Behaviour of the very-low-temperature crystallization peak of linear low-density polyethylene

Proceedings of the Estonian Academy of Sciences

Andres Krumme¹  Arja Lehtinen¹  Anti Viikna¹  Triinu Poltimäe¹  Elvira Tarasova¹ 

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关键词: materials technology;    linear low-density polyethylene;    copolymers;    low-temperature crystallization peak;    differential scanning calorimetry;   

DOI  :  10.3176/proc.2009.1.10

学科分类：化学（综合）

来源: Teaduste Akadeemia Kirjastus

【 摘 要 】

The crystallization behaviour of Ziegler–Natta (ZN) and single-site catalyst based ethylene–1-butene and ethylene–1-hexene copolymers with different comonomer content were studied by differential scanning calorimetry. In addition to a high-temperature crystallization peak, and for ZN copolymers in addition to a low-temperature crystallization peak, quite often a very-low-temperature crystallization peak (VLTCP) was observed at temperatures in between approximately 330 and 345 K. It was found that the VLTCP temperature decreased with increasing comonomer content and did not depend on the type of catalyst used. The fractional degree of crystallinity calculated from the VLTCP was independent of the chemical nature and content of the comonomers present as well as of the polydispersity of molar mass within the used range of magnitudes. However, crystallinity as related to the area of the VLTCP was strongly catalyst type dependent and was higher for the single-site catalyst used compared to the ZN catalyst used.

【 授权许可】

Unknown