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1993 Volume 10 Issue 6
1993, 10(6): 1-5
Abstract:
A novel class of nonionie fluoroalkylated poly(oxyethylene)-type surfactants has been prepared in good yields in three steps,namely O-allylation of polyethylene glycol (PEG),perfluoroalkyiation using RFI/Na2S2O4 and reduction.
A novel class of nonionie fluoroalkylated poly(oxyethylene)-type surfactants has been prepared in good yields in three steps,namely O-allylation of polyethylene glycol (PEG),perfluoroalkyiation using RFI/Na2S2O4 and reduction.
1993, 10(6): 6-9
Abstract:
An enzyme microeleetrode for glucose determination has been prepared from glucose oxidase and dimerhylferrocene (DMFc) immobilized in Eastman-AQ film on microdisk array of carbon fibers.The ferrocene derivative couple(Fc/Fc+) plays the role of mediator for electron transfer between immobilized glucose oxidase and the electrode. A linear current response to the glucose concentration over a range of 1~12mmol/L was observed at this en zyme microelectrode. The influences of pH and temperature on the enzyme electrode behavior are also presented. The response times was found to be less than 15s. The interference of the electroactive species such as ascorbic and uric acid could be effectively depressed. The resuits of analysis of serum samples were in good agreement with those obtained by photometric analysis.
An enzyme microeleetrode for glucose determination has been prepared from glucose oxidase and dimerhylferrocene (DMFc) immobilized in Eastman-AQ film on microdisk array of carbon fibers.The ferrocene derivative couple(Fc/Fc+) plays the role of mediator for electron transfer between immobilized glucose oxidase and the electrode. A linear current response to the glucose concentration over a range of 1~12mmol/L was observed at this en zyme microelectrode. The influences of pH and temperature on the enzyme electrode behavior are also presented. The response times was found to be less than 15s. The interference of the electroactive species such as ascorbic and uric acid could be effectively depressed. The resuits of analysis of serum samples were in good agreement with those obtained by photometric analysis.
1993, 10(6): 10-13
Abstract:
Interpenetrating polymer networks(IPN) were formed by simultaneous polymerization of castor oil, toluene diisocyanate and vinyl monomers using redox initiator and dibutyl tin dilaurate as catalyst at room temperature. The effect of composition of the IPNs on lap shear strength of the IPN between iron plates without rust removal has been studied. The results showed that the lap shear strength increases with increasing glass transition temperature of the polymer prepared. The higher the molar ratio of NCO/OH, the higher the lap shear strength. The coating formed by the castor oil polyurethane/poly(styrene-acryloni-trile) IPN on the iron plate without rust removal showed very good properties with respect to adherence, impact strength, flexibility and resistance to oil, dilute acid, alkali and brine.The surface of the rusted iron plate and the coated film were examined by SEM.
Interpenetrating polymer networks(IPN) were formed by simultaneous polymerization of castor oil, toluene diisocyanate and vinyl monomers using redox initiator and dibutyl tin dilaurate as catalyst at room temperature. The effect of composition of the IPNs on lap shear strength of the IPN between iron plates without rust removal has been studied. The results showed that the lap shear strength increases with increasing glass transition temperature of the polymer prepared. The higher the molar ratio of NCO/OH, the higher the lap shear strength. The coating formed by the castor oil polyurethane/poly(styrene-acryloni-trile) IPN on the iron plate without rust removal showed very good properties with respect to adherence, impact strength, flexibility and resistance to oil, dilute acid, alkali and brine.The surface of the rusted iron plate and the coated film were examined by SEM.
1993, 10(6): 14-18
Abstract:
The single-ion conducting polymer electrolytes with carboxylate groups immobilized on the backbones have been synthesized by alcoholysis of maleic anhydride-styrene or maleic anhydride-vinyl acetate copolymers with PEO monomethyl ether. The plasticized comblike polymeric lithium salt film showed conductivity up to 10-6 S/cm at room temperature. The effects of polymer structure, cation radius, plasticizer, temperature and frequency on the conductivity were investigated.
