Preparation And Applied Research Of Polyurethane/Wood Powder Foamed Composite Materials

The application of wood plastic composite materials products is limited, because it has high density. In order to reduce the density of material, this article, using the orthogonal experimental method optimize the preparation process of polyurethane/wood powder foamed composite materials without adhesive and response surface methodology optimize the preparation process with adhesive, to get a optimal process parameters. In this experiment, we had used scanning electron microscope and energy dispersive spectroscopy to observe the interfacial bonding and elemental composition, used infrared spectroscopy to study the changes in chemical group. The results are as follows:(1) The results of orthogonal test showed that, when 40% of wood content, silane coupling agent for 3%, temperature for 35℃ and time for 60min, we can get the strength for 1.687MPa. In this test indicators, four experimental factors influence the compressive strength of the composite material strength are:wood flour content> heating time>coupling agent content> heating temperature; When 20% of wood content, silane coupling agent for 3%, temperature for 45℃ and time for 40min, we can get the density for 0.087 g/cm3. In this test indicators, four experimental factors on the impact strength of density are:wood flour content> heating temperature> coupling agent content> heating time.(2) The results of response surface methodology showed that, the interaction of optimization of the wood content was the strongest. And optimization of the preparation process are follows:the wood content is 33%, adhesive for 4%, the reaction temperature is 49℃. Under this condition, we can get the strength for 4.702MPa and the density for 0.3796g/cm3.(3) Using scanning electron microscope to observe, after joining wood powder, bubble hole diameter became smaller and the section structure was close. Adhesive in materials is conducive to the distribution of stress. By elemental analysis shows, C and O content is higher than that of pure foamed polyurethane foam, the content of N elements and Cl element is reduced.(4) By infrared spectroscopy, polyurethanes and polyurethane/wood flour composite foam materials have NCO peak at 2278 cm-1 and 614 cm-1. Described by 2D-IR, the strength of the peak in composite material is similar to polyurethane and wood. In 1600～1750cm-1,2D-IR spectra of the composites is different from polyurethane and wood. This is consistent with the experimental results of IR.(5) Preliminary exploration the applications of foamed wood plastic composite materials in furniture, use wood flour content of 40%, the coupling agent content of 4% and the adhesive content of 5% to make furnished model, and make some finishing process on the surface.