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1994 Volume 12 Issue 4
1994, 12(4): 289-295
Abstract:
Polysiloxane-polystyrene composite latexes were prepared by two-stage emulsionpolymerization. Polymerization of styrene in swollen polysiloxane latex particles were studied.Formation of simple polystyrene particle in the 2nd-stage polymerization depends on the particlesize of the lst-stage latex and the polymerization temperature. Polystyrene domains in thevulcanizates reinforce the silicone rubbers effectively.
Polysiloxane-polystyrene composite latexes were prepared by two-stage emulsionpolymerization. Polymerization of styrene in swollen polysiloxane latex particles were studied.Formation of simple polystyrene particle in the 2nd-stage polymerization depends on the particlesize of the lst-stage latex and the polymerization temperature. Polystyrene domains in thevulcanizates reinforce the silicone rubbers effectively.
1994, 12(4): 296-301
Abstract:
Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of the multicomponent polymers were derived in terms of WAXDtheory and improved graphic multipeak resolution methods. The results calculated aresatisfactory in comparison with the density measurement.
Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of the multicomponent polymers were derived in terms of WAXDtheory and improved graphic multipeak resolution methods. The results calculated aresatisfactory in comparison with the density measurement.
1994, 12(4): 302-308
Abstract:
Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line 1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.
Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line 1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.
1994, 12(4): 309-315
Abstract:
The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO3blends are investigated. Not all HDPE can be toughened by CaCO3 particles. The ability of thematrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (Isc≈45J/m) below which HDPE can not be toughenedobservably by CaCO3 particle at given average size, and above which the critical matrix ligamentthickness (τc) is proportional to matrix impact strength.
The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO3blends are investigated. Not all HDPE can be toughened by CaCO3 particles. The ability of thematrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (Isc≈45J/m) below which HDPE can not be toughenedobservably by CaCO3 particle at given average size, and above which the critical matrix ligamentthickness (τc) is proportional to matrix impact strength.
1994, 12(4): 316-322
Abstract:
The title polymer was prepared from 5-diethylamino-3-thia-pentyl glycidyl ether anddiethylene glycol bisglycidyl ether via ring-opening copolymerization. It was found that thisreaction could be catalyzed by sodium, but not Lewis acid. The obtained polymer can coordinatewith platinum compound, and the platinum complex is a new kind of catalyst for thehydrosilylation of olefins with triethoxysilane.
The title polymer was prepared from 5-diethylamino-3-thia-pentyl glycidyl ether anddiethylene glycol bisglycidyl ether via ring-opening copolymerization. It was found that thisreaction could be catalyzed by sodium, but not Lewis acid. The obtained polymer can coordinatewith platinum compound, and the platinum complex is a new kind of catalyst for thehydrosilylation of olefins with triethoxysilane.
1994, 12(4): 323-330
Abstract:
The adsorption of protein on nanoparticles was studied by using dynamic light scattering tomeasure the hydrodynamic size of both pure protein and nanoparticles adsorbed with differentamounts of protein. The thickness of the adsorbed protein layer increases as proteinconcentration, but decreases as the initial size of nanoparticles. After properly scaling thethickness with the initial diameter, we are able to fit all experimental data with a single mastercurve. Our experimental results suggest that the adsorbed proteins form a monolayer on the nanoparticle surface and the adsorbed protein molecules are attached to the particle surface at many points through a possible hydrogen-bonding.Our results also indicate that as protein concentration increases,the overall shape of the adsorbed protein molecule continuously changes from a flat layer on the particle surface to a stretched coil extended into water.During the change,the hydrodynamic volume of the adsorbed protein increases linearly with protein concentration.
The adsorption of protein on nanoparticles was studied by using dynamic light scattering tomeasure the hydrodynamic size of both pure protein and nanoparticles adsorbed with differentamounts of protein. The thickness of the adsorbed protein layer increases as proteinconcentration, but decreases as the initial size of nanoparticles. After properly scaling thethickness with the initial diameter, we are able to fit all experimental data with a single mastercurve. Our experimental results suggest that the adsorbed proteins form a monolayer on the nanoparticle surface and the adsorbed protein molecules are attached to the particle surface at many points through a possible hydrogen-bonding.Our results also indicate that as protein concentration increases,the overall shape of the adsorbed protein molecule continuously changes from a flat layer on the particle surface to a stretched coil extended into water.During the change,the hydrodynamic volume of the adsorbed protein increases linearly with protein concentration.
