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1985 Volume 3 Issue 4
1985, 3(4): 305-312
Abstract:
In a capacitively coupled discharge with external electrodes, He, H2, N2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C1S region in ESCA spectra,effect of the reaction conditions on degree of branching of the polymerized products and the relationship of the polymer structure with the mechanism of the competitive ablation and polymerization process were studied.In addition,polymer deposition process occurring in glow discharge was discussed.
In a capacitively coupled discharge with external electrodes, He, H2, N2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C1S region in ESCA spectra,effect of the reaction conditions on degree of branching of the polymerized products and the relationship of the polymer structure with the mechanism of the competitive ablation and polymerization process were studied.In addition,polymer deposition process occurring in glow discharge was discussed.
1985, 3(4): 313-323
Abstract:
The polymerization rate of butadiene in toluene initiated by n-butyllithium and tetramethyl ethy-lene diamine as well as the micro-structure and degree of association of polybutadiene were deter-mined. The effect of TMEDA/n-BuLi (abbr. A/Li) and temperature on the polymerization rate,molecular weight, molecular weight distribution and structure of polybutadiene was investigated. Ac-tivation energy of the propagation reaction and chain transfer reaction, together with the chain trans-fer reaction rate constant were estimated.Kinetic parameters and contribution of different reactive species to polymerization rate were calculated by Nonlinear Least-Squares Method.A kinetic equation was proposed.The mechanism of anionic chain transfer reaction was discussed.
The polymerization rate of butadiene in toluene initiated by n-butyllithium and tetramethyl ethy-lene diamine as well as the micro-structure and degree of association of polybutadiene were deter-mined. The effect of TMEDA/n-BuLi (abbr. A/Li) and temperature on the polymerization rate,molecular weight, molecular weight distribution and structure of polybutadiene was investigated. Ac-tivation energy of the propagation reaction and chain transfer reaction, together with the chain trans-fer reaction rate constant were estimated.Kinetic parameters and contribution of different reactive species to polymerization rate were calculated by Nonlinear Least-Squares Method.A kinetic equation was proposed.The mechanism of anionic chain transfer reaction was discussed.
1985, 3(4): 324-331
Abstract:
The reliability of the values of equilibrium heat of fusion, △Hm, of polytetrafluoroethylene (PTFE)reported in the literature and the inadequacy of the generally accepted value of 13 .7 or 14.6 cal/gwere discussed. Through extrapolating linear plot of △Hm vs. Vsp of the thermally aged PTFE virginas-polymerized samples prepared in accord with ASTM D 1457-81a, △Hmo=79.6J/g (19.0 cal/g)and Vsp (specific volume of amorphous PTFE at 23℃)=0.480 cm3/g (or ρa=2 .08g/cm3) were ob-tained. The heats of fusion,△Hm,of the thermally aged and γ-irradiated samples are different irrespective of the same Vsp value for both samples.A qualitative explanation of this phenomenon was given based on the HV patterns of SALS and Kawai's model.
The reliability of the values of equilibrium heat of fusion, △Hm, of polytetrafluoroethylene (PTFE)reported in the literature and the inadequacy of the generally accepted value of 13 .7 or 14.6 cal/gwere discussed. Through extrapolating linear plot of △Hm vs. Vsp of the thermally aged PTFE virginas-polymerized samples prepared in accord with ASTM D 1457-81a, △Hmo=79.6J/g (19.0 cal/g)and Vsp (specific volume of amorphous PTFE at 23℃)=0.480 cm3/g (or ρa=2 .08g/cm3) were ob-tained. The heats of fusion,△Hm,of the thermally aged and γ-irradiated samples are different irrespective of the same Vsp value for both samples.A qualitative explanation of this phenomenon was given based on the HV patterns of SALS and Kawai's model.