The single-ion conducting polymer electrolytes with carboxylate groups immobilized on the backbones have been synthesized by alcoholysis of maleic anhydride-styrene or maleic anhydride-vinyl acetate copolymers with PEO monomethyl ether. The plasticized comblike polymeric lithium salt film showed conductivity up to 10-6 S/cm at room temperature. The effects of polymer structure, cation radius, plasticizer, temperature and frequency on the conductivity were investigated.
1993, 10(6): 19-22
Abstract:
Ionic conductivity of a new kind of polyelectrolyte, polyphenyleneoxide sulfonic lithium (SPPOLi) blended with polyethyleneglycol has been examined. The blends bear the characteristics of single ion conductor. Both the molar ratio of SPPOLi to PEG and the molecular weight of PEG showed influences on the conductivity. Ionic conductivity up to 8×10-5S/cm at room temperature was observed.
Ionic conductivity of a new kind of polyelectrolyte, polyphenyleneoxide sulfonic lithium (SPPOLi) blended with polyethyleneglycol has been examined. The blends bear the characteristics of single ion conductor. Both the molar ratio of SPPOLi to PEG and the molecular weight of PEG showed influences on the conductivity. Ionic conductivity up to 8×10-5S/cm at room temperature was observed.
1993, 10(6): 23-26
Abstract:
The catalytic activity of NiSO4/γ-Al2O3 in propene oligomerization is greatly influenced by the acidity of the catalyst used. It was found that the acid sites related to propene oligomerization are only those of H0≤-3.0. The generation of Ni+ and its role as an active site in the oligomerization were demonstrated by the electronspin resonance method (ESR) and CO poisoning. The oligomerization is believed to be proceeded by coordination catalysis over Ni+ as well as acid catalysis over the acid sites of the supported catalyst.
The catalytic activity of NiSO4/γ-Al2O3 in propene oligomerization is greatly influenced by the acidity of the catalyst used. It was found that the acid sites related to propene oligomerization are only those of H0≤-3.0. The generation of Ni+ and its role as an active site in the oligomerization were demonstrated by the electronspin resonance method (ESR) and CO poisoning. The oligomerization is believed to be proceeded by coordination catalysis over Ni+ as well as acid catalysis over the acid sites of the supported catalyst.
1993, 10(6): 27-30
Abstract:
The crystals of YPxV1-xO4 (0 ≤x ≤1) are tetragonal. With increase of x, their lattice parameters linearly decrease, the Stokes shifts increase and the peak of excitation spectra shifts to shorter wavelenghth. The luminescence effieiencies of the matrix and Dy3+ and the yellow-to-blue intensity ratio of Dy3+ are related to x. For compound YPxV1-xO4: 0.006Dy3+ the matrix emission is caused by PO43-, when x>0.4. The influences of Bi3+ and temperature On the emission intensity of Dy3+ were also investigated.
The crystals of YPxV1-xO4 (0 ≤x ≤1) are tetragonal. With increase of x, their lattice parameters linearly decrease, the Stokes shifts increase and the peak of excitation spectra shifts to shorter wavelenghth. The luminescence effieiencies of the matrix and Dy3+ and the yellow-to-blue intensity ratio of Dy3+ are related to x. For compound YPxV1-xO4: 0.006Dy3+ the matrix emission is caused by PO43-, when x>0.4. The influences of Bi3+ and temperature On the emission intensity of Dy3+ were also investigated.
1993, 10(6): 31-34
Abstract:
The extraction of scandium picrate by benzo-15-crown-5 (B15C5) and dibenzo-18-crown-6(DB18C6) has been studied. The compositions of the extracts have been determined by the slope analysis method as Sc(B15C5)1.5(OH)(Pi)2 and Sc(DB18C6)(OH)(Pi)2(Pi=pi-crate ion) with apparent extraction equilibrium constants logKex=5.69 and 3.59 (25℃), respectively. The crystal of the Sc(B15C5)Pi3·2H2O·CH3CN belongs to triclinic system,space group P1, a=1.2678(2), b=1.3764(3), c=1.9440(4)nm, α=81.03(2)°, β=70.88 (1)°, γ=70.71(2)°, Z=2. The mechanism of the extraction has been elucidated.
