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1988 Volume 6 Issue 1
1988, 6(1): 1-13
Abstract:
This review is a concise survey about the works in our laboratory on the polymerization of aromatic and heterocyclic dinitriles, including the polymerization kinetics and mechanism, synthesis of heterocyclic dinitriles, the structure of polymers, and the correlation between the structures of dinitriles and polymerization rates and thermal performances of Polymers.
This review is a concise survey about the works in our laboratory on the polymerization of aromatic and heterocyclic dinitriles, including the polymerization kinetics and mechanism, synthesis of heterocyclic dinitriles, the structure of polymers, and the correlation between the structures of dinitriles and polymerization rates and thermal performances of Polymers.
1988, 6(1): 14-19
Abstract:
In this paper the Ce(Ⅳ) salt initiated graft copolymerization of acrylamide onto the film of polyesterpolyether block copolymer irradiated by UV-ray was reported. The UV-irradiation of the film and its graft process have been investigated by UV spectrum, ESR and ESCA and the influence of other factors on the graft copolymerization has been discussed.
In this paper the Ce(Ⅳ) salt initiated graft copolymerization of acrylamide onto the film of polyesterpolyether block copolymer irradiated by UV-ray was reported. The UV-irradiation of the film and its graft process have been investigated by UV spectrum, ESR and ESCA and the influence of other factors on the graft copolymerization has been discussed.
1988, 6(1): 20-29
Abstract:
Heat shrinking material of γ-radiation erosslinked polyethylene is widely used for various application in industry. In this study, DSC, TMA, WAXD and density measurement techniques were used to investigate the influence of MI and thermal history of LDPE on the effectiveness of network formation. Based on the results of heat stretching and heat shrinkage tests, it is found that the formation of a network as perfect as possible is indispensable to the irradiated material if good heat shrinkage property is desired.To this end,quenching technique and polyethylene with appropriate MImust be used so that an effective radiation effect will be obtained with a minimum amount of radiation dose.In spite of that the mechanical property of the irradiated polyethylene in the rubbery state is basically in agreement with the classical expression of the theory of high elasticity,only about 90% shrinkage can be reached.Besides,the heat shrinkage temperature Ts and the % shrinkage S are both related to the radiation dose.
Heat shrinking material of γ-radiation erosslinked polyethylene is widely used for various application in industry. In this study, DSC, TMA, WAXD and density measurement techniques were used to investigate the influence of MI and thermal history of LDPE on the effectiveness of network formation. Based on the results of heat stretching and heat shrinkage tests, it is found that the formation of a network as perfect as possible is indispensable to the irradiated material if good heat shrinkage property is desired.To this end,quenching technique and polyethylene with appropriate MImust be used so that an effective radiation effect will be obtained with a minimum amount of radiation dose.In spite of that the mechanical property of the irradiated polyethylene in the rubbery state is basically in agreement with the classical expression of the theory of high elasticity,only about 90% shrinkage can be reached.Besides,the heat shrinkage temperature Ts and the % shrinkage S are both related to the radiation dose.
1988, 6(1): 30-35
Abstract:
The volume change of the copolymer epoxy resins can be controlled by copolymerizing epoxy resin ESI with 3,9-di (5-norbornene-2, 2)-1, 5, 7, 11-tetraoxaspiro [5, 5] undecane (NSOC). During curing, the volume changes of copolymer epoxy resins with various amounts of NSOC were measured with a dilatometer. Cure process does not produce volume change when epoxy resin E51 : NSOC is 5.88 : 1 in equivalent.
The volume change of the copolymer epoxy resins can be controlled by copolymerizing epoxy resin ESI with 3,9-di (5-norbornene-2, 2)-1, 5, 7, 11-tetraoxaspiro [5, 5] undecane (NSOC). During curing, the volume changes of copolymer epoxy resins with various amounts of NSOC were measured with a dilatometer. Cure process does not produce volume change when epoxy resin E51 : NSOC is 5.88 : 1 in equivalent.
