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1989 Volume 7 Issue 2
1989, 7(2): 97-102
Abstract:
The fluorescence behaviours of a new polymer poly [oxy-2 (4-N, N-dimethylaminobenzyl) propane-1 , 3-diyloxy-terephthaloyl] (Ⅰ) in solution were studied. Inter-and intra -molecular exciplex is formed between the singlet excited state of N, N- dimethylanilino group (abbreviated to DMA) and the ground state of terephthalate group (abbreviated to TP). The intensity ratio of the long wavelength exciplex fluorescence to the short wavelength emission of DMA group is used as an index for the inter-and intra-molecular interaction of chromophores.The results are compared with model polymer polyoxy-2-(4-N,N-dimethylaminobenzyl)propane-1,3-diyloxyadipoly(Ⅱ),model monomer compound 4-N,N-dimethylaminobenzylmethyl terephthalate(Ⅲ) and diethyl 2-(4-N,N-dimethylaminobenzyl) malonate(Ⅳ).Polymer association derived by electron donor and acceptor interaction(EDA) is further verified as a key role in the interpolymer exciplex formation.The fluorescence decay time of (I) and monomer (Ⅱ) are measured in solutions.
The fluorescence behaviours of a new polymer poly [oxy-2 (4-N, N-dimethylaminobenzyl) propane-1 , 3-diyloxy-terephthaloyl] (Ⅰ) in solution were studied. Inter-and intra -molecular exciplex is formed between the singlet excited state of N, N- dimethylanilino group (abbreviated to DMA) and the ground state of terephthalate group (abbreviated to TP). The intensity ratio of the long wavelength exciplex fluorescence to the short wavelength emission of DMA group is used as an index for the inter-and intra-molecular interaction of chromophores.The results are compared with model polymer polyoxy-2-(4-N,N-dimethylaminobenzyl)propane-1,3-diyloxyadipoly(Ⅱ),model monomer compound 4-N,N-dimethylaminobenzylmethyl terephthalate(Ⅲ) and diethyl 2-(4-N,N-dimethylaminobenzyl) malonate(Ⅳ).Polymer association derived by electron donor and acceptor interaction(EDA) is further verified as a key role in the interpolymer exciplex formation.The fluorescence decay time of (I) and monomer (Ⅱ) are measured in solutions.
1989, 7(2): 103-110
Abstract:
The morphology of shear-oriented films of a thermotropic liquid crystalline polyester containing a triad ester mesogenic unit and a flexible spacer has been investigated in details. The formation conditions and process, the fine structures and the relaxation process of mat structure in the oriented films have been observed and discussed.
The morphology of shear-oriented films of a thermotropic liquid crystalline polyester containing a triad ester mesogenic unit and a flexible spacer has been investigated in details. The formation conditions and process, the fine structures and the relaxation process of mat structure in the oriented films have been observed and discussed.
1989, 7(2): 111-118
Abstract:
In a capacitively coupled RF discharge system with external electrodes ,hexamethyicyclotrisiloxane was polymerized, and the effects of discharge power and plasma gas on polymer deposition rate were studied. The polymer structures and properties were studied by IR spectroscopy, XPS measurement, PGC/MS combined technique, TG analysis and contact angle measuring. The results showed that the polymers prepared in H2 or O2 have higher C/Si ratio in comparison with those prepared in inert gases. PGC/MS results revealed the existence of many short carbon chains in the polymer structure.TG analysis suggested that the polymers prepared in the inert gas would possess better thermal stabilities.
In a capacitively coupled RF discharge system with external electrodes ,hexamethyicyclotrisiloxane was polymerized, and the effects of discharge power and plasma gas on polymer deposition rate were studied. The polymer structures and properties were studied by IR spectroscopy, XPS measurement, PGC/MS combined technique, TG analysis and contact angle measuring. The results showed that the polymers prepared in H2 or O2 have higher C/Si ratio in comparison with those prepared in inert gases. PGC/MS results revealed the existence of many short carbon chains in the polymer structure.TG analysis suggested that the polymers prepared in the inert gas would possess better thermal stabilities.
