INFLUENCE OF THERMOPLASTIC ELASTOMERS ON ADHESION IN POLYETHYLENE WOOD FLOUR COMPOSITES

The mechanical properties of recycled low-density polyethylene/wood fl our (LDPE/WF) composites are improved when a maleated triblock copolym er styrene-ethylene/butylene-styrene (SEBS-MA) is added as a compatibi lizer. The composites' tensile strength reached a maximum level with 4 wt % SEES-MA content. The compatibilizer had a positive effect on the impact strength and elongation at break but decreased the composites' stiffness. Dynamic mechanical thermal analysis (DMTA), a lap shear ad hesion test, and a scanning electron microscope (SEM) were used to inv estigate the nature of the interfacial adhesion between the WF/SEBS an d between the WF/SEBS-MA. Tan delta peak temperatures for the various combinations showed interaction between the ethylene/butylene (EB) par t of the copolymer and the wood flour in the maleated system. The shea r lap test showed that adhesion between the wood and SEES-MA is better than between the wood and SEES. The electron microscopy study of the fracture surfaces confirmed good adhesion between the wood particles a nd the LDPE/SEBS-MA matrix. (C) 1998 John Wiley & Sons, Inc.