• 研究简报 •

单链和寡链等规聚苯乙烯聚集体的结晶行为

1. 复旦大学材料科学系, 上海200433
• 收稿日期:2004-12-18 出版日期:2005-10-10 发布日期:2005-10-10
• 基金资助:

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.

Crystallization Behavior of Single or Pauci Chain Congeries of Isotactic Polystyrene

XIN Yan, YU Ying, He Yong, ZHANG Yu, FAN Zhong-Yong

1. Department of Materials Science,Fudan University,Shanghai 200433,China
• Received:2004-12-18 Online:2005-10-10 Published:2005-10-10

Abstract: 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.