1994, 12(4): 331-336
Abstract:
Samples of polyphenylsilsisquioxane (PPSQ)using CaF2 or MgF2 as the main catalysts hadbeen prepared under different polymerization conditions. The results were treated on anorthogonal design L9 (34). All weight-average molecular weights (MW ) of PPSQ had beenmeasured by gel permeation chromatography (GPC). Effects of polymerization conditionsincluding reaction temperature, composition of the dual catalysts (CaF2 or MgF2 and DCC),mixture of solvents and reaction time on MW of PPSQ have been discussed.The quantity of the catalysts is the most important factor that affects MW of PPSQ.Reaction temperature is the second important factor.Appropriate polymerization condition has been established to get PPSQ with high Mw.
Samples of polyphenylsilsisquioxane (PPSQ)using CaF2 or MgF2 as the main catalysts hadbeen prepared under different polymerization conditions. The results were treated on anorthogonal design L9 (34). All weight-average molecular weights (MW ) of PPSQ had beenmeasured by gel permeation chromatography (GPC). Effects of polymerization conditionsincluding reaction temperature, composition of the dual catalysts (CaF2 or MgF2 and DCC),mixture of solvents and reaction time on MW of PPSQ have been discussed.The quantity of the catalysts is the most important factor that affects MW of PPSQ.Reaction temperature is the second important factor.Appropriate polymerization condition has been established to get PPSQ with high Mw.
1994, 12(4): 337-344
Abstract:
The transitions and morphology of a series of main-chain liquid crystalline polymer with X-shaped mesogens were studied by means of DSC,SALS and polarizing microscopy techniques. Aneven-odd effect was observed for samples with different size of the substituents on the mesogenends. The isotropization process was similar to that of main-chain polymers with rod-likemesogens. No crystallization was detected for specimens cooling down from their isotropic meltstate. However two of the samples may crystallize in cooling process directly from the liquid srystalline state.
The transitions and morphology of a series of main-chain liquid crystalline polymer with X-shaped mesogens were studied by means of DSC,SALS and polarizing microscopy techniques. Aneven-odd effect was observed for samples with different size of the substituents on the mesogenends. The isotropization process was similar to that of main-chain polymers with rod-likemesogens. No crystallization was detected for specimens cooling down from their isotropic meltstate. However two of the samples may crystallize in cooling process directly from the liquid srystalline state.
1994, 12(4): 345-351
Abstract:
The ionic transport process in polymer electrolytes (such as polyethylene oxide) wassimulated numerically on a two dimensional square lattice where charge carriers areaccommodated by the lattice sites connected randomly with available bonds to represent theamorphous chain configuration. Following the dynamic bond percolation theory(DBPT),the chainmotion contribution to the ionic conduction was incorporated via periodical renewal of the randombond configuration. To check and extend the prediction made by DBPT employing global abrupt bond renewal,spatial correlation of the bond reassignment was introduced to the system by:1）regional bond renewal and 2) organized bond motion.It is found that the difference between the diffusivities simulated involving regional bond renewal and those of DBPT becomes negligible when the bond renewal rate approaches the carrier hopping rate.
The ionic transport process in polymer electrolytes (such as polyethylene oxide) wassimulated numerically on a two dimensional square lattice where charge carriers areaccommodated by the lattice sites connected randomly with available bonds to represent theamorphous chain configuration. Following the dynamic bond percolation theory(DBPT),the chainmotion contribution to the ionic conduction was incorporated via periodical renewal of the randombond configuration. To check and extend the prediction made by DBPT employing global abrupt bond renewal,spatial correlation of the bond reassignment was introduced to the system by:1）regional bond renewal and 2) organized bond motion.It is found that the difference between the diffusivities simulated involving regional bond renewal and those of DBPT becomes negligible when the bond renewal rate approaches the carrier hopping rate.
1994, 12(4): 352-357
Abstract:
A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed bypolycondensation with silanol-terminated polydimethylsiloxane to give the title crownfunctionalized linear polysiloxane. It was found that the polysiloxane could be coordinated withplatinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins withtriethoxysilane efficiently.
A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed bypolycondensation with silanol-terminated polydimethylsiloxane to give the title crownfunctionalized linear polysiloxane. It was found that the polysiloxane could be coordinated withplatinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins withtriethoxysilane efficiently.