The extraction of scandium picrate by benzo-15-crown-5 (B15C5) and dibenzo-18-crown-6(DB18C6) has been studied. The compositions of the extracts have been determined by the slope analysis method as Sc(B15C5)1.5(OH)(Pi)2 and Sc(DB18C6)(OH)(Pi)2(Pi=pi-crate ion) with apparent extraction equilibrium constants logKex=5.69 and 3.59 (25℃), respectively. The crystal of the Sc(B15C5)Pi3·2H2O·CH3CN belongs to triclinic system,space group P1, a=1.2678(2), b=1.3764(3), c=1.9440(4)nm, α=81.03(2)°, β=70.88 (1)°, γ=70.71(2)°, Z=2. The mechanism of the extraction has been elucidated.
1993, 10(6): 35-38
Abstract:
Blends of thermotropic liquid crystalline ethylcellulose and polypropylene (EC/PP) were investigated by polarizing microscopy, DSC,X-ray diffractometry, rheometeric and mechanical measurements. It is found that the blends have a clear and flocky strip structure in the orientation direction. The spherules of PP were found to be damaged with the EC content in the blends. An increase of EC content in the blends led to the increase of Tc,decrease of △Hm and Tm,the nucleation ability as well as the crystallinity of the blends. It also caused reduction of crystalline size of (110) plane and increase of crystalline size of (040) plane. Blend with EC:PP=10:90 showed an increase in tensile modulus.
Blends of thermotropic liquid crystalline ethylcellulose and polypropylene (EC/PP) were investigated by polarizing microscopy, DSC,X-ray diffractometry, rheometeric and mechanical measurements. It is found that the blends have a clear and flocky strip structure in the orientation direction. The spherules of PP were found to be damaged with the EC content in the blends. An increase of EC content in the blends led to the increase of Tc,decrease of △Hm and Tm,the nucleation ability as well as the crystallinity of the blends. It also caused reduction of crystalline size of (110) plane and increase of crystalline size of (040) plane. Blend with EC:PP=10:90 showed an increase in tensile modulus.
1993, 10(6): 39-43
Abstract:
UV-curable epoxy acrylates were prepared by reacting epoxy resin with acrylic acid in the presence of quaternary ammonium salt. The effects of temperature, inhibitors,catalysts and others on the reaction have been examined. The mechanism and the kinetics are discussed. The UV-curing was determined by IR spectra. In the presence of 0.6%~1.2% quaternary ammonium salt at 90~110℃, after 4.5~8 hours, the conversion of the epoxy group achieved over 97% and the paint obtained could be cured fast by UV-light irradiation.
UV-curable epoxy acrylates were prepared by reacting epoxy resin with acrylic acid in the presence of quaternary ammonium salt. The effects of temperature, inhibitors,catalysts and others on the reaction have been examined. The mechanism and the kinetics are discussed. The UV-curing was determined by IR spectra. In the presence of 0.6%~1.2% quaternary ammonium salt at 90~110℃, after 4.5~8 hours, the conversion of the epoxy group achieved over 97% and the paint obtained could be cured fast by UV-light irradiation.
1993, 10(6): 44-48
Abstract:
The effects of maleic anhydride (MA) and triallylisoeyanurate (TAIC) on the structure and properties of PPC/NBR elastomers have been examined. Dynamic mechanical and TEM results showed that MA or TAIC can effectively improve the cross-linking structure of the elastomers. The mechanical properties and thermo-oxidative resistance of the elastomers were greatly improved by adding MA;Addition of TAIC increased the oil resistance and the mechanical properties of PPC/NBR elastomers.
The effects of maleic anhydride (MA) and triallylisoeyanurate (TAIC) on the structure and properties of PPC/NBR elastomers have been examined. Dynamic mechanical and TEM results showed that MA or TAIC can effectively improve the cross-linking structure of the elastomers. The mechanical properties and thermo-oxidative resistance of the elastomers were greatly improved by adding MA;Addition of TAIC increased the oil resistance and the mechanical properties of PPC/NBR elastomers.
