Influence of maleic anhydride as a coupling agent on the performance of wood fiber-polystyrene composites

The lack of polar groups in thermoplastics (e.g., in polystyrene) provides low adhesion with cellulosic fibers. To improve compatibility between reinforcement and matrix, maleic anhydride (MA) was selected as a coupling agent for wood fiber-filled polystyrene composites. In general, the mechanical properties improved along with increased concentrations of MA, initiator (e.g., benzoyl peroxide) and wood fiber up to a certain limit and then decreased. The concentrations of MA and fiber which produced maximum improvements in the mechanical properties varied according to wood species, pulping techniques and type of polystyrene. Moreover, properties were further enhanced when another coupling agent (e.g., isocyanate) was used in addition to the MA.