最新刊期
卷 ， 期 6 ， 1997
- 摘要：Novel [ABm]n segmented copolymers with PDMS as soft segments were synthesized by condensation reaction.The product thus obtained was characterized by IR.Spectroscopy,viscosity and DMA.The results indicate that polycondensation took place intermolecularly as well intramolecularly.Depending the PDMS and rigid segments molecular weight and content, m is in the range from 1 to 6.AB m n segmented copolymers exhibit microphase separation,and partial compatibility between rigid and soft segments.The Tg of rigid segment's phase is dependent on the value ofm.The modulus of these materials is higher than that of [AB]n segmented copolymers.
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发布时间：2021-03-19 - 摘要：Chain conformational distribution in a two dimensional space of the chain dimension and the conformational energy have been studied using the rotational isomeric state model in the present work.It shows that (1) the number of chain conformation considerably enhances in the area of small chain dimensions; (2) in the small chain dimension area there still exist some of stable chain conformations; (3) these conformations in the small chain dimension area possess structures of rod like shape; (4) the chain conformational distribution studied implies an asymmetry of entropy elasticity of the polymer chain system.
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发布时间：2021-03-19 - 摘要：Eight polyimide polymers containing NLO azobenzene sidi chain have been synthesized and characterized.High chromophore content up to 100%(mol) has been achieved due to the utilizing of a novel synthetic route.The prepolymers are soluble in many organic solvents and have good film forming property.The sofetening points of the materials after imidization are rather high.
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发布时间：2021-03-19 - 摘要：A broad range of miscibility was observed in blends of carboxylated poly (phenylene oxide) ionomers/sulfonated polystyrene ionomers,Compared with blends containing only one component ionomers,compared with blends containing only one component ionomers.It was suggested that it was because the different ionic groups in different components aggregate miscellaneouslly rather than respectively,which acts as one of driving forces to mix more evenly the components.In addition,the types of cation influence the miscibility.
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发布时间：2021-03-19 - 摘要：The solution behavior of sulfonated Polystyrene (SPS) ionomer/Poly(styrene co 4 vinylpyridine) (PSVP)、sulfonatded Poly(phenylene oxide) (SPPO) ionomer/PSVP and SPPO ionomer/aminated PPO was investigated.The reduced viscosities of these three series of blends were higher than those of comparable blends not containing ionic groups.These were attributed to the ion interactions resulting from the acid groups (or metal ion) of ionomer and the vinylpyridine groups of PSVP.The effects of solvent,types of functional groups and structure of main chain were discussed.
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发布时间：2021-03-19 - 摘要：Ring opening polymerization of ε caprolactone catalyzed by (ArO) 2Sm(THF) 4 (ArO=2,6 ditertbutyl 4 methyl phenoxo ) was systematically studied.The polymerization system has “living ” characteristic and shows high activity,the conversion is as high as 98% in toluene at 60℃ for 1h under /=2000.The central ions and ligands have effect on the activity of catalysts.The initiation mechanism by divalent lanthanide complexes has been studied through oligomer end group analysis by NMR.The results demonstrate that catalyst reacts first with ε-caprolactone to give a trivalent lanthanide enolate which then catalyzes caprolactone polymerization.
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发布时间：2021-03-19 - 摘要：The microstructure of PTMPS and PTMPS DMS were studied by SAXS and polarzing microscope.The results showed that the morphology of spherulites,the crystal surface free energies, T m,T g ,crystallinity index(d,s,c) were in close relationship with long spacing,crystal thickness,amorphous thickness and crystallinity index of one dimension.A turning point was present at 50% of DMS content for any curve of above parameters vs.DMS content.
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发布时间：2021-03-19 - 摘要：Statistical group transfer copolymrization of acrylates with methacrylate have been performed for six binary systems using 1 methoxy 2 methyl 1 trimethylsilyloxy propene(initiator) and tetrabutylammonium bibenzoate(catalyst) in THF solution.The copolymer compositions were determined by 1H NMR spectroscopy and the results eval uated by the extented Kelen Tudos method.The monomer pairs concerned are (1) methyl acrylate (MA) and methyl methacrylate (MMA),(2) ethyl acrylate (EA) and MMA,(3) butyl acrylate(BA) and MMA,(4) MA and ethyl methacrylate (EMA).(5)MA and butyl methacrylate (BMA),(6) MA and iso-buytl methacrylate (iBMA),The reactivity ratios were found to be γMA=9.23,γMMA=0.06;γEA=14.15,γMMA=0.01;γBA=7.51;γMMA=0.02;γMA=14.41,γEMA=0.01;γMA=13.96,γBMA=0.23;γMA=0.23;γMA=8.66,γi-BMA=0.08.Anionic copolymerization of EA with MMA and MA with EMA was also carried out to compare with the result of GTP,the date are γEA=9.67,γMMA=0.11;γMA=3.51;γEMA=0.20.It was shown that acrylate is much more reactive than methacrylate for GTP and anionic copolymerization the reactivity ratios are quity diffrernt from unity and show a high similarly.
