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1988 Volume 6 Issue 3
1988, 6(3): 193-198
Abstract:
In order to study the miscibility of a copolymer with its corresponding homopolymers, varieties of multicomponent polymers including simple graft, muhibranch, diblock, triblock and four-arm block copolymers and so-called ABCPs were synthesized and characterized. The morphologies of the blends comprising the copolymers and the corresponding homopolymers were examined by electron microscopy. It is concluded that besides molecular weight, architecture of a copolypaers has apparent effect on the miscibility, i.e. the more complex is molecular architecture,the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains.In addition,a density gradient model is suggested for describing the segment distribution of the bound and free chains in block-homopolymer systems.Using this model,Helfand's theory is extended to the blends of copolymer and homopolymer predicting the miscibility which is in good agreement with the experimental results.
In order to study the miscibility of a copolymer with its corresponding homopolymers, varieties of multicomponent polymers including simple graft, muhibranch, diblock, triblock and four-arm block copolymers and so-called ABCPs were synthesized and characterized. The morphologies of the blends comprising the copolymers and the corresponding homopolymers were examined by electron microscopy. It is concluded that besides molecular weight, architecture of a copolypaers has apparent effect on the miscibility, i.e. the more complex is molecular architecture,the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains.In addition,a density gradient model is suggested for describing the segment distribution of the bound and free chains in block-homopolymer systems.Using this model,Helfand's theory is extended to the blends of copolymer and homopolymer predicting the miscibility which is in good agreement with the experimental results.
1988, 6(3): 199-207
Abstract:
Formation of intermacromolecular complexes containing viologen and electron-transfer reaction occurred on the electrode modified by the complex films were studied. Compositions and morphology of the complexes depend on the properties of polyanion and chemical environment of complexation. The analytical results of cyclic voltammetry (CV) and rotating disk voltammetry(RDV) indicated: (1) active sites of viologen in network of complexes transferred single electron reversibly; (2) the redox peak currents showed excellent symmetry and stability;(3)redox potentials were related to properties of polyanions,varying from-0.4 to -0.6V(vs.SCE).Electrochromic materials with different displaying colors could be obtained by changing the structure of polyviologen.
Formation of intermacromolecular complexes containing viologen and electron-transfer reaction occurred on the electrode modified by the complex films were studied. Compositions and morphology of the complexes depend on the properties of polyanion and chemical environment of complexation. The analytical results of cyclic voltammetry (CV) and rotating disk voltammetry(RDV) indicated: (1) active sites of viologen in network of complexes transferred single electron reversibly; (2) the redox peak currents showed excellent symmetry and stability;(3)redox potentials were related to properties of polyanions,varying from-0.4 to -0.6V(vs.SCE).Electrochromic materials with different displaying colors could be obtained by changing the structure of polyviologen.
1988, 6(3): 208-215
Abstract:
Poly(phthalocyaninatosiloxane), [Si(Pc)O]n, with the number average degree of polymerization of about 130 was prepared by heating its monomer Si(Pc) (OH)2, in solid state at 420℃ for 42 hrs at 10-3 torr dynamic vacuum. The [Si(Pc)O]n powder was iodine doped with I2-bensene solution for 48 hrs. Pure iodine doped poly(phthalocyaninatosiloxune), {[Si(Pc)O]Iy}n, fibers and {[Si(Pc)O]Iy}n/poly(p-pbenylene terephthalamide) blend fibers were wet-spun with dry nitrogen-sealed Teflon lined device. D.C. electrical conductivity of the fibers was measured by the four-probe method with an automated charge transport measurement system from 80K to room temperature.It was found that the dependence of conductivity,σ on temperature,T,could fit a group of thermal fluctuation-induced tunnelling(TFIT) equations,and that the dependence of conductivity on volume fraction,φ,of the iodine doped{[Si(Pc)O]Iy}n could fit a group of modified percolation equations.A three-dimensional composite composite polt of σ-1/T-φ shows that these two groups of equations match each other quite well.It has been pointed out that for the blend fibers their composition is the most important factor for both mechanical and electrical properties.