1993, 10(6): 49-52
Abstract:
In this work, the adjacency matrices of molecules are extended. The extended matrices are defined as EA matrices. Two new topological indexes based on the eigenvalues of the EA matrices are EAΣ and EAmax. EAΣ is the sum of the absolute eigenvalues of the EA matrices, and EAmax is the maximum of the absolute eigenvalues of the EA matrices EAΣ and EAmax are called EA Seriers Indexes(EASI). Research shows that EASI are highly discriminating and well correlated with some physicochemical properties of organic compounds.
In this work, the adjacency matrices of molecules are extended. The extended matrices are defined as EA matrices. Two new topological indexes based on the eigenvalues of the EA matrices are EAΣ and EAmax. EAΣ is the sum of the absolute eigenvalues of the EA matrices, and EAmax is the maximum of the absolute eigenvalues of the EA matrices EAΣ and EAmax are called EA Seriers Indexes(EASI). Research shows that EASI are highly discriminating and well correlated with some physicochemical properties of organic compounds.
1993, 10(6): 53-55
Abstract:
Trioetyl amine (TOA) was microencapsulated on ethyl cellulose for Cr(Ⅵ) extraction in acid medium. An column form apparatus has been assembled. The extractive capacity of the microcapsules was 158.0mg·mL-1,4.9 times that of the pure TOA. The microcapsules can be regenerated by NaOH solution and water and used repeatedly.
Trioetyl amine (TOA) was microencapsulated on ethyl cellulose for Cr(Ⅵ) extraction in acid medium. An column form apparatus has been assembled. The extractive capacity of the microcapsules was 158.0mg·mL-1,4.9 times that of the pure TOA. The microcapsules can be regenerated by NaOH solution and water and used repeatedly.
1993, 10(6): 56-60
Abstract:
Condensation of 3-(3'-pyridyl)-4-amino-5-mercapto-1,2,4-triazole 4 with aromatic or fatty acids in the presence of phosphorus oxychloride gave 24 novel 3-(3'-Pyridyl)-6-alkyl/aryl-s-triazolo[3,4-b]-1, 3,4-thiadiazoles 5α-x. Their structures were confirmed by elemental and spectral analyses. Some of the compounds were found to have some moderately fungicidal and herbicidal activities.
Condensation of 3-(3'-pyridyl)-4-amino-5-mercapto-1,2,4-triazole 4 with aromatic or fatty acids in the presence of phosphorus oxychloride gave 24 novel 3-(3'-Pyridyl)-6-alkyl/aryl-s-triazolo[3,4-b]-1, 3,4-thiadiazoles 5α-x. Their structures were confirmed by elemental and spectral analyses. Some of the compounds were found to have some moderately fungicidal and herbicidal activities.
1993, 10(6): 61-65
Abstract:
The homogeneous graft copolymerization of nitrocellulose with methyl methacrylate has been carried out and the mechanism has been evaluated by FTIR, SEM and TEM techniques. It is suggested that the graft copolymerization might proceed through denitration of nitrocellulose and take place not only on the surface of nitrocellulose but also in some oriented crystalline rigion of nitrocellulose polymer.
The homogeneous graft copolymerization of nitrocellulose with methyl methacrylate has been carried out and the mechanism has been evaluated by FTIR, SEM and TEM techniques. It is suggested that the graft copolymerization might proceed through denitration of nitrocellulose and take place not only on the surface of nitrocellulose but also in some oriented crystalline rigion of nitrocellulose polymer.
1993, 10(6): 66-70
Abstract:
The kinetics of isothermal crystallization of ethylene oxide and propylene oxide copolymers has been investigated by differential scanning calorimetry. The values of Avrami exponent n were found as 1.8~2.4. The nueleanlon process in crystallization temperature takes place according to regime Ⅱ The eqilibrium melting points of EO/PO copolymer decrease with increasing content of PO. The crystal growtb rate Gis in dependence on the composition of the copolymer and the crystalization temparature.
