proposed.Crude 1 contained compounds6,11,13 as impurities which were removed by low temperature crystallization followed by filtration through a short alumina column.The monomer 1 was polymerized by UV-irradiation in the presence of Hg with or without solvent.Polyperfluorooxaalkyl triazine 17 thus obtained showed good thermal stability.In the main chain of the polymer there was no weak unit of the uncyclized ring.Polymer 17 had an average molecular weight of ca.1.33—2.0×104(D.P=27—42) and the temperature of 10% weight loss in nitrogen was 340℃.
1983, 1(1): 53-59
Abstract:
Two main types of amine-containing initiation systems were studied in this work. In the case of MMA polymerization initiated by BPO-amine (DMT, DHET, DMA) redox systems, it was found that the polymerization rate and colour stability of the polymer for different amine systems were in the following order: DMT≈DHET>DMA. Accordingly, BPO-DMT and BPO-DHET are effective initiators. In the case of MEMA polymerization by amine (DMT, DHET, DMA) alone, it was found that the polymerization rate and the percentage of conversion for these different amine systems were in the following order:SMT≥DHET>DMA.The polymerization rate and the percentage of conversion also increased with increase of DMT concentration.From the kinetic investigation the rate equation Rp=K[DMT]1/2[MEMA]3/2 was obtained,and the overall activetion energy of polymerization was calculated to be 34.3KJ/mol (8.2 Kcal/mol).Moreover,the polymerization of MEMA in the presence of DMT was strongly inhibited by hydroquinone,indicating the polymerization being free radical in nature.From these results,the mechanism of MEMA polymerization initiated by amine was proposed.
Two main types of amine-containing initiation systems were studied in this work. In the case of MMA polymerization initiated by BPO-amine (DMT, DHET, DMA) redox systems, it was found that the polymerization rate and colour stability of the polymer for different amine systems were in the following order: DMT≈DHET>DMA. Accordingly, BPO-DMT and BPO-DHET are effective initiators. In the case of MEMA polymerization by amine (DMT, DHET, DMA) alone, it was found that the polymerization rate and the percentage of conversion for these different amine systems were in the following order:SMT≥DHET>DMA.The polymerization rate and the percentage of conversion also increased with increase of DMT concentration.From the kinetic investigation the rate equation Rp=K[DMT]1/2[MEMA]3/2 was obtained,and the overall activetion energy of polymerization was calculated to be 34.3KJ/mol (8.2 Kcal/mol).Moreover,the polymerization of MEMA in the presence of DMT was strongly inhibited by hydroquinone,indicating the polymerization being free radical in nature.From these results,the mechanism of MEMA polymerization initiated by amine was proposed.
1983, 1(1): 60-69
Abstract:
The ultrasonic degradation of poly(ethylene oxide) and poly(vinyl acetate) in benzene solution, and grafting reaction of poly(vinyl acetate) with poly(ethylene oxide) were studied. It is found that the chain-scission reactions follow the course suggested by D. W. Ovenall. The structure of the copolymer was identified by IR, NMR and DTA, showing that the copolymer prepared is a graft copolymer mainly. The copolymer formed by irradiating 1% PEO/PVAc solution (PEO/PVAc:1/1 by weight) for a period of 10 min at 18.2 kHz with 2.0 A input current on reversed main circuit,amounts to 10.5%.
The ultrasonic degradation of poly(ethylene oxide) and poly(vinyl acetate) in benzene solution, and grafting reaction of poly(vinyl acetate) with poly(ethylene oxide) were studied. It is found that the chain-scission reactions follow the course suggested by D. W. Ovenall. The structure of the copolymer was identified by IR, NMR and DTA, showing that the copolymer prepared is a graft copolymer mainly. The copolymer formed by irradiating 1% PEO/PVAc solution (PEO/PVAc:1/1 by weight) for a period of 10 min at 18.2 kHz with 2.0 A input current on reversed main circuit,amounts to 10.5%.
1983, 1(1): 70-75
Abstract:
Several new monomers, β-(acetylsalicylyloxy)ethyl methacrylate, β-(acetylsalicylyloxy)propyl methacrylate, β-(acetylsalicylyloxy)ethyl acrylate, β-hydroxy-Υ-(acetylsalicylyloxy)propyl methacrylate,β-hydroxy-Υ-(acetylsalicylyloxy)propyl acrylate have been synthesized from aspirin with corresponding hydroxyalkyl or glycidyl acrylates, and then polymerized by free radical initiator.
Several new monomers, β-(acetylsalicylyloxy)ethyl methacrylate, β-(acetylsalicylyloxy)propyl methacrylate, β-(acetylsalicylyloxy)ethyl acrylate, β-hydroxy-Υ-(acetylsalicylyloxy)propyl methacrylate,β-hydroxy-Υ-(acetylsalicylyloxy)propyl acrylate have been synthesized from aspirin with corresponding hydroxyalkyl or glycidyl acrylates, and then polymerized by free radical initiator.
