Login In
1964 Volume 6 Issue 1
1964, 6(1): 1-12
Abstract:
Some theoretical considerations about the controversy between Charlesby’S and Tang’s theories concerning the solubility of crosslinked polymer induced by irradiation are given．Bas．ed on Charlesby’s definition of the sol fraction，calculations were carried out for the polymer with initial molecular weight distribution(MWD)of the Flory type by method of direct summation；when q→O，Charlesby’s formula of solubility was obtained.
Some theoretical considerations about the controversy between Charlesby’S and Tang’s theories concerning the solubility of crosslinked polymer induced by irradiation are given．Bas．ed on Charlesby’s definition of the sol fraction，calculations were carried out for the polymer with initial molecular weight distribution(MWD)of the Flory type by method of direct summation；when q→O，Charlesby’s formula of solubility was obtained.
1964, 6(1): 13-24
Abstract:
A theoretical calculation on the sol fraction of the cross-linked long-chain polymers is given． It is based on the following three assumptions：1)that gel is an infinite network；2)that either units of sol or units of gel are cross—linked with equal probability；3)that the cross-linking process within a molecule (cyclization) occurs in gel，but may be neglected in sol．By using two independent methods，namely，the direct summation of infinite series and the probability derivation，the sol fraction formula of cross-linked high polymer produced from initial linear polymer obeying an arbitrary distribution is obtained．Vari-ous special cases are discussed．
A theoretical calculation on the sol fraction of the cross-linked long-chain polymers is given． It is based on the following three assumptions：1)that gel is an infinite network；2)that either units of sol or units of gel are cross—linked with equal probability；3)that the cross-linking process within a molecule (cyclization) occurs in gel，but may be neglected in sol．By using two independent methods，namely，the direct summation of infinite series and the probability derivation，the sol fraction formula of cross-linked high polymer produced from initial linear polymer obeying an arbitrary distribution is obtained．Vari-ous special cases are discussed．
1964, 6(1): 25-30
Abstract:
1964, 6(1): 31-35
Abstract:
The structure of graft copolymer has been investigated by X-ray diagrams. The grafting process was carried out through prelin inary irradiation of oriented polypropylene with gamma-radiation and then treated with acrylonitrile.With the aid of X-ray diagrams, a model for the state of molecular aggregation of the copolymer under investigation was suggested. It was found that shrinkage of the said copolymer is smaller than that of oriented polypropylene and that of the oriented graft copolymer made from acrylotrile and polypropylene. The present graft system is in a quasi-stable stat which fixes the molecular orientation in the polymer.
The structure of graft copolymer has been investigated by X-ray diagrams. The grafting process was carried out through prelin inary irradiation of oriented polypropylene with gamma-radiation and then treated with acrylonitrile.With the aid of X-ray diagrams, a model for the state of molecular aggregation of the copolymer under investigation was suggested. It was found that shrinkage of the said copolymer is smaller than that of oriented polypropylene and that of the oriented graft copolymer made from acrylotrile and polypropylene. The present graft system is in a quasi-stable stat which fixes the molecular orientation in the polymer.