Poly(phthalocyaninatosiloxane), [Si(Pc)O]n, with the number average degree of polymerization of about 130 was prepared by heating its monomer Si(Pc) (OH)2, in solid state at 420℃ for 42 hrs at 10-3 torr dynamic vacuum. The [Si(Pc)O]n powder was iodine doped with I2-bensene solution for 48 hrs. Pure iodine doped poly(phthalocyaninatosiloxune), {[Si(Pc)O]Iy}n, fibers and {[Si(Pc)O]Iy}n/poly(p-pbenylene terephthalamide) blend fibers were wet-spun with dry nitrogen-sealed Teflon lined device. D.C. electrical conductivity of the fibers was measured by the four-probe method with an automated charge transport measurement system from 80K to room temperature.It was found that the dependence of conductivity,σ on temperature,T,could fit a group of thermal fluctuation-induced tunnelling(TFIT) equations,and that the dependence of conductivity on volume fraction,φ,of the iodine doped{[Si(Pc)O]Iy}n could fit a group of modified percolation equations.A three-dimensional composite composite polt of σ-1/T-φ shows that these two groups of equations match each other quite well.It has been pointed out that for the blend fibers their composition is the most important factor for both mechanical and electrical properties.
1988, 6(3): 216-222
Abstract:
The thermal behaviour of γ-irradiated nylon 610 was investigated. In DSC (differential scanning calorimetry) thermograms in addition to general features characteristic of γ-irradiatinn cross-linked crystalline polymers, a typical cold-crystallization phenomenon was observed during the sceond scan for samples that had been subjected to high radiation dose. G-values for cresslinking nylon 610 were estimated from gel fraction measurement and TMA (thermomechanical analysis), From TMA curves it was estimated that the dimensional stability of properly irradiated nylon 610 articles might be raised up to ca.300℃。
The thermal behaviour of γ-irradiated nylon 610 was investigated. In DSC (differential scanning calorimetry) thermograms in addition to general features characteristic of γ-irradiatinn cross-linked crystalline polymers, a typical cold-crystallization phenomenon was observed during the sceond scan for samples that had been subjected to high radiation dose. G-values for cresslinking nylon 610 were estimated from gel fraction measurement and TMA (thermomechanical analysis), From TMA curves it was estimated that the dimensional stability of properly irradiated nylon 610 articles might be raised up to ca.300℃。
1988, 6(3): 223-229
Abstract:
The radical copolymerizations of 2,2,6, 6-tetramethyl 4-piperidinyl methacrylate (TMPM) with styrene in various solvents have been studied. The monomer reactivity ratios r1 and r2 were determined. It is observed that in all of these reaction systems, there are appreciable solvent effects on both r1 and r2, which can be correlated to the difference in chemical shifts of olefinic protons of TMPM. And the variance of the copolymer microstructure in various media was discussed.
The radical copolymerizations of 2,2,6, 6-tetramethyl 4-piperidinyl methacrylate (TMPM) with styrene in various solvents have been studied. The monomer reactivity ratios r1 and r2 were determined. It is observed that in all of these reaction systems, there are appreciable solvent effects on both r1 and r2, which can be correlated to the difference in chemical shifts of olefinic protons of TMPM. And the variance of the copolymer microstructure in various media was discussed.
1988, 6(3): 230-235
Abstract:
The fracture surfaces of a number of silicone vulcanizates were investigated by the use of scanning electron microscopy (SEM). It was found that the difference in the presence and absence of filler, the variation of its surface modification as well as the history of thermal aging of the vulcanizates, all of these factors made difference in surface morphology of the fractured surface. This was correlated with the strength of the vulcanizates. The reinforcing effect of filler and the process of fracture were discussed.
The fracture surfaces of a number of silicone vulcanizates were investigated by the use of scanning electron microscopy (SEM). It was found that the difference in the presence and absence of filler, the variation of its surface modification as well as the history of thermal aging of the vulcanizates, all of these factors made difference in surface morphology of the fractured surface. This was correlated with the strength of the vulcanizates. The reinforcing effect of filler and the process of fracture were discussed.