1983, 1(1): 76-79
Abstract:
The crystalline morphology of some FEP copolymers, prepared by different methods, with different hexafluoropropylene (F6) contents was studied by means of small angle light scattering technique.The results obtained show that the main factors which affect the crystalline morphology are the content of F6 and the conditions for crystallization. The morphological structure of these copolymers could change from rod-like to spherulitical, as the F6 content changed from 2% to 14—19% under usual air-quenching condition.However,rod-like crystalline structure would form under very low rate of cooling(0.2℃/min).Some Hv patterns show that fine structure also exists in addition to the two-and three-dimensional spherulites coexisting in the specimens prepared under certain crystallization conditions.
The crystalline morphology of some FEP copolymers, prepared by different methods, with different hexafluoropropylene (F6) contents was studied by means of small angle light scattering technique.The results obtained show that the main factors which affect the crystalline morphology are the content of F6 and the conditions for crystallization. The morphological structure of these copolymers could change from rod-like to spherulitical, as the F6 content changed from 2% to 14—19% under usual air-quenching condition.However,rod-like crystalline structure would form under very low rate of cooling(0.2℃/min).Some Hv patterns show that fine structure also exists in addition to the two-and three-dimensional spherulites coexisting in the specimens prepared under certain crystallization conditions.
1983, 1(1): 80-82
Abstract:
A new peak at 39.0 ppm in the 13C-NMR spectrum of polybutadiene (PBD) was discovered. This peak is assigned to the fourth peak (T4) of trans-1,4-sequence marked with an asterisk as shown in Fig. 3 in the text.The occurrence of T4 carbon nuclei is strongly affected by their neighboring 1,2-units. So long as both contents of trans-1,4- and 1,2-units attain their proper amounts the peak (T4) with appear in the 13C-NMR spectrum of PBD.
A new peak at 39.0 ppm in the 13C-NMR spectrum of polybutadiene (PBD) was discovered. This peak is assigned to the fourth peak (T4) of trans-1,4-sequence marked with an asterisk as shown in Fig. 3 in the text.The occurrence of T4 carbon nuclei is strongly affected by their neighboring 1,2-units. So long as both contents of trans-1,4- and 1,2-units attain their proper amounts the peak (T4) with appear in the 13C-NMR spectrum of PBD.
1983, 1(1): 83-91
Abstract:
Three sets of PET samples, comprising original (undrawn), uniaxially drawn and biaxially ones, after annealed at 230°, 240° and 250℃ respectively, were subjected to DSC thermal analysis, X-ray diffraction analysis and IR analysis. The results indicate that the phenomenon of double melting peaks during DSC analysis is due to the partial melting and recrystallization of the crystallite at the moment of thermal scanning. The lower temperature peak, which varies slightly according to annealing condition, corresponds to the melting of imperfect crystallite,and the higher temperature peak corresponds to the melting of better organized crystallite.In the course of temperature scanning,the unit cell parameters of PET remains unchanged while the crystals turn to better crystal lattice,greater crystal size and more regular folding.We also found that there is a slight reduction in crystal size between the two melting peaks,and an explanation is suggested for this phenomenon.
Three sets of PET samples, comprising original (undrawn), uniaxially drawn and biaxially ones, after annealed at 230°, 240° and 250℃ respectively, were subjected to DSC thermal analysis, X-ray diffraction analysis and IR analysis. The results indicate that the phenomenon of double melting peaks during DSC analysis is due to the partial melting and recrystallization of the crystallite at the moment of thermal scanning. The lower temperature peak, which varies slightly according to annealing condition, corresponds to the melting of imperfect crystallite,and the higher temperature peak corresponds to the melting of better organized crystallite.In the course of temperature scanning,the unit cell parameters of PET remains unchanged while the crystals turn to better crystal lattice,greater crystal size and more regular folding.We also found that there is a slight reduction in crystal size between the two melting peaks,and an explanation is suggested for this phenomenon.
1983, 1(1): 92-100
Abstract:
The (cis-1,4 and 1,2) polybutadiene polymerized with iron catalyst was investigated by 13C-NMR. Assignments have been made on the spectra for all peaks of the aliphatic and olefinic carbons using chemical shift corrective terms together with Furukawa parameters. The relative intensities of peaks were calculated from the Bernoulli distribution of cis-1,4 and 1,2 units.Quantification of cis-1,4 and 1,2 contents, sequence distribution, alternation pattern of cis-1,4 and 1,2 units, and the chain propagation mechanism were discussed as a result of the detailed study of the spectra.
The (cis-1,4 and 1,2) polybutadiene polymerized with iron catalyst was investigated by 13C-NMR. Assignments have been made on the spectra for all peaks of the aliphatic and olefinic carbons using chemical shift corrective terms together with Furukawa parameters. The relative intensities of peaks were calculated from the Bernoulli distribution of cis-1,4 and 1,2 units.Quantification of cis-1,4 and 1,2 contents, sequence distribution, alternation pattern of cis-1,4 and 1,2 units, and the chain propagation mechanism were discussed as a result of the detailed study of the spectra.
