Premium
Effect of molecular structure and rheology on the compression foam molding of ethylene‐α‐olefin copolymers
Author(s) -
Zhang Ying,
Kontopoulou Marianna,
Ansari Mahmoud,
Hatzikiriakos Savvas,
Park Chul B.
Publication year - 2011
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21851
Subject(s) - comonomer , materials science , blowing agent , octene , copolymer , rheology , composite material , compression molding , polymer , polyurethane , mold
The morphology and mechanical properties of foams made out of a series of ethylene‐α‐olefin copolymers having well‐characterized rheological properties were investigated. A compression foaming molding technique was implemented, using azodicarbonamide as the blowing agent. The polymers differed in the amount of comonomer contained (resulting in a range of densities), type of comonomer (octene vs. butene) and molecular weight, resulting in variable thermal properties and different rheological responses under shear and extensional flow. The results showed that the majority of the octene‐based copolymers with comparable rheological properties had similar foam morphology. A distinct behaviour was observed for the butene‐based copolymer, as well as the octene‐containing one having the lowest density and lowest melting/crystallization points. The poor foamability of these grades was attributed to their differences in extensional and thermal properties, respectively. Increasing density resulted in a higher secant modulus of the foamed samples. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers