最新刊期
卷 ， 期 6 ， 1998
- 摘要：The solution properties of P(TM-co-AAM) with different cationic degree and molecular weight in various solvents by viscometer have been studied.The reduced viscosity is measured in water,CH 3OH H 2O,CH3COOH H2O and different salt solutions such as NaCl,KCl,KBr and Na2SO4 respectively at 30℃.The effects of Mw, CD of cationic polymers,different solvents and added salts on the reduced viscosity and the polyelectrolyte behavior are investigated.
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发布时间：2021-03-19 - 摘要：LDPE/PP-co-PE blends are prepared by solution blending and freeze drying, and characterized by DSC and selective extraction. The dependence of compatibility of the blend system on composition and quench conditions is discussed. Freeze drying is demonstrated to be a useful method to promote the compatibility of the blend system.
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发布时间：2021-03-19 - 摘要：Polyanhydrides are of particular interests as materials for controlled drug release systems due to their excellent surface erosion properties.A novel series of diacids containing ester groups were prepared from 4 (hydroxyalkoxy) benzoic acid reacted with succinic anhydride,maleic anhydride and succinyl dichloride.The polymers were synthesized by melt polycondensation.Monomers and their polymers were characterized by IR, 1H-NMR and elemental analyses.The effects of the catalyst on the structure and molecular weights of the polymers were investigated.
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发布时间：2021-03-19 - 摘要：Polymerizations of methyl methacrylate in microemulsion stabilized with emulsifier BOA were initiated with γ ray,KPS,BPO and AIBN,respectively.The microemulsion with high monomer content remained clear after polymerization.The growth of particles and their size distribution were detected at different conversions.The average hydrodynamic diameter of final polymer particles was between 50～70nm.It was found that there was some resemblance among polymerization initiated with the four initiators.However,there were also obvious differences.When the microemulsion polymerization was initiated with KPS or γray,homogenous nucleation predominated at low conversion,and micellar nucleation dominated at high conversion.When it was initiated with BPO or AIBN,at low conversion,polymerization mainly took place in the big droplets,and micellar nucleation became the only nucleation route at high conversion.
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发布时间：2021-03-19 - 摘要：In the synthesis of tricomponent poly(ethylene terephthalate) copolyesters through the direct esterification route, in order to control process of production to obtain the desired molecular weights of polymers, the simplified and nonsimplified calculation equations for the number average degree of polymerization n and the number average molecular weights n of oligomers and polycondensates were given, respectively. The calculation equations, derived on the basis of reaction mechanism and technological characteristics,relate Xn and Mn to the extent of reaction of carboxyl groups and the amounts of small molecules produced.The various main reactions and important side reactions were all considered for the nonsimplified calculation equations,but for the simplified calculation equations,the various side reactions were neglected.The simplified Xn calculation equations were compared with carothers wquation by calculation,the results are the same.Applied to the dicomponent polyester systems,the simplified Xn equations are the same as that used conventionally for the dicomponent linear polycondensates.The simolified and nonsimplified calculation wquations for An and Mn of tricomponent poly(ethylene terephthalate) copolyesters can be extended and applied to the dicomponent polyester systems and multicomponent copolyester systems over three components.
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发布时间：2021-03-19 - 摘要：The influence of nucleating agent on the process of nucleation and crystallization of isotactic polypropylene from melt state was studied by different characterization methods including the measurements of the crystallization temperature in a non isothermal colling process, halftime and velocity constant in an isothermal crystallization process, the density of nuclei or the size of spherulites and the specific surface free energy for nucleus formation during crystallization. The nucleating agents used were calcium carbonate,sodium benzoate and terephthalic acid.It was found that all the three nucleating agents may have their influence on the crystallization of polypropylent.The results obtained by using diffrernt characterization methods were consistent with each other.It implies that there are some correlations between the parameters used for characterization in different methods.So it is feasible to use any one of these methods to evaluate the effect of additives on polymer crystallization in an applied research.However,the use of various characterization techniques may give you a comprehensive usderstanding of the effect of nucleating agents on the crystallization process of polymers.
