Tensile Recovery in Nylon 6/Modified Butyl-Rubber Blend System Consisting of Rubber Particles Distributed in a Nylon Matrix

• Published in: KOBUNSHI RONBUNSHU Vol. 62; no. 7; pp. 301 - 309
• Main Authors: KAIDO, Hiroyuki, ENOMOTO, Tatsuya, SAWAI, Daisuke, HARA, Yuichi, KANAMOTO, Tetsuo, MOROOKA, Naoyuki, SOEDA, Yoshihiro
• Format: Journal Article
• Language: Japanese
• Published: The Society of Polymer Science, Japan 01.01.2005
• Subjects: Morphology; Nylon 6-Modified Butyl-Rubber Blends; Tensile Recovery; Tensile Set; Young's Modulus
• ISSN: 0386-2186; 1881-5685
• DOI: 10.1295/koron.62.301

The effect of morphology on the tensile recovery was studied for a series of blends of nylon 6 (PA6) and a brominated poly (isobutylene-co-p-methylstyrene) copolymer (BIMS rubber) having wide variations in composition and morphology. To modify the morphology of the simple blends consisting of the two components, we added a small amount of sulfur (0.5 wt% of the rubber component) and kneaded the mixtures by two different manners at around 250°C. Microscopic observations of a simple blend of PA6/BIMS=60/40 revealed that rubber particles of a diameter=0.2-0.8μm were uniformly dispersed in the continuous PA6 matrix. However, upon kneading of sulfur, the rubber particles aggregated to form a large domain (1-5μm) with an irregular shape; such domains were distributed in the PA6 matrix. Closer inspections of the transmission electron micrographs revealed that small domains of the PA6 component were included within a larger rubber domain. Such blends with heterogeneous morphology showed a lower dynamic Young's modulus and a superior strain recovery compared to those with uniformly dispersed rubber particles. It was found that the tensile set for a series of the blends could be represented by a unique function of the dynamic Young's modulus, independently of the blend composition.