1964, 6(1): 36-41
Abstract:
Two epoxylated novolacs based on phenol-formaldehyde and resorcinol-formaldehyde condensation products respectively were synthesized． Both of them contained more than two epoxy groups per molecule．After curing with various curing agents，the deformation under constant lpad and the weight loss at elevated temperatures of the cured resin were measured． It was proved that with an increase in the number of functionality present in the resin，the degree of cross linking was increased． As a consequence，the cured resin showed higher glass transition temperature and smaller deformation in high elastic state．Their high temperature performance was thus better than similar system based on the diglycidyl ether of bisphenol A resin．
Two epoxylated novolacs based on phenol-formaldehyde and resorcinol-formaldehyde condensation products respectively were synthesized． Both of them contained more than two epoxy groups per molecule．After curing with various curing agents，the deformation under constant lpad and the weight loss at elevated temperatures of the cured resin were measured． It was proved that with an increase in the number of functionality present in the resin，the degree of cross linking was increased． As a consequence，the cured resin showed higher glass transition temperature and smaller deformation in high elastic state．Their high temperature performance was thus better than similar system based on the diglycidyl ether of bisphenol A resin．
1964, 6(1): 48-54
Abstract:
The polymerization of butadiene catalysed by the TiBr4-i-Bu3A1，TiBr4-Et3A1，and TiBr4-BuLi systems has been studied．In the catalyst system of TiBr4-i-Bu3Al with ben-zene as solvent there are two molar ratios of i-Bu3Al to TiBr4，which exhibit maximum catalytic activity．The geI content，molecular weight and cis-1，4-content of the soluble part of the polymer decrease with increase of the i-Bu3Al／TiBr4 ratio．The atalytic ac-tivity seems to be greater，when the monomer is first mixed with i-Bu3Al than first with TiBr4．The maximum activity appears to move towards greater i-Bu3Al／TiBr4 ratio，when the polymerization temperature is lowered． If heptane is used as solvent．the rate of polymerization is reduced and only one catalyst ratio exhibits maximum activity．The gel content，molecular weight and cis-1，4-content of the soluble part of the polymer oh-tained all seem to be lower． If triethyl aluminium is used instead of triisobutyl alumi-nium．there are also two catalyst ratios exhibiting maximum activity． When the tem-perature of polymerization is lower the catalytic activity of the Et3Al-TiBr4 system seems to be greater than that of the i-Bu3Al-TiBr4 system．The products obtained from both systems appear very alike．They consist of a large amount of gel and the cis-1，4-content of the soluble part of the polymer iS below 70％．Catalysed by a new catalytic syscem-the BuLi-TiBr4 system butadiene can be polymerized to a product containing the cis-1，4-form higher than 90％． Catalytic activity was observed for BuLi／TiBr4 with molar ratios of 1.5—2.5．The cis-4-content of the product becomes smaller，when the catalyst ratio is greater．The valence states of the titanium existing in the above three catalytic sys-tems have been compared．When the metal alkyl to titanium tetrabromide ratio is lower than 2．the trivalent titanium increases with increase of catalyst ratio． When the catalyst ratio is higher than 2, the trivalent titanium decreases with increase of catalyst ratio in the BuLi／TiBr4 system，while in th eI other two systems the trivalent titanium still in-creases till 100％． It is interesting to note that the catalytic activity of the BuLi—TiBr4 system lies just between the range of catalyst ratios Which possess higher content of trivalent titanium．
The polymerization of butadiene catalysed by the TiBr4-i-Bu3A1，TiBr4-Et3A1，and TiBr4-BuLi systems has been studied．In the catalyst system of TiBr4-i-Bu3Al with ben-zene as solvent there are two molar ratios of i-Bu3Al to TiBr4，which exhibit maximum catalytic activity．The geI content，molecular weight and cis-1，4-content of the soluble part of the polymer decrease with increase of the i-Bu3Al／TiBr4 ratio．The atalytic ac-tivity seems to be greater，when the monomer is first mixed with i-Bu3Al than first with TiBr4．The maximum activity appears to move towards greater i-Bu3Al／TiBr4 ratio，when the polymerization temperature is lowered． If heptane is used as solvent．