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发布时间：2021-03-19 - 摘要：The polymerization behaviour of isoprene conducted by using a novel C60 Supported neodymium catalyst system Nd(nhph)3(Nd) C60 X(X) Al( i Bu) 3(Al)was investigated.It revealed that this catalyst system in hydrogenated gasoline was a homogeneous catalyst, and the molar ratios of Al/Nd and X/Nd seriously affect catalytic activity, molecular weight and its distribution. The formation of active center complexes and the catalytic activity have well stability with the aging time and aging temperature.The intrinsic viscosity of polymer obtained is from 1to 4 dL/g;the molecular weight distribution is from 2 to 4.The content of cis-1,4 unit of PIp is about 98%.
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发布时间：2021-03-19 - 摘要：The effects of the initial phase morphology and interfacial tension were investigated on the formation of gradient morphology in the polymer blends.For the same blends system, different initial phase morphology can be obtained by changing the rotating rate of the rotor during mixing. By means of scanning electron microscope(SEM), the morphologies of the polymer blends before and after annealing were examined. Computer Image Analyzer was also applied to get the information about the radius and distribution of the dispersed phase.It was found that the initial diameter of the dispersed phase particles decreased with increasing the rotating rate of the rotor.After annealing for a certain time,the blend system with smaller initial dispersed particle size shows faster speed for the formation of gradient morphology.However,if the initial particle size is too small,it could be predicted that the formation of gradient morphology is difficult during a certain period of time.So it is expected that there is an optimum initial diameter for the formation of gradient morphology.The blend systems with different interfacial tension can be got through blending PP/EVAc、PE and EVAc with various VAc contents.It was found that all the blend systems could form gradient morphology under certain annealing conditions.The larger the interfacial tension in the blends,the faster the formation speed of gradient morphology.Interfacial tension as the driving force for dispersed phase droplet coarsing plays an important role in the formation of gradient morphology.
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发布时间：2021-03-19 - 摘要：By grafting copolymerization of hydrogen containing polymethylsiloxane(PHMS) and acrylic ester monomer, a new kind of hydrogen containing polymethylsiloxane(PHMS)/butyl acrylate(BA)/hydroxymethyl amide(NMA) composite emulsion was prepared which possessed excellent properties of the components. The paper discussed the effect of PHMS,NMA and initiator amount on the conversion, the stability of polymerization, storage and viscosity of this composite emulsion. The particle size of latexes prepared by different reaction condition was measured by transmission electron microscope(TEM) and particle size measuree.The polymerization mechanism,the polymer molecule structure and the film forming properties of the latexes were also investigated.The results showed that the PHMS/BA/NMA copolymer was obtained by emulsion polymerization and the copolymerization between PHMS and BA,NMA and homopolymerization of BA were simultaneously existing in the systems.Stable PHMS/BA/NMA composite emulsion with moderate particle size,Viscosity and high conversion could be produced when the proportion of raw materials such as PHMS.NMA and initiator was suitable.The film made from this composite emulsion had good film forming properties and other excellent properties.
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发布时间：2021-03-19 - 摘要：The cationic polymerizations of α and β pinenes and limonene were compared, and the possibility of living polymerization of the three monomers was also examined. With Lewis acid AlCl 3 catalyst, the polymerization rate decreased in the following order: β pinene>limonene> α pinene. The addition of SbCl 3 accelerated the polymerizations of α pinene and limonene, and retarded the polymerization of β pinene. In contrast to the polymerizations with AlCl3, the polymerization of α-pinene and limonene,and retarded the polymerization of β-pinene.In contrast to the polymerizations with AlCl3,the polymerization of α-pinene was faster than that of limonene when catalyzed with AlCl3/SbCl3.As compared with the AlCl3 catalyst,AlCl3/SbCl3 binary system gave polymers of α-pinene with higher molecular weight,polymers of limonene with similar molecular weight,and polymers of β-pinene with lower molecular weight.In contrast to the structure of α-pinene polymer,the structures of β-pinene and limonene polymers were not affected by the addition of SbCl3.The living polymerization of reactive β-pinene monomer could be achieved with Styrene-HCl adduct/TiCl3(OiPr) initiating system,however,attempts of the living polymerizations of α-pinene and limonene with a series initiating system failed because of the low monomer reactivity.
