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1993 Volume 11 Issue 3
1993, 11(3): 193-197
Abstract:
Unmixing kinetics in a binary polymer mixture of polyethersulphones with poly (ethylene oxide) by spinodal decomposition has been investigated with time-resolved light scattering and microscope methods. The results showed that time evolution of scattered light intensity is of an exponential growth The maximum growth rate R(qm) of phase separation has been obtained. The experimental data did not satisfy the condition that the plot of R(q)/q2 vs q2 should be linear For unmixing system annealing at 30℃ for three hours its morphology manifested dish structure The expenmental data of the Bragg spacing Dm can be correlated with a straight line which expresses the power-law relation,Dm=bta.
Unmixing kinetics in a binary polymer mixture of polyethersulphones with poly (ethylene oxide) by spinodal decomposition has been investigated with time-resolved light scattering and microscope methods. The results showed that time evolution of scattered light intensity is of an exponential growth The maximum growth rate R(qm) of phase separation has been obtained. The experimental data did not satisfy the condition that the plot of R(q)/q2 vs q2 should be linear For unmixing system annealing at 30℃ for three hours its morphology manifested dish structure The expenmental data of the Bragg spacing Dm can be correlated with a straight line which expresses the power-law relation,Dm=bta.
1993, 11(3): 198-203
Abstract:
The synthetic method and structural characteristics of urushiol-titanium chelates (UT) and urushiol-titanium chelate polymer for anticorrosive coatings have been studied.Two kinds of coating films made from UT polymer show excellent physico-mechanical properties and possess good chemical resistance to strong acids and alkalis, many kinds of salt solutions and organic solvents, stable at high temperature.
The synthetic method and structural characteristics of urushiol-titanium chelates (UT) and urushiol-titanium chelate polymer for anticorrosive coatings have been studied.Two kinds of coating films made from UT polymer show excellent physico-mechanical properties and possess good chemical resistance to strong acids and alkalis, many kinds of salt solutions and organic solvents, stable at high temperature.
1993, 11(3): 204-209
Abstract:
Macroreticular bead PAN/PVC IPN resins with cyano and chloro groups were synthesized by interpenetrating polymerization of acrylonitrile, or acrylonitrile and divinylbenzene into a macroporous polyvinyl chloride bead. The composition and structure of the bead IPN resins have been investigated by means of FT-IR, NMR, SEM, mercury porosimetry and elemental analysis. During the process of interpenetrating polymerization, the chain propagation obeys Bernoullian statistical law, and no grafting polymerization has been observed.The content of cyano group in the resulting IPN resins can be adjusted by the amount of acrylonitrile added.The morphology of the IPN resins basically resembles that of the polyvinyl chioride bead,whereas the pore structures vary to a certain degree.
Macroreticular bead PAN/PVC IPN resins with cyano and chloro groups were synthesized by interpenetrating polymerization of acrylonitrile, or acrylonitrile and divinylbenzene into a macroporous polyvinyl chloride bead. The composition and structure of the bead IPN resins have been investigated by means of FT-IR, NMR, SEM, mercury porosimetry and elemental analysis. During the process of interpenetrating polymerization, the chain propagation obeys Bernoullian statistical law, and no grafting polymerization has been observed.The content of cyano group in the resulting IPN resins can be adjusted by the amount of acrylonitrile added.The morphology of the IPN resins basically resembles that of the polyvinyl chioride bead,whereas the pore structures vary to a certain degree.
1993, 11(3): 210-219
Abstract:
Two kinds of fishbone-like, β-diketone-based liquid crystalline polysilsesquioxanes(FBDKLCP'S), homopolymeric (H-FBDKLCP) and copolymeric (C-FBDKaLCP) have been first synthesized via the hydrosilylation reaction of a vinyl-terminated β-diketone with the homopolymeric ladderlike polyhydrosilsesquioxane (LPHSQ) and random copolymethylhydrosilsesquioxane (LRPMHSQ) respectively. These new kinds of FBDKLCP with M of 104 is thermotroic liquid crystalline polymer and its clearing temperatures Ti's and mesophase range △T's are much higher than those of the corresponding comb-like β-diketone liquid crystalline polysiloxane (DKLCP) by about 200℃.Similar results have been observed with the comparison of the two different structure Cu-coordinating compounds The significant increases in Tcl's and △T's of the FBDKLCP and Cu-FBDKLCP are mainly attributed to the great rigidity of the ladderlike polysilsesquioxane backbone.
