Study On Interfacial Compatibility Of Polypropylene/Wood Flour Composites

Wood-plastics composites (WPCs) are a type of composites that taking wood flour(WF) or cellulose and plastics as primary material. As a new-type circumstance composites, it is not only has the ligneous feeling of wood but also has more excellent performance than wood. What's more, it can be drilled, cut, napped, milled and planed like wood. For its excellent performance and environmentally friendly, it received lots of attention from people,increasing rapidly, used in diverse areas of our life.In this paper,several methods have been adopted to improve the interface compatibility of PP-based WPCs. Several modern instrumental analysis such as X-ray Diffraction(XRD),Polarization Microscope(POM),Scanning Electron Microscopy (SEM),Scanning Electron Microscope with an Energy Dispersive X-ray Spectroscopy (SEM-EDS),Fourier Transform Infrared Absorption Spectrum (FTIR),X-ray Photoelectron Spectra (XPS),Dynamic Mechanical Analysis (DMA) were used to characterize the influence of modification methods on performance and structure of WPCs, interface reaction, evolution of interface and structure during compounding. The results indicate that:(1)Bothγ-aminopropyltriethoxy silane(γ-APS) coupling agent,compatibilizer maleic anhydride grafted ethylene– octene copolymer (POE-g-MAH) can improve the interface compatibility and mechanical properties of WPCs. The best dosage ofγ-APS is 1%～3%, while 15% is the optimum dosage of POE-g-MAH .γ-APS have little influence on proeessing performance,while POE-g-MAH can improve the proeessing performance significant. Silane coupling agentγ-APS,compatibilizer POE-g-MAH has a very significant synergistic effect. When useγ-APS and POE-g-MAH simultaneously,interface compatibility,mechanical properties and proeessing performance can be improved significant.(2)The addition of silane coupling causes higher crystallnity of WF/PP composites, while compatibilizer POE-g-MAH causes lower crystallnity of WF/PP composites. Transcrystals are observered at the interface,whileγ-APS and POE-g-MAH are used simultaneously.(3)Both silane coupling agentγ-APS and compatibilizer POE-g-MAH can chemical adsorption on the surface of wood flour. And there are interfacial interactions between MAH group on POE-g-MAH and–NH2 on the surface of theγ-APS treated wood flour.(4)Vinyl triethoxysilane grafted ethylene–octene copolymer(POE-g-Si) were prepared. As the addition of POE-g-Si, the interface compatibility,mechanical properties and proeessing performance of WPCs improved. At the same time, crystallnity of WF/PP composites decrease,βcrystal of PP disappear, transcrystals are observered at the interface of the samples. POE-g-Si decrease the storage modulus of WF/PP composites, improveing the damping properties.(5)With the increasing of processing time, silane coupling agent and compatibilizer migrate from the interface to PP matrix, the storage modulus decrease, interface compatibility and damping improved.