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发布时间：2021-03-19 - 摘要：Many industrial processes involve dispersion of immiscible liquids into a blend. Since the mixing equipment and conditions play an essential role on the morphology of a blend,it is important to realize dispersed processes. A dumbbell dispersion model of viscous drops is established according to the analysis of the dispersed force to the drops of a liquid/liquid mixing system in steady state plane hyperbolic flow fields. The dispersed force is a function of viscosity ratio, flow type and its intensity, drops radius,orientation and size of the dumbbell.The model reveals the relation between dispersed force and the types of flow fields.Different effects on the dispersion of drops.The dispersed force in an elongation flow is double what it is in a simple shear flow.This shows that the elongation flow is more rfficient than the shear flow in dispersion,which agrees with the results of former experiments.The model converts to the rigid particle dumbbell model when viscosity ratio tends to infinite.
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发布时间：2021-03-19 - 摘要：The Mark Houwink constants of poly ( p diethynylbenzene) (PDEB) in THF at 25℃ were determined from GPC and intrinsic viscosity η of broad distribution samples based on the principle of GPC universal calibration and Weiss method,and the values of K =7.62×10-3 and α =0.26 were obtained.The obtained K and α values were reliable and could be used for calculating the molecular weights of PDEB within the relative error of 6%,which was proved by [η] error checking and VPO analysis.The effects of monomer concentration,polymerization temperature,polymerization time on molecular weights and molecular weight distribution of PDEB were studied with GPC.The crosslinking,grafting,and chain-transferring to monomer may exist in the polymerization of p-diethynylbenzene.
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发布时间：2021-03-19 - 摘要：By means of micromechanics and statistical method,the non linear consitutive relation of particulate reinforced polymer is studied.In the deformation process,the debonding damage of the particle matrix interface may occur and will lead to microvoid nucleation.The statistical behavior of microvoids' nucleation and evolution are investigated by using Eshelby's equivalent inclusion method and Mori Tanaka's mean stress field concept.The stiffness of the material will decrease due to microvoid evolution and the macroscopic constitutive relation will gradually be changed from linear one to nonlinear one.Such a phenomenon,on the other hand,shows that the material may be toughened.The reinforcing effect due to intact rigid particles and the weakening effect due to microvoids evolution,as well as their coupling effect on the macroscopic constitutive relations are studied in this paper.The influences of interface strength particle-size dispersity,and average particle-size on the macroscopic constitutive relation are also discussed.The research results indicate that higher interface strength,lower particle size dispersity,and smaller average particle size will be effective for reinforcing and toughening polymer materials under the condition that matrix strngth is higher than interface strngth.
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发布时间：2021-03-19 - 摘要：The PE b sPS block copolymers were synthesized with η5 cyclopentadiencyltri furfuryloxyltitanium/MAO and η5 cyclopentadiencyltribenzyloxyltitanium/MAO catalyst systems respectively.The effect of TMA and ethene prepolymerization time on catalytic efficiency were investigated.The results showed that total catalytic efficiency came down with the increasing of ethene prepolymerization time and the TMA had a optimum value for different catalyst system.The PE b sPS block copolymers were obtained by butanone extraction fractionation.The PE-b-sPS block copolymers accounted for 40wt%～60wt% of the total copolymerization products and the weight content of styrene segment in the block copolymer is up to 80%～85%.The block copolymers were characterized by DSC,WAXD,DTIR and 13C-BMR methods.
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发布时间：2021-03-19 - 摘要：A theoritical study of the reaction rate control step on the carbonlation of methanol to acetic acid catalyzed by copolymercoordinated rhodium has been investigated in terms of the ASED MO method(including atomic repellent energy).The energy barriers of oxidative addition reactions for different systems were calculated.The way of electron transfer and space factor influencing the activation energies during oxidative addition were studied.It showed that the calculating results were bassically in agreement with the experimental results.The differences of catalysis activity between 2-vinylpridine system and 4-vinylpridine system were explained theoretically.
