Study On Preparation And Properties Of Wood Plastic Composites By FRP Waste And Straw Fiber

Corn straw is the Shandong region common agricultural waste, and most of it has been piled up and burned. This way wasted a lot of cultivated land as well as a large number of natural fibers. The corn straw fiber used in this paper was self-made from corn straw. The corn straw fiber was firstly treated by alkali solution, and then treated by titanate coupling agent. Corn straw fiber /PVC composite material was modified by continuously mixing and hot press molding preparation. Because of glass fiber reinforced plastic(short for FRP) waste was difficult to recycled, this paper selected FRP waste that sieved to different particle size range to prepare the FRP waste /straw fiber/PVC composite material, and we researched the influence of FRP waste to structure and performance of the wood plastic composite(short for WPC).Micro morphology, surface groups, chemical and phase constitutions, heat resisting property of corn straw fibers and FRP waste were investigated by metallographic microscope,field emission scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR), X ray fluorescence spectrometer(XRF), simultaneous thermal analyzer(TG/DSC).SEM images showed that surface roughness of alkali treated corn straw fibers was increased significantly, and some fine fibers stripped from the fiber bundle. The bending strength of WPC was 77.15 MPa when dosage of alkali treated straw fiber was 50 phr, as well as its VEKA softening temperature was 95.9℃. When the dosage of alkali treated straw fiber was 45 phr, tensile strength of this WPC was 27.06 MPa. Changes of Torque Rheological Parameters of WPC made by different straw fiber dosage was measured by HAAKE torque rheometer( HAAKE PolyLab QC). With the dosage of alkali treated straw fiber increased,the fusion time, maximum torque of WPC was increased, which illustrated the handling characteristics of WPC became bad.Two ways were used to modify straw fibers: alkali treatment and titanate coupling agent treatment after alkali treatment. FTIR analysis showed that, there was chemical reaction between titanate coupling agent and the surface groups of corn straw fiber. Compared with WPC made by alkali treated straw fiber, WPC has better comprehensive properties when dosage of titanate coupling agent was 1.5 phr. Bending strength of this WPC was increased by13.3%, and its tensile strength was increased by 2.8%, and its impact strength was increased by 34%. SEM images of WPC impact fracture surface showed that titanate coupling agent improved the interface bonding between corn straw fibers and the matrix.Burning loss experiment of FRP waste samples with different particle size showed that the smaller the particle size of FRP waste particles were, the bigger its loss on ignition(LOI)was, and FRP waste had glass less glass fiber. Thermo-gravimetric analysis of FRP waste showed that FRP waste had no significant thermal decomposition within the processing temperature range of composite materials. When the number of FRP waste increased, the tensile strength and bending strength of WPC increased first and then decreased. When the dosage of FRP waste was 15 phr, WPC had the maximum bending strength and tensile strength. Compared with WPC made by no FRP waste, bending strength and tensile strength of WPC contained 15 phr FRP waste were increased by 10.9% and 12.1%, at the same time,water absorption rate of this WPC was the lowest. VEKA softening temperature of WPC was increased as a result of FRP waste. SEM images of WPC impact fracture surface showed that it was difficult for glass fibers to disperse uniformly in the matrix, and interface bonding between matrix and glass fibers of FRP waste was not good. Simultaneous thermal analyzer was used to study influence the number of FRP waste and the particle size of it on the thermal stability of WPC. Thermal stability of WPC was increased with the number of FRP waste improved.Torque rheometer was used to measure the changes of torque rheological parameters of different formulations of FRP waste / straw fiber /PVC composites, by that study the influence of FRP waste on the processing properties of WPC. WPC processing performance became bad with the number of FRP waste residue increased.