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1995 Volume 13 Issue 2
1995, 13(2): 97-106
Abstract:
The melting and crystallization behavior have been investigated for an aromatic poly(azomethine ether) with non-linearly shaped molecular conformations. This polymer wasfound to undergo multiple melting processes and its phase transition behavior wasinfluenced sensitively by the thermal history of sample. A significant difference between thepolymer chain aggregation abilities of samples cooled from the different states wasobserved. The possible molecular morphology and aggregation models for describing the structures of this polymer were proposed and discussed.The crystallization behavior of the samples cooled from the partially istropic state and the influence of cooling rate on it have also been examined with DSC.
The melting and crystallization behavior have been investigated for an aromatic poly(azomethine ether) with non-linearly shaped molecular conformations. This polymer wasfound to undergo multiple melting processes and its phase transition behavior wasinfluenced sensitively by the thermal history of sample. A significant difference between thepolymer chain aggregation abilities of samples cooled from the different states wasobserved. The possible molecular morphology and aggregation models for describing the structures of this polymer were proposed and discussed.The crystallization behavior of the samples cooled from the partially istropic state and the influence of cooling rate on it have also been examined with DSC.
1995, 13(2): 107-111
Abstract:
A method of determining branching parameter of lacquer polysaccharide wasestablished by acid-base back-titration of terminal uronic acid of branches. The branchingfactors obtained are in agreement with the values determined by colorimetric method withcarbazole and the results estimated by using Zimm-Stockmayer equation from viscositydata. Influences of molecular weights and branching factors of five fractions of lacquerpolysaccharide on the bioactivities were studied. The results show that the polysaccharids have bioactivities in motivating the growth of leucocytes,and the effect increases with the decrease of molecular weight and branching factor in the range studied(17×104>Mw>4×104.
A method of determining branching parameter of lacquer polysaccharide wasestablished by acid-base back-titration of terminal uronic acid of branches. The branchingfactors obtained are in agreement with the values determined by colorimetric method withcarbazole and the results estimated by using Zimm-Stockmayer equation from viscositydata. Influences of molecular weights and branching factors of five fractions of lacquerpolysaccharide on the bioactivities were studied. The results show that the polysaccharids have bioactivities in motivating the growth of leucocytes,and the effect increases with the decrease of molecular weight and branching factor in the range studied(17×104>Mw>4×104.
1995, 13(2): 112-125
Abstract:
This paper reported the research results concerning the surface characterization ofpolystyrene-graft-w-stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood compatibility assessment by measuringthe plasma recalcification time (RT) and partial thromboplastin time (PTT). The XPSresults demonstrated that the surface and bulk composition of the PS-g-SPEO graftcopolymers differ remarkably from each other,and that SPEO component was constantly enriched at the copolymer/air interface.Contact angle studies indicated that the surface water wettability can be adjusted effectively by changing the composition of the copolymer,PS-g-SPEO graft copolymers can undergo microphase separation as clearly illustrated by TEM photographs.The relationship between the surface properties of PS-g-SPEO graft copolymer and its blood compatibility was also discussed.
This paper reported the research results concerning the surface characterization ofpolystyrene-graft-w-stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood compatibility assessment by measuringthe plasma recalcification time (RT) and partial thromboplastin time (PTT). The XPSresults demonstrated that the surface and bulk composition of the PS-g-SPEO graftcopolymers differ remarkably from each other,and that SPEO component was constantly enriched at the copolymer/air interface.Contact angle studies indicated that the surface water wettability can be adjusted effectively by changing the composition of the copolymer,PS-g-SPEO graft copolymers can undergo microphase separation as clearly illustrated by TEM photographs.The relationship between the surface properties of PS-g-SPEO graft copolymer and its blood compatibility was also discussed.
1995, 13(2): 126-135
Abstract:
Electrochrometic measurements were carried on the Z-type Langmuir-Blodgett films oftwo liquid crystalline polymers: mono-{6-[4-(phenylazo) naphthyloxy] hexyl} (1a) andmono-{6-[4-(anthraquinone-1-azo) naphthyloxy] hexyl} (2a) ester of polymaleic acid. Itwas found that for both polymers, poling fields parallel and antiparalle1 to dipole momentsof the polymer side chains induce red and blue shift in absorption bands, respectively. Forpolymer la blue shift is accompanied by absorbance increase, while red shift sy absorbance decrease;but for polymer 2a only decrease in absorbance is observed.A simple model was proposed to analyze the results.
