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1986 Volume 4 Issue 1
1986, 4(1): 1-7
Abstract:
The relationship between intrinsic viscosity[η] and yield strength [σγ] of SBR-1500 raw rubberwas studied. It was found that the critical molecular weight for yielding varied with temperature.The critical yield temperature of SBR--1500 is 18℃, which is equivalent to transition temperature T'llas determined by linear expansion. The transition temperature T'll of SBR increased with styrenecontent in the sample.
The relationship between intrinsic viscosity[η] and yield strength [σγ] of SBR-1500 raw rubberwas studied. It was found that the critical molecular weight for yielding varied with temperature.The critical yield temperature of SBR--1500 is 18℃, which is equivalent to transition temperature T'llas determined by linear expansion. The transition temperature T'll of SBR increased with styrenecontent in the sample.
1986, 4(1): 8-16
Abstract:
Proton decoupled, partially relaxed, Fourier-transform 50.3 MHz carbon-13 NMR in natural abundance was used to determine spin-lattice times (T1) and nuclear Overhauser enhancement fac-tors (NOE) of individual carbon of a serics of 1,2-polybutadienes with different structures in solutionin CDCl2. The structure dependence of molecular metion and the internal motion of vinyl group in 1,2-polybutadiene have been studied by nT1 and NOE values. The nT1 values of the carbons in cis-1,4-units are the highest and those of the carbons in 1,2-units are the lowest in three types of units in 1,2-polybutadiene.The nT1 values of carbons in the same unit become greater when the adjacent 1,2-units are replaced by 1,4-units,and nT1 values of the carbons in all units decrease sharply with the increase of content of 1,2-units in the polymers.The fact that nT1 values of —CH=are larger than those of =CH2 in vinyl group implies that there are complex internal motions of vinyl group.It is shown by calculation that the dominant factor causing the difference in nT1 of—CH=and=CH2 in vinyl group is a swing of vinyl group in a plane perpendicular to the chain backbone.
Proton decoupled, partially relaxed, Fourier-transform 50.3 MHz carbon-13 NMR in natural abundance was used to determine spin-lattice times (T1) and nuclear Overhauser enhancement fac-tors (NOE) of individual carbon of a serics of 1,2-polybutadienes with different structures in solutionin CDCl2. The structure dependence of molecular metion and the internal motion of vinyl group in 1,2-polybutadiene have been studied by nT1 and NOE values. The nT1 values of the carbons in cis-1,4-units are the highest and those of the carbons in 1,2-units are the lowest in three types of units in 1,2-polybutadiene.The nT1 values of carbons in the same unit become greater when the adjacent 1,2-units are replaced by 1,4-units,and nT1 values of the carbons in all units decrease sharply with the increase of content of 1,2-units in the polymers.The fact that nT1 values of —CH=are larger than those of =CH2 in vinyl group implies that there are complex internal motions of vinyl group.It is shown by calculation that the dominant factor causing the difference in nT1 of—CH=and=CH2 in vinyl group is a swing of vinyl group in a plane perpendicular to the chain backbone.
1986, 4(1): 17-23
Abstract:
The resin solution of NA capped‘PMR' type polyamide-imide was prepared from bicyclo [2.2.1]-hept-5-ene-2, 3-dicarboxylic acid ethyl ester,1, 2, 4-trimellitic acid-2-(or-1-) ethyl ester and 4,4'-methylenedianiline in ethanol. This resin solution is specially suitable for the preparation of compo-sites. The fiexural strength of the glass cloth reinforced plastics was 6000--7000 kg/cm2 (RM) and4000--kg/cm2 (260°--300℃), respectively. The result of isothermal aging for 800 hours in-dicated that this composite can be used at 260℃.The mechanism of the formation of polyamideimide was discussed by using appropriate model compounds.
The resin solution of NA capped‘PMR' type polyamide-imide was prepared from bicyclo [2.2.1]-hept-5-ene-2, 3-dicarboxylic acid ethyl ester,1, 2, 4-trimellitic acid-2-(or-1-) ethyl ester and 4,4'-methylenedianiline in ethanol. This resin solution is specially suitable for the preparation of compo-sites. The fiexural strength of the glass cloth reinforced plastics was 6000--7000 kg/cm2 (RM) and4000--kg/cm2 (260°--300℃), respectively. The result of isothermal aging for 800 hours in-dicated that this composite can be used at 260℃.The mechanism of the formation of polyamideimide was discussed by using appropriate model compounds.