The kinetics of isothermal crystallization of ethylene oxide and propylene oxide copolymers has been investigated by differential scanning calorimetry. The values of Avrami exponent n were found as 1.8~2.4. The nueleanlon process in crystallization temperature takes place according to regime Ⅱ The eqilibrium melting points of EO/PO copolymer decrease with increasing content of PO. The crystal growtb rate Gis in dependence on the composition of the copolymer and the crystalization temparature.
1993, 10(6): 71-75
Abstract:
The infrared spectra of three series of thirty-one kinds heteropoly compounds (2:18,1:11 and bis series) related to the Keggin structure e.g. NP2W18(N=(CH3)4N+,(C2H5),N+, (C4H9)4N+), MP2W18 (M=Li+, Na+, Ag+, Cu2+); KnZW11 (Z=P, B, Ge, Si),MSiW11(M=Mn,Zn,Cu,Co,Ni) and M(PW11)2(M=Ce,Pr,Nd,Sm,Eu,Gd,Tb,Ho,Yb),M(PMo11)2(M=La, Ce, Pr, Sm, Gd, Tb) have been compared. The vibrational regularity of oxygen-containing bonds in all heteropoly compounds has been deduced. The effects of countercations on the oxygen bonds of the heteropolyanion were discussed. The verical relationship of compounds related to the fifteen kinds were analysed. The results proved that 1:11 series of heteropoly compounds are octahadral weak-field ligands.
The infrared spectra of three series of thirty-one kinds heteropoly compounds (2:18,1:11 and bis series) related to the Keggin structure e.g. NP2W18(N=(CH3)4N+,(C2H5),N+, (C4H9)4N+), MP2W18 (M=Li+, Na+, Ag+, Cu2+); KnZW11 (Z=P, B, Ge, Si),MSiW11(M=Mn,Zn,Cu,Co,Ni) and M(PW11)2(M=Ce,Pr,Nd,Sm,Eu,Gd,Tb,Ho,Yb),M(PMo11)2(M=La, Ce, Pr, Sm, Gd, Tb) have been compared. The vibrational regularity of oxygen-containing bonds in all heteropoly compounds has been deduced. The effects of countercations on the oxygen bonds of the heteropolyanion were discussed. The verical relationship of compounds related to the fifteen kinds were analysed. The results proved that 1:11 series of heteropoly compounds are octahadral weak-field ligands.
1993, 10(6): 76-79
Abstract:
The kinetics of the extraction of Nd(Ⅲ) by di-(1-methyl heptyl)methyl phosphonate (P350) in nitric acid solution has been studied by using the constant-interface cell technique. The effects of the stirring speed,interfacial area between two phases,temperature,and concentration of P350,NO3-,amd H+ on the extraction rate have been examined. The apparent activation energy was found to be 11.8kJ/mol. The experimental results showed that the rate-controlling step may be the chemical reaction at the interface. A cation exchange mechanism has been proposed.
The kinetics of the extraction of Nd(Ⅲ) by di-(1-methyl heptyl)methyl phosphonate (P350) in nitric acid solution has been studied by using the constant-interface cell technique. The effects of the stirring speed,interfacial area between two phases,temperature,and concentration of P350,NO3-,amd H+ on the extraction rate have been examined. The apparent activation energy was found to be 11.8kJ/mol. The experimental results showed that the rate-controlling step may be the chemical reaction at the interface. A cation exchange mechanism has been proposed.
1993, 10(6): 80-82
Abstract:
Zeolite ZSM-12 has been synthesized by the hydrothermal method from the mixture of Na2O-Al2O3-SiO2-methyhriethylammonium iodide-H2O at 433K in a static autoclave.The products have SiO2/Al2O3≥32.2. The thermal stability and catalytic activity of ZSM-12 in the alkylation of benzene-ethylene have been examined.
Zeolite ZSM-12 has been synthesized by the hydrothermal method from the mixture of Na2O-Al2O3-SiO2-methyhriethylammonium iodide-H2O at 433K in a static autoclave.The products have SiO2/Al2O3≥32.2. The thermal stability and catalytic activity of ZSM-12 in the alkylation of benzene-ethylene have been examined.
