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1990 Volume 8 Issue 3
1990, 8(3): 197-203
Abstract:
Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃ gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃ and this degradation was studied. From measurements in DMF with unfractionated PVCA a Mark-Houwink equation was obtained:[η](dl g -1)=1.63×10-4M0.736w
Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃ gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃ and this degradation was studied. From measurements in DMF with unfractionated PVCA a Mark-Houwink equation was obtained:[η](dl g -1)=1.63×10-4M0.736w
1990, 8(3): 204-210
Abstract:
A new polyelectrolyte (SPU) has been prepared. It can depress the water-loss of drilling-mud much more effective than the commonly used acrylic polyelectrolytes even in 30% NaCl solution. SPU has phenyl group in the backbone with -SO3- in the side chain while the acrylic polyelectrolytes have C—C and -COO- respectively, there exists an intrinsic relationship between the structure of polymer and its tolerance to salts, it has been found: 1) The adsorption amount of polymer on clay is related closely to the flexibility of polymer chain.2)The salt-tolerance of -SO3- is superior to -COO-.3) Both SPU - mud and HPAN - mud are plastic fluids.The dependence of yield point on salts to the molecular weight of polymer and hydration of ionogenic group,which is quite different for SPU - mud and HPAN - .4) The extent of raising zeta- potential of base- mud by SPU is greater than by HPAN,but the extent of dropping zeta-potential of SPU - mud by NaCl is smaller than HPAN -mud.According to these results we suppose the salt-tolerance of SPU-mud is attributed mainly to hydration of-SO3- and that of HPAN - mud mainly to network structure formed in the driling - mud.
A new polyelectrolyte (SPU) has been prepared. It can depress the water-loss of drilling-mud much more effective than the commonly used acrylic polyelectrolytes even in 30% NaCl solution. SPU has phenyl group in the backbone with -SO3- in the side chain while the acrylic polyelectrolytes have C—C and -COO- respectively, there exists an intrinsic relationship between the structure of polymer and its tolerance to salts, it has been found: 1) The adsorption amount of polymer on clay is related closely to the flexibility of polymer chain.2)The salt-tolerance of -SO3- is superior to -COO-.3) Both SPU - mud and HPAN - mud are plastic fluids.The dependence of yield point on salts to the molecular weight of polymer and hydration of ionogenic group,which is quite different for SPU - mud and HPAN - .4) The extent of raising zeta- potential of base- mud by SPU is greater than by HPAN,but the extent of dropping zeta-potential of SPU - mud by NaCl is smaller than HPAN -mud.According to these results we suppose the salt-tolerance of SPU-mud is attributed mainly to hydration of-SO3- and that of HPAN - mud mainly to network structure formed in the driling - mud.
1990, 8(3): 211-216
Abstract:
Acrylamide-sodium acrylate copolymer hydrogels have been obtained by radiation techniques. Two different methods have been used to introduce—COONa groups into polymer chains of the gels: (1) by partial hydrolysis of acrylamide homopolymer gel; (2) by direct copolymerization and crosslinking of acrylamide and sodium acrylate in aqueous solutions. It was found that the gels obtained in different ways had different properties, the swelling character of the gels obtained by partial hydrolysis were more sensitive to pH of swelling aqueous media.In order to explain these differences,13C-NMR techniques were used to investigate the sequence distribution of monomer units of both gels.
Acrylamide-sodium acrylate copolymer hydrogels have been obtained by radiation techniques. Two different methods have been used to introduce—COONa groups into polymer chains of the gels: (1) by partial hydrolysis of acrylamide homopolymer gel; (2) by direct copolymerization and crosslinking of acrylamide and sodium acrylate in aqueous solutions. It was found that the gels obtained in different ways had different properties, the swelling character of the gels obtained by partial hydrolysis were more sensitive to pH of swelling aqueous media.In order to explain these differences,13C-NMR techniques were used to investigate the sequence distribution of monomer units of both gels.
1990, 8(3): 217-223
Abstract:
A novel polyetheretherketone (PEK-C) prepared from phenolphthalein has been synthesized. In order to improve some of its properties for application in high performance membrane, the PEK-C has been sulfonated with concentrated sulfuric acid. Degree of sulfonation can be regulated by controlling the temmperature and time of sulfonation. The characterization of the sulfonated PEK-C in sodium salt form has been made by IR, 1H NMR and 13C NMR etc. It is shown that the sulfonation appears to take place exclusively in the ortho position to phenolic ether of phenolphthalein unit.The result is in agreement with theoretical deduction.Some properties of the sulfonated PEK-C,such as solubility,transition temperature,thermal degradation and hydrophilicity have also been discussed.
