Composites processed from wood fibers and automobile polymer fluff

The objective of this research effort was to investigate the physical and mechanical properties of composites processed from wood fiber and automobile polymer fluff. To this end, a study was conducted to investigate the feasibility of incorporating polymer fluff in dry-process wood fiberboard using polymeric diphenylmethane diisocyanate and phenol - formaldehyde resins. The effect of polymer fluff content and polymer fluff particle size on the physical and mechanical properties of wood fiber/fluff composites was also investigated. The surface properties (dispersive energy and acid-base properties) of the polymer fluff materials and the thermal mechanically pulped hardwood fibers were characterized using contact angle analysis and inverse gas chromatography. Detailed studies were conducted on the moisture related properties of the wood fiber/fluff composites such as moisture transfer and thickness swelling, using both a water immersion test and moisture vapor test. A model to predict the maximum water absorption of water immersion was established for wood fiber/fluff composites as a function of board density and polymer fluff content. A swelling model was also established to predict the hygroscopic thickness swelling rate of composites in a water vapor environment. A moisture diffusion model based on Fick's second law of diffusion was applied to the moisture absorption process of the composites from which the diffusion coefficients and surface emission coefficients were calculated using a nonlinear curve fitting algorithm.; The experimental results indicated that automobile polymer fluff, after processing through several simple procedures including separation, cleansing, and granulation, could be recycled by manufacturing dry-process wood fiber/fluff composites. The smaller the polymer fluff particle size, the higher the internal bond, and the lower the thickness swelling and water absorption. Polymer fluff size did not have a significant effect on the bending properties of the composites. Internal bond of the wood fiber/fluff composites decreased linearly with the increase in fluff content. The modulus of rupture and modulus of elasticity of the composites also decreased with the increase in fluff content. Incorporating polymer fluff material improved thickness swelling, moisture resistance and decay resistance of the wood fiberboard. The prediction of the maximum water absorption model has the 95% accuracy for most of the specimens. The swelling model also provided a good prediction of the hygroscopic swelling process of wood composites. The surface emission coefficient did not influence the moisture absorption process of the composites. The systematic prediction errors were found in the diffusion model when it was applied to moisture absorption process of the composites.