1993, 10(6): 83-85
Abstract:
Eight amide derivatives of β-carboxyethylgermanium sesquioxides of ethyl glycihate,ethyl phenylalaninate,piperidine, 2-amino-benzothiazole and 4-aminopyridine were prepared by two defferent methods and characterized by elemental analysis, IR and 1H NMR spectra. The influence of three of these compounds on human cancer and diploid cells were observed in vitro.
Eight amide derivatives of β-carboxyethylgermanium sesquioxides of ethyl glycihate,ethyl phenylalaninate,piperidine, 2-amino-benzothiazole and 4-aminopyridine were prepared by two defferent methods and characterized by elemental analysis, IR and 1H NMR spectra. The influence of three of these compounds on human cancer and diploid cells were observed in vitro.
1993, 10(6): 86-88
Abstract:
α-Methyl pyrazones have been reacted with aryl diazonium salts to form 3-arylhy-drazones-6-methyl-2,4-dioxopyranones,which are converted to 1-aryl-6-methyl-4-oxo-pyri-dazinone-3-carboxylic acids by cyclization. A series of 4-pyridazinone-3-amides were obtained by reacting the carboxylic acids with ethylchlorocarboxylate and corresponding amines. The structures of new compounds thus obtained were checked by elemental analyses,IR,NMR and MS measurements.
α-Methyl pyrazones have been reacted with aryl diazonium salts to form 3-arylhy-drazones-6-methyl-2,4-dioxopyranones,which are converted to 1-aryl-6-methyl-4-oxo-pyri-dazinone-3-carboxylic acids by cyclization. A series of 4-pyridazinone-3-amides were obtained by reacting the carboxylic acids with ethylchlorocarboxylate and corresponding amines. The structures of new compounds thus obtained were checked by elemental analyses,IR,NMR and MS measurements.
1993, 10(6): 89-91
Abstract:
Triphenylmethyl acrylate and diphenyl-o-tolylmethyl acrylate were synthesized for the first time. Optically active polymers with one-handed helical conformations can be obtained through asymmetric polymerization of the above two monomers in the presence of chiral ligands. Compared with poly(triphenylmethyl methacrylate), both poly(triphenylmethyl acrylate) and poly(diphenyl-o-tolylmethyl acrylate) showed lower specific rotations due to the absence of methyl group at the a position of the double bonds.
Triphenylmethyl acrylate and diphenyl-o-tolylmethyl acrylate were synthesized for the first time. Optically active polymers with one-handed helical conformations can be obtained through asymmetric polymerization of the above two monomers in the presence of chiral ligands. Compared with poly(triphenylmethyl methacrylate), both poly(triphenylmethyl acrylate) and poly(diphenyl-o-tolylmethyl acrylate) showed lower specific rotations due to the absence of methyl group at the a position of the double bonds.
1993, 10(6): 92-94
Abstract:
Poly (styrene-4-vinylpyridine)-neodymium complexes (NdCl3·PS4VPY) with various contents of the functional group and neodymium have been prepared and characterized. The infrared and X-ray photoelectron spectra indicate that the uncoordinated 4vinylpyridine (4VPY) units remain in the NdCl3·PS4VPY complexes. A novel binary catalytic system for butadiene polymerization can be formed from NdCl3·PS4VPY and iBu3Al, showing a catalytic activity much greater than the similar low molecular catalysts.
Poly (styrene-4-vinylpyridine)-neodymium complexes (NdCl3·PS4VPY) with various contents of the functional group and neodymium have been prepared and characterized. The infrared and X-ray photoelectron spectra indicate that the uncoordinated 4vinylpyridine (4VPY) units remain in the NdCl3·PS4VPY complexes. A novel binary catalytic system for butadiene polymerization can be formed from NdCl3·PS4VPY and iBu3Al, showing a catalytic activity much greater than the similar low molecular catalysts.
1993, 10(6): 95-96
Abstract:
A spectrophotometric method has been described for determination of isoniazide based on its charge transfer reaction with p-benzoquinone in ethanol.
