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利用溶液的光散射,测定高聚物的分子量和分子形态参数,在目前已经得到广泛的应用。光散射实验的最大困难在于测定液中尘埃颗粒的干扰,实验要求测定的溶液和溶剂都需要经过特殊的除尘处理,以达到光学洁净。最常用的除尘方法有高速离心和过滤,但是在实验中还需要将经过除尘处理的液体,从一个容器转换到另一个容器,或需要在貯液瓶中貯藏和在测定池中稀释或加浓,因此对这些容器也就同样需要予以除尘处理。 Thurmond很早就报导了他所设计的这类仪器。最近Schipmann和Farber又提出了新的设计。 相似文献
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In this paper, the effects of shear rate on the intrinsic viscosity measurement of partiallyHydrolysed Polyacrylamide (HPAM) in salt solution were studied with homemade multi-bulb viscometer and low shear rate rheometer. The critical shear rate of HPAM in saltsolution for high molecular weight HPAM was determined. A low shear rate capillaryviscometer was designed in which the [η] approached to value at zero shear rate can beobtained for HPAM-salt system. The effect of molecular weight on shear rate dependenceof viscosity was also studied. 相似文献
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甲基丙烯酸甲酯 甲基丙烯酸共聚物(P(MMA MAA))与低分子量或高分子量梯形聚苯基硅倍半氧烷(PPSQ)的共混物经原位聚合法制成.用光学透明法、荧光光谱、DSC等技术研究了该共混体系的相容性及组分间的相互作用及结构转变.结果表明,当PPSQ含量较小时,由于PPSQ与P(MMA MAA)间存在着较强的氢键作用,该共混体系在一定配比下相容,且低分子量PPSQ与P(MMA MAA)间的相容性较好.当PPSQ的含量≤1%时,PPSQ的加入对该共混物的Tg影响不大,但其Tf随PPSQ含量增加而增大.此外,还测试了P(MMA MAA)/PPSQ原位共混物的硬度及冲击强度. 相似文献
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The chemical structure of copolymer formed in the transesterification of PPSQ/PET blendsduring melt-processing is deduced from the ~1H-NMR spectra. The transesterification extent ofthis blend is interpreted by the changes of crystalline melting peak in DSC thermograms of the in-soluble products containing unreacted PET and some block PPSQ segments. Effects of composi-tion of blend ladderlike regularity of PPSQ on the reaction extent have also been discussed.Inclusion of some block PPSQ segments in PET has no influence on the crystalline morphology ofPET. 相似文献
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