等温结晶热历史对聚乙烯非等温结晶行为影响  

Effect of the Melt History and Isothermal Crystallization History on the Non-Isothermal Crystallization Behavior of Polyethylene

作　　者：王立娟[1] 张艺怀 张瑞[1] 杨琦[1] 卢影 门永锋[2,3] Li-juan Wang;Yi-hua Zhang;Rui Zhang;Qi Yang;Ying Lu;Yong-feng Men(Daqing Petrochemical Research Center,Petrochemical Research Institute of PetroChina,Daqing 163714;State Key Laboratory of Polymer Science and Technology,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026)

机构地区：[1]中国石油天然气股份有限公司、大庆化工研究中心,大庆163714 [2]中国科学院长春应用化学研究所高分子科学与技术全国重点实验室,长春130022 [3]中国科学技术大学应用化学与工程学院,合肥230026

出　　处：《高分子学报》2025年第4期632-643,共12页Acta Polymerica Sinica

摘　　要：聚乙烯的链段序列长度存在一定的分布并且活动能力较强,其在降温过程中不同长度的链段序列将在不同温度下结晶.我们研究了不同熔体温度出发的聚乙烯在不同温度等温结晶一定时间后,在随后降温过程中的非等温结晶行为.相对熔体温度,等温结晶温度与结晶时间对后续的非等温结晶行为影响更大.在选定的等温结晶温度下,随着等温时间的延长,体系内参与结晶的链段逐渐增多,在后续降温过程中参与结晶的链段多为短链,因此非等温结晶对应的结晶温度会随着前序等温结晶时间的延长而逐渐降低.在选定的等温结晶时间内,尤其是较短的结晶时间,结晶温度越高,体系内大部分链段来不及结晶,从而对后续的主链与支链的非等温结晶影响均较大.In general,the chain sequence length of polyethylene has a certain distribution and its molecular chain has a high mobility,which can continue to crystallize during cooling and forming ordered crystal structures with different thicknesses.The non-isothermal crystallization behavior of polyethylene after isothermal crystallization at different temperatures for a certain period of time starting from different melt temperatures was investigated by using differential scanning calorimetry(DSC)technique in the present work.Compared to the melt temperature,the isothermal crystallization temperature and crystallization time have a stronger influence on the subsequent non-isothermal crystallization behavior.At the selected isothermal crystallization temperature,the number of crystallizable chain segments gradually increases with the extension of the isothermal time.As a consequence,the chain segments that can crystallize in the subsequent cooling process are mostly short chains,so the crystallization temperature corresponding to non-isothermal crystallization will gradually decrease with the extension of the preisothermal crystallization time.Within the selected isothermal crystallization time,especially the shorter the crystallization time,the higher the crystallization temperature,most of the chain segments in the system hardly crystallize,resulting in a significant effect on the subsequent non-isothermal crystallization process.Under such a condition,a higher crystallization temperature was always observed during non-isothermal crystallization process.

关 键 词：聚乙烯 熔化温度 熔化时间 结晶温度 非等温结晶 

分 类 号：TQ317[化学工程—高聚物工业]