Mesophase features in isotactic poly(propylene-co-1-heptene) copolymers

详细信息    查看全文

• 作者：Alberto Garc&#237 ; a-Peñ ; as ; José ; M Gó ; mez-Elvira ; Mar&#237 ; a U de la Orden ; Mar&#237 ; a L Cerrada and Ernesto Pé ; rez
• 关键词：propylene-co-1-heptene copolymers ; polymorphism ; mesophase formation ; DSC study ; variable-temperature diffraction experiments ; transparency
• 刊名：Polymer International
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：65
• 期：5
• 页码：596-604
• 全文大小：1828K
• ISSN：1097-0126

文摘

The influence of crystallization rate on the interesting polymorphism of random isotactic poly(propylene-co-1-heptene) copolymers was studied, with particular attention to the conditions for obtaining the mesomorphic phase. Owing to the important decrease of cooling rate involved as the 1-heptene content increases, the mesophase can be clearly observed by DSC for co-unit contents above about 5 mol%. Furthermore, only the mesophase (or the amorphous phase) was found for the copolymer with 13.9 mol% 1-heptene at common cooling rates of the calorimeter. Additionally, the copolymer with 21.4 mol% co-units was found to be completely amorphous under any thermal treatment analyzed. Variable-temperature diffraction experiments were carried out to ascertain unambiguously the nature of the phases involved. Finally, a remarkable transparency was attained (above 80% transmittance in the visible light region) at intermediate and high 1-heptene contents, using easily accessible cooling rates.