Preparation Of P34HB/Wood Flovur Blended Bio-degradable Pachaging Material

Biodegradability composites were prepared by hot pressing method after blending,using tomentosa wood flour and P34HB as raw materials, hoping to find a new alternative to the package pallet. The structure and properties of composite were studied with the characterization by scanning electron microscopy (SEM), differential scanning calorimetry(DSC), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy(FTIR),dynamic mechanical analysis (DMA) and mechanical property analysis. The following studies were performed on the composites:(1) The effects of different wood flour content on the properties of the composites were studied, and the optimal mass ratio of P34HB and wood fiber was found out. The results show that with the increasing of wood flour content, the tensile strength, breaking elongation and flexural strength of the composite increase first and then decrease, but the impact strength decreases continuously. DMA analysis shows that,tan? peaks of the composite material first decrease and then increase and the storage modulus E' increase as the content of wood flour increasing. The high frequency modulus of the composite is greater than the low frequency modulus, dynamic stiffness is better than static stiffness.TGA and DSC show that the added in of wood flour improving the thermal stability widening the thermal processing window, reducing the degree of crystallinity of the composite material,. Based on the research, the optimum wood flour content of P34HB /wood flour composites is 50%.(2) Maleic anhydride (MAH) was added into the mixtures of P34HB and wood flour(mass ratio of 1:1) as coupling agent in different proportions. The effects of maleic anhydride content on the structure and properties of the composites were characterized.DSC shows that maleic anhydride reduced the crystallinity of composites but increased the degree of crystallinity of rich-4HB micro- region. Small amounts of maleic anhydride could increase the integrity of P34HB crystals. A large number of ester bonds and hydrogen bonds were found between P34HB matrix and flour fibers in FTIR. The storage modulus E' of composite was firstly increased and then decreased. All the mechanical properties of composites showed the tendency of firstly increased and then downward along with the increasing of maleic anhydride, except the Young's modulus decreased continuously. On the comprehensive view, the enhancement effect of 0.5%MAH was the best among all the samples.(3) The P34HB/MAH/wood flour composites with the best quality addition of 0.5%maleic anhydride were chosen as the raw materials. The degradation process of the composites in the natural environment within 100 days was studied by the natural embedding method, and the properties of the composites were analyzed. The results showed that the degradation of wood flours was mainly after the degradation of P34HB matrix. The P34HB matrix was showing a honeycomb mainly due to the degradation of P34HB matrix amorphous portion and the incomplete degradation of P34HB matrix crystal portion. After about 60 days, the macromolecular chain segments were decomposed into small molecular chain segments and the wood flours began to degrade.The mass loss of the composites showed a linear upward trend, and the mass decreased by 34.43% in 100 days. The flexural strength and Young's modulus curve of the composites showed logarithmic growth after degradation. The flexural strength and Young's modulus decreased rapidly at 10 days, and decreased with the increase of degradation time, and became equilibrium after 80 days.