Two kinds of fishbone-like, β-diketone-based liquid crystalline polysilsesquioxanes(FBDKLCP'S), homopolymeric (H-FBDKLCP) and copolymeric (C-FBDKaLCP) have been first synthesized via the hydrosilylation reaction of a vinyl-terminated β-diketone with the homopolymeric ladderlike polyhydrosilsesquioxane (LPHSQ) and random copolymethylhydrosilsesquioxane (LRPMHSQ) respectively. These new kinds of FBDKLCP with M of 104 is thermotroic liquid crystalline polymer and its clearing temperatures Ti's and mesophase range △T's are much higher than those of the corresponding comb-like β-diketone liquid crystalline polysiloxane (DKLCP) by about 200℃.Similar results have been observed with the comparison of the two different structure Cu-coordinating compounds The significant increases in Tcl's and △T's of the FBDKLCP and Cu-FBDKLCP are mainly attributed to the great rigidity of the ladderlike polysilsesquioxane backbone.
1993, 11(3): 220-229
Abstract:
The molecular motion in polyepichlorohydrin (PEPCH), in solution and bulk, was studied by high resolution NMR by means of line width, spin-lattice relaxation time T1 and nuclear Overhauser effect NOE. The results show that the VJGM model can describe the main chain motion of PEPCH in solution perfectly. In bulk state, the relationship between the line width and the temperature is consistent with WLF equation, but that between the high frequency molecular motion correlation time (in T1 scale ) and temperature is consistent with Arrhenius equation.The motion parameters of PEPCH in both states were calculated.The internal rotation motion of side-CH2Cl group was analyzed by using equal three-site jump and diffusion internal rotation model in both states.
The molecular motion in polyepichlorohydrin (PEPCH), in solution and bulk, was studied by high resolution NMR by means of line width, spin-lattice relaxation time T1 and nuclear Overhauser effect NOE. The results show that the VJGM model can describe the main chain motion of PEPCH in solution perfectly. In bulk state, the relationship between the line width and the temperature is consistent with WLF equation, but that between the high frequency molecular motion correlation time (in T1 scale ) and temperature is consistent with Arrhenius equation.The motion parameters of PEPCH in both states were calculated.The internal rotation motion of side-CH2Cl group was analyzed by using equal three-site jump and diffusion internal rotation model in both states.
1993, 11(3): 230-235
Abstract:
Nine thermotropic liquid crystalline terpolyesters based on vaniUic acid(V), p-hydroxybenzoic acid(H) and poly(ethylene terephthalate)(E) were investigated by thermogravimetry to ascertain their thermostability and the kinetic parameters for thermal degradation. Overall activation energy data of the degradation had been calculated over the range 5 ～ 70% weight loss. The temperatures and the activation energy of the degradation lie in the ranges of 384 ～ 394 ℃ at a heating rate of 1℃/min and 176 ～ 205 KJ/mol at the weight loss of 5%,respectively,which suggests that the terpolyesters have good thermostability.
Nine thermotropic liquid crystalline terpolyesters based on vaniUic acid(V), p-hydroxybenzoic acid(H) and poly(ethylene terephthalate)(E) were investigated by thermogravimetry to ascertain their thermostability and the kinetic parameters for thermal degradation. Overall activation energy data of the degradation had been calculated over the range 5 ～ 70% weight loss. The temperatures and the activation energy of the degradation lie in the ranges of 384 ～ 394 ℃ at a heating rate of 1℃/min and 176 ～ 205 KJ/mol at the weight loss of 5%,respectively,which suggests that the terpolyesters have good thermostability.
1993, 11(3): 236-241
Abstract:
In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)5CH3I and W(CO)4I2 produced from UV laser photolysis of W (CO)6 in CH3I, I2—C6H6 and CHI3—C6H6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)6 in CH3I, I2—C6H6 and CHI3—C6I6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W(CO)5CH3I and W(CO)4I2 catalysts were characterized by IR spectra and 1 NMR spectra.
In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)5CH3I and W(CO)4I2 produced from UV laser photolysis of W (CO)6 in CH3I, I2—C6H6 and CHI3—C6H6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)6 in CH3I, I2—C6H6 and CHI3—C6I6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W(CO)5CH3I and W(CO)4I2 catalysts were characterized by IR spectra and 1 NMR spectra.