A novel polyetheretherketone (PEK-C) prepared from phenolphthalein has been synthesized. In order to improve some of its properties for application in high performance membrane, the PEK-C has been sulfonated with concentrated sulfuric acid. Degree of sulfonation can be regulated by controlling the temmperature and time of sulfonation. The characterization of the sulfonated PEK-C in sodium salt form has been made by IR, 1H NMR and 13C NMR etc. It is shown that the sulfonation appears to take place exclusively in the ortho position to phenolic ether of phenolphthalein unit.The result is in agreement with theoretical deduction.Some properties of the sulfonated PEK-C,such as solubility,transition temperature,thermal degradation and hydrophilicity have also been discussed.
1990, 8(3): 224-233
Abstract:
A series of N-substituted acrylamide monomers and the temperature sensitive hydrogels of their copolymer with N, N'-methylene-bis-acrylamide (Bis) have been synthesized. The effects of monomer structures, composition of the initial monomer mixture, polymerization temperature, the extent of ionization of the network and the presence of acid, base, salt or organic compound on the formation and the swelling characteristics of the temperature sensitive hydrogels have been systematically studied. The mechanism of the temperature sensitive phase transformation of the hydrogels was also investigated.
A series of N-substituted acrylamide monomers and the temperature sensitive hydrogels of their copolymer with N, N'-methylene-bis-acrylamide (Bis) have been synthesized. The effects of monomer structures, composition of the initial monomer mixture, polymerization temperature, the extent of ionization of the network and the presence of acid, base, salt or organic compound on the formation and the swelling characteristics of the temperature sensitive hydrogels have been systematically studied. The mechanism of the temperature sensitive phase transformation of the hydrogels was also investigated.
1990, 8(3): 234-239
Abstract:
Nylon-6 has been modified by polyorganosiloxane. It was realized by radical addition of caprolactam to the vinyl group of silicone and anionic polymerization of the monomer in the presence of the silicone macromer. The mechanical properties of the modified plastics are not far from that of the unmodified one whereas its frictional properties are significantly improved.
Nylon-6 has been modified by polyorganosiloxane. It was realized by radical addition of caprolactam to the vinyl group of silicone and anionic polymerization of the monomer in the presence of the silicone macromer. The mechanical properties of the modified plastics are not far from that of the unmodified one whereas its frictional properties are significantly improved.
1990, 8(3): 240-246
Abstract:
Several novel aromatic liquid crystalline copolyesters with regular sequence structure were prepared by melt Sehotten-Baumann polycondensation via complex monomer. Polarizing microscope with hot stage, thermal analysis and X-ray diffraction were used to investigate the structure and properties of the copolyesters. The effects of structural units, such as flexible spacer, noncolinear meta-linked phenylene unit, crankshaft unit, kink with flexible bridging unit and various substituted benzene rings on melting temperature of aromatic copolyesters were studied and discussed on the basis of crystalline structure of the polymers.
Several novel aromatic liquid crystalline copolyesters with regular sequence structure were prepared by melt Sehotten-Baumann polycondensation via complex monomer. Polarizing microscope with hot stage, thermal analysis and X-ray diffraction were used to investigate the structure and properties of the copolyesters. The effects of structural units, such as flexible spacer, noncolinear meta-linked phenylene unit, crankshaft unit, kink with flexible bridging unit and various substituted benzene rings on melting temperature of aromatic copolyesters were studied and discussed on the basis of crystalline structure of the polymers.
1990, 8(3): 247-252
Abstract:
Styrene-acrylic acid copolymer (SAAC)-supported iron complex (SAAC·Fe)was characterized and the effect of the characteristic parameters on the catalytic activity of the complex was investigated. IR spectrum suggested that the complex SAAC·Fe possesses a structure of(C)and the Fe-O bond is higher in covalency. The complex SAAC·Fe with the structure of(C)shoved a higher catalytic activity in butadiene polymerization. When Fe/-COOH molar ratio in SAAC·Fe was about 0.2 the complex gave optimum catalytic activity.The catalytic of SAAC.Fe with the higher content of long sequence of acrylic acid units was low.When the content of short sequence of acrylic acid units was predominant and at the same time the content of the short sequence was approximately equal to that of the long sequence for stryrene,the activity of the complex was high.