1986, 4(1): 24-34
Abstract:
Liquid organosilane polmers have been synthesized by sodium coupling of diorganodichloro-silanes with diphenylmethylchlorosilane in toluene. These polysilanes can be formed into desiredshape by potting, casting or coating and crosslinked under ultraviolet irradiation in the presenceof multifunctional vi?ylsilanes. The molecular weight distributions, infra-red, ultraviolet andnuclear magnetic resonance spectra for the organosilane polymers have been described.
Liquid organosilane polmers have been synthesized by sodium coupling of diorganodichloro-silanes with diphenylmethylchlorosilane in toluene. These polysilanes can be formed into desiredshape by potting, casting or coating and crosslinked under ultraviolet irradiation in the presenceof multifunctional vi?ylsilanes. The molecular weight distributions, infra-red, ultraviolet andnuclear magnetic resonance spectra for the organosilane polymers have been described.
1986, 4(1): 35-42
Abstract:
A polymeric method was explored for the preparation of polyester-polyether multiblock copoly-mers using polyesters and polpethers as starting materials. The mechanism of the reaction and theeffect of the segment structure on it, the segment sequence of the block copolymers prepared havebeen studied. It has been shown that to the polymeric method the degree of compatibility betweenstarting polyester and polyether is of paramount importance, which determines not only the com-positional homogeneity of the block copolymers formed but also the success of the polymeric method to get the block copolymers of the expected structure.
A polymeric method was explored for the preparation of polyester-polyether multiblock copoly-mers using polyesters and polpethers as starting materials. The mechanism of the reaction and theeffect of the segment structure on it, the segment sequence of the block copolymers prepared havebeen studied. It has been shown that to the polymeric method the degree of compatibility betweenstarting polyester and polyether is of paramount importance, which determines not only the com-positional homogeneity of the block copolymers formed but also the success of the polymeric method to get the block copolymers of the expected structure.
THE OVERALL KINETICS OF FREE RADICAL (CO)POLYMERIZATION WITH HIGHLY DIFFUSION CONTROLLED TERMINATION
1986, 4(1): 43-53
Abstract:
The overall reaction rate kinetics of polymerization of diethyleneglycol dimethacrylate and copolymerization of it with styrene in bulk and in the presence of inert diluents were investigated. The results indicated that these reactions can be treated as free radical polymerization with highly diffu-sion controlled termination reaction in which the termination rate constant is an empirically derivedfunction of monomer conversion: Kt=Kto(1-c ln[M]/ [M0])-1 in which Kto is the initial termination rate constant and c is a factor related to the magnitude of diffusion contro! The following equantion of monomer conversion as a function of time could then be derived:U=1-exp{1/c[1-(1+ckt/2)2]} in which k=Kp(Ri/2Kt0)1/2 and t is the time of reaction.Excellent agreement between the thoretical and experimental overall reaction kinetic curves was obtained.The equation is valid for crosslinking and noncrosslinking free radical polymerizations in which the self-acceleration effect is effective from the very begining of the reaction.The equantion can be expressed in a more generally applicable form:U=1-exp{1/c[1-1(1+cks/n)n]} in which n ≥0.
The overall reaction rate kinetics of polymerization of diethyleneglycol dimethacrylate and copolymerization of it with styrene in bulk and in the presence of inert diluents were investigated. The results indicated that these reactions can be treated as free radical polymerization with highly diffu-sion controlled termination reaction in which the termination rate constant is an empirically derivedfunction of monomer conversion: Kt=Kto(1-c ln[M]/ [M0])-1 in which Kto is the initial termination rate constant and c is a factor related to the magnitude of diffusion contro! The following equantion of monomer conversion as a function of time could then be derived:U=1-exp{1/c[1-(1+ckt/2)2]} in which k=Kp(Ri/2Kt0)1/2 and t is the time of reaction.Excellent agreement between the thoretical and experimental overall reaction kinetic curves was obtained.The equation is valid for crosslinking and noncrosslinking free radical polymerizations in which the self-acceleration effect is effective from the very begining of the reaction.The equantion can be expressed in a more generally applicable form:U=1-exp{1/c[1-1(1+cks/n)n]} in which n ≥0.
1986, 4(1): 54-64
Abstract:
The melting behavior of poly(ethylene-alt-tetrafluoroethylene) γ-irradiated in air and vacuumwas studied by DSC. From the results of DSC and density measurements the equilibrium heat offusion, △AHom,and the density of the amorphous phase, ρα, of the polymer were estimated as 172J/gand 1.63g/cm3 respectively. Thereby the degree of crystallinity of this copolymer can be evaluatedby both density and calorimetric methods. The crystal structure was damaged gradually and eventuallycompletely destroyed with the increase in radiation dose from 0.3 to 900 Mrads.Exclusion of air was advantageous in lessening the damage of the crystal while increase in the degree of vacuum favored the formation of crosslinks.Small peaks appearing both on the DSC endotherm(600K) and on the exotherm(540K) resulted from the presence of small amount of tetrafluoroethylene blocks along the main chain of poly(ethylene-alt-tetrafluoroethylene).