Electrochrometic measurements were carried on the Z-type Langmuir-Blodgett films oftwo liquid crystalline polymers: mono-{6-[4-(phenylazo) naphthyloxy] hexyl} (1a) andmono-{6-[4-(anthraquinone-1-azo) naphthyloxy] hexyl} (2a) ester of polymaleic acid. Itwas found that for both polymers, poling fields parallel and antiparalle1 to dipole momentsof the polymer side chains induce red and blue shift in absorption bands, respectively. Forpolymer la blue shift is accompanied by absorbance increase, while red shift sy absorbance decrease;but for polymer 2a only decrease in absorbance is observed.A simple model was proposed to analyze the results.
1995, 13(2): 136-143
Abstract:
Poly (phenylene sulfide amide) (PPSA) has been synthesized by using sulfur as Ssource which reacts with dichlorobenzamide (DCBA) and alkali in polar organic solvent atthe atmospheric pressure. The polymer structures were determined by elemental analysis,FT-IR and 1H-NMR. It is shown that the yielded polymer has linear structure and itsstructure unit is -p-C6H4-CONH-p-C6H4-S-. The polymer morphology was studied byX-ray diffraction and polarized microscopy. The results show that PPSA is a crystalline polymer and its spherulites are the aggregation of nontwisting lamella or micro-thread structure.Under shearing force,these crystals are dispersed to form micro-dibrillar structure.The decomposition kinetics of PPSA was also studied at different heating rates.The decomposition energy of PPSA is higher than that of PPS.
Poly (phenylene sulfide amide) (PPSA) has been synthesized by using sulfur as Ssource which reacts with dichlorobenzamide (DCBA) and alkali in polar organic solvent atthe atmospheric pressure. The polymer structures were determined by elemental analysis,FT-IR and 1H-NMR. It is shown that the yielded polymer has linear structure and itsstructure unit is -p-C6H4-CONH-p-C6H4-S-. The polymer morphology was studied byX-ray diffraction and polarized microscopy. The results show that PPSA is a crystalline polymer and its spherulites are the aggregation of nontwisting lamella or micro-thread structure.Under shearing force,these crystals are dispersed to form micro-dibrillar structure.The decomposition kinetics of PPSA was also studied at different heating rates.The decomposition energy of PPSA is higher than that of PPS.
1995, 13(2): 144-153
Abstract:
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl etherof bisphenol A) (DGEBA) and poly(ethylene oxide) (PEO) and crosslinked by phthalicanhydride (PA) was studied using dynamic mechanical method. Single glass transitiontemperatures intermediate between the two pure components were observed for all blendlevels. The secondary relaxation mechanism should relate to not only diester linkage, butalso hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system.The results indicate the PEO participates the crosslinking reaction,accelerates the curing reaction and make the reaction more perfect.The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend.Moreover,the molecular interaction between the side hydroxyl in the hudroxyether units and the ether bond in PEO macromolecules is stronger.
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl etherof bisphenol A) (DGEBA) and poly(ethylene oxide) (PEO) and crosslinked by phthalicanhydride (PA) was studied using dynamic mechanical method. Single glass transitiontemperatures intermediate between the two pure components were observed for all blendlevels. The secondary relaxation mechanism should relate to not only diester linkage, butalso hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system.The results indicate the PEO participates the crosslinking reaction,accelerates the curing reaction and make the reaction more perfect.The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend.Moreover,the molecular interaction between the side hydroxyl in the hudroxyether units and the ether bond in PEO macromolecules is stronger.
1995, 13(2): 154-161
Abstract:
The drug release behavior of degradable polymer--polycaprolactone-poly (ethyleneglycol)block copolymer(PCE) in vitro was investigated by using 5-Fluoro-uracil (5-Fu) asa model drug under a condition of pH 7. 4 at 37C. It is found that the release rate of 5-Fufrom PCE increased with increasing polyether content of the copolymer. The results showthat the increasing polyether content of the copolymer caused increasing hydrophilicity anddecreasing crystallinity of the PCE copolymer. Thus, the drug release behavior and the degradable property of the PCE can be controlled by adjusting the composition of the copolymer.
