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采用广角X射线衍射(WAXD)与偏光显微镜(POM)等手段研究了硅氧烷液晶共聚物(LCP-O2)作为新型成核剂对聚丙烯(PP)共混样品结晶结构与形态的影响.结果表明,低浓度的LCP-O2在PP共混体系中起到异相成核的作用,使PP的晶核数目增多,球晶细化,并提高了结晶速度,同时也诱导出了β晶的形成.LCP-O2的成核效果主要依赖于其在PP中的相对含量、液晶的分子结构与结晶的热处理过程,且随着结晶温度或成核剂含量的增加,对应PP试样的β晶含量(Kβ)呈现先增加,后降低的趋势.当LCP-O2质量分数为1.0%,在130℃等温结晶1h,对应PP试样的Kβ最大,为58%.此外,属于单斜晶的α球晶呈现黑白颜色,晶束呈放射状生长,边界清晰;而属于三方晶的β球晶亮度要高于α球晶,其颜色艳丽多彩,束状晶片聚集体呈支化生长,内部排列比α晶疏散,边界相对模糊,且β晶与α晶的形态分别在157和171℃完全消失.
The effects of LCP-O2 as a new nucleating agent on the crystalline structure and morphology of polypropylene (PP) blends were investigated by means of WAXD and POM. The results showed that low concentration of LCP-O2 played a heterogeneous nucleation role in the PP blends, which led to the increase of the nucleation number of PP, the refinement of spherulites and the increase of the crystallization rate, as well as the β crystal The nucleation effect of LCP-O2 mainly depends on its relative content in PP, the molecular structure of liquid crystal and the heat treatment process of crystallization, and with the increase of crystallization temperature or nucleating agent content, When the mass fraction of LCP-O2 is 1.0% and the isothermal crystallization temperature is 130 ℃ for 1h, the Kβ of the corresponding PP sample is the largest, which is 58% .In addition, the content of Kβ is the highest in monoclinic α spherulites appear black and white color, the beam grows radially, the boundary is clear; and belongs to the tripartite crystal β spherulite brightness is higher than α spherulites, the color is bright and colorful, bundles of bundles showed branching growth, the internal arrangement ratio The α crystal evacuates and the boundary is relatively fuzzy, and the morphology of β crystal and α crystal completely disappear at 157 and 171 ℃ respectively.