1985, 3(4): 332-340
Abstract:
The effect of50Co γ-radiation on plain polyamide 1010 (PA1010 Ⅰ) and PA1010 containing dif-ferent amount of crosslinking agent (BMI) (PA1010 Ⅱ) both in vacuum and in air at room tempera-ture was investigated with DSC. It was found that the crystallization temperature Tc of crosslinked sample determined with DSC at constant cooling rate decreased as the radiation dose increased. Thedifference between crystallization temperatures before and after crosslinking (Tco)-TcR) is linearly related to the radiation dose for PA10101.Based on the Charlesby-Pinner's equation an expression was derived S+S1/2=A+B(Tco)-TcR) where S is the sol fraction,A and B are constants.Since there is evidence that Tc is relative to S only and independent of the way of irradiation,the equation is also applicable to the enhanced γ-irradiation crosslinked PA1010 II.Therefore,determination of Tc of crosslinked polymer by DSC offers a convenient approach to study quantitatively the random and especially non-random crosslinking reaction of crystalline polymer.
The effect of50Co γ-radiation on plain polyamide 1010 (PA1010 Ⅰ) and PA1010 containing dif-ferent amount of crosslinking agent (BMI) (PA1010 Ⅱ) both in vacuum and in air at room tempera-ture was investigated with DSC. It was found that the crystallization temperature Tc of crosslinked sample determined with DSC at constant cooling rate decreased as the radiation dose increased. Thedifference between crystallization temperatures before and after crosslinking (Tco)-TcR) is linearly related to the radiation dose for PA10101.Based on the Charlesby-Pinner's equation an expression was derived S+S1/2=A+B(Tco)-TcR) where S is the sol fraction,A and B are constants.Since there is evidence that Tc is relative to S only and independent of the way of irradiation,the equation is also applicable to the enhanced γ-irradiation crosslinked PA1010 II.Therefore,determination of Tc of crosslinked polymer by DSC offers a convenient approach to study quantitatively the random and especially non-random crosslinking reaction of crystalline polymer.
1985, 3(4): 341-349
Abstract:
Initiation mechanism of the photopolymerization of acrylonitrile and methyl methacrylate, usingbinary condensed aromatic hydrocarbon (CAH)-aniline systems as initiator, was studied. The strongerthe electron-donating ability of the aniline derivatives, the faster the the of photopolymerizationwill be. The radical intermediates produced by photoreaction between anthracene and anilinewere detected with ESR spectra. The initiation scheme involves the formation of exciplex betweenthe excited singlet state of CAH and the ground state of aniline as the first step,and then followed by proton transfer,leading to the generation of two kinds of radicals.From the end-group analysis of the polymers obtained,it is suggested that both kinds of radicals are involved in the initiation.
Initiation mechanism of the photopolymerization of acrylonitrile and methyl methacrylate, usingbinary condensed aromatic hydrocarbon (CAH)-aniline systems as initiator, was studied. The strongerthe electron-donating ability of the aniline derivatives, the faster the the of photopolymerizationwill be. The radical intermediates produced by photoreaction between anthracene and anilinewere detected with ESR spectra. The initiation scheme involves the formation of exciplex betweenthe excited singlet state of CAH and the ground state of aniline as the first step,and then followed by proton transfer,leading to the generation of two kinds of radicals.From the end-group analysis of the polymers obtained,it is suggested that both kinds of radicals are involved in the initiation.
1985, 3(4): 350-355
Abstract:
The unperturbed dimension of polymer is measured by a gel permeation chromatography (GPC)coupling with viscometer. The intrinsic viscosities of the fractions are measured with an automaticviscometer, and the molecular weight of the fractions are calculated based on the universal calibration.Using a theoretical expression with linearized Mark-Houwink's equation an unperturbed dimensionis obtained by extrapolating to the unperturbed state. The results agree with the values measured by conventional method comparisons with various theoretical expressions are made.
The unperturbed dimension of polymer is measured by a gel permeation chromatography (GPC)coupling with viscometer. The intrinsic viscosities of the fractions are measured with an automaticviscometer, and the molecular weight of the fractions are calculated based on the universal calibration.Using a theoretical expression with linearized Mark-Houwink's equation an unperturbed dimensionis obtained by extrapolating to the unperturbed state. The results agree with the values measured by conventional method comparisons with various theoretical expressions are made.