A spectrophotometric method has been described for determination of isoniazide based on its charge transfer reaction with p-benzoquinone in ethanol.
1993, 10(6): 97-98
Abstract:
Six aryloxy(arylthio)carboxylic acids have been synthesized using supersonic wave radiation in solid-liquid medium. Compared with the phase-transfer catalysis and the classical methods, this method has advantages of good yields, short reaction time, easy preparation and mild reaction conditions.
Six aryloxy(arylthio)carboxylic acids have been synthesized using supersonic wave radiation in solid-liquid medium. Compared with the phase-transfer catalysis and the classical methods, this method has advantages of good yields, short reaction time, easy preparation and mild reaction conditions.
1993, 10(6): 99-101
Abstract:
La1-xMxFeyCo1-yO3(M=Sr,Ba,x=0.1~0.9,y=0.1~0.9) have been prepared. The crystal of La0.7Sr0.3FeyCo1-yO3(y=0.1,0.3) is rbombohedral. The crystal of other compounds is cubic. The lattice parameters of La1-xMxFeyCo1-yO3 increase with increasing the yvalue. The lattice parameters of La1-xSrxFe0.7Co0.3O3 decrease with the increase of the x value, but that of La1-xBaxFe0.7Co0.3O3 increase with the increase of the x value. All the compounds are semiconductors. Their resistivities increase with increasing the y value when x=0.3; decrease with increasing the x value when y=0.7 and x=0.1~0.5; and increase with increasing the x value when y=0.7 and x=0.5~0.9.
La1-xMxFeyCo1-yO3(M=Sr,Ba,x=0.1~0.9,y=0.1~0.9) have been prepared. The crystal of La0.7Sr0.3FeyCo1-yO3(y=0.1,0.3) is rbombohedral. The crystal of other compounds is cubic. The lattice parameters of La1-xMxFeyCo1-yO3 increase with increasing the yvalue. The lattice parameters of La1-xSrxFe0.7Co0.3O3 decrease with the increase of the x value, but that of La1-xBaxFe0.7Co0.3O3 increase with the increase of the x value. All the compounds are semiconductors. Their resistivities increase with increasing the y value when x=0.3; decrease with increasing the x value when y=0.7 and x=0.1~0.5; and increase with increasing the x value when y=0.7 and x=0.5~0.9.
1993, 10(6): 102-105
Abstract:
The aromatic polyamides were prepared by polyeondensation of terephthaloyl or isophthaloyl dichloride with 2,4,6-trimethyl-1,3-phenylenediamine. The influences of the monomer concentration and polymerization conditions on the degree of polymerization were studied. The polymers obtained have a greater solubility than common polyamides with less methyl groups on the benzene ring.
The aromatic polyamides were prepared by polyeondensation of terephthaloyl or isophthaloyl dichloride with 2,4,6-trimethyl-1,3-phenylenediamine. The influences of the monomer concentration and polymerization conditions on the degree of polymerization were studied. The polymers obtained have a greater solubility than common polyamides with less methyl groups on the benzene ring.
1993, 10(6): 106-107
Abstract:
A kind of polyetheretherketone ketone has been prepared by copolyeondensation of 4,4'-diphenol,1,3-bis(4-fluorobenzoyl) benzene and 1,4-bis(4-fluorobenzoyl) benzene with alkali metal carbonates at 310~320℃ using diphenylsulphone as solvent. The copolymer has Tg=169℃,Tm=339℃, 2.5% weight loss at 555℃;tensile strength 68.5MPa and tensile modulus 0.915GPa.
A kind of polyetheretherketone ketone has been prepared by copolyeondensation of 4,4'-diphenol,1,3-bis(4-fluorobenzoyl) benzene and 1,4-bis(4-fluorobenzoyl) benzene with alkali metal carbonates at 310~320℃ using diphenylsulphone as solvent. The copolymer has Tg=169℃,Tm=339℃, 2.5% weight loss at 555℃;tensile strength 68.5MPa and tensile modulus 0.915GPa.
