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Investigation of thermoplastic elastomer (TPE) foaming process using blowing agent by rheological and morphological methods
Author(s) -
Kong Hyo Jae,
Lee Seung Hak,
Kim Dong Gun,
Kim Hyo Jun,
Park Gun Wook,
Hyun Kyu
Publication year - 2019
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.47358
Subject(s) - blowing agent , materials science , rheology , composite material , curing (chemistry) , ultimate tensile strength , copolymer , elongation , dynamic mechanical analysis , elastomer , modulus , thermoplastic , polymer , polyurethane
The effects of a chemical blowing agent (CBA) or an encapsulated physical blowing agent (PBA) on morphological development in ethylene octene copolymer (EOC) matrix using dicumyl peroxide (DCP) as a curing agent were investigated by rheological, mechanical, and morphological methods. Temperature ramp tests were carried out to understand curing and foaming processes. Curing temperature ( T cure ) was determined as the crossover temperature where storage modulus G ′ coincided with loss modulus G ′′ in the rheological point of view. For the CBA, T cure increased with increasing CBA concentration, whereas for the PBA, T cure decreased with increasing PBA concentration. Other critical temperatures T 1st , T 2nd by foaming process were determined using the axial normal force. With these critical temperatures ( T cure , T 1st , T 2nd ), curing and foaming mechanisms can be estimated. Simultaneously, volume expansions of samples were observed with camera. Morphology and mechanical analysis were conducted on fully cured and foamed ECP (is defined as EOC with DCP) with blowing agent. ECP with the CBA exhibited an irregular open‐cell structure, whereas when produced using the PBA, it formed a regular closed‐cell structure. Specific tensile strength tended to increase with increasing PBA concentration but as blowing agent concentration increased elongation at break decreased. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47358.