Functionalized cork-polymer composites (CPC) by reactive extrusion using suberin and lignin from cork as coupling agents

• Main Author: Fernandes, E. M.
• Publication Date: 2014
• Other Authors: Aroso, Ivo Manuel Ascensão, Mano, J. F., Covas, J. A., Reis, R. L.
• Format: Article
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: http://hdl.handle.net/1822/30701
• topic: Cork; Cork composite; Coupling agent; Electron microscopy; Extrusion; Fibre/matrix bond; Lignin; Suberin; Polymer–matrix composites (PMCs); A. Polymer-matrix composites (PMCs); B. Fibre/matrix bond; D. Electron microscopy; E. Extrusion; Science & Technology

High density polyethylene (HDPE) and cork powder were compounded in a co-rotating twin-screw extruder to obtain cork-polymer composites (CPC) with improved properties. Benzoyl peroxide (BPO) was used as initiator agent, and suberin or lignin isolated from cork enhanced filler-matrix bonding and promoted mechanical reinforcement with environmental benefits. The novel composites were characterised in terms of dimensional stability, evolution of morphology, thermal and mechanical properties and their performance was compared with that of composites containing polyethylene-grafted maleic anhydride (PE-g-MA) as coupling agent. As expected, composites with coupling agent present higher mechanical properties, lower water uptake and thickness swelling variation. Suberin acts as plasticizer with antioxidant benefits, while lignin works as a coupling agent, improving tensile modulus and maximum strength. Increasing lignin content does not improve the mechanical properties but improves thermal stability.