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1993 Volume 11 Issue 4
1993, 11(4): 293-299
Abstract:
Acrylonitrile (AN)-chlorinated polyethylene (CPE)-styrene (St) (ACS) terpolymer was synthesized by suspension-swelling graft copolymerization method, in which two key factors such as dispersing system and time were studied. Highly effective comples dispersing system was chosen and determined, and two-layer protection model was put forward to clarify the stable effect mechanism Varying the swelling time of CPE in AN and St monomer mixture, some results such as grafting effect, particle characteristics, rubber particle morphology and its size distribution,and properties of ACS resins were investigated,thus the optimum swelling time was proposed.
Acrylonitrile (AN)-chlorinated polyethylene (CPE)-styrene (St) (ACS) terpolymer was synthesized by suspension-swelling graft copolymerization method, in which two key factors such as dispersing system and time were studied. Highly effective comples dispersing system was chosen and determined, and two-layer protection model was put forward to clarify the stable effect mechanism Varying the swelling time of CPE in AN and St monomer mixture, some results such as grafting effect, particle characteristics, rubber particle morphology and its size distribution,and properties of ACS resins were investigated,thus the optimum swelling time was proposed.
1993, 11(4): 300-306
Abstract:
A novel class of aromatic polyimide-silicone segmented copolymer was synthesized with α, ω-bis (γ-aminopropyl) polydimethyldiphenylsiloxane (APMPS) as a silicone segment precursor, from which the segmented polyamic acid-b-silicone intermediate could be prepared simply with DMF as solvent. The segmented copolymer displays microphase separation and exhibits improved antithrombogenicity, which depends mainly upon both the content level and the DP of the silicone segment. Thermal stability and mechanical property of the copolymer are between that of the aromatic polyimide and the silicone,and also relate to both the content level and the DP of the silicone segment.
A novel class of aromatic polyimide-silicone segmented copolymer was synthesized with α, ω-bis (γ-aminopropyl) polydimethyldiphenylsiloxane (APMPS) as a silicone segment precursor, from which the segmented polyamic acid-b-silicone intermediate could be prepared simply with DMF as solvent. The segmented copolymer displays microphase separation and exhibits improved antithrombogenicity, which depends mainly upon both the content level and the DP of the silicone segment. Thermal stability and mechanical property of the copolymer are between that of the aromatic polyimide and the silicone,and also relate to both the content level and the DP of the silicone segment.
1993, 11(4): 307-315
Abstract:
New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer chains. The relationship between the intramolecular orientational order parameter and the molecular geometrical parameters such as the bond angle, the bond rotational angle and the rotational potential energy of chemical bonds was deduced. A significant even-odd oscillation of the intramolecular orientational order parameter of LCPswith different length of flexible spacer was found and rationally related to even-odd zig-zag manner of transition properties.The venification and application of the theory are also discussed.The isotropic transition temperature predicted by the theory is shown to be in favourable agreement with the experiments.
New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer chains. The relationship between the intramolecular orientational order parameter and the molecular geometrical parameters such as the bond angle, the bond rotational angle and the rotational potential energy of chemical bonds was deduced. A significant even-odd oscillation of the intramolecular orientational order parameter of LCPswith different length of flexible spacer was found and rationally related to even-odd zig-zag manner of transition properties.The venification and application of the theory are also discussed.The isotropic transition temperature predicted by the theory is shown to be in favourable agreement with the experiments.
1993, 11(4): 316-326
Abstract:
Basea on the new model and concept of mtramolecular orientational order parameter, a molecular field theory was built up for main chain liquid crystalline polymer (MC-LCPs) with flexible spacers. The theory takes account of orientational correlation among all mesogens in a polymer chain and the relationship between the intramolecular orientation and spatial orientation of the mesogens. The free energy, temperature and entropy of the nematic-isotropic transition were determined with the theory and compared with experiments in current work.It was found that many unique transition properties of the MC-LCPs comprising flexible spacer are correctly predicted by the theory and the agreement of the theory with the experiments is impressive.
Basea on the new model and concept of mtramolecular orientational order parameter, a molecular field theory was built up for main chain liquid crystalline polymer (MC-LCPs) with flexible spacers. The theory takes account of orientational correlation among all mesogens in a polymer chain and the relationship between the intramolecular orientation and spatial orientation of the mesogens. The free energy, temperature and entropy of the nematic-isotropic transition were determined with the theory and compared with experiments in current work.It was found that many unique transition properties of the MC-LCPs comprising flexible spacer are correctly predicted by the theory and the agreement of the theory with the experiments is impressive.