The melting behavior of poly(ethylene-alt-tetrafluoroethylene) γ-irradiated in air and vacuumwas studied by DSC. From the results of DSC and density measurements the equilibrium heat offusion, △AHom,and the density of the amorphous phase, ρα, of the polymer were estimated as 172J/gand 1.63g/cm3 respectively. Thereby the degree of crystallinity of this copolymer can be evaluatedby both density and calorimetric methods. The crystal structure was damaged gradually and eventuallycompletely destroyed with the increase in radiation dose from 0.3 to 900 Mrads.Exclusion of air was advantageous in lessening the damage of the crystal while increase in the degree of vacuum favored the formation of crosslinks.Small peaks appearing both on the DSC endotherm(600K) and on the exotherm(540K) resulted from the presence of small amount of tetrafluoroethylene blocks along the main chain of poly(ethylene-alt-tetrafluoroethylene).
1986, 4(1): 65-71
Abstract:
Several polymer-supported palladium complex catalysts containing two different coordinating groups were prepared and the cooperative effect of the coordinating groups on the catalytic behaviors of polymer catalysts was studied. It was found that poly(acrylic acid-co-acrylonitrile)-Pd complex(PAA-AN-Pd) is a more active and stable catalyst for hydrogenation than both poly(acrylic acid)-Pd and poly(acrylonitrile)-Pd complexes. A marked change of catalytic behaviors of poly(N-substituted maleamic acid-co-styrene)-Pd complexes was observed in comparison with poly(maleic acid-co-styrene)-Pd complex.Acetophenone was reduced to 1-phenyl ethanol by poly(N-phenyl maleamic acid-co-styrene)-Pd complex (N-1-Pd),but ethylbenzene was obtained using poly(maleic acid-co-styrene)-Pd complex as a catalyst.The influence of solvents,additives and N/Pd gram atomic ratio on the catalttic behaviors of the polymer complexes was investigated.
Several polymer-supported palladium complex catalysts containing two different coordinating groups were prepared and the cooperative effect of the coordinating groups on the catalytic behaviors of polymer catalysts was studied. It was found that poly(acrylic acid-co-acrylonitrile)-Pd complex(PAA-AN-Pd) is a more active and stable catalyst for hydrogenation than both poly(acrylic acid)-Pd and poly(acrylonitrile)-Pd complexes. A marked change of catalytic behaviors of poly(N-substituted maleamic acid-co-styrene)-Pd complexes was observed in comparison with poly(maleic acid-co-styrene)-Pd complex.Acetophenone was reduced to 1-phenyl ethanol by poly(N-phenyl maleamic acid-co-styrene)-Pd complex (N-1-Pd),but ethylbenzene was obtained using poly(maleic acid-co-styrene)-Pd complex as a catalyst.The influence of solvents,additives and N/Pd gram atomic ratio on the catalttic behaviors of the polymer complexes was investigated.
1986, 4(1): 72-77
Abstract:
The 1H and 13C NMR spectra of polyether-polyurethancs (A) based on 4, 4'-diphenylmethanediisocyanate (MDI), N-methyl diethanolamine (MDEA), and polytetramethyleneoxide (PTMO)and the zwitterionomers derived from A with various degree of ionization was assigned by comparingwith model compounds. Phase separation of the samples was visualized through pulsed NMR investigations. The FID signals of these multiphase elastomers were recorded and decomposed by non-linear least squaresregression into fast Gaussian and slow exponential components associated with the hard,the soft and the interface respectively.Thus pulsed NMR gives both qualitative and quantitative information about the existence of multiphases and the relative amounts of materials in each phase.
The 1H and 13C NMR spectra of polyether-polyurethancs (A) based on 4, 4'-diphenylmethanediisocyanate (MDI), N-methyl diethanolamine (MDEA), and polytetramethyleneoxide (PTMO)and the zwitterionomers derived from A with various degree of ionization was assigned by comparingwith model compounds. Phase separation of the samples was visualized through pulsed NMR investigations. The FID signals of these multiphase elastomers were recorded and decomposed by non-linear least squaresregression into fast Gaussian and slow exponential components associated with the hard,the soft and the interface respectively.Thus pulsed NMR gives both qualitative and quantitative information about the existence of multiphases and the relative amounts of materials in each phase.