1989, 7(2): 119-123
Abstract:
The behaviour of monolayers of copolymers of oxyethylene and oxypropylene (UH29 and UH68), polypropylene glycol (UHPPG)and their binary mixtures on air-water interface has been investigated carefully on compression-expansion cycles. The first compression isotherm is approximately an equilibrium one. In the UHPPG-UH29 and UHPPG-UH68 systems, the calculated average π-a curves based on simple additivity of the two individual components coincide with the experimental results reasonably well. It is suggested that the two components are miscible and from near-ideal solution at the air-water interface.The compression-expansion cycle experiments shows some degree of hysteresis.The order of degree of hysteresis for individual components is UH68>UH29>UHPPG.The explanation for the hysteresis is proposed.
The behaviour of monolayers of copolymers of oxyethylene and oxypropylene (UH29 and UH68), polypropylene glycol (UHPPG)and their binary mixtures on air-water interface has been investigated carefully on compression-expansion cycles. The first compression isotherm is approximately an equilibrium one. In the UHPPG-UH29 and UHPPG-UH68 systems, the calculated average π-a curves based on simple additivity of the two individual components coincide with the experimental results reasonably well. It is suggested that the two components are miscible and from near-ideal solution at the air-water interface.The compression-expansion cycle experiments shows some degree of hysteresis.The order of degree of hysteresis for individual components is UH68>UH29>UHPPG.The explanation for the hysteresis is proposed.
1989, 7(2): 124-131
Abstract:
The PVC/EBBA ultrathin composite membranes with thickness of about 100 nm were prepared by spreading the solution on water surface. The overlapped composite membrane showed a characteristic aggregation structure in which the polymer matrix exists as a three-dimensional spongy network and the liquid crystal domains werc observed. Tne surface modification for the overlapped membranes was carried out by means of plasma-polymerization with the monomers of fluorocarbon compounds. Both Arrhenius plots of permeability coefficients for oxygen(Po2)in the membrane samples before and after modification showed significant increase in the vicinity of the TKN of EBBA.
The PVC/EBBA ultrathin composite membranes with thickness of about 100 nm were prepared by spreading the solution on water surface. The overlapped composite membrane showed a characteristic aggregation structure in which the polymer matrix exists as a three-dimensional spongy network and the liquid crystal domains werc observed. Tne surface modification for the overlapped membranes was carried out by means of plasma-polymerization with the monomers of fluorocarbon compounds. Both Arrhenius plots of permeability coefficients for oxygen(Po2)in the membrane samples before and after modification showed significant increase in the vicinity of the TKN of EBBA.
1989, 7(2): 132-142
Abstract:
Film specimens of four segmented polyurethanes with different soft segments, namely polycaprolactone, polytetramethylene adipate, polytetramethylene oxide and polypropylene oxide, and their blends with PVC of different compositions were obtained by solution cast. The permeability of these films to O2, N2 and H2 and their density were measured by using gas chromatography and technique of density gradient column. The polyether polyurethanes were found to have higher permeability than the polyester ones due to their low glass transition temperature and or the low density value.The blends of PVC and polyether polyurethanes,especially the PPO-based polyurethane,are incompatible,and their permeability coefficient-conposition dependence has the typical S-shaped curves.PVC is well compatible with the soft segments in its blends with polyester polyurethanes.For these blends the composition dependence of permeability is characterized by a negative deviation from the semilogarithmic additivity rule,and it is possible to prepare blends having Tg 20℃ lower than that of PVC,but retaining its low permeability almost unchanged.results were discussed in according with the different approaches for the permeation behavior of compatible and incompatible blends.
