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1984 Volume 2 Issue 1
1984, 2(1): 1-6
Abstract:
In the study of molecular motion of polymer by means of ESR in combination with spin probe, owing to that the ESR spectrum depicts only the behavior of spin probe, the information obtained is of indirect nature. Hence the relationship between them must first be investigated before any conclusion could be drawn. In this paper, two parameters TR and CR are introduced to characterize the changing of tumbling rate of spin probe, and the concept of rotation barrier of spin probe is proposed. It is considered that the magnitude of the rotation barrier is determined by the internal cavity size and distribution in polymer.When the temperature is raised,the size and distribution of the cavities change accordingly,thus the tumbling of spin probe changes gradually from a slower to a higher rate.
In the study of molecular motion of polymer by means of ESR in combination with spin probe, owing to that the ESR spectrum depicts only the behavior of spin probe, the information obtained is of indirect nature. Hence the relationship between them must first be investigated before any conclusion could be drawn. In this paper, two parameters TR and CR are introduced to characterize the changing of tumbling rate of spin probe, and the concept of rotation barrier of spin probe is proposed. It is considered that the magnitude of the rotation barrier is determined by the internal cavity size and distribution in polymer.When the temperature is raised,the size and distribution of the cavities change accordingly,thus the tumbling of spin probe changes gradually from a slower to a higher rate.
1984, 2(1): 7-11
Abstract:
1,3-Dialkyl-5-fluorouracil compounds and polymers containing 5-fluorouracil in the main chain were synthesized by the reaction of 5-fluorouracil with alkylbromidcs and polymethylene bromides respectively. The structures of the new compounds and polymers were confirmed by IR and NMR spectra as well as elemental analyses. The factors affecting the polycondensation, such as the temperature and time of the reaction were investigated. The anti-tumor activity of some of the 5-fluorouracil containing compounds and polymers were also measured.
1,3-Dialkyl-5-fluorouracil compounds and polymers containing 5-fluorouracil in the main chain were synthesized by the reaction of 5-fluorouracil with alkylbromidcs and polymethylene bromides respectively. The structures of the new compounds and polymers were confirmed by IR and NMR spectra as well as elemental analyses. The factors affecting the polycondensation, such as the temperature and time of the reaction were investigated. The anti-tumor activity of some of the 5-fluorouracil containing compounds and polymers were also measured.
1984, 2(1): 12-18
Abstract:
Polymerization of butadiene catalysed first with V(acac)3-Al(i-Bu)2Cl, then with Co(acac)3-H2O-Al(i-Bu)2Cl has been studied. The polymer obtained was identified to be a new variety of cis-1,4-polybutadiene which contained a fraction of trans-1,4-polybutadiene chemically bonded to the cis-1,4-polybutadiene chains. Its molecular weight and trans-1,4 content can be regulated by varying the catalyst composition and concentration as well as other polymerization conditions. The trans-1,4 fraction, although it presents only in 9—16% forms a crystalline phase in the matrix at room temperature and facilitates the crystallization of the polymer.
Polymerization of butadiene catalysed first with V(acac)3-Al(i-Bu)2Cl, then with Co(acac)3-H2O-Al(i-Bu)2Cl has been studied. The polymer obtained was identified to be a new variety of cis-1,4-polybutadiene which contained a fraction of trans-1,4-polybutadiene chemically bonded to the cis-1,4-polybutadiene chains. Its molecular weight and trans-1,4 content can be regulated by varying the catalyst composition and concentration as well as other polymerization conditions. The trans-1,4 fraction, although it presents only in 9—16% forms a crystalline phase in the matrix at room temperature and facilitates the crystallization of the polymer.
1984, 2(1): 19-24
Abstract:
Copolymerization of butadiene and isoprene catalyzed by the catalyst system V(acac)3-Al(i-Bu)2Cl-Al2Et3Cl3 has been studied. Composition, microstructure, crystallinity and melting point of the copolymer obtained were determined by PGC, IR, X-ray diffraction and DSC methods respectively. The results revealed that the product was a copolymer and not a blend. The butadiene units presented in the copolymer were of trans-1,4-configuration, while the isoprene units were of both trans-1,4-and 3,4-forms. The melting point and crystallinity of the copolymer decreased decreased with increase of molar ratio of isoprene to butadiene.