1988, 6(3): 236-243
Abstract:
Textures of the oriented mesomorphic solutions of cyanoethyl celluloss/dimethyl acetamide were studied by polarized light microscopy, small angle light scattering and depolarized light transmission. If the mesomorphic solutions were sheared, they could form the band-like texture. Molecular chains in the solutions highly oriented almost along the shear direction. But the orientation directions of the molecular chains in the bands neighbouring each other were slightly different.
Textures of the oriented mesomorphic solutions of cyanoethyl celluloss/dimethyl acetamide were studied by polarized light microscopy, small angle light scattering and depolarized light transmission. If the mesomorphic solutions were sheared, they could form the band-like texture. Molecular chains in the solutions highly oriented almost along the shear direction. But the orientation directions of the molecular chains in the bands neighbouring each other were slightly different.
1988, 6(3): 244-250
Abstract:
In this paper, a series of interpenetrating polymer networks (IPNs) based on polyurethane acrylate and epoxy resin was prepared by simultaneous photoinitiating by both free-radical and cationic polymerization. The effects of the polyurethane acrylate prepolymer's molecular weight, various components ratio and polymerization methods on IPN's dynamic mechanical and mechanical properties were investigated.
In this paper, a series of interpenetrating polymer networks (IPNs) based on polyurethane acrylate and epoxy resin was prepared by simultaneous photoinitiating by both free-radical and cationic polymerization. The effects of the polyurethane acrylate prepolymer's molecular weight, various components ratio and polymerization methods on IPN's dynamic mechanical and mechanical properties were investigated.
1988, 6(3): 251-256
Abstract:
The polymerization kinetics of benzonitrile were studied, and the formation rate constants of s-triazine structure and linear polymer were determined. The influence of polymerization temperature and the amount of zinc chloride as catalyst on the ratio of linear to cyclic structure were also investigated, and the obtained results were discussed.
The polymerization kinetics of benzonitrile were studied, and the formation rate constants of s-triazine structure and linear polymer were determined. The influence of polymerization temperature and the amount of zinc chloride as catalyst on the ratio of linear to cyclic structure were also investigated, and the obtained results were discussed.
1988, 6(3): 257-265
Abstract:
This paper describes the preparation and Langmuir-Blodgett (LB) monomolecular film formation of H2, Cu, Ni, Co, and Zn phthaloeyanine compounds with p-vinyiphenoxy peripheral substituent on each benzo ring at either 2- or 3- position [i.e., tetra (p-vinylphenoxy) substituted isomer mixture]. These phthalocyanine derivatives form stable LB films at the film pressures greater than 10 dynes/cm. The surface pressure-area isotherms indicate that the phthalocyanine units are densely packed with a eofacial orientation.Schottky cells of [Indium-Tin Oxide/LB film/Al] were prepared and their electronic properties were examined.Much better rectifying properties,diode parameter,break-down potential and mechanical strength were notified by the post-polymerization of LB-layers.On exposing the polymerized films to tetrahydrofuran vapor,the absorption maxima of Q-band shift bathochromically by about 100nm,being sensitive to diode laser light.
This paper describes the preparation and Langmuir-Blodgett (LB) monomolecular film formation of H2, Cu, Ni, Co, and Zn phthaloeyanine compounds with p-vinyiphenoxy peripheral substituent on each benzo ring at either 2- or 3- position [i.e., tetra (p-vinylphenoxy) substituted isomer mixture]. These phthalocyanine derivatives form stable LB films at the film pressures greater than 10 dynes/cm. The surface pressure-area isotherms indicate that the phthalocyanine units are densely packed with a eofacial orientation.Schottky cells of [Indium-Tin Oxide/LB film/Al] were prepared and their electronic properties were examined.Much better rectifying properties,diode parameter,break-down potential and mechanical strength were notified by the post-polymerization of LB-layers.On exposing the polymerized films to tetrahydrofuran vapor,the absorption maxima of Q-band shift bathochromically by about 100nm,being sensitive to diode laser light.
