单链和寡链等规聚苯乙烯聚集体的结晶行为  

Crystallization Behavior of Single or Pauci Chain Congeries of Isotactic Polystyrene

作　　者：辛雁[1] 于瀛[1] 何勇[1] 张宇[1] 范仲勇[1] 

机构地区：[1]复旦大学材料科学系,上海200433

出　　处：《高等学校化学学报》2005年第10期1969-1971,共3页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:90103037;20474013);教育部博士学科点基金资助.

摘　　要：Single- and a few-chain aggregates of isotactic polystyrene（i-PS） were prepared by the freeze-drying procedure from dilute solutions with the concentration from 1×10-3 to 2×10-5 g/mL.It was found that the melting point of crystals was gradually shifted to lower temperatures as the solution concentration decreased by the differential scanning calorimetry（DSC）.As a result, the thickness of the lamellas of bulk samples and the samples prepared by the freeze-drying procedure from 2×10-5 g/mL solution decreased from 19.3 nm to 12.6 nm,respectively.The half crystallization time（t1/2） of samples by freezing-dried from 1×10-4 g/mL solution was about 36 s,it was merely a tenth of the period of the bulk sample annealed at 468.3 K.In addition,the growth rate of spherulite（dr/dt） of the samples prepared from 2×10-5 g/mL solution was more faster than ones of the bulk samples annealed at 478.3 K.All these should be attributed to the samples with less entanglement prepared by freeze-drying procedure from dilute solution.A preliminary study on the crystallization of the samples indicates that entanglements has a pronounced effect on crystallization behavior of polymer.Single- and a few-chain aggregates of isotactic polystyrene （i-PS） were prepared by the freeze-drying procedure from dilut,＇ solutions with the concentration from 1 × 10^-3 to 2 ×10^-5 g/mL. It was found that the melting point of crystals was gradually shifted to , lower temperatures as the solution concentration decreased by the differential scanning calorimetry （DSC）.As a result, the thickness of the lamellas of bulk samples and the samples prepared by the freeze-drying procedure from 2 × 10 ^-5 g/mL solution decreased from 19.3 nm to 12.6 nm, respectively. The half crystallization time（ t1/2 ） of samples by freezing-dried from 1 × 10^-4 g/mL solution was about 36 s, it was merely a tenth of the period of the bulk sample annealed at 468.3 K. In addition, the growth rate of spherulite（dr/dt） of the samples prepared from 2 ×10 ^-5 g/mL solution was more faster than ones of the bulk samples annealed at 478.3 K. All these should be attributed to the samples with less entanglement prepared by freeze-drying procedure from dilute solution. A preliminary study on the crystallization of the samples indicates that entanglements has a pronounced effect on crystallization behavior of polymer.

关 键 词：等规聚苯乙烯 单链 寡链 结晶 

分 类 号：O63[理学—高分子化学] O645[理学—化学]