Copolymerization of butadiene and isoprene catalyzed by the catalyst system V(acac)3-Al(i-Bu)2Cl-Al2Et3Cl3 has been studied. Composition, microstructure, crystallinity and melting point of the copolymer obtained were determined by PGC, IR, X-ray diffraction and DSC methods respectively. The results revealed that the product was a copolymer and not a blend. The butadiene units presented in the copolymer were of trans-1,4-configuration, while the isoprene units were of both trans-1,4-and 3,4-forms. The melting point and crystallinity of the copolymer decreased decreased with increase of molar ratio of isoprene to butadiene.
1984, 2(1): 25-32
Abstract:
Chelating resin with macrocyclic mercaptal group supported on macroporous polystyrene beads was synthesized, which showed good selectivity to Hg2+: its complexing capacity amounted to 30—60 mg Hg2+/g resin, two orders of magnitude greater than for other metal ions such as Ca2+, Zn2+, Cd2+, Pb2+ etc. This resin could restore the activity of urease which had been deactivated by poisoning with Hg2+. Its restoring power was far better than that of the mercapto-resin and common anionic exchange resins.It showed some promising use as an oral polymeric detoxifying drug for mercury poisoning.
Chelating resin with macrocyclic mercaptal group supported on macroporous polystyrene beads was synthesized, which showed good selectivity to Hg2+: its complexing capacity amounted to 30—60 mg Hg2+/g resin, two orders of magnitude greater than for other metal ions such as Ca2+, Zn2+, Cd2+, Pb2+ etc. This resin could restore the activity of urease which had been deactivated by poisoning with Hg2+. Its restoring power was far better than that of the mercapto-resin and common anionic exchange resins.It showed some promising use as an oral polymeric detoxifying drug for mercury poisoning.
1984, 2(1): 33-39
Abstract:
Four γ-substituted-propylcyclotetrasiloxanes have been synthesized. Emulsion copolymerizations of these cyclosiloxanes with octamethylcyclotetrasiloxane have been carried out both in cationic and anionic emulsion systems. By way of these reactions, stable emulsions of organosilicon polymers which contain carbonfuctional groups such as γ-hydroxypropyl, γ-acetoxypropyl and γ-chloropropyi have been obtained. The effects of temperature, catalyst and the amount of γ-substituted-propylcyclotetrasiloxanes in emulsion copolymerizations have been studied.
Four γ-substituted-propylcyclotetrasiloxanes have been synthesized. Emulsion copolymerizations of these cyclosiloxanes with octamethylcyclotetrasiloxane have been carried out both in cationic and anionic emulsion systems. By way of these reactions, stable emulsions of organosilicon polymers which contain carbonfuctional groups such as γ-hydroxypropyl, γ-acetoxypropyl and γ-chloropropyi have been obtained. The effects of temperature, catalyst and the amount of γ-substituted-propylcyclotetrasiloxanes in emulsion copolymerizations have been studied.
1984, 2(1): 40-47
Abstract:
The UV-photolysis of vinylidene chloride-methyl acrylate copolymer (VDC-MA) has been studied by X-ray photoelectron spectroscopy (ESCA) under atmospheric and inert environment. From the results of ESCA study with different irradiation time, several possible photochemical reactions, such as cleavage of C—Cl bond and photo-oxidation, have been proposed and discussed.
The UV-photolysis of vinylidene chloride-methyl acrylate copolymer (VDC-MA) has been studied by X-ray photoelectron spectroscopy (ESCA) under atmospheric and inert environment. From the results of ESCA study with different irradiation time, several possible photochemical reactions, such as cleavage of C—Cl bond and photo-oxidation, have been proposed and discussed.