1986, 4(1): 78-83
Abstract:
The compositional heterogeneity has been studied for a series of PCL/MDI/BDO segmentedpolyurethanes. Their average hard segment content measured by NMR method was ranging from 17% to 42%. Macromolecules of segmented polyurethanes can be separated according to theircomposition by TLC technique with a mixed solvent of toluene/acetone/ tetrahydrofuran as the devel-oper. A dual wavelength TLC spectrodensitometer was used for quantitative analysis of TLC results,and method for data treatment is proposed to obtain the composition distribution with no need of any reference samples as TLC eluticn standards.The polyurethane samples are found to be heterogeneous in composition,having bimodal distribution curves.
The compositional heterogeneity has been studied for a series of PCL/MDI/BDO segmentedpolyurethanes. Their average hard segment content measured by NMR method was ranging from 17% to 42%. Macromolecules of segmented polyurethanes can be separated according to theircomposition by TLC technique with a mixed solvent of toluene/acetone/ tetrahydrofuran as the devel-oper. A dual wavelength TLC spectrodensitometer was used for quantitative analysis of TLC results,and method for data treatment is proposed to obtain the composition distribution with no need of any reference samples as TLC eluticn standards.The polyurethane samples are found to be heterogeneous in composition,having bimodal distribution curves.
1986, 4(1): 84-91
Abstract:
A series of liquid chloroprene-hydroxyethyl methacrylate copolymer (CP-HEMA) modifiedepoxy resin were prepared. The effects of CP-HEMA content, curing conditions on physical pro-perties of the modified system were examined. With IR and Viscoelastocuremeter, the curing reactionrate was determined and the mechanism of the curing reaction was discussed. The effects of CP-HEMA content and curing conditions on morphology were mainly observed by scanning electronmicroscopy.
A series of liquid chloroprene-hydroxyethyl methacrylate copolymer (CP-HEMA) modifiedepoxy resin were prepared. The effects of CP-HEMA content, curing conditions on physical pro-perties of the modified system were examined. With IR and Viscoelastocuremeter, the curing reactionrate was determined and the mechanism of the curing reaction was discussed. The effects of CP-HEMA content and curing conditions on morphology were mainly observed by scanning electronmicroscopy.
1986, 4(1): 92-99
Abstract:
The effects of Morpholine, N-methyl morpholine, and N-ethyl morpholine on methyl methacrylatepolytherization initiated with organic peroxides were studied. The polymerization rate Rp, theoverall activation energy of polymerization Ea, and the rate equation of polymerization weredetermined.
The effects of Morpholine, N-methyl morpholine, and N-ethyl morpholine on methyl methacrylatepolytherization initiated with organic peroxides were studied. The polymerization rate Rp, theoverall activation energy of polymerization Ea, and the rate equation of polymerization weredetermined.
1986, 4(1): 100-104
Abstract:
Active esters, 8-acryloyloxyquinoline (AQ) and 8--methacryloyloxyquinoline (MAQ) were synthe-sized and characterized. It was found that polymers of these two monomers can react with nucleophilicreagents such as amines or alcohols under mildcondition. The ammonolysis yield of P(AQ) for aliphaticamines were above 60% and the specific activity of the immobilized glucoamylase on P(AQ) andP(MAQ) was 5328 u/g and 4320 u/g, respectively.
Active esters, 8-acryloyloxyquinoline (AQ) and 8--methacryloyloxyquinoline (MAQ) were synthe-sized and characterized. It was found that polymers of these two monomers can react with nucleophilicreagents such as amines or alcohols under mildcondition. The ammonolysis yield of P(AQ) for aliphaticamines were above 60% and the specific activity of the immobilized glucoamylase on P(AQ) andP(MAQ) was 5328 u/g and 4320 u/g, respectively.
1986, 4(1): 105-108
Abstract:
Carboxylated poly-n-butyl acrylates were used as model polymeric dispersant. The effect ofpolymers on the dispersion of γ-Fe2O3 in cyclohexanone were studied through sedimentation testand rheological measurement. The polymers with strong anchoring groups at one end of the polymerchain were the most effective polymeric dispersant, which improved magnetic properties of the preparedcoatings significantly.
Carboxylated poly-n-butyl acrylates were used as model polymeric dispersant. The effect ofpolymers on the dispersion of γ-Fe2O3 in cyclohexanone were studied through sedimentation testand rheological measurement. The polymers with strong anchoring groups at one end of the polymerchain were the most effective polymeric dispersant, which improved magnetic properties of the preparedcoatings significantly.
