梳形支化聚苯乙烯的制备及其溶液形态研究_高分子.rar

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摘要:通过稳定自由基聚合与原子转移自由基聚合联用技术合成了具有不同支化结构的梳形支化聚苯乙烯,采用NMR和GPC对梳形支化聚苯乙烯的链结构进行了表征。使用示差折光指数(RI)/多角激光光散射(MALLS)/示差粘度(DV)三检测器凝胶渗透色谱研究了梳形支化聚苯乙烯在THF中的溶液形态和性质。结果表明,支化密度相同时,随支链长度增加,梳形支化PS的均方回转半径及特性粘数均随分子量增加而增大,但增大幅度随着支链长度增加而逐渐变缓,表现为斜率值减小,HMS方程中的值下降。支链长度相同时,随支化密度增加,梳形支化PS的均方回转半径及特性粘数随分子量增大而增大,增大幅度随支化密度的增加表现出更加明显的下降趋势。对得到的各种梳形支化PS的支化因子g和g’值分析表明,随支化密度增加,g和g’值明显减小;在相同支化密度下,支化因子会随着支链长度的增大而呈现微小下降。 

关键词:梳形支化聚苯乙烯;原子转移自由基聚合;氮氧稳定自由基聚合;溶液性质

 

Abstract:Comb-like branched polystyrene of different structure were synthesized by using nitroxide mediated polymerization and atom transfer radical polymerization in this experiment, and these molecules were characterized by the technique of GPC and NMR. The solution morphology and property of comb-like branched polystyrene in the THF were studied by GPC/RI/MALLS/DV. It turns out that the mean square radius of gyration and intrinsic viscosity of comb-like branched polystyrene are increasing with the weight molecular weight when the branching density is invariant, however, the amplitude of variation is decreasing with the branch length increase. It shows that the slopeand are decreasing. When the branch length is invariant, the mean square radius of gyration and intrinsic viscosity of comb-like branched polystyrene are increasing with the weight molecular weight, but the amplitude of variation is markedly decreasing with the changed branching density. The structure factors g and g’ of different comb-like branched polystyrene obtained are analysized showing that the value of g and g’ are dramatically decreasing with the increasing of branching density. When the branching density is same, structure factors are slightly decreasing with the branch length increase.

Key words: comb-like branched polystyrene; ATRP; NMP; solution property

 

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