1984, 2(1): 48-56
Abstract:
Polyethers could form hydroperoxide under air-oxidation or photo-oxidation in the presence of H2O2. The scission of ether linkage induced by moderate oxidation was prevented by controlling the reaction time and hydroperoxide concentration. The oxidation rate was affected by the end groups of polyethers. The decreasing order of oxidation rate for various poly(tetramethylene ether) glycol derivatives having different end groups are as follows: poly(tetramethylene ether) glycol (PTMG)>poly(tetramethylene ether) phenyl carbamate (ptmgpc).The urethane end groups in PTMGPC increase the resistance toward oxidation.Polyether hydroperoxide reacts with ferrous ion or N,N-dimethyl toluidine(DMT) to form polymericoxy radical which then initiates the graft copolymerization of vinyl monomers at low temperature,and was devoid of homopolymerization.The copolymer after separation and purification was proved to be a graft one by IR analysis and elemental analysis.
Polyethers could form hydroperoxide under air-oxidation or photo-oxidation in the presence of H2O2. The scission of ether linkage induced by moderate oxidation was prevented by controlling the reaction time and hydroperoxide concentration. The oxidation rate was affected by the end groups of polyethers. The decreasing order of oxidation rate for various poly(tetramethylene ether) glycol derivatives having different end groups are as follows: poly(tetramethylene ether) glycol (PTMG)>poly(tetramethylene ether) phenyl carbamate (ptmgpc).The urethane end groups in PTMGPC increase the resistance toward oxidation.Polyether hydroperoxide reacts with ferrous ion or N,N-dimethyl toluidine(DMT) to form polymericoxy radical which then initiates the graft copolymerization of vinyl monomers at low temperature,and was devoid of homopolymerization.The copolymer after separation and purification was proved to be a graft one by IR analysis and elemental analysis.
1984, 2(1): 57-63
Abstract:
Morphological changes during stretching of two PET samples (S and T) with different crystallization rate have been studied by means of SALS, solvent etching and polarizing microscope techniques. Results show that under the same drawing conditions larger and more perfect rod-like and spherulitic superstructures were formed more easily in the sample with higher crystallization rate (sample S). The amount of less compact regions which may be easily attacked by the vapor of allyl amine decreases more rapidly insample S than in sample T during stretching,and these regions are more randomly distributed in sample T especially at low elongations.The difference of the two samples in morphological changes is coincident with their differece in tensile behavior.
Morphological changes during stretching of two PET samples (S and T) with different crystallization rate have been studied by means of SALS, solvent etching and polarizing microscope techniques. Results show that under the same drawing conditions larger and more perfect rod-like and spherulitic superstructures were formed more easily in the sample with higher crystallization rate (sample S). The amount of less compact regions which may be easily attacked by the vapor of allyl amine decreases more rapidly insample S than in sample T during stretching,and these regions are more randomly distributed in sample T especially at low elongations.The difference of the two samples in morphological changes is coincident with their differece in tensile behavior.
1984, 2(1): 64-70
Abstract:
Radical polymerization of methyl mcthacrylate (MMA) initiated with various diacyl peroxideamine systems was studied. Benzoyl peroxide (BPO) and lauroyl peroxide (LPO) were used as diacyl peroxide component, N,N-dimethyl aniline (DMA) and its para substituted derivatives, i.e., N,N-dimethyl-p-toluidine (DMT), p-hydroxymethyl-N,N-dimethyl aniline (HDMA), p-nitro-N,N-dimethyl aniline (NDMA) and p-dimethylamino benzaldehyde (DMAB) were used as amine components. It was found that the peroxide-DMT systems give higher rates of bulk polymerization RP of MMA than the organic hydroperoxide-DMT systems with the following descending order BPO-DMT>LPO-DMT>CHP(cumene hydroperoxide)-DMT>TBH(tert-butyl hydroperoxide)-DMT.The aromatic tertiary amines possess obvious structural effect on the Rp values in the diacyl peroxideamine system.The overall activation energy of MMA polymerization was determined and the kinetics of polymerization of MMA initiated with BPO-DMT system was investigated.