The drug release behavior of degradable polymer--polycaprolactone-poly (ethyleneglycol)block copolymer(PCE) in vitro was investigated by using 5-Fluoro-uracil (5-Fu) asa model drug under a condition of pH 7. 4 at 37C. It is found that the release rate of 5-Fufrom PCE increased with increasing polyether content of the copolymer. The results showthat the increasing polyether content of the copolymer caused increasing hydrophilicity anddecreasing crystallinity of the PCE copolymer. Thus, the drug release behavior and the degradable property of the PCE can be controlled by adjusting the composition of the copolymer.
1995, 13(2): 162-172
Abstract:
The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA),2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate(HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solidcontent. The effects of monomer emulsion feed rates (Ra) and (R/E)E values, the ratio ofemulsifier amount between the initial charge (R) and the addition monomer emulsion (E),on the polymerization reaction features, the viscosities, surface tensions,particle sizes distributions of latexes,T and the insoluble fractions of films,the 180° peel strength,tack and holding power of pressure-sensitive adhesive (PSA) tapes,prepared from the latexes,were studied.Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180°peel strength,tack and holding power.
The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA),2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate(HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solidcontent. The effects of monomer emulsion feed rates (Ra) and (R/E)E values, the ratio ofemulsifier amount between the initial charge (R) and the addition monomer emulsion (E),on the polymerization reaction features, the viscosities, surface tensions,particle sizes distributions of latexes,T and the insoluble fractions of films,the 180° peel strength,tack and holding power of pressure-sensitive adhesive (PSA) tapes,prepared from the latexes,were studied.Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180°peel strength,tack and holding power.
1995, 13(2): 173-179
Abstract:
A modified method of preparing crown functionalized linear polysiloxane has beendescribed. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation withmethyldichlorosilane, followed by polycondensation with silanol-terminatedpolydimethylsiloxane to give the title crown functionalized linear polysiloxane. Thetransport properties of sodium, potassium, and ammonium salt through a bulk liquidmembrane system using the new type of crown functionalized linear polysiloxane as acarrier were investigated. It is worthy to point out that the carrier can be used repeatedly at least six runs with no apparent change in the tranport rate of potassium ion.
A modified method of preparing crown functionalized linear polysiloxane has beendescribed. 4'-Allyldibenzo-18-crown-6 was subjected to hydrosilylation withmethyldichlorosilane, followed by polycondensation with silanol-terminatedpolydimethylsiloxane to give the title crown functionalized linear polysiloxane. Thetransport properties of sodium, potassium, and ammonium salt through a bulk liquidmembrane system using the new type of crown functionalized linear polysiloxane as acarrier were investigated. It is worthy to point out that the carrier can be used repeatedly at least six runs with no apparent change in the tranport rate of potassium ion.
1995, 13(2): 180-184
Abstract:
The Rouse-Zimm model with slippage was improved and the basic parameters of modelwere modified to explain the rheological properties of star-type branched polymersolutions. The theoretical results show good agreement with experimental data.
The Rouse-Zimm model with slippage was improved and the basic parameters of modelwere modified to explain the rheological properties of star-type branched polymersolutions. The theoretical results show good agreement with experimental data.
1995, 13(2): 185-188
Abstract:
Pervaporation separation of water-acetic acid mixtures through Poly (AN-co-AA)membranes and rare earth metal ions treated Poly(AN-co-AA)membranes was investigatedfor the first time. The results showed that the treatment with rare earth metal ions couldgreatly improve the characteristics of the separation of water-acetic acid mixtures.
Pervaporation separation of water-acetic acid mixtures through Poly (AN-co-AA)membranes and rare earth metal ions treated Poly(AN-co-AA)membranes was investigatedfor the first time. The results showed that the treatment with rare earth metal ions couldgreatly improve the characteristics of the separation of water-acetic acid mixtures.
1995, 13(2): 189-192
Abstract:
It is found that there is a linear relationship between log Pw and the parameter termVf/0. 5 Ecoh[1+(δw-δp)2/δp2], from the water permeability (Pw) data of 21 polymerscovering 4 orders of magnitude. This correlation may be useful in choosing membranematerials for dehumidification of gases.
It is found that there is a linear relationship between log Pw and the parameter termVf/0. 5 Ecoh[1+(δw-δp)2/δp2], from the water permeability (Pw) data of 21 polymerscovering 4 orders of magnitude. This correlation may be useful in choosing membranematerials for dehumidification of gases.