1988, 6(3): 266-273
Abstract:
The copolymerization of six 2-substituted 4-methylene-1, 3-dioxolane with aerylonitrile(AN) gives rise spontaneously to the alternating copolymers by the participation of charge-transfer(CT) complexes. The structures of copolymers was ascertained by their IR,1H and 13C NMR spectra, etc.. The electron effect of suhstituents on 2-position of monomer 2 is the most important factor in predicting the reactivity of CT complexes. However the steric effect determines the ring-opening degree of monomer 2. The spontaneous copolymerization mechanism has been discussed.
The copolymerization of six 2-substituted 4-methylene-1, 3-dioxolane with aerylonitrile(AN) gives rise spontaneously to the alternating copolymers by the participation of charge-transfer(CT) complexes. The structures of copolymers was ascertained by their IR,1H and 13C NMR spectra, etc.. The electron effect of suhstituents on 2-position of monomer 2 is the most important factor in predicting the reactivity of CT complexes. However the steric effect determines the ring-opening degree of monomer 2. The spontaneous copolymerization mechanism has been discussed.
1988, 6(3): 274-281
Abstract:
The morphology of a special blend system composed of liquid crystalline aromatic random copolyester (LCP) and semiflexible polyester PET over the whole composition range has been studied by means of polarized microscope, density measurement, DSC, FTIR and SEM. Based on the microscopic observation, it is found that under suitable mechanical mixing condition, LCP may be rather homogeneously dispersed in the PET matrix, with the middle composition range of the contents of LCP at 30--70 wt % the anisotropic and isotropic phase segregation appears.while with LCP contents over 80 wt% the blends exhibit wholly anisotropic.The DSC thermographs of the melt-pressed and quenched films show single Tg,Tcc and T m,Tg increases with increasing with increasing content of LCP and approaches to the Tg of pure LCP.The experimental results indicate that the two components of this blend system are miscible,there exist some specific interactions between them.
The morphology of a special blend system composed of liquid crystalline aromatic random copolyester (LCP) and semiflexible polyester PET over the whole composition range has been studied by means of polarized microscope, density measurement, DSC, FTIR and SEM. Based on the microscopic observation, it is found that under suitable mechanical mixing condition, LCP may be rather homogeneously dispersed in the PET matrix, with the middle composition range of the contents of LCP at 30--70 wt % the anisotropic and isotropic phase segregation appears.while with LCP contents over 80 wt% the blends exhibit wholly anisotropic.The DSC thermographs of the melt-pressed and quenched films show single Tg,Tcc and T m,Tg increases with increasing with increasing content of LCP and approaches to the Tg of pure LCP.The experimental results indicate that the two components of this blend system are miscible,there exist some specific interactions between them.
1988, 6(3): 282-284
Abstract:
A bulk photopolymerization of methyl methacryhte (MMA) initiated by 3-benzolocoumarin (Sen. 1)——triethylamine (TEA) coinitiated has been studied. Results were compared with a well known photoinitiator system, benzopbenone (BP)——TEA. The mechanism of the reaction has been discussed.
A bulk photopolymerization of methyl methacryhte (MMA) initiated by 3-benzolocoumarin (Sen. 1)——triethylamine (TEA) coinitiated has been studied. Results were compared with a well known photoinitiator system, benzopbenone (BP)——TEA. The mechanism of the reaction has been discussed.
1988, 6(3): 285-288
Abstract:
The photo-oxidative degradation process of polypropylene film containing iron ions was investigated via FTIR and absorbance substraction technique. It is shown that the iron ions play an important role in the decomposition of hydroperoxide and the increase of the degradation rate of polypropylene film. The amorphous region of PP film undergoes degradation prior to the crystalline one.
The photo-oxidative degradation process of polypropylene film containing iron ions was investigated via FTIR and absorbance substraction technique. It is shown that the iron ions play an important role in the decomposition of hydroperoxide and the increase of the degradation rate of polypropylene film. The amorphous region of PP film undergoes degradation prior to the crystalline one.