the rate of polymerization is reduced and only one catalyst ratio exhibits maximum activity．The gel content，molecular weight and cis-1，4-content of the soluble part of the polymer oh-tained all seem to be lower． If triethyl aluminium is used instead of triisobutyl alumi-nium．there are also two catalyst ratios exhibiting maximum activity． When the tem-perature of polymerization is lower the catalytic activity of the Et3Al-TiBr4 system seems to be greater than that of the i-Bu3Al-TiBr4 system．The products obtained from both systems appear very alike．They consist of a large amount of gel and the cis-1，4-content of the soluble part of the polymer iS below 70％．Catalysed by a new catalytic syscem-the BuLi-TiBr4 system butadiene can be polymerized to a product containing the cis-1，4-form higher than 90％． Catalytic activity was observed for BuLi／TiBr4 with molar ratios of 1.5—2.5．The cis-4-content of the product becomes smaller，when the catalyst ratio is greater．The valence states of the titanium existing in the above three catalytic sys-tems have been compared．When the metal alkyl to titanium tetrabromide ratio is lower than 2．the trivalent titanium increases with increase of catalyst ratio． When the catalyst ratio is higher than 2, the trivalent titanium decreases with increase of catalyst ratio in the BuLi／TiBr4 system，while in th eI other two systems the trivalent titanium still in-creases till 100％． It is interesting to note that the catalytic activity of the BuLi—TiBr4 system lies just between the range of catalyst ratios Which possess higher content of trivalent titanium．
ВЛИЯНИЕ НЕКОТОРЫХ ДОБАВОК НА ПОЛИМЕРИЗАЦИЮ БУТАДИЕНА С КАТАЛИТИЧЕСКОЙ СИСТЕМОЙ (C2H5)2AlCl-CoCl2·4Py
1964, 6(1): 55-60
Abstract:
1964, 6(1): 61-70
Abstract:
Through kinetic method, the reaction mechanism of cyclopolymerization of 1,1-diallyl-diethylmalonate (DDM) and diallyl-phthalate (DAP) has been studied. Besides mono-molecular mechanism of ordinary inter-intramolecular polymerization consideration, we proposed the linear equation of cyclopolymerization through consideration of both mono-molecular and bimolecular reaction mechanism. It was found that this linear equation could be applied successfully not only to the above two cases but also to the cyclopoly-merization data from Aso.
Through kinetic method, the reaction mechanism of cyclopolymerization of 1,1-diallyl-diethylmalonate (DDM) and diallyl-phthalate (DAP) has been studied. Besides mono-molecular mechanism of ordinary inter-intramolecular polymerization consideration, we proposed the linear equation of cyclopolymerization through consideration of both mono-molecular and bimolecular reaction mechanism. It was found that this linear equation could be applied successfully not only to the above two cases but also to the cyclopoly-merization data from Aso.
1964, 6(1): 71-77
Abstract:
The benzoyl peroxide-induced polymerization of phenylacetylene has been studied．At 60°．when the amount of the initiator used was less than 1 mole per cent of the monomer，very little polymerization occurred；when 2—4 mole per cent of the initiator was used，polymerization took place readily． When the temperature of polymerization was raised from 60°to 130°，the rate of polymerization increased markedly．The average molecular weight of the polyphenylacetylenes obtained was 600—1500．The in-frared spectrum of the polymer showed characteristic absorption for the C6H5COO-ter-minal group．In the infrared spectrum of the polymer obtained at 160°，the charac-teristic absorption peaks for the C=O and C—O bonds essentially vanished．The thermal polymerization of phenylacetylene occurred to a negligible extent be-low 100°；at 100—160°，the rate of polymerization、increased with increasing tempera-ture．Boron trifluoride could induce the rapid polymerization of phenylacetylene whether at room temperature or lower．The average molecular weight of the polyphenylacetylene obtained was over 2000．The infrared spectra of the polyphenylacetylenes showed great similarities，except the characteristic absorption for the C6H5COO-grouping in the benzoyl peroxide-initiated polymerization product．In comparison with the infrared spectrum of polyphenylace-tylene reported bv Okamoto et al[6] there was a minor difference in the 770—700 cm-1 region，while most parts of the spectra are very much similar；this indicates that the poly-phenylacetylenes obtained by the various methods reported in this work have probably the same chain structure.
