STUDY ON POLYPHENYLSILSESQUIOXANE''''S SHAPE IN DILUTE SOLUTION

Based on relations between the limiting viscosity number, the translational diffusion coefficient and the molecular weight, the shape of polyphenylsilsesquioxane (PPSQ) in dilute solution was simulated with different models. It is found that the oblate ellipsoid of revolution and free-draining random coil are two suitable models, showing that PPSQ is a polymer with rigid chains, and its shape is closer to sphere due to chain branching rather than flexibility.     

小角激光散射法研究聚苯基喹 啉在稀溶液中的缔合现象

聚[2,2'-(1,4-苯撑)-6,6'-双(3-苯基喹 啉)](PPQ)是一种耐高温材料, 其合成方法, 机械性能及应用方面的研究已有很多报导, 但是有关其溶液性质和分子形态的研究还甚少。本文用小角激光散射法研究了PPQ的稀溶液性质, 并报导了PPQ在溶液中的缔合现象。     

SOLUTION PROPERTIES OF POLYPHENYLSILSESQUIOXANE

The limiting viscosity number [η] and translational diffusion coefficient D of polyphenylsilsesquioxane (PPSQ) and their dependence on molecular weight M_w were studied by static and dynamic light scattering and viscometry techniques. NMR measurement was also performed to investigate PPSQ's structure. Results show that PPSQ molecules are not rigid rods and do not have fully regular ladder structure but with branches and uncondensed hydroxy groups, and their extensibility decreases with the increase of molecular weight.     

SIS的正电子湮没寿命谱的研究

用正电子湮没技术,在-80°～100℃温度范围内,测量了苯乙烯-异戊二烯-苯乙烯三嵌段聚合物(SIS)的正电子寿命谱。在长寿命成分的温度谱中,实验发现除了有和聚异戊二乙烯及聚苯乙烯的玻璃化温度相对应的温度转变区外,在37℃还存在一个温度转变区。这个中间转变温度可以解释为SIS嵌段共聚物的中间相的玻璃化转变温度。     

小角激光散射法研究聚苯基喹 啉在稀溶液中的缔合现象

聚[2,2'-(1,4-苯撑)-6,6'-双(3-苯基喹 啉)](PPQ)是一种耐高温材料, 其合成方法, 机械性能及应用方面的研究已有很多报导, 但是有关其溶液性质和分子形态的研究还甚少。本文用小角激光散射法研究了PPQ的稀溶液性质, 并报导了PPQ在溶液中的缔合现象。     

PHOTOCOPOLYMERIZATION OF MALEIC ANHYDRIDE AND VINYL ACETATE IN TETRAHYDROFURAN~*

The copolymerization of maleic anhydride and vinyl acetate in tetrahydrofuran was studied. Results show that the maximum copolymerization rate is in 0.6 mole fraction of maleic anhydride, indicating the involvement of maleic anhydride-tetrahydrofuran charge transfer complex in the chain initiation process. ESR study provides collateral evidence for the formation of maleic anhydride radical and tetrahydrofuran radical.     

PHOTOCOPOLYMERIZATION OF MALEIC ANHYDRIDE AND VINYL ACETATE

The charge-transfer complex of maleic anhydride and vinyl acetate was copolymerized under UV light. The chain composition and structure of the copolymer were analyzed with conductometry and NMR, and the chain sequence was determined as alternating. The copolymerization rates at different feed ratios, temperatures and in different solvents were investigated, giving evidence to the very active involvement of the CT complexes in the copolymerization. Terpolymerization with acrylonitrile also showed that the complex mechanism was a proper one for this system.     

小角激光散射法研究聚苯基喹噁啉在稀溶液中的缔合现象

聚[2,2’-(1,4-苯撑)-6,6’-双(3-苯基喹噁啉)](PPQ)是一种耐高温材料,其合成方法、机械性能及应用方面的研究已有很多报道,但是有关其溶液性质和分子形态的研究还甚少。我们用小角激光散射法研究了PPQ的稀溶液性质。本文报道PPQ在溶液中的缔合现象。实验 PPQ试样由本系孙猛提供。以体积比为3比2的四氯乙烷-苯酚混合溶剂为良溶剂,正庚烷为沉淀剂对样品进行分级,所得狭分布样品按分子量由大到小排列,依次记为PPQ-1,PPQ-2和PPQ-3。