1993, 11(3): 242-248
Abstract:
The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interaction on the pervaporation of water-ethanol mixtures and to prepare much improved membranes, the membranes have been treated with alkali metal, alkali earth metal and transition metal salt aqueous solutions. The treated membranes (ionized membranes) exhibited higher separation factors than the untreated membranes.The separation factors of warious alkali metal cation membranes decreased in the follwing order:L+>Na+>K+,and the permeation rates showed an opposite tendency.The dependence of pervaporation behavior on the copolymer composition ,feed concentration and operating temperature have been studied with both ionized and non-ionized membranes.The apparent activation energies of water and ethanol permeation were calculated.
The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interaction on the pervaporation of water-ethanol mixtures and to prepare much improved membranes, the membranes have been treated with alkali metal, alkali earth metal and transition metal salt aqueous solutions. The treated membranes (ionized membranes) exhibited higher separation factors than the untreated membranes.The separation factors of warious alkali metal cation membranes decreased in the follwing order:L+>Na+>K+,and the permeation rates showed an opposite tendency.The dependence of pervaporation behavior on the copolymer composition ,feed concentration and operating temperature have been studied with both ionized and non-ionized membranes.The apparent activation energies of water and ethanol permeation were calculated.
1993, 11(3): 249-254
Abstract:
Bis (7- diethylaminocoumarin) ketone- 3(DACK) and diphenyliodonium salt (DPIO)combination as an effective photoinitiation system for radical polymerization has been investigated. The sensitized photolysis of DACK/DPIO leads to bleaching of DACK and decomposition of DPIO to generate initiating radical species. The electron transfer sensitization occurs mainly from the triplet state of DACK. The photobleaching obeyed a second-order kinetics and the rate constant was evaluated to be 31.3mol-1·1·s-1 Photopolymerization of MMA initiated by DACK/DPIO was carried out in acetonitrile solution.The polymerization rate was found to be proportional to the concentration of DACK,DPIO and MMA with the exponents of 0.34,0.40 and 1.0 respectively.The initiated efficiency is comparable to those of small molecular ketones.The sensitized photoinitiation mechanism has been discussed.
Bis (7- diethylaminocoumarin) ketone- 3(DACK) and diphenyliodonium salt (DPIO)combination as an effective photoinitiation system for radical polymerization has been investigated. The sensitized photolysis of DACK/DPIO leads to bleaching of DACK and decomposition of DPIO to generate initiating radical species. The electron transfer sensitization occurs mainly from the triplet state of DACK. The photobleaching obeyed a second-order kinetics and the rate constant was evaluated to be 31.3mol-1·1·s-1 Photopolymerization of MMA initiated by DACK/DPIO was carried out in acetonitrile solution.The polymerization rate was found to be proportional to the concentration of DACK,DPIO and MMA with the exponents of 0.34,0.40 and 1.0 respectively.The initiated efficiency is comparable to those of small molecular ketones.The sensitized photoinitiation mechanism has been discussed.
1993, 11(3): 255-261
Abstract:
The polymerization of acrylonitrile (AN) initiated by polypropylene based-polyamidoxime (PPAO)-thiourea (TU) system was investigated at [TU]/[PPAO]>0.5 molar ratio. It shows that the variation of the concentrations of PPAO, thiourea and nitric acid does not exert an observable influence on the reaction rate. The overall rate of polymerization (Rp) isRp = 2.07e-7,800/RT[ AN]2.0The zero order dependence on PPAO and thiourea concentrations and the lowest value of the collision frequence factor were considered to be a feature of the primary radical termination.
The polymerization of acrylonitrile (AN) initiated by polypropylene based-polyamidoxime (PPAO)-thiourea (TU) system was investigated at [TU]/[PPAO]>0.5 molar ratio. It shows that the variation of the concentrations of PPAO, thiourea and nitric acid does not exert an observable influence on the reaction rate. The overall rate of polymerization (Rp) isRp = 2.07e-7,800/RT[ AN]2.0The zero order dependence on PPAO and thiourea concentrations and the lowest value of the collision frequence factor were considered to be a feature of the primary radical termination.