1993, 11(4): 327-336
Abstract:
The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by " cage " vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate of polymerization is Rp=9.7×105e-10,500/RT[AN][HNO3]1.5[P=VO]0.50[TU]0.76 The relationship between the induction period (τ) and the temperature of polymerization as well as the concentrations of reactants can be expressed as follows :1/τ=4.6×1012e-13,500/RT[HNO3]3[P=VO][TU]3/2=KτRi The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreases with increasing temperature of polymerization and concentrations of vanadyl polycarboxylate and thiourea Mn=KM1/T·[AN]/[HNO3]3/2[P=VO]1/2[TU]3/4=KM·1/T·Rp/Rt The polymerization mechanism was proposed and discussed.
The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by " cage " vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate of polymerization is Rp=9.7×105e-10,500/RT[AN][HNO3]1.5[P=VO]0.50[TU]0.76 The relationship between the induction period (τ) and the temperature of polymerization as well as the concentrations of reactants can be expressed as follows :1/τ=4.6×1012e-13,500/RT[HNO3]3[P=VO][TU]3/2=KτRi The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreases with increasing temperature of polymerization and concentrations of vanadyl polycarboxylate and thiourea Mn=KM1/T·[AN]/[HNO3]3/2[P=VO]1/2[TU]3/4=KM·1/T·Rp/Rt The polymerization mechanism was proposed and discussed.
1993, 11(4): 337-341
Abstract:
Our objectives were to develop a new chemical method for the polymerization of pyrrole. CuCl2 dissolved in C2H5OH solvent is primarily used for the initiation polymerization of pyrrole. The polymers with different yield and conductivity were obtained by raring the initial concentration of Cu2+. The initial concentrations of Cu2+ varied from 1.2 × 10-4 mole to 6.48 × 10-3 mole Cu2+ with 2.16 × 10-2 mole pyrrole. The polypyrrole obtained was characterized with elemental analyzer, XPS, IR spectroscopy,Four-point probe and SEM.
Our objectives were to develop a new chemical method for the polymerization of pyrrole. CuCl2 dissolved in C2H5OH solvent is primarily used for the initiation polymerization of pyrrole. The polymers with different yield and conductivity were obtained by raring the initial concentration of Cu2+. The initial concentrations of Cu2+ varied from 1.2 × 10-4 mole to 6.48 × 10-3 mole Cu2+ with 2.16 × 10-2 mole pyrrole. The polypyrrole obtained was characterized with elemental analyzer, XPS, IR spectroscopy,Four-point probe and SEM.
1993, 11(4): 342-347
Abstract:
The insertion of 1,1-bis (1′-naphthyl) ethylene monomer unit into the active polystyrene chain end greatly decreased the reactivity of the active chain end to the carbonyl group, and allowed the polymeric chain end to react only with the double bond in N-methacryloyl caprolactam, resulting in N-acylcaprolactam functionalized polystyrene in 100% conversion. New diblock copolymer of polystyrene with polycaprolactam was synthesized by direct reaction of the functionalized polymer with caprolactam without adding additional alkali metal or their caprolactam salts.
The insertion of 1,1-bis (1′-naphthyl) ethylene monomer unit into the active polystyrene chain end greatly decreased the reactivity of the active chain end to the carbonyl group, and allowed the polymeric chain end to react only with the double bond in N-methacryloyl caprolactam, resulting in N-acylcaprolactam functionalized polystyrene in 100% conversion. New diblock copolymer of polystyrene with polycaprolactam was synthesized by direct reaction of the functionalized polymer with caprolactam without adding additional alkali metal or their caprolactam salts.
1993, 11(4): 348-353
Abstract:
A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature Tm (except that with substituent of methoxy) and the clearing temperature Ti of the polymers change regularly with varying of the length of the alkyl substituent groups.
A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature Tm (except that with substituent of methoxy) and the clearing temperature Ti of the polymers change regularly with varying of the length of the alkyl substituent groups.
1993, 11(4): 354-357
Abstract:
The NdCl3/MgCl2 bisupported catalyst was prepared by using NdCl3 ,MgCl2, (CH3)2(CH2)2 OH and TiCl4. It is shown that the structure of bisupported catalyst was different from those of either NdCl3 or MgCl2 single supported catalyst. A peculiar type of kinetic curve for ethylene polymerization was found.
The NdCl3/MgCl2 bisupported catalyst was prepared by using NdCl3 ,MgCl2, (CH3)2(CH2)2 OH and TiCl4. It is shown that the structure of bisupported catalyst was different from those of either NdCl3 or MgCl2 single supported catalyst. A peculiar type of kinetic curve for ethylene polymerization was found.
1993, 11(4): 358-363
Abstract:
Acetone diffusion in polycarbonate was investigated by spin-echo 1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is 13.8nm sec-1(0.05mm/h).
Acetone diffusion in polycarbonate was investigated by spin-echo 1H NMR imaging method at room temperature. The result shows that the diffusion process satisfies Case Ⅱ diffusion. The velocity of diffusion front is 13.8nm sec-1(0.05mm/h).