Radical polymerization of methyl mcthacrylate (MMA) initiated with various diacyl peroxideamine systems was studied. Benzoyl peroxide (BPO) and lauroyl peroxide (LPO) were used as diacyl peroxide component, N,N-dimethyl aniline (DMA) and its para substituted derivatives, i.e., N,N-dimethyl-p-toluidine (DMT), p-hydroxymethyl-N,N-dimethyl aniline (HDMA), p-nitro-N,N-dimethyl aniline (NDMA) and p-dimethylamino benzaldehyde (DMAB) were used as amine components. It was found that the peroxide-DMT systems give higher rates of bulk polymerization RP of MMA than the organic hydroperoxide-DMT systems with the following descending order BPO-DMT>LPO-DMT>CHP(cumene hydroperoxide)-DMT>TBH(tert-butyl hydroperoxide)-DMT.The aromatic tertiary amines possess obvious structural effect on the Rp values in the diacyl peroxideamine system.The overall activation energy of MMA polymerization was determined and the kinetics of polymerization of MMA initiated with BPO-DMT system was investigated.
1984, 2(1): 71-77
Abstract:
Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropylsiloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.
Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropylsiloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.
1984, 2(1): 77-81
Abstract:
The study on the molecular weight and its distribution of 1, 2-polybutadienes prepared with MoCl4OR-i-Bu2AlOR' catalyst systems has been carded out by viscosity and GPC methods. 1, 2-Polybutadienes with Mw/Mn=1.2-2.0can be obtained with these catalyst systems at 30—70℃. There is a linear relation between theMw/Mn and the polymerization temperature. It was found by extrapolation that these catalyst systems may possibly initiate a living polymerization at the temperature near 18℃. The molecular weight of the polymers can be regulated either by polymerization temperature or by adding polar compounds such as allyl halides.
The study on the molecular weight and its distribution of 1, 2-polybutadienes prepared with MoCl4OR-i-Bu2AlOR' catalyst systems has been carded out by viscosity and GPC methods. 1, 2-Polybutadienes with Mw/Mn=1.2-2.0can be obtained with these catalyst systems at 30—70℃. There is a linear relation between theMw/Mn and the polymerization temperature. It was found by extrapolation that these catalyst systems may possibly initiate a living polymerization at the temperature near 18℃. The molecular weight of the polymers can be regulated either by polymerization temperature or by adding polar compounds such as allyl halides.
1984, 2(1): 82-91
Abstract:
The bulk polymerization of methyl methacrylate which was carried out in a metallic dilatometer and in a differential scanning calorimeter has been studied over the complete course of the reaction. An attempt was made to quantitatively express the relation on the onset of gel effect and the final conversion with polymerization conditions such as temperature, kinds and concentration of initiators. It was demonstrated further that the final conversion of polymerization in homogeneous ideal systems is only dependent upon the reaction temperature.
The bulk polymerization of methyl methacrylate which was carried out in a metallic dilatometer and in a differential scanning calorimeter has been studied over the complete course of the reaction. An attempt was made to quantitatively express the relation on the onset of gel effect and the final conversion with polymerization conditions such as temperature, kinds and concentration of initiators. It was demonstrated further that the final conversion of polymerization in homogeneous ideal systems is only dependent upon the reaction temperature.
1984, 2(1): 92-104
Abstract:
Some organosilane polymers with high molecular weights have been synthesized by cocondensztion of organosilicon dihalide monomers with sodium metal in toluene. These polymers are both soluble in common solvents and meltable at lower temperatures, and can be molded, cast into films or drawn into fibers. Exposure of the solid polymers to ultraviolet light leads to degradation or crosslinking.
Some organosilane polymers with high molecular weights have been synthesized by cocondensztion of organosilicon dihalide monomers with sodium metal in toluene. These polymers are both soluble in common solvents and meltable at lower temperatures, and can be molded, cast into films or drawn into fibers. Exposure of the solid polymers to ultraviolet light leads to degradation or crosslinking.
1984, 2(1): 105-108
Abstract:
A new polymeric tetraphenylporphyrin and its manganese complex were synthesized. Their structures were identified by examining the visible absorption, IR, 1H-NMR spectra.
A new polymeric tetraphenylporphyrin and its manganese complex were synthesized. Their structures were identified by examining the visible absorption, IR, 1H-NMR spectra.
