| Energy and environmental issues are a serious problem that the whole world is common facing. Some of non-renewable resources dropped rapidly, such as petroleum resources, coal resources, forest resources, water resources. In order to reduce damage to the environment and alleviate the excessive dependence on forest resources and oil, we could develop/product/use of new composite materials and replace the existing materials which are backward is inevitable trend of the development of material engineering. This direction has been focused by worldwide. It is a great significance that study rice straw and starch composite to development environment-friendly, resource-saving economic model of sustainable development.This thesis focus on the rice straw/starch composite were prepared and properties. Firstly in the experiment I designed orthogonal tests refer to the performance of composite materials mechanics, thermal properties, water resistance and so on. I will find different types of starch(including:corn starch, tapioca starch, pea starch), different mixing water content(6%±0.5%,7%±0.5%,8%±0.5%) and different molding temperature(130℃,145 ℃,165℃)which molding effects and best combination. The next step, I preparation of different densities sample, such as ρ1(1.41×103kg/m3), p2(1.37×103kg/m3), p3 (1.33×103kg/m3), p4(1.30x103kg/m3). In addition from composite material loading level point, preparing filling of rice straw 90%,80%,70%,60%,40%,20%six samples test; finally, I choose four fiber sizes of rice straw, such as 100mesh,80mesh,60mesh and 40mesh, to above scheme. All of these aspects of mechanical properties, thermal properties, water resistance and microstructure analysis. The main conclusions:(1)Using the orthogonal test plan and range analysis method, I found that the use of corn starch mix with rice straw ratio of 1:4, including the use of fiber size 60mesh rice straw powder, and mixing water content is 6%±0.5%, molding temperature 145℃-165℃, molding pressure is 12Mpa, molding time is 10min could get the best mechanical and physicochemical properties.(2)Comparing the mechanical and physicochemical properties of different density composite material. I found that when rice straw/starch composite density is pi (1.41×103kg/m3) the composite tensile strength was 9.22Mpa, flexural strength was 28.05Mpa, the impact strength is 4.3749KJ/m2,water absorption rate is 81%, moisture absorption rate is 5.23%, the contact angle is 59.49′,heat conductivity coefficient is 0.07536W/(m·K) were the best value. Therefore, selection of density ρ1(1.41×103kg/m3) is the good for composite materials.(3)Through comparing mechanical and physicochemical properties of four different loading levels composite could summarized that the choice of filler content 90% can be prepared with good comprehensive properties, the tensile strength is 8.35Mpa, bending strength is 28.94Mpa, impact strength is 4.1084KJ/m2, heat coefficient is 0.09949W/(m·K), water absorption rate is 272%, moisture absorption rate is 6.86%, contact angle is 61.61°(4)Through comparing the mechanical and physicochemical properties of filled with different straw fiber size in composite. The better performance of composite materials is when I selected 80mesh straw powder. Under this condition the tensile strength is 7.47Mpa, bending strength is 23.87Mpa, impact strength is 3.7709KJ/m2, heat coefficient is 0.09157W/(m·K), water absorption rate is 109%, moisture absorption rate is 6.14% and contact angle is 68.54°... |
PDF Full Text Request