1993, 11(3): 262-266
Abstract:
This paper reports the synthesis of methoxyoligo (oxyethylene) methacrylate (MEOn, n is the repeating unit number of (CH2CH2O) in the macromonomer), and its polymerization in different solvents. MEOn is prepared through such two independent reactions as (1) anionic polymerization of oxirane initiated by potassium alkoxide and (2) end-capping of methoxy oligo(oxyethylene) by methacrylic group. The n value can be conveniently controlled over the range of 5 ～ 30 by varying the molar ratio of oxirane to intiator and the molecular weight distribution of MEOn be narrowed by increasing reaction time only in step(1).MEOn thus obtained shows a rapid polymerization in water and benzene respectively,and both give water-soluble polymers as long as suitable conditions are used.
This paper reports the synthesis of methoxyoligo (oxyethylene) methacrylate (MEOn, n is the repeating unit number of (CH2CH2O) in the macromonomer), and its polymerization in different solvents. MEOn is prepared through such two independent reactions as (1) anionic polymerization of oxirane initiated by potassium alkoxide and (2) end-capping of methoxy oligo(oxyethylene) by methacrylic group. The n value can be conveniently controlled over the range of 5 ～ 30 by varying the molar ratio of oxirane to intiator and the molecular weight distribution of MEOn be narrowed by increasing reaction time only in step(1).MEOn thus obtained shows a rapid polymerization in water and benzene respectively,and both give water-soluble polymers as long as suitable conditions are used.
1993, 11(3): 267-272
Abstract:
Complexes of comb-shaped polyether and lithium aromatic sulfonates bearing different negative charge number were prepared by in situ thermal polymerization. Their conductivity depends deeply on salt content, ambient temperature and negative charge number of the added salts. Results show that anions can be partly immobilized by increasing their negative charges at lower temperature. Against discharge time the short circuit current of the battery (Li/complex film/Lix V3O8) is stabilized by increasing the anionic charge number of the complex.
Complexes of comb-shaped polyether and lithium aromatic sulfonates bearing different negative charge number were prepared by in situ thermal polymerization. Their conductivity depends deeply on salt content, ambient temperature and negative charge number of the added salts. Results show that anions can be partly immobilized by increasing their negative charges at lower temperature. Against discharge time the short circuit current of the battery (Li/complex film/Lix V3O8) is stabilized by increasing the anionic charge number of the complex.
1993, 11(3): 273-278
Abstract:
The bulk polymerization of benzonitrile catalyzed by Co(Ⅱ), Co(Ⅲ) and Fe(Ⅲ) acetylacetonate was studied. The results of kinetics study show that the rate of polymerization was proportional to first power of the concentration of catalyst and second power of the concentration of monomer.
The bulk polymerization of benzonitrile catalyzed by Co(Ⅱ), Co(Ⅲ) and Fe(Ⅲ) acetylacetonate was studied. The results of kinetics study show that the rate of polymerization was proportional to first power of the concentration of catalyst and second power of the concentration of monomer.
1993, 11(3): 279-283
Abstract:
Ethyl cellulose (EC), taken as a thermotropic liquid crystalline polymer, was blended with polypropylene (PP), followed by injection molding. Fibre-forming of EC in the PP matrix is analyzed,based on the rheological data,dynamic mechanical analysis and fracture micrographs of EC/PP blends. The addition of maleated PP, for the modification of the interphasial interaction between the PP matrix and the EC fibrils, did not impair the fiber formation substantially.
Ethyl cellulose (EC), taken as a thermotropic liquid crystalline polymer, was blended with polypropylene (PP), followed by injection molding. Fibre-forming of EC in the PP matrix is analyzed,based on the rheological data,dynamic mechanical analysis and fracture micrographs of EC/PP blends. The addition of maleated PP, for the modification of the interphasial interaction between the PP matrix and the EC fibrils, did not impair the fiber formation substantially.
1993, 11(3): 284-291
Abstract:
Controlled release of TDI and hence the cure characteristics of several blocked TDI with HTPB are reported. The reactions were followed through viscosity measurements as a function of time and temperature under the catalytic influence of triethylamine. The effect of nature of substituents present on the end capping substrate, temperature, solvent, basicity of catalyst and kinetics thereon have been studied.
Controlled release of TDI and hence the cure characteristics of several blocked TDI with HTPB are reported. The reactions were followed through viscosity measurements as a function of time and temperature under the catalytic influence of triethylamine. The effect of nature of substituents present on the end capping substrate, temperature, solvent, basicity of catalyst and kinetics thereon have been studied.
