STRENGTH PROPERTIES OF WOOD-PE COMPOSITES - INFLUENCE OF PULP RATIO AND PRETREATMENT OF PE FIBERS

Composite sheets were formed by blending synthetic polyethylene (PE) p ulp and conventional wood pulps. Sheets were pressed at 5500 psi for 5 min at 110 degrees C. Pulp ratios ranged from pure PE to pure wood pu lp, with sheet strength increasing with wood-pulp content. However, sh eet strength also was improved by pretreating PE fibers with ozone or oxygen-fluorine gas. Improvement was remarkable in the case of oxygen- flourine pretreatment. The extent of polymer treatment was evaluated u sing I-sp, a measure of the specific (acid-base) interactions at the f iber surface. I-sp was calculated from a classical equation using data from inverse gas chromatography. The increase in I-sp showed linear c orrelations with the increased strength properties of the composite sh eets.