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NMR Characterization of Vis‐Broken Heterophasic Ethylene−Propylene Copolymers
Macromolecular Reaction Engineering ( IF 1.5 ) Pub Date : 2020-09-10 , DOI: 10.1002/mren.202000039 Megan Matthews 1 , Sifiso Magagula 1 , Albert Reenen 1
Macromolecular Reaction Engineering ( IF 1.5 ) Pub Date : 2020-09-10 , DOI: 10.1002/mren.202000039 Megan Matthews 1 , Sifiso Magagula 1 , Albert Reenen 1
Affiliation
Solution 13C nuclear magnetic resonance (NMR) is used in conjunction with in situ solid‐state NMR to determine the effect of peroxide treatment on the chemical structure and morphology of ethylene−propylene copolymers. The copolymers contain increasing quantities of ethylene with the lowest ethylene content corresponding to pure isotactic polypropylene. The vis‐breaking of heterophasic ethylene‐propylene copolymers (HEPCs) is found to be influenced by the homogeneity of the chain sequences. The in situ vis‐breaking in solid‐state NMR reveals significant changes in mobility of the crystalline domains and the formation of a disordered crystal phase within the α structure is observed. Both solution and solid‐state NMR experiments confirm the greater sensitivity of copolymers containing short ethylene sequences to peroxide degradation. It is proposed that longer chain ethylene sequences resist chemical changes and provide some degree of protection from degradation as a result of the reactivity of the ethylene units.
中文翻译:
裂变的多相乙烯-丙烯共聚物的NMR表征
解决方案13C核磁共振(NMR)与原位固态NMR结合使用可确定过氧化物处理对乙烯-丙烯共聚物的化学结构和形态的影响。所述共聚物包含增加量的乙烯,具有最低的乙烯含量,对应于纯全同立构聚丙烯。发现多相乙烯丙烯共聚物(HEPC)的减粘裂化受链序列同质性的影响。固态NMR中的原位裂化揭示了晶域迁移率的显着变化,并且观察到了α结构内无序晶体相的形成。溶液NMR和固态NMR实验均证实,含有短乙烯序列的共聚物对过氧化物降解的敏感性更高。
更新日期:2020-10-19
中文翻译:
裂变的多相乙烯-丙烯共聚物的NMR表征
解决方案13C核磁共振(NMR)与原位固态NMR结合使用可确定过氧化物处理对乙烯-丙烯共聚物的化学结构和形态的影响。所述共聚物包含增加量的乙烯,具有最低的乙烯含量,对应于纯全同立构聚丙烯。发现多相乙烯丙烯共聚物(HEPC)的减粘裂化受链序列同质性的影响。固态NMR中的原位裂化揭示了晶域迁移率的显着变化,并且观察到了α结构内无序晶体相的形成。溶液NMR和固态NMR实验均证实,含有短乙烯序列的共聚物对过氧化物降解的敏感性更高。