Effect of styrene maleic anhydride on physical and mechanical properties of recycled polystyrene wood flour composites

Matheus Poletto

doi:10.4067/s0718-221x2016005000046

Abstract

In this work, the influence of three types of styrene maleic anhydride (SMA) oligomers on the adhesion of polystyrene wood plastic composites (WPC) was investigated. The composites were processed on a twin-screw co-rotating extruder below 200°C using 20 wt% of wood flour. The styrene maleic anhydride with different content of maleic anhydride groups, 30%, 25% and 20% (w/w) and levels of 1, 2 and 4% of coupling agents (styrene maleic anhydride 2000, styrene maleic anhydride 3000 and styrene maleic anhydride EF40) in the composite formulations were tested. Mechanical, physical and morphologic properties were evaluated. The styrene maleic anhydride improves the compatibility of hydrophilic wood flour with hydrophobic polystyrene matrix. It has been observed that the addition of styrene maleic anhydride increased the wood plastic composites mechanical properties with the incorporation of 2% wt of styrene maleic anhydride 2000. The mechanical properties showed to be dependent on content of maleic anhydride in the coupling agent. Treated and non-treated wood plastic composites showed similar density values, but the void content was reduced for treated composites. Scanning electron microscopy revel the better adhesion between polymer and matrix when coupling agent were used.

Highlights

The utilization of biomass for processing novel composites has attracted growing interest because of this eco-friendly and renewable nature (Sliwa et al 2012, Nafchi et al 2015)
Short and tiny fibers are preferable for the development of wood plastic composites (WPC) formulations, since these provide a higher specific surface area and greater surface area of contact with the polymer matrix which usually produces better fiber-matrix adhesion when the coupling agent is used and an increase in the mechanical properties are normally observed (Gallagher et al 2013)
The improvement in composite mechanical properties using styrene maleic anhydride (SMA) as coupling agent was strongly dependent on the amount of maleic anhydride into the oligomer and the molecular weight of SMA

Summary

Introduction

The utilization of biomass for processing novel composites has attracted growing interest because of this eco-friendly and renewable nature (Sliwa et al 2012, Nafchi et al 2015). Materials reinforced with wood flour and others natural fibres increased considerably in recent years (Ornaghi Jr. et al 2014). The main application areas of wood plastic composites (WPC) are the automotive and building industries (Nafchi et al 2015) in which they are used in structural applications as door panels, decking, furniture, window parts, etc. In wood industry a large amount of wood waste is generated at different stages of the wood processing and such waste is mainly destined for landfill. Plastic waste is one the major components of global municipal solid waste and, as such, it presents a promising raw materials source for WPC, especially because of large volume (Cui et al 2008).

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