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发布时间：2021-03-19 - 摘要：A series of cholesteric liquid crystalline side chain terpoly(olefin sulphone)s with different composition have been prepared from cholesteryl (or/and cholestanyl) 10 undecenoate, heptene 1 and sulphur dioxide. The structures of these terpolymers have been characterised with FTIR, 1H NMR, HPGPC and LC properties measured by polarising microscope. The experimental results showed that each series of terpolymers are significantly lowered as the proportion of heptene 1 residues increases within the polymeric mass.
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发布时间：2021-03-19 - 摘要：The morphology of PSF—PDMS—PHS n segmented ternary copolymer has been investigated by DMA, TEM and SAXS techniques. It is shown that a complicated morphology was found for the microphase separated structure of PSF—PDMS—PHS n . The new morphology is considered to consist of continuous domains formed by honey comb framewords, which is PDMS phase, and disperse domains, which is PSF and PHS mixed phase with small PDMS particle inclusions. When the contents of PSF and PHS segments are equal, this structure occurs in 0.50 for the weight fractions of PDMS segment.It is clearly seen that the [PSF-PDMS-PHS]n has a distinct interface phase.The boundary phase should be a mixture of the PDMS,PSF and PHS segments.
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发布时间：2021-03-19 - 摘要：Nylon 6 showed low impact strength values. Whereas the addition of thermoplastic polyamide elastomers (TPAE)2533SA and E40S3, Nylon 6/2533SA and Nylon 6/E40S3 alloys showed high impact strength values. POM and SEM observations of the fracture surfaces and deformed regions beneath the fracture surfaces revealed that the fracture process of nylon 6 was brittle which was originated from plastic constraint at the notch tip. The fracture of alloys was also caused by plastic constratint at the notch tip. However,the plastic deformation zone at the notch tip was composed of many voids and partially elongated fibrils,and this absorbed impact energy.The plastic deformation was enhnaced by the transition of the stress state from plane strain to plane stress.The final fracture occurred from the notch tip connecting voids in the plastic deformation zone.
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发布时间：2021-03-19 - 摘要：When the acrylates containing rosin or hydrogenated rosin were emulsion copolymerized in one step, the conversion of monomers was obviously reduced because of the chain transfer of free radical to the tackifiers. The overall conversion of monomers can be largely increased if the seed emulsions were first prepared by the copolymerization of most of acrylates and then the remainder acrylates in which tackifiers have dissolved were copolymerized by adding them into the seed emulsion. The morphology of the emulsion particles formed by two-step copolymerization were investigated by TEM and the mechanism of the second-step copolymerization was discussed.The adhesion properties of the emulsion copolymers obtained bu using two-step emulsion copolymerization of the acrtlates in which tackifiers have been dissolved are much better than those of the emulsion copolymers obtained by using one-step method.
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发布时间：2021-03-19 - 摘要：The graft copolymerization of vinyl monomer onto carbon black with,respectively,ceric ions, n butylithium,acetylacetonate copper complex and manganic pyrophosphate complex as initiator were studied. The effects of initiator concentration, monomer concentration and reaction time on the percent graft have been investigated. The structure and properties of grafted carbon black were characterized with the help of TEM, FT IR and Light Adsorption Ratio. The results showed that the highest percentage of graft could be achieved by means of n-butylithium initiating system and the percentage of graft was as high as 200%.But the percentage of graft was only about 30% with the various redox system.The dispersed stability of grafted carbon black was improved obviously in the dispersing medium.
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发布时间：2021-03-19 - 摘要：Block copolymers containing different compositions of terephthaloyl bis(4 oxy benzoyl) (triad) mesogen and polycarbonate(PC) units were synthesized by polycondensation of two oligomers. The structure thermal properties and crystallization behaviour of the block copolymers were investigated by IR, POM, DSC, WAXD. Thermotropic liquid crystalline nematic phase of these block copolymers were identificd by DSC and POM with a hot stage, It is shown that for the copolymers no phase separation at lower temperature and biphase behaviour above 280℃ is observed,The copolymers are crystalline polymers similar to HTH-6, The crystallinity measured by DSC decreases with decreasing HTH-6 content,The rate of crystallization is affected bu PC content.
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发布时间：2021-03-19 - 摘要：A new relationship between relaxation time and temperature through the rubber glass transition in amorphous polymers is proposed, by fitting the dynamic mechanical data of amorphous PVC. A satisfactory agreement between experimental data and theory is obtained, and clear physical meaning is given for each parameters. Especially, this relationship provides a reasonable resolution for Kauzmann paradox.
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发布时间：2021-03-19
Research Article
- 摘要：Measurements of the current in Poly(phenyl acetylene)s with different configuration (PPAs) as a function of the voltage were carried out at temperatures between 233 and 300K. The current voltage dependence is of J∝V n type. Under the lower applied field the exponent n 1,it showed ohmic behavior, while the Space Charge Limited Current (SCLC) was observed at the high applied field the exponent 8≥ n ≥3. A conductivity and conducting activation energy were obtained in the ohmic range. Using the SCLS theory,the trap level with Caussion distribution of trap energy has been found. The trap energy agress closely with the apparent activation energy observed for conduction,indicating that the dark conduction of the PPAs is by no means intrinsic one but a manifestation of thermal detrapping.