Film specimens of four segmented polyurethanes with different soft segments, namely polycaprolactone, polytetramethylene adipate, polytetramethylene oxide and polypropylene oxide, and their blends with PVC of different compositions were obtained by solution cast. The permeability of these films to O2, N2 and H2 and their density were measured by using gas chromatography and technique of density gradient column. The polyether polyurethanes were found to have higher permeability than the polyester ones due to their low glass transition temperature and or the low density value.The blends of PVC and polyether polyurethanes,especially the PPO-based polyurethane,are incompatible,and their permeability coefficient-conposition dependence has the typical S-shaped curves.PVC is well compatible with the soft segments in its blends with polyester polyurethanes.For these blends the composition dependence of permeability is characterized by a negative deviation from the semilogarithmic additivity rule,and it is possible to prepare blends having Tg 20℃ lower than that of PVC,but retaining its low permeability almost unchanged.results were discussed in according with the different approaches for the permeation behavior of compatible and incompatible blends.
1989, 7(2): 143-149
Abstract:
In this paper the change of segment ratio, segmental sequence distribution and randonmess B of PET-PTMG block copolymer have been investigated by IR and 13C-NMR spectra during the polycondensation reaction.
In this paper the change of segment ratio, segmental sequence distribution and randonmess B of PET-PTMG block copolymer have been investigated by IR and 13C-NMR spectra during the polycondensation reaction.
1989, 7(2): 150-158
Abstract:
Three specimens from a solution-cast poly (ethylene terephthalate) (PET) film, one being liquid-N2 quenched from 92℃(Q), one being slowly cooled from 92℃(SC) and one being quenched and sub-Tg annealed at 67℃(AN), have been studied by specimen difference spectra Q-SC and AN-Q and temperature difference spectra T-70 and T2-T1 for every 2℃ steps on heating to 90℃ at 2℃ /min. SC and AN showed more gauche conformers than Q. That means that the PET chain has more trans conformers at higher temperatures and some of these are frozen during quenching through Tg.A band at 1340 cm-1 has been found to be complex containing overlapping bands reflecting trans in crystalline regions and trans in amorphous regions.The temperature difference spectra on heating through Tg showed that the spectral changes in Q are gradual while a rather abrupt change occurs in AN at 80 - 82℃ for the bands at 1340,1042 and 1020 cm-1.No New conformational structure or new vibrational mode is involved.A kind of locking mechanism is suggested which hinders the molecular vibrational changes in AN below Tg until a sudden release occurs at Tg.These locking sites can be nothing else than sites of tighter local packing of chain segments.Consequently it is believed that inter-chain van der Waals attraction energy plays a dominating role in the volume relaxation and sub-Tg annealing of quenched amorphous polymers.
Three specimens from a solution-cast poly (ethylene terephthalate) (PET) film, one being liquid-N2 quenched from 92℃(Q), one being slowly cooled from 92℃(SC) and one being quenched and sub-Tg annealed at 67℃(AN), have been studied by specimen difference spectra Q-SC and AN-Q and temperature difference spectra T-70 and T2-T1 for every 2℃ steps on heating to 90℃ at 2℃ /min. SC and AN showed more gauche conformers than Q. That means that the PET chain has more trans conformers at higher temperatures and some of these are frozen during quenching through Tg.A band at 1340 cm-1 has been found to be complex containing overlapping bands reflecting trans in crystalline regions and trans in amorphous regions.The temperature difference spectra on heating through Tg showed that the spectral changes in Q are gradual while a rather abrupt change occurs in AN at 80 - 82℃ for the bands at 1340,1042 and 1020 cm-1.No New conformational structure or new vibrational mode is involved.A kind of locking mechanism is suggested which hinders the molecular vibrational changes in AN below Tg until a sudden release occurs at Tg.These locking sites can be nothing else than sites of tighter local packing of chain segments.Consequently it is believed that inter-chain van der Waals attraction energy plays a dominating role in the volume relaxation and sub-Tg annealing of quenched amorphous polymers.
1989, 7(2): 159-164
Abstract:
Copolymer of divinyl ether and maleic anhydride (DVE-co-MA) derivatives of cis-platinum complexes were synthesized and characterized by elementary analysis, IR and XPS ( X-ray photoelectron spectroscopy). The behavior of the products in biological environment was also studied. UV-visible and fluorescence spectra show that these polymer derivatives are able to exchange ligands with selected nucleophilic groups in biological environment.