The benzoyl peroxide-induced polymerization of phenylacetylene has been studied．At 60°．when the amount of the initiator used was less than 1 mole per cent of the monomer，very little polymerization occurred；when 2—4 mole per cent of the initiator was used，polymerization took place readily． When the temperature of polymerization was raised from 60°to 130°，the rate of polymerization increased markedly．The average molecular weight of the polyphenylacetylenes obtained was 600—1500．The in-frared spectrum of the polymer showed characteristic absorption for the C6H5COO-ter-minal group．In the infrared spectrum of the polymer obtained at 160°，the charac-teristic absorption peaks for the C=O and C—O bonds essentially vanished．The thermal polymerization of phenylacetylene occurred to a negligible extent be-low 100°；at 100—160°，the rate of polymerization、increased with increasing tempera-ture．Boron trifluoride could induce the rapid polymerization of phenylacetylene whether at room temperature or lower．The average molecular weight of the polyphenylacetylene obtained was over 2000．The infrared spectra of the polyphenylacetylenes showed great similarities，except the characteristic absorption for the C6H5COO-grouping in the benzoyl peroxide-initiated polymerization product．In comparison with the infrared spectrum of polyphenylace-tylene reported bv Okamoto et al[6] there was a minor difference in the 770—700 cm-1 region，while most parts of the spectra are very much similar；this indicates that the poly-phenylacetylenes obtained by the various methods reported in this work have probably the same chain structure.
1964, 6(1): 78-85
Abstract:
Vinyl copolymers containing glycidyl methacrylate as one component are thermal reactive．They are valuable in preparing thermosetting and graft copolymers．When glycidyl methacrylate，methyl methacrylate，and methacrylic acid were copoly-merized，a linear copolymer was formed at first，which，on further heating at higher temperatures．was transformed into a crosslinked polymer．It was shown by IR spectro-scopy that intermolecular reaction of epoxy group and carboxyl group has taken place at the higher temperatures．Crosslinking of the copolymer chains raised the glass tem-perature appreciably．By heating the、glycidyl methacrylate-methyl methacrylate copolymer with polycapro-lactam in benzyl alcohol solution，a graft copolymer was obtained．This graft copoly-met，after being dried，could not be dissolved in most solvents including benzyl alcohol and m-cresol at room temperature，except the very polar ones，such as 98％ formic acid．This abnormal behaviour was ascribed to the formation of H-bonds between molecular chains．Viscosities of both the back—bone copolymer and the graft copolymer in benzyl alcohol and in m-cresol were determined．It was shown that the Huggins constant K'increases owing to grafting in the case of m-cresol solution，but not in the case of benzyl alcohol solution．Therefore，the effect of grafting on the solution viscosity is not always the same as branching，because of the nature of the backbone and that of the graft being different，and hence the solvent effect on them is also different．
Vinyl copolymers containing glycidyl methacrylate as one component are thermal reactive．They are valuable in preparing thermosetting and graft copolymers．When glycidyl methacrylate，methyl methacrylate，and methacrylic acid were copoly-merized，a linear copolymer was formed at first，which，on further heating at higher temperatures．was transformed into a crosslinked polymer．It was shown by IR spectro-scopy that intermolecular reaction of epoxy group and carboxyl group has taken place at the higher temperatures．Crosslinking of the copolymer chains raised the glass tem-perature appreciably．By heating the、glycidyl methacrylate-methyl methacrylate copolymer with polycapro-lactam in benzyl alcohol solution，a graft copolymer was obtained．This graft copoly-met，after being dried，could not be dissolved in most solvents including benzyl alcohol and m-cresol at room temperature，except the very polar ones，such as 98％ formic acid．This abnormal behaviour was ascribed to the formation of H-bonds between molecular chains．Viscosities of both the back—bone copolymer and the graft copolymer in benzyl alcohol and in m-cresol were determined．It was shown that the Huggins constant K'increases owing to grafting in the case of m-cresol solution，but not in the case of benzyl alcohol solution．Therefore，the effect of grafting on the solution viscosity is not always the same as branching，because of the nature of the backbone and that of the graft being different，and hence the solvent effect on them is also different．
