相對分子質(zhì)量及立構缺陷分布對β晶聚丙烯結晶及形態(tài)的影響
發(fā)布時間:2018-04-05 09:48
本文選題:等規(guī)聚丙烯 切入點:立構缺陷分布 出處:《高分子材料科學與工程》2017年05期
【摘要】:制備了具有不同立構缺陷分布均勻性、不同相對分子質(zhì)量的系列等規(guī)聚丙烯(iPP)樣品,利用差示量熱掃描儀、廣角X射線衍射儀、掃描電子顯微鏡等深入研究了雙組分β晶成核劑作用下,iPP的相對分子質(zhì)量、立構缺陷分布均勻性對其多晶型行為、非等溫結晶動力學行為,尤其是β晶含量、形態(tài)和熱穩(wěn)定性的影響。結果表明,立構缺陷分布的均勻性決定了iPP結晶溫度的高低;而立構缺陷分布均勻性與相對分子質(zhì)量都是結晶活化能的重要影響因素。在熔融方面,相對分子質(zhì)量和立構缺陷均勻性都是影響β晶含量、β晶熱穩(wěn)定性的重要決定因素。相對分子質(zhì)量越低、立構缺陷分布越不均勻,越不利于形成高含量β晶;然而,立構缺陷分布越不均勻,相對分子質(zhì)量越高,越容易形成熱穩(wěn)定性高的β晶。上述研究結果表明,在雙組分β晶成核劑作用下,iPP的相對分子質(zhì)量和立構缺陷均勻性對iPP的β結晶具有不同的影響特征,因此在實際研究及加工過程中需綜合考慮。
[Abstract]:A series of isotactic polypropylene (IPP) samples with different structural defects and different molecular weights were prepared. The samples were obtained by differential calorimeter and wide-angle X-ray diffractometer.Scanning electron microscopy (SEM) has been used to study the relative molecular weight, the distribution uniformity of orthotropic defects and the non-isothermal crystallization kinetics, especially the 尾 -crystalline content, of PP under the action of two-component 尾 -crystal nucleating agent.Effects of morphology and thermal stability.The results show that the homogeneity of the distribution of orthotropic defects determines the crystallization temperature of iPP, and that the uniformity of the distribution of orthotropic defects and the relative molecular weight are important factors affecting the activation energy of crystallization.In the aspect of melting, the relative molecular weight and the homogeneity of the vertical defects are the important determinants of the content of 尾 -crystal and the thermal stability of 尾 -crystal.The lower the relative molecular weight, the more uneven the distribution of orthotropic defects is, which is not conducive to the formation of high content 尾 crystals. However, the more uneven the distribution of orthotropic defects is, the higher the relative molecular weight is, and the easier it is to form 尾 crystals with high thermal stability.The above results show that the relative molecular weight and the homogeneity of orthotropic defects of iPP have different effects on the 尾 -crystallization of iPP under the action of two-component 尾 -crystal nucleating agent. Therefore, it is necessary to consider comprehensively in the process of practical research and processing.
【作者單位】: 重慶交通大學土木工程學院;重慶市智翔鋪道技術工程有限公司;招商局重慶交通科研設計院有限公司;四川大學高分子研究所高分子材料工程國家重點實驗室;
【基金】:國家自然科學基金資助項目(NSFC 51202214) 重慶市杰出青年基金資助項目(cstc2014jcyjjq30002)
【分類號】:O632.12
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