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发布时间：2021-03-19 - 摘要：Ring opening polymerization of ε caprolactone (Cl) catalyzed by bis(tert butyl cyclopentadienyl) methyl neodymium was studied. The yield was obviously dependent on the catalyst concentration and the polymerization temperature. The molecular distribution of the polymer changed little with the increase of polymerization time. The initiation mechanism of polymerization has been studied through oligomer end group analysis by NMR. The results demonstrate that catalyst reacts first with ε-caprolactoner to give a lanthanide alkoxide which then catalyzed caprolactone polymerization.
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发布时间：2021-03-19 - 摘要：The thermal stability and kinetics of thermal degradation for water soluble polyester (WSP), which is prepared by the copolycondensation of dimethyl terephthalate (DMT), dimethyl isophthalate (DMI) and 5 sodium sulfonate isophthalate methyl (SIPM) with ethylene glycol (EG), were studied using the conventional static and dynamic thermogravimetric techniques in a flowing nitrogen atmosphere. The thermal degradation rate parameter k and apprarent activation energy E were calculated using first order reaction intregal methold and Ozawa method respectively.It was found that the thermal degradation of WSPat 290℃ belongs to first order reaction,its rate parameter of thermal degradation k is 12.84×10-6s-1,and average apparent activation energy Eis 156.8 kJ/mol.
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发布时间：2021-03-19 - 摘要：Based on the equilibrium size of PBT minor phase vs. its concentration at 250℃ and 280℃, the effects of viscoelasticity change and coalescence in the melt on the morphology of immiscible PBT/PS blends were investigated. It is shown that the viscoelasticity of blend components, degradation of polymers, and coalescence of minor phase have different influences on the minor phase size. At the initial stage of blending, the dispersed phase size is mainly determined by the viscosity ratio and elasticity ratio of blend components.The dispersed phase size of 280℃ is larger than that of 250℃ due to the much larger elasticity ratio of PBT to PS at 280℃,With increasing mixing time,the viscoelasticity ratio of PBT to PS are changed by the degradation.For lower PBT contents,e.g.5%,the minor phase size at 250℃ is larger than that of 280℃ because of a sharp decrease of elasticity ratio of PBT to PS at 280℃.For higher PBT contents,the coalescence of the minor plays a more important role,which keeps the phase size at 280℃ greater than that of 250℃.
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发布时间：2021-03-19 - 摘要：Titanium 8 hydroxyquinolinate complexes in combination with methylalumin oxane (MAO) as cocatalyst are highly active towards styrene polymerization, giving polymers with high sydiotacticity. The molecular weight distribution of polymers is broader, indicating the titanium 8 hydroxyquinolinate complexes may be a “multi site” catalyst.
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发布时间：2021-03-19 - 摘要：Photopolymerization of acrylonitrile initiated by photoredox initiation system consisting of N (4 benzoylphenyl) itaconimide(NBPII) and N,N dimethylaminoethyl methacrlate (DMAEMA) has been undertaken.It has been fund the polymerization rate is proportional to 0 32th power of NBPII concentration,0 25th power of DMAEMA concentration and 0 9th power of AN concentration.The overall activation engergy for the photopolymerization is obtained to be 21.4KJ/mol.From the UV analysis of the PAN treated with tetracyanoethylene and 2,4-dinitrophenylhydrazine,it is confirmed that the combination of NBPII and DMAEMA not only sensitizes the photopolymerization of AN,but also incoporated into the polymer chains.This means that NBPII and DMEMA forms a polymerizable photo-redox initiation system.The photopolymerization rates of AN sensitized by NBPII-DMAEMA,P(NBPII)-DMAEMA,and NBPII-P(DMAEMA)are also compared. It shows that the polymerization rate initiated by P(NBPII)-DMAEMA system is faster than that of NBPII-DMAEMA system.
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发布时间：2021-03-19 - 摘要：Four acryloyl modified polymerizable lipids derived from malate and aspartate, i.e. O acryloyl dihexadecyl malate (LM16 A),O methacryloyl dihexadecyl malate (LM16 MA),N acryloyl dihexadecyl aspartate (Asp16 A),N methacryloyl dihexadecyl aspartate (Asp16 MA),were synthesized and copolymerized with two hydrophilic monomers:2 hydroxyethyl methacrylate (HEMA) and 3 sulfopropyl methacrylate potassium salt (SPMAP) to form amphiphilic copolymers.The selforganization of these copolymers was investigated in water.It is found that the formation of stable liposomes from these copolymers depends largely on the nature of the comonomers.Thus,the copolymers with weak hydrophilic groups (HEMA) couldn't form liposome,while the copolymers with strong hydrophilicity and large size (SAMAP) could form stable liposomes.
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发布时间：2021-03-19
Research Bulletin
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