1994, 12(4): 358-365
Abstract:
The thermal decomposition kinetics of urushiol-Cu, urushiol-Nd and urushiol-Ti chelatepolymers has been studied by non-isothermal thermogravimetry. The results suggest that thethermal decomposition kinetics of three chelate polymers are all of first order. Their averageactivation energy values of the thermal decomposition calculated by Ozawa-(I) method are 110,79, 136. 98 and 163. 64 kJ mol-1 respectively, which increase linearly with the metal valence of themetal chelate polymers
The thermal decomposition kinetics of urushiol-Cu, urushiol-Nd and urushiol-Ti chelatepolymers has been studied by non-isothermal thermogravimetry. The results suggest that thethermal decomposition kinetics of three chelate polymers are all of first order. Their averageactivation energy values of the thermal decomposition calculated by Ozawa-(I) method are 110,79, 136. 98 and 163. 64 kJ mol-1 respectively, which increase linearly with the metal valence of themetal chelate polymers
1994, 12(4): 366-371
Abstract:
The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH3 (CH3),OCH2CH--CH2 modified PET. The rate of dye diffusion (diffusion coefficient D) hasbeen related to the time-dependent mechanical property, dynamic loss modulus E", which iscontrolled by the mobility of chain segments. In this modified copolyester system, the variance ofamount of modifier in the copolyester fibers causes the change in disperse dye diffusion coefficient to fiber,and in the dynamic loss modulus of the fibers,but the relationship between the diffusion and the dynamic loss modulus is in agreement with the theoretical relation derived by Bell and Dumbleton.The relation obtained in this paper is :LnD=-2.28LnE>′′+26.81.
The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH3 (CH3),OCH2CH--CH2 modified PET. The rate of dye diffusion (diffusion coefficient D) hasbeen related to the time-dependent mechanical property, dynamic loss modulus E", which iscontrolled by the mobility of chain segments. In this modified copolyester system, the variance ofamount of modifier in the copolyester fibers causes the change in disperse dye diffusion coefficient to fiber,and in the dynamic loss modulus of the fibers,but the relationship between the diffusion and the dynamic loss modulus is in agreement with the theoretical relation derived by Bell and Dumbleton.The relation obtained in this paper is :LnD=-2.28LnE>′′+26.81.
SYNTHESIS AND ANIONIC POLYMERIZATION OF 2-METHYL-2-METHOXY CARBONYL-5-METHYLENE-1, 3-DIOXOLAN-4-ONE*
1994, 12(4): 372-378
Abstract:
A new cyclic monomer, 2-methyl-2-methocycarbonyl-5-methylene 1,3-dioxlan-4-one,wassynthesized successfully. The monomer and intermediate were characterized by 1H NMR,13C NMR, INEPT (Intensive Nuclei Enhanced by Polarization Transfer) technique, IR andelemental analysis. Anionic polymerization of the monomer was carried out in anhydrous THF at.70℃, and 9-fluorenyllithium was used as initiator. The polymer strucure was determined byIR, NMR and elemental analysis. Molecular weight of the polymer was estimated by viscosity measurement in DMSO at 30℃.
A new cyclic monomer, 2-methyl-2-methocycarbonyl-5-methylene 1,3-dioxlan-4-one,wassynthesized successfully. The monomer and intermediate were characterized by 1H NMR,13C NMR, INEPT (Intensive Nuclei Enhanced by Polarization Transfer) technique, IR andelemental analysis. Anionic polymerization of the monomer was carried out in anhydrous THF at.70℃, and 9-fluorenyllithium was used as initiator. The polymer strucure was determined byIR, NMR and elemental analysis. Molecular weight of the polymer was estimated by viscosity measurement in DMSO at 30℃.
1994, 12(4): 379-384
Abstract:
Optically active copolymers of pairs of three monomers, triphenyl (methyl methacrylate)and one or two pyridyl substituted methyl methacrylate homologues, were obtained by helix-sense-selective copolymerization using complexes of organolithium with chiral ligand as anionicinitiators in toluene at low temperature. The copolymers obtained with (-)-sparteine (Sp) and(S,S)-(+)-and (R, R)-(-)-2, 3-dimethoxy-1, 4-bis (dimethylamino) butanes((+)-and (-)-DDB) complexes of organolithium showed low optical activity, but PMP complex with N,N-diphenylethyleneamine monolithium amide (PMP-DPEDA-Li) was effective in synthesizing copolymers of high optical rotation ([α]D25 about+320～370°)which were comparable to those of relative homopolymers with one-handed helical astructure.
Optically active copolymers of pairs of three monomers, triphenyl (methyl methacrylate)and one or two pyridyl substituted methyl methacrylate homologues, were obtained by helix-sense-selective copolymerization using complexes of organolithium with chiral ligand as anionicinitiators in toluene at low temperature. The copolymers obtained with (-)-sparteine (Sp) and(S,S)-(+)-and (R, R)-(-)-2, 3-dimethoxy-1, 4-bis (dimethylamino) butanes((+)-and (-)-DDB) complexes of organolithium showed low optical activity, but PMP complex with N,N-diphenylethyleneamine monolithium amide (PMP-DPEDA-Li) was effective in synthesizing copolymers of high optical rotation ([α]D25 about+320～370°)which were comparable to those of relative homopolymers with one-handed helical astructure.
