\r马 哲，王 威，郑力荣，王 彬，潘 莉，马桂秋，李悦生\r
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AuthorsHTML:\r马 哲，王 威，郑力荣，王 彬，潘 莉，马桂秋，李悦生\r
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AuthorsListE:\rMa Zhe，Wang Wei，Zheng Lirong，Wang Bin，Pan Li，Ma Guiqiu，Li Yuesheng\r
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AuthorsHTMLE:\rMa Zhe，Wang Wei，Zheng Lirong，Wang Bin，Pan Li，Ma Guiqiu，Li Yuesheng\r
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Unit:\r天津大学材料科学与工程学院，天津 300350\r
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Unit_EngLish:\rSchool of Materials Science and Engineering，Tianjin University，Tianjin 300350，China\r
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Abstract_Chinese:\r利用力学拉伸和广角X 射线衍射联用方法，原位研究了含有1.5%(摩尔分数)共聚单元的丁烯/乙烯无规共聚物在循环拉伸过程中Form Ⅱ晶型向Form Ⅰ晶型相转变过程．通过力学性质和相转变动力学关联，发现第一次拉伸过程中相转变开始于屈服区域；在循环拉伸过程中，相转变在回复及二次拉伸屈服前都可进行，但大于第一次屈服强度的拉伸应力可以显著加速相转变动力学．同时，还在该丁烯/乙烯共聚物体系中发现转变相Form Ⅰ含量与拉伸应力的对应性．研究成果有助于认识丁烯/乙烯共聚物的宏观性质与微观晶体结构关系，为晶体结构调控和新型共聚物开发提供基础和指导．\r
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Abstract_English:\rThe cyclic-stretching induced phase transition of a butene/ethylene copolymer containing 1.5% (mole fraction) co-units was explored with mechanical testing and wide angle X-ray diffraction，and the mechanical performance was correlated with phase transition kinetics．The results show that during the initial stretching，the phase transition was triggered with yielding．On the other hand，during the recovery and secondary stretching，the phase transition was independent of yielding．However，the phase transition kinetics can be significantly accelerated when the stretching strength exceeds the stress of the initial yielding．Moreover，the correspondence between the mechanical properties and the FormⅠ fraction indicates a stress-dominant mechanism for the phase transition．The results shed light on the relationship between macroscopic mechanical properties and microscopic crystalline structures and provide the foundation for the structural control and design of novel copolymers．\r
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Keyword_Chinese:丁烯/乙烯无规共聚物；循环拉伸；广角X 射线衍射；相转变\r

Keywords_English:butene/ethylene random copolymer；cyclic-stretching；wide angle X-ray diffraction；phase transition\r


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