Preparation And Properties Of Polylactic Acid / Wood Flour Composites

The poly(lactic acid)/wood powder composite as a sort of biodegradable materialwas prepared. The mechanical properties, rheological properties and conformation ofprepared samples were studied. The results show the two aspects, the improvement ofcompatibility of poly(lactic acid) and wood powder and preventing the degradation athigh temperature, are important to improve the properties of composite. It is effectiveto alleviate the degradation by modifying the wood powder with alkali solution in aproper concentration. Coupling agent YDH-201 could efficiently improve themechanical properties, and the optimum amount is 3.2％. The average granulediameter and mass amount of wood powder would influence mechanical propertiesrelatively greatly. The 150μm wood powder is preferable and the optimum amount is20％. Lubricant has a certain effect on the mechanical properties and smooth finish,and the optimum amount is 1.5％. The research on rheological properties reveals thatthe surface modification of wood powder with coupling agent would make theapparent viscosity ascend; wood powder with greater average granule diameter leadsto higher viscosity; the more the amount of wood powder used, the higher theviscosity would be. The extrusion die swell of the prepared composites is slighter thanpure poly(lactic acid), which shows the dimension stability is improved. Comparedwith pure poly(lactic acid), the prepared composites shows more sensitivity totemperature. The microstructure of samples is studied by means of scanning electronmicroscope. The pictures imply the coupling agent could improve the dispersivity ofwood powder and the compatibility of poly(lactic acid) and wood powder.