polypropylene对isotactic.pdfVIP

Atactic polypropylene 對isotactic polypropylene 之結晶行為及其物性行為之影響 蔡風洲、張立綸、陳建宏 崑山科技大學應用纖維系 Abstract 礙 iPP 分子鏈之結晶成長並導致材料之物理性質明顯改變 In this study, a set of blending isotactic polypropylene (iPP) 而呈現截然不同的物性。在偏光顯微鏡觀測也證實不同aPP with different weight content of atactic polypropylene (aPP) 含量之添加也導致其球晶之外觀產生明顯之差異。 have been investigated and their overall crystallization and 二、前言： physical properties determined by differential scanning calorimetry, polarized optical microscopy, and dynamic 對於同排聚丙烯(isotactic polypropylene, iPP)之結晶化 mechanical analysis experiments. The observations of DSC 行為及其物理性質與 iPP 之微細構造及外在環境有關 indicate that the melt temperature, Tm, and the heat of fusion, (1-6) ，如結晶之過冷溫度效應、分子量效應、分子量分布效 Dh , decreased with increasing the aPP content, however, the 應及分子規則性效應及添加劑等等均會改變 PP 之結晶結構 f results of isothermal crystallization and Avrami’s analysis 及其結晶行為進而影響變 PP 之物理性質與(3,5,7-9) 。 carried out the half time of crystallization, t1/2, increase with the 目前針對高分子材料之結晶化行為主要分為等溫結晶 aPP added with other ones. The Avrami’s analysis for overall 化及非等溫結晶化，而在等溫結晶化之研究中主要為利用 crystallization kinetics of iPP/aPP blended generally shows a Avrami equation(10-11)加以分析高分子材料之結晶行為： lowly primary Avrami exponent, n was about 2~3, and then a n 1 1-Xv = exp [ -K t ] (1) secondary Avrami exponent, n2 was about 1, these results 其中q為尚未轉化結晶之含量，k 為成核及成長之常 indicate the primary crystallization behavior is combine three dimensional spherulite growth and one dimensional rodlike 數，公式中之 n 為結晶化過程中球晶型態及成長時間因子之 growth at secondary crystallization. The overall 和，n值