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以美国Exxon公司生产的茂金属短支链聚乙烯 (SCBPE)为研究对象 ,用DSC热分级方法研究了不同支链含量聚乙烯的支化非均匀性 ,并用TEM表征茂金属聚乙烯在不同条件下熔体结晶的形态 .SCBPE经逐步结晶分级后 ,其DSC熔融曲线出现多峰 ,表明茂金属SCBPE仍具有很大的非均匀性 .支链含量愈高 ,熔点愈低 ,非均匀性增加 .SCBPE的晶体形态随平均支链含量的增加片晶厚度减小 ,片晶尺寸分布增加 ;含量较低时 ,SCBPE在不同温度下均生成球晶结构 .随结晶温度的降低支链含量较多的分子也能参与结晶 ,故生成的片晶厚度减小 .从相分离的熔体中结晶 ,大尺度的片晶集聚体间的分离和小尺度的片晶之间相分离同时存在 .
Based on the metallocene short-chain polyethylene (SCBPE) produced by Exxon in the United States, the branching heterogeneity of polyethylene with different branched contents was studied by DSC thermal grading. The effects of metallocene polyethylene The morphology of the melt crystallized.SCBPE after gradual crystallization grading, the DSC melting curve appears multi-peak, indicating that the metallocene SCBPE still has a great heterogeneity.Coupled content is higher, the lower the melting point, the non-uniformity increases. The crystal morphology of SCBPE decreases with the increase of the average branched content, and the size distribution of the crystallites increases. When the content of SCBPE is lower, the spherulite structure is formed at different temperatures. With the decrease of crystallization temperature, The molecules can also participate in the crystallization, so the thickness of the generated lamellae decreases.The crystallization of the phase separation melt, the separation of large-scale lamellar aggregates and the phase separation of small-scale lamellae exist simultaneously.