Styrene-acrylic acid copolymer (SAAC)-supported iron complex (SAAC·Fe)was characterized and the effect of the characteristic parameters on the catalytic activity of the complex was investigated. IR spectrum suggested that the complex SAAC·Fe possesses a structure of(C)and the Fe-O bond is higher in covalency. The complex SAAC·Fe with the structure of(C)shoved a higher catalytic activity in butadiene polymerization. When Fe/-COOH molar ratio in SAAC·Fe was about 0.2 the complex gave optimum catalytic activity.The catalytic of SAAC.Fe with the higher content of long sequence of acrylic acid units was low.When the content of short sequence of acrylic acid units was predominant and at the same time the content of the short sequence was approximately equal to that of the long sequence for stryrene,the activity of the complex was high.
1990, 8(3): 253-260
Abstract:
The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)2 with EB (ethylbenzoate) and treating with TiCl4 solution. When TiCl4/(Mg(OEt)2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)2 with EB no reactions have taken place. But after treatment with TiCl4 solution, Mg(OEt)2 converts into MgCl2 and EB coordinates on the resulting MgCl2 carrier,a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group.The kinetic curves of propene polymerization obtained with present catalysts system display decay curves.It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that,ethoxyl group in catalyst has an effect on the configuration of polymer chain.
The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)2 with EB (ethylbenzoate) and treating with TiCl4 solution. When TiCl4/(Mg(OEt)2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)2 with EB no reactions have taken place. But after treatment with TiCl4 solution, Mg(OEt)2 converts into MgCl2 and EB coordinates on the resulting MgCl2 carrier,a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group.The kinetic curves of propene polymerization obtained with present catalysts system display decay curves.It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that,ethoxyl group in catalyst has an effect on the configuration of polymer chain.
1990, 8(3): 261-268
Abstract:
The charge-transfer complex of maleic anhydride and vinyl acetate was copolymerized under UV light. The chain composition and structure of the copolymer were analyzed with conductometry and NMR, and the chain sequence was determined as alternating. The copolymerization rates at different feed ratios, temperatures and in different solvents were investigated, giving evidence to the very active involvement of the CT complexes in the copolymerization. Terpolymerization with acrylonitrile also showed that the complex mechanism was a proper one for this system.
The charge-transfer complex of maleic anhydride and vinyl acetate was copolymerized under UV light. The chain composition and structure of the copolymer were analyzed with conductometry and NMR, and the chain sequence was determined as alternating. The copolymerization rates at different feed ratios, temperatures and in different solvents were investigated, giving evidence to the very active involvement of the CT complexes in the copolymerization. Terpolymerization with acrylonitrile also showed that the complex mechanism was a proper one for this system.
1990, 8(3): 269-278
Abstract:
The quantitative description of the sequence structure of emulsion-processed SBR and solution-processed SBR (by lithium catalyst)was carried out based on their spectral data Of13C-NMR. The calculating formulae which could be used to obtain diad concentration from the peak intensifies of carbon spectra, average block length, average number of block, and the microstructure composition of the molecular chain were derived. The quantitative result showed that on the molecular chain styrene unit had the tendency to attach to trans-1,4 butadiene unit.The calculated result of the microstructure was in good agreement with that obtained through IR measurement.
The quantitative description of the sequence structure of emulsion-processed SBR and solution-processed SBR (by lithium catalyst)was carried out based on their spectral data Of13C-NMR. The calculating formulae which could be used to obtain diad concentration from the peak intensifies of carbon spectra, average block length, average number of block, and the microstructure composition of the molecular chain were derived. The quantitative result showed that on the molecular chain styrene unit had the tendency to attach to trans-1,4 butadiene unit.The calculated result of the microstructure was in good agreement with that obtained through IR measurement.
1990, 8(3): 279-282
Abstract:
The radiation crosslinking of EPR/SBR blend has been studied. A relationship between sol fraction and radiation dose for the different weight ratio polymer blends and the method to calculate βb value of EPR/SBR blend system have been established.
The radiation crosslinking of EPR/SBR blend has been studied. A relationship between sol fraction and radiation dose for the different weight ratio polymer blends and the method to calculate βb value of EPR/SBR blend system have been established.
1990, 8(3): 283-286
Abstract:
In this paper, radiation-induced crosslinking mechanism and characterization of the crosslinking density of F-40 and F-4 by X-ray photoelectron spectroscopy (XPS) have been studied. The dose of gelation of F-40 obtained from XPS is 4.1×104 Gy. It is found that crosslinking density is the largest in the range of certain dose for F-40 and F-4.
In this paper, radiation-induced crosslinking mechanism and characterization of the crosslinking density of F-40 and F-4 by X-ray photoelectron spectroscopy (XPS) have been studied. The dose of gelation of F-40 obtained from XPS is 4.1×104 Gy. It is found that crosslinking density is the largest in the range of certain dose for F-40 and F-4.
