Positron annihilation study on PP/EPDM polymer blend

Abstract

Positron lifetimes in polypropylene/ethylene‐propylene‐diene monomer blend (PP/EPDM, with the EPDM volume content of 40%), pure PP, and EPDM are measured in the temperature range of 95 to 370 K. We observe the γ and glass transitions in all samples and the transition temperatures Tγ and Tg are determined. The blend has two lower Tg values compared with pure EPDM and PP. At room temperature, the measured concentration and size of free volume in the blend versus EPDM volume fraction φv are smaller than those calculated by the rule of simple mixing. The different free‐volume properties and Tg values of blend, PP, and EPDM indicate the existence of interfacial interaction between PP and EPDM phases in PP/EPDM blend.

Abnormal increase of glass transition temperature of poly(propylene carbonate) modified with rubber particles

“…According to the Ref. [14], if there is no interaction between PPC and CBS‐UFPR, the “hole” concentration ( I 3 ) and the fractional free volume ( R ) will be linear with the CBS‐UFPR volume fraction (φ). where the subscripts B, F, and M refer to the blend, filler CBS‐UFPR and matrix PPC, respectively, and R is the average hole radius.…”

“…According to the Ref. [14], if there is no interaction between PPC and CBS-UFPR, the ''hole'' concentration (I 3 ) and the fractional free volume (R) will be linear with the CBS-UFPR volume fraction (u).…”

The Effect of a Peroxide Modification Coagent on the Viscous Properties of Binary Blends of Polypropylene and Ethylene Propylene Rubber

“…Since then, the production of high-impact polypropylene (PP) has developed at exceptionally high rates. However, in spite of structural similarity, PP and SKEPT are incompatible polymers, and the rubber exists as individual particles in the polypropylene matrix, while poor dispersion of these particles and their large size may work against any increase in the impact strength of the composites obtained [3].…”

聚合物玻璃化转变温度的异常变化及其机理探讨

“…且由于橡胶粒子直径不到 100 nm, 这个界面层的曲 率半径很小, 可以在很大的压力下保持不变形, 这也 是改性材料热变形温度大幅度提高的主要原因. 聚合物共混体系微观结构的方法得到了越来越广泛 的应用 [14,15] . PALS 主要用于表征自由体积尺寸和浓 度.…”

“…我们采用 PALS 表征了 PPC、CBS-UFPR 和改性后的 PPC 自由体积, 具体数值如表 3 所示. 如果 PPC 和 CBS-UFPR 之间 没有相互作用, "空穴"的强度 I 3 应该与添加的体积分 数成线性关系 [14] , 即:…”