1988, 6(1): 36-44
Abstract:
The segmented block copoly(ether ester)s were swollen by tetrahydrofuran (THF) at 60℃ and formedfibers by gel-drawing. The morphology and properties of these fibers were investigated by optical and electron microscopes, X-ray diffraction, DSC and an Instron test machine. The band structure morphology was observed in the gel-drawing fibers. The molecular chains were highly oriented as proved by X-ray diffraction data. The results indicated that the gel-drawing fibers have much better mechanical properties than those obtained otherwise.The tensile strength and elastic modulus were found to be 280 MPa and 802 MPa,repsectively.The mechanism of the gel-drawing process was also discussed.
The segmented block copoly(ether ester)s were swollen by tetrahydrofuran (THF) at 60℃ and formedfibers by gel-drawing. The morphology and properties of these fibers were investigated by optical and electron microscopes, X-ray diffraction, DSC and an Instron test machine. The band structure morphology was observed in the gel-drawing fibers. The molecular chains were highly oriented as proved by X-ray diffraction data. The results indicated that the gel-drawing fibers have much better mechanical properties than those obtained otherwise.The tensile strength and elastic modulus were found to be 280 MPa and 802 MPa,repsectively.The mechanism of the gel-drawing process was also discussed.
1988, 6(1): 45-50
Abstract:
This paper offers some new evidence on the polymorphism of solid state of liquid crystalline aromatic copolyesters which were prepared in our laboratory. The effects of different treatment conditions(quenching and annealing) on solid structure have been examined mainly by DSC and X-ray diffraction. The discussion focuses on the supercooled mesophase and low temperature solid-solid transition, the shifting of double melting peaks of annealed samples and the changing of their ΔH data depending on the treatment temperature,time and thermal scanning rate.
This paper offers some new evidence on the polymorphism of solid state of liquid crystalline aromatic copolyesters which were prepared in our laboratory. The effects of different treatment conditions(quenching and annealing) on solid structure have been examined mainly by DSC and X-ray diffraction. The discussion focuses on the supercooled mesophase and low temperature solid-solid transition, the shifting of double melting peaks of annealed samples and the changing of their ΔH data depending on the treatment temperature,time and thermal scanning rate.
THE STUDIES OF THE CURING OF AN EPOXY RESIN ON COPPER WIRE BY FTIR EXTERNAL REFLECTION SPECTROSCOPY*
1988, 6(1): 51-55
Abstract:
The epoxy coating on copper wire has been studied by a modified sampling technique using Fourier transform infrared (FTIR) diffuse reflectance attachment. As the wire axis was parallel to the incident plane, a reflection spectrum of thin layer coating on a copper wire can be obtained. The study found that imidszole, especially the acetic acid treated imidazole, can be used as an effective curing catalyst of the epoxy resin on copper. This is the first report about the IR study of coatings on metal wires.
The epoxy coating on copper wire has been studied by a modified sampling technique using Fourier transform infrared (FTIR) diffuse reflectance attachment. As the wire axis was parallel to the incident plane, a reflection spectrum of thin layer coating on a copper wire can be obtained. The study found that imidszole, especially the acetic acid treated imidazole, can be used as an effective curing catalyst of the epoxy resin on copper. This is the first report about the IR study of coatings on metal wires.
1988, 6(1): 56-63
Abstract:
The effect of five ethers on alternating copolymerization of br+ adiene and propylene were investigated. It was found that under appropriate conditions, by adding ether into reaction system, the conversion could be increased by 10-20% and the catalytic efficiency doubled at -45℃. The interaction between ether and active center was also studied.
The effect of five ethers on alternating copolymerization of br+ adiene and propylene were investigated. It was found that under appropriate conditions, by adding ether into reaction system, the conversion could be increased by 10-20% and the catalytic efficiency doubled at -45℃. The interaction between ether and active center was also studied.
