By means of gel permeation chromatography(GCP),differential scanning calorimetry(DSC),polarizing microscope and infrared spectroscopy,the composition and formation of crystal point of metallocene polyethylene films were analyzed from the molecular chain structure of the raw materials.The results show that the crystalline morphology of the crystal point of metallocene polyethylene film is different from that of normal film,and the uniformity of the crystal size constituting the crystal point is far lower than that of normal film.The reason is that the crystal point contains fibrous crystals,in which the fibrous crystals crystallize first,resulting in the uneven growth of the subsequently formed crystals here.In addition,the intermolecular cross-linking are caused by the end group double bond on the molecular chain(RCH=CH2)in the film blowing process and the regular structure of the longer methylene sequence in the molecular chain are the main factors for the formation of fibrous crystal,while the regular structure of the longer methylene sequence is caused by the uneven distribution of comonomers.
关键词
茂金属聚乙烯/晶点/纤维状晶体/分子链结构/端基双键/亚甲基序列/共聚单体
Key words
Metallocene Polyethylene/Crystal Point/Fibrous Crystal/Molecular Chain Structure/End Group Double Bond/Methylene Sequence/Comonomer
维普
万方数据