PA56球晶生长的光学偏振反转现象  

Optical Inversion Characteristics of PA56 Spherulites

作　　者：来悦 王煜 王莉莉[3] 李璇 赵京波[5] 董侠[1,2] 王笃金 Yue Lai;Yu Wang;Li-li Wang;Xuan Li;Jing-bo Zhao;Xia Dong;Du-jin Wang(Beijing National Laboratory for Molecular Sciences,Key Laboratory of Engineering Plastics,Institute of Chemistry Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049;Collaborative Innovation Center of Marine Biobased Fiber and Ecological Textile Technology,Institute of Marine Biobased Materials,State Key Laboratory of Bio-Fibers and Eco-Textiles,Qingdao University,Qingdao 266071;College of Materials Science and Engineering,Shenzhen Key Laboratory of Polymer Science and Technology,Shenzhen University,Shenzhen 518060;College of Materials Science and Engineering,Beijing University of Chemical Technology,Beijing 100029)

机构地区：[1]中国科学院化学研究所北京分子科学国家实验室中国科学院工程塑料院重点实验室,北京100190 [2]中国科学院大学,北京100049 [3]青岛大学山东省海洋生物质纤维材料及纺织品协同创新中心海洋纤维新材料研究院生物多糖纤维成形与生态纺织国家重点实验室,青岛266071 [4]深圳大学材料学院深圳市高分子材料及制造技术重点实验,深圳518060 [5]北京化工大学材料科学与工程学院,北京100029

出　　处：《高分子学报》2020年第11期1267-1274,I0004,共9页Acta Polymerica Sinica

基　　金：国家重大研发计划重点专项(项目号2017YFB0307604)资助.

摘　　要：研究了生物基聚酰胺56(PA56)等温和非等温结晶条件下球晶生长的光学偏振反转现象.通过“一步法”等温结晶研究发现,PA56球晶形貌及光学性质强烈依赖于等温结晶温度.在低温区域内(220℃),PA56球晶边界清晰,亮度明亮,形状规整,呈正光学性;在中间温度区域内(235℃),PA56球晶明显呈现边界不清晰的形貌特征,视野较暗,多呈正负混合光学性球晶;在高温度区域间内(245℃),PA56球晶呈现正负混合花瓣型球晶.“两步法”和“三步法”等温结晶实验同样证明了PA56球晶的光学性质强烈依赖于等温结晶温度.在非等温结晶过程中,降温速率分别为10、30℃/min时,所得PA56球晶的双折射特征均为正光学性;而当降温速率升高到60℃/min时,PA56球晶发生明显的正-负-正光学偏振反转.高的等温结晶温度和高的降温速率导致球晶生长过程中分子链的运动加快,与球晶半径方向平行的链与链之间的氢键面方向发生偏转,变为垂直,使得正光学球晶转变为负光学特性.The optical polarization inversion phenomena of spherulite growth of bio-based polyamide 56(PA56)under isothermal and non-isothermal crystallization conditions were studied.The results of isothermal crystallization by“one step procedure”indicate that the morphology and optical properties of PA56 strongly depended on the temperature.At a low temperature as 220℃,PA56 spherulites are optically positive which have clear boundaries and bright brightness with regular shape.At a medium temperature as 235℃,PA56 spherulites show morphological features obviously with unclear boundary,dark field of vision,belonging to the mixed spherulites type.At a high temperature as 245℃,PA56 spherulites are positive and negative mixed petal type spherulites.The morphology and optical properties of PA56 spherulites are strongly dependent on the temperature of the isothermal crystallization,demonstated by both“two step procedure”and“three step procedure”.During the non-isothermal crystallization with a cooling rate of 10 and 30℃/min,respectively,the birefringence characteristics of PA56 spherulites show the positive optical property.However,PA56 spherulites undergo a transition of positive ones into negative ones through a higher cooling rate(60℃/min).High isothermal crystallization temperature and high cooling rate will lead to the acceleration of molecular chain movement during spherulite growth.The direction of the hydrogen bonding plane between the chain parallels to the spherulite radius direction and the chain becomes vertical,making the positive optical spherulite transformation negative optical characteristics.

关 键 词：聚酰胺56 球晶 结晶动力学 光学偏振反转 

分 类 号：TQ323.6[化学工程—合成树脂塑料工业]