Chain extension of poly(butylene terephthalate)/organically modified clay nanocomposites

Abstract

Thermal degradation of poly(butylene terephthalate) (PBT)/organically modified clay (organoclay) nanocomposites at elevated extrusion temperatures is inevitable and restricts the extensive use for these nanocomposites. This study aimed to prepare PBT/organoclay nanocomposite with enhanced properties by chain extender assisted reactive extrusion approach. A commercial organoclay, Cloisite 30B (C30B), was employed to prepare nanocomposite and a chain extender having multi epoxy functional groups, Joncryl ADR 4300 (Joncryl), was used to compensate thermal degradation of PBT accelerated by the organoclay for the first time. The morphological observations revealed high delamination of C30B within the matrix and the incorporation of Joncryl led to a well-exfoliated structure. The non-chain extended nanocomposite showed the matrix degradation in the rheological tests, where the notable benefit of the chain extender to offset degradation was observed by improvements in the viscoelastic properties. Compared to neat PBT, the tensile modulus of non-chain extended nanocomposite increased by 33 %, whereas a 56 % enhancement was measured for nanocomposite with chain extender. Thermogravimetric analyses indicated higher thermal decomposition temperature with addition of Joncryl into the nanocomposites. It was concluded that Joncryl recoupled degraded chains of PBT and effectively improved the features of nanocomposites.