1985, 3(4): 356-361
Abstract:
Percentages of P or/and F in polymers and organic compounds are found by using Nd3+ as pre-cipitant and subsequent titration of excess Nd3+ with EDTA after decomposing sample in oxygenflask. The errors of determination are for P<±0.20% and F<±0.30% except fully fluorinatedcompounds.
Percentages of P or/and F in polymers and organic compounds are found by using Nd3+ as pre-cipitant and subsequent titration of excess Nd3+ with EDTA after decomposing sample in oxygenflask. The errors of determination are for P<±0.20% and F<±0.30% except fully fluorinatedcompounds.
1985, 3(4): 362-366
Abstract:
In the present work, radiation crosslinking of different branched poly (vinyl acetate) have beemstudied and the validity of the relationship[4] between sol fraction and radiation dose: R(S+√S=1/U1qo+p′o/qoRβto branched poly(vinyl acetate) have been assured.
In the present work, radiation crosslinking of different branched poly (vinyl acetate) have beemstudied and the validity of the relationship[4] between sol fraction and radiation dose: R(S+√S=1/U1qo+p′o/qoRβto branched poly(vinyl acetate) have been assured.
1985, 3(4): 367-372
Abstract:
This paper describes the polymerization of acetylene by coordination catalysts composed ofvarious neodymium compounds, (Nd (P204)3; Nd (P507)3; Nd (NO3)3 3P350; Nd (BA)3.2H2O; and Nd (acac)3.2H2O), aluminum trialkyl and an electron donor. The catalysts show fairly high catalyticactivity and high cis stereospecificity on acetylene polymerization at 30℃.
This paper describes the polymerization of acetylene by coordination catalysts composed ofvarious neodymium compounds, (Nd (P204)3; Nd (P507)3; Nd (NO3)3 3P350; Nd (BA)3.2H2O; and Nd (acac)3.2H2O), aluminum trialkyl and an electron donor. The catalysts show fairly high catalyticactivity and high cis stereospecificity on acetylene polymerization at 30℃.
1985, 3(4): 373-381
Abstract:
The effects of hindered amines, such as TMP, TMPM, TUV-770, on MMA and St homopoly-merization have been studied. It was found that in the MMA polymerization initiated with BPO orAIBN, the presence of TMPM, TUV-770 prolonged the induction period and a little change on Rp wasobserved. However, in the presence of TMP Rp increased slightly. The activation energy of poly-merization and polymerization rate equation were determined.
The effects of hindered amines, such as TMP, TMPM, TUV-770, on MMA and St homopoly-merization have been studied. It was found that in the MMA polymerization initiated with BPO orAIBN, the presence of TMPM, TUV-770 prolonged the induction period and a little change on Rp wasobserved. However, in the presence of TMP Rp increased slightly. The activation energy of poly-merization and polymerization rate equation were determined.
1985, 3(4): 382-389
Abstract:
Polycations and polyanions of polyvinyl alcohol (PVA) with various substitution degrees were pre-pared by acetalization of PVA with aldehyde derivatives such as p-formylbenzoic acid, glyoxalic acid, p-formyl-benzenesulfonic acid, p-formylpyridine, and p-dimethylaminobenzaldehyde and then neutral-ized or quaternarized with methyl iodide. The corresponding PVA type polyionic complexes wereobtained by mixing the aqueous solutions of these polycations and polyanions. The solvation behaviourof these polyionic complexes were investigated.It was found that the H2O-DMF-NaSCN solvent system is superior to the H2O-DMF-NaBr system for these PVA type polyionic complexes.
Polycations and polyanions of polyvinyl alcohol (PVA) with various substitution degrees were pre-pared by acetalization of PVA with aldehyde derivatives such as p-formylbenzoic acid, glyoxalic acid, p-formyl-benzenesulfonic acid, p-formylpyridine, and p-dimethylaminobenzaldehyde and then neutral-ized or quaternarized with methyl iodide. The corresponding PVA type polyionic complexes wereobtained by mixing the aqueous solutions of these polycations and polyanions. The solvation behaviourof these polyionic complexes were investigated.It was found that the H2O-DMF-NaSCN solvent system is superior to the H2O-DMF-NaBr system for these PVA type polyionic complexes.
1985, 3(4): 390-394
Abstract:
Effect of both structure of substituents and degree of substitution of polyions derived from poly-vinyl alcohol on water-absorbility and antithrombogenecity of formed polyionic complexes (PIC)have been investigated. It was found that the water content of the PIC formed from p-formylben-zenesulfonic acid substituted PVA was higher than that of the PIC formed from p-formylbenzoicacid substituted PVA. When the substitution degree of polycation increased from 27% to 64%,the water content of the formed PIC increased from 170% to 1270%.Effect of water content and net charge of PVA-type PIC on the antithrombogenecity was also investigated by plasma recalcification method.
Effect of both structure of substituents and degree of substitution of polyions derived from poly-vinyl alcohol on water-absorbility and antithrombogenecity of formed polyionic complexes (PIC)have been investigated. It was found that the water content of the PIC formed from p-formylben-zenesulfonic acid substituted PVA was higher than that of the PIC formed from p-formylbenzoicacid substituted PVA. When the substitution degree of polycation increased from 27% to 64%,the water content of the formed PIC increased from 170% to 1270%.Effect of water content and net charge of PVA-type PIC on the antithrombogenecity was also investigated by plasma recalcification method.
1985, 3(4): 395-399
Abstract:
The morphology of films of PDS/PP blends with various contents of PDS and with PDS of dif-ferent molecular weights was examined by scanning electron microscopy and the photostability of these films was studied by infrared spectrometry. Experimental results show that PDS is dispersedin PP matris as spherical globules being in size of the order of 10-1μm when content of PDS is in therange of 0.1 % to 1%. The phase separation of PDS from PP results in decrease in photostabilizingaction of PDS to some extent.It is found that films of PP blended with PDS of different molecular weights show similar morphology and photostabilizing action if the content of PDS is kept constant.
The morphology of films of PDS/PP blends with various contents of PDS and with PDS of dif-ferent molecular weights was examined by scanning electron microscopy and the photostability of these films was studied by infrared spectrometry. Experimental results show that PDS is dispersedin PP matris as spherical globules being in size of the order of 10-1μm when content of PDS is in therange of 0.1 % to 1%. The phase separation of PDS from PP results in decrease in photostabilizingaction of PDS to some extent.It is found that films of PP blended with PDS of different molecular weights show similar morphology and photostabilizing action if the content of PDS is kept constant.
1985, 3(4): 400-404
Abstract:
The living chains were obtained in the bulk copolymerization of tetrahydrofuran (THF) withpropylene oxide (PO) (10--20 wt.%) initiated by adipoyl chloride (AC)AgC104 ([ACl0,=0.02-0.09 mo1.1-1) catalyst at-10--0℃ without chain termination and transfer reactions. The estimationof reactivity ratios gave values of 0.8±0.2 and 0.08±0.03 for THF and PO, respectively. The func-tionality of living chains with 10% PO in the feed is close to 2. Four different telechelic THF-PO co-polymers with amine or hydroxyl end-grpups [P(THF-co-PO)R,where R=-NHBu、-NHPh,-NET2 or -OH were synthesized.
The living chains were obtained in the bulk copolymerization of tetrahydrofuran (THF) withpropylene oxide (PO) (10--20 wt.%) initiated by adipoyl chloride (AC)AgC104 ([ACl0,=0.02-0.09 mo1.1-1) catalyst at-10--0℃ without chain termination and transfer reactions. The estimationof reactivity ratios gave values of 0.8±0.2 and 0.08±0.03 for THF and PO, respectively. The func-tionality of living chains with 10% PO in the feed is close to 2. Four different telechelic THF-PO co-polymers with amine or hydroxyl end-grpups [P(THF-co-PO)R,where R=-NHBu、-NHPh,-NET2 or -OH were synthesized.