1993, 11(4): 364-369
Abstract:
The properties of immobilized glucose oxidase (GOD) by the complexes of diethylaminoethyl cellulose(DEAEC) with different polymers, such as polymethylacrylic acid (PMAA), polyacrylic acid (PAA), polystyrene sulfonic acid (PSSA), polyvinylaleohol (PVA), polyethylene oxide (PEO) and styrene-maleic acid copolymer (PSMA) were investigated. The activity of immobilized GOD was obviously influenced by the component of the DEAEC complexes. The relative activity of the immobilized GOD reached to maximum and over 90% of the native GOD,when the DEAEC-PMAA DEAEC-PAA complexes were used as a carrier with the molar ratio of DEAEC and polyacid of about one.Michaelis constants(Km) of the immobilized enzymes of DEAEC-GOD-PMAA and DEAEC-GOD-PAA were determined to be 1.25 and 1.00,respectively.Moreover,the immobilized GOD has a good strage stability and cyclic life.
The properties of immobilized glucose oxidase (GOD) by the complexes of diethylaminoethyl cellulose(DEAEC) with different polymers, such as polymethylacrylic acid (PMAA), polyacrylic acid (PAA), polystyrene sulfonic acid (PSSA), polyvinylaleohol (PVA), polyethylene oxide (PEO) and styrene-maleic acid copolymer (PSMA) were investigated. The activity of immobilized GOD was obviously influenced by the component of the DEAEC complexes. The relative activity of the immobilized GOD reached to maximum and over 90% of the native GOD,when the DEAEC-PMAA DEAEC-PAA complexes were used as a carrier with the molar ratio of DEAEC and polyacid of about one.Michaelis constants(Km) of the immobilized enzymes of DEAEC-GOD-PMAA and DEAEC-GOD-PAA were determined to be 1.25 and 1.00,respectively.Moreover,the immobilized GOD has a good strage stability and cyclic life.
1993, 11(4): 370-374
Abstract:
Four polymer-supported Fe-Co tetrametallic clusters have been prepared by ion exchange and ligand exchange. Their structures were characterized by IR, UV/visible diffuse reflectance spectra and elemental analysis, and by analogy with the reference cluster PhCH2NMe3FeCo3 (CO)2 . The four heterogenous clusters were efficient catalysts in the hydroformylation of 1-hexene, turnover numbers amounted to 823 — 924 with the yield of 83.2—92.4% heptyl aldehydes and ratios of normal aldehyde to iso-aldehyde of 1.2 — 1.6,they are facilitated forming the normal aldehyde in comparison with the homogenous analogus.For the polymer-supported clusters prepared by ion exchange,the polymer-cation parts had no obvious effect on the activity of the cluster anion.The polymer-phosphine substituted cluster prepared by ligand exchange was more stable than the clusters preparedby ion exchange.
Four polymer-supported Fe-Co tetrametallic clusters have been prepared by ion exchange and ligand exchange. Their structures were characterized by IR, UV/visible diffuse reflectance spectra and elemental analysis, and by analogy with the reference cluster PhCH2NMe3FeCo3 (CO)2 . The four heterogenous clusters were efficient catalysts in the hydroformylation of 1-hexene, turnover numbers amounted to 823 — 924 with the yield of 83.2—92.4% heptyl aldehydes and ratios of normal aldehyde to iso-aldehyde of 1.2 — 1.6,they are facilitated forming the normal aldehyde in comparison with the homogenous analogus.For the polymer-supported clusters prepared by ion exchange,the polymer-cation parts had no obvious effect on the activity of the cluster anion.The polymer-phosphine substituted cluster prepared by ligand exchange was more stable than the clusters preparedby ion exchange.
1993, 11(4): 375-379
Abstract:
A well-dispersed metallic palladium catalyst modified by polymer-anchored thioether ligands was used for the hydrogenation of cyclopentadiene to cyclopentene with high activity and selectivity in ambient condition. The evidences to show the modification of catalytic properties by polymer anchored ligands were given.
A well-dispersed metallic palladium catalyst modified by polymer-anchored thioether ligands was used for the hydrogenation of cyclopentadiene to cyclopentene with high activity and selectivity in ambient condition. The evidences to show the modification of catalytic properties by polymer anchored ligands were given.
1993, 11(4): 380-383
Abstract:
A side chain liquid crystalline copolysiloxane, which would show electro-optic effects as known from low mass liquid crystal, was synthesized by hydrosilylation reaction, and the two homologous monomers with different length spacers containing Schiff's base mesogen with—NO2 terminated group were grafted toa polysiloxane main chain. Residual monomer in crude product is effective in reinforcing the response to an electric field over that of pure polymeric liquid crystal.
A side chain liquid crystalline copolysiloxane, which would show electro-optic effects as known from low mass liquid crystal, was synthesized by hydrosilylation reaction, and the two homologous monomers with different length spacers containing Schiff's base mesogen with—NO2 terminated group were grafted toa polysiloxane main chain. Residual monomer in crude product is effective in reinforcing the response to an electric field over that of pure polymeric liquid crystal.