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发布时间：2021-03-19 - 摘要：Poly(styrene co maleic anhydride)/silica hybrid material has been successfully prepared from styrene maleic anhydride copolymer and tetraethoxysilane(TEOS) in the presence of a coupling agent 3 aminopropyltriethoxysilane(APTES) by in situ sol gel process.It was observed that the gel time of sol gel solution was dramatically influenced by the amount of APTES.The sol gel time decrease with the increasing of APTES.The covalent bonds between organic and inorganic phases was introduced by the aminolysis reaction of amino group with maleic anhydride units of copolymer to form a copolymer bearing trimethoxysilyl groups,which undergo hydrolytic polycondensation with TEOS.The amount of catalysis,HCl or NH3,as well as the ageing temperature of samples,heavily affect the sol fraction of samples.The differential scanning calorimetry(DSC) showed that glass transition temperature of hybrid materials increases with increasing of SiO2 composition.
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发布时间：2021-03-19
Research Article
- 摘要：By using Bороховскии,Ziabicki A and Zhishen Mo,et al.equations,the non isothermal crystallization kinetics and mechanism of poly( α chloromethyl α methyl β propiolactone)(PCMMPL) have been studied by DSC at cooling rate 1 to 10℃/min.The Avrami exponent n in the primary crystallization period of P(CMMPL) is about 19 close to 2.The results indicate that the crystallization process is heterogeneous nucleation and growth in two dimensions,and the crystallization rate constants are 10 2～10 4 times to those of PET,Nylon-6 and Nylon-66.The kinetic crystallizibility per unit cooling rate(Gc) is 0.6～0.7 which is similar to those of PET.Nylon-6,Nylon-66 and Nylon-1010.
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发布时间：2021-03-19 - 摘要：Precipitation polymerization of acrylic acid in supercritical CO2 is studied. The effect of the temperature, the pressure of CO2, the concentration of the monomer and the initiator ae explored. It shows that the decrease of the concentration of the monomer, the increase of the pressure of CO2, the decrease of the temperature of the increase of the concentration of the initiator will all decrease the molecular weight of the product. The scanning electron micrographs indicate that the water-soluble polyacrylic acid powder obtained from this experiment is formed by primary particles of about 1～2 μ m size.In addition,the pressure increases with the increasing of the yield,it is speculaed to be due to the separation of phases during polymerization.
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发布时间：2021-03-19 - 摘要：The side chain liquid crystalline polymers were prepared by a self assembly process using 4 (4' nitrophenylazo) phenol or 4 (4' methoxyphenylazo) phenol as hydrogen bond donors and poly(4 vinylpyridine co butyl acrylate) as the acceptor.The hydrogen bond association was confirmed by FTIR.While some dissociation occurs at the isotropic temperature,the complete dissociation needed much higher temperature.The hydrogen bonding was restored as the complex was cooled to room temperature again.The nematic liquid crystallinity of the polymer complex was shown by WXRF and FOM.
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发布时间：2021-03-19 - 摘要：Two monomers containing sulfur,2,2' mercaptoethyl sulfide dimethacrylate(MESDMA) and 2 phenylthioethyl thiolmethacrylate(MEPSMA),were synthesized from methacrylate and respective thiol by dehydration with N,N dicyclohexylcarbodiimide.Styrene was used as modification monomer to adjust the properties of MESDMA/St and MESDMA/MEPSMA/St copolymer.When styrene was used,the impact strength of resulting copolymers was much better than that of MESDMA homopolymer and MESDMA/MEPSMA.Several optical plastics with high refractive index,good mechanical and heat-resistant properties could be obtained finally.
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发布时间：2021-03-19 - 摘要：Tetrahydrofuran was polymerized using a heteropolyacid,H3PW12O40 (PW12 ) in low concentration (molar ratio of PW12/THF2.5×10-3 ) as the initiator and ethylene oxide as the polymerization promoter,which effectively increased the rate and conversion of the polymerization.Water was used to control the molecular weight of the product.The polymerization proceeded well even when the molar ratio of H 2O/PW 12 reaches 30.The yield reached 50%～60% per cycle and the average molecular weight could be controlled around 2000.The products were found to be polyether glycol with hydroxyl groups at both ends.The melting point was lower by ～ 10℃ as compared with polytetramethylene ether glycol having the same molecular weight.The concentration of active species maintained unchanged throughout the polymerization,whith indicated the absence of chain termination.
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发布时间：2021-03-19
Research Bulletin
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