1988, 6(1): 64-74
Abstract:
Polyethylene terephthalate(PET)/polycaprolactone(PCL) segmented copolymers with different hard segment contents and a blend of two of them were studied by using DSC, WAXS, TEM and IR techniques and dynamic mechanical, stress-strain and isothermal crystallization measurements. Emphasis was laid on the studies of influence of compositional heterogeneity on the morphology and properties of these segmented copolymers. It was found that the solution cast specimens of the more heterogeneous sample exhibit better segregation of segments,high crystallinity and melting temperature.They have higher thermal stability of mechanical properties at small deformations.However,they are less stable against large deformations and may become softer than the more homogeneous ones.
Polyethylene terephthalate(PET)/polycaprolactone(PCL) segmented copolymers with different hard segment contents and a blend of two of them were studied by using DSC, WAXS, TEM and IR techniques and dynamic mechanical, stress-strain and isothermal crystallization measurements. Emphasis was laid on the studies of influence of compositional heterogeneity on the morphology and properties of these segmented copolymers. It was found that the solution cast specimens of the more heterogeneous sample exhibit better segregation of segments,high crystallinity and melting temperature.They have higher thermal stability of mechanical properties at small deformations.However,they are less stable against large deformations and may become softer than the more homogeneous ones.
1988, 6(1): 75-83
Abstract:
Functional monomers having phenylcarbamoyl and p-tolylcarbamoyl were synthesized. Binary initiation system consisted of Ce4+ and these functional monomers could initiate acrylamide polymerization. It was found that acrylamide could graft copolymerize onto macromolecules having these functional monomers units. The formation of graft copolymer has been verified by its percentage of water absorption, contact angle with water, XPS and SEM photographs. The reaction mechanism was proposed and the main reactive site of graft copolymerization by Ce4+ would take place predominantly at the functional pendant group.
Functional monomers having phenylcarbamoyl and p-tolylcarbamoyl were synthesized. Binary initiation system consisted of Ce4+ and these functional monomers could initiate acrylamide polymerization. It was found that acrylamide could graft copolymerize onto macromolecules having these functional monomers units. The formation of graft copolymer has been verified by its percentage of water absorption, contact angle with water, XPS and SEM photographs. The reaction mechanism was proposed and the main reactive site of graft copolymerization by Ce4+ would take place predominantly at the functional pendant group.
1988, 6(1): 84-96
Abstract:
Blends of PVC and polyurethanes with four different soft segments of molecular weight 1000 were prepared and studied by dynamic mechanical and DSC techniques. It was found that the compatibility of PVC with segmented polyurethanes was related to the mixing of PVC molecules and the soft segments of the polyurethanes. Polyester based polyurethanes are more compatible with PVC than polyether based polyurethanes. Solution cast blends of PVC with PCL-polyurethane (1/2/1) exhibit single and narrow glass transition,while the blends with PPO-polyurethane(1/2/1)are completely incompatible.The compatibility was found to decrease with increasing hard segment content for all the polyurethanes used.The methods of blend preparation may change the compatibility of PVC/PU blends through their influence on the mixing or demixing of the hard and soft segments.
Blends of PVC and polyurethanes with four different soft segments of molecular weight 1000 were prepared and studied by dynamic mechanical and DSC techniques. It was found that the compatibility of PVC with segmented polyurethanes was related to the mixing of PVC molecules and the soft segments of the polyurethanes. Polyester based polyurethanes are more compatible with PVC than polyether based polyurethanes. Solution cast blends of PVC with PCL-polyurethane (1/2/1) exhibit single and narrow glass transition,while the blends with PPO-polyurethane(1/2/1)are completely incompatible.The compatibility was found to decrease with increasing hard segment content for all the polyurethanes used.The methods of blend preparation may change the compatibility of PVC/PU blends through their influence on the mixing or demixing of the hard and soft segments.