Copolymer of divinyl ether and maleic anhydride (DVE-co-MA) derivatives of cis-platinum complexes were synthesized and characterized by elementary analysis, IR and XPS ( X-ray photoelectron spectroscopy). The behavior of the products in biological environment was also studied. UV-visible and fluorescence spectra show that these polymer derivatives are able to exchange ligands with selected nucleophilic groups in biological environment.
1989, 7(2): 165-173
Abstract:
Effects of N-alkyi substituted ethylenediamine derivatives on vinyl polymerization using persulfate as initiator were studied. The apparent kinetic equations and overall activation energies of acrylamide polymerization were determined using the above mentioned system as initiator. The promoting activities of different diamine derivatives on vinyl polymerization are in the order of tertiary diamine>secondary diamine>primary diamine. Diamines having methyl groups as the substituent on their nitrogen atom possess higher promoting activity than that of having larger alkyl groups.The initial free radicals produced through the redox reaction of persulfate and diamines were studied by spin strapping technique and ESR spectroscopy.The results obtained confirm the fact that the initial free radicals of the diamine species can initiate vinyl polymerization and become the amino end group of the resulting polymers.
Effects of N-alkyi substituted ethylenediamine derivatives on vinyl polymerization using persulfate as initiator were studied. The apparent kinetic equations and overall activation energies of acrylamide polymerization were determined using the above mentioned system as initiator. The promoting activities of different diamine derivatives on vinyl polymerization are in the order of tertiary diamine>secondary diamine>primary diamine. Diamines having methyl groups as the substituent on their nitrogen atom possess higher promoting activity than that of having larger alkyl groups.The initial free radicals produced through the redox reaction of persulfate and diamines were studied by spin strapping technique and ESR spectroscopy.The results obtained confirm the fact that the initial free radicals of the diamine species can initiate vinyl polymerization and become the amino end group of the resulting polymers.
1989, 7(2): 174-178
Abstract:
The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness of lamellae is about 300A, being independent of the crystalline temperature. But the size and density of lamellae were dependent on the crystallization temperature. If the molten film was sheared during the crystallzation process the oriented lamellae grew with their long axes perpendicular to the direction of shear and the chain direction was normal to the lamellar surface.
The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness of lamellae is about 300A, being independent of the crystalline temperature. But the size and density of lamellae were dependent on the crystallization temperature. If the molten film was sheared during the crystallzation process the oriented lamellae grew with their long axes perpendicular to the direction of shear and the chain direction was normal to the lamellar surface.
1989, 7(2): 179-182
Abstract:
Eight new polyphosphates containing both nucleic acid base and phosphonoacetic acid ethyl ester were synthesized by the polycondensation of P, P-dichloride of phosphonoacetic acid ethyl ester with 1, 3-dihydroxyalkyl-5-fluorouracil, 1,3-dihydroxyalkyl-uracil and 1,3-dihydroxyalkylthymine. These polyphosphates were tested against Ehrlich Ascites Carcinoma in mice. Polymer IIa and IIc exhibited excellent antitumor activity. IIc also showed lower toxicity.
Eight new polyphosphates containing both nucleic acid base and phosphonoacetic acid ethyl ester were synthesized by the polycondensation of P, P-dichloride of phosphonoacetic acid ethyl ester with 1, 3-dihydroxyalkyl-5-fluorouracil, 1,3-dihydroxyalkyl-uracil and 1,3-dihydroxyalkylthymine. These polyphosphates were tested against Ehrlich Ascites Carcinoma in mice. Polymer IIa and IIc exhibited excellent antitumor activity. IIc also showed lower toxicity.
1989, 7(2): 183-188
Abstract:
new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((MW)=105—106) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and 29Si-NMR spectroscopy. The thermal property was studied by TGA and DSC.
new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((MW)=105—106) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and 29Si-NMR spectroscopy. The thermal property was studied by TGA and DSC.
1989, 7(2): 189-192
Abstract:
