The Research On Rheological Properties Of Wood-inorganic Nanocomposites

Wood plastic composite(WPC)uses wood as the main raw material.It is treated as a filler in the form of fiber or powder and added to HDPE,PP,PVC.Among thermoplastic plastics,a new type of material is prepared through conventional extrusion,hot pressing,injection molding and other processing techniques.WPC has the woody feel of solid wood materials and the advantages of weather resistance and microbiological resistance of plastic substrates.It has the characteristics of low cost,recyclable processing,and can replace the use of some solid wood materials,reflecting the concept of green environmental protection.This paper closely combines with the National Natural Science Foundation of China:"Rheologically-induced self-assembly of wood-based surface foamed carbon layer formation and its flame-retardant and smoke-suppression mechanism(31670563)" studies were carried out to formulate and process wood-plastic composite materials.The rheological properties in the study provide a theoretical basis and experimental support for the development of wood-plastic composite materials,and have important research value and application prospects.To this end,this paper mainly studied the influence of wood flour content,nanoparticle content and temperature on the dynamic rheological properties of wood-plastic composites,and explored the formation and destruction of the internal particle network structure of the wood-plastic composite system.Its main work and innovations are as follows:(1)Through experimental studies,the thermal stability of PP was found to be good,and cross-linking oxidation was not likely to occur at high temperatures.The addition of a small amount of calcium carbonate did not change the thermal stability of the PP matrix.Only when the amount added was ? 40%,would it The dynamic rheological properties of plastic composites have an impact.(2)By changing the content of wood flour,the effect of wood flour content on the Payne effect and like-solid behavior of wood plastic composites was studied.The experimental results show that with the increase of the content of wood powder,the high-filling system is more sensitive to the Payne effect,and it is easier to appear the second platform in the low-frequency region,showing a solid-like behavior.At the same time,the low filling system has a wider linear viscoelastic region in the small strain region than the high filling system.With increasing temperature,the viscoelastic modulus of wood-plastic composites decreases and the viscosity decreases.The increase in temperature lowers the sensitivity of the Payne effect of wood-plastic composites and has no significant effect on the sensitivity of the solid-like behavior.(3)When the content of wood flour is the same,the change of nano-calcium carbonate content has no obvious effect on the Payne effect of wood-plastic composites,but it reduces the sensitivity of the composite system to the behavior of like solids,and the amount of nano-calcium carbonate filling With the increase,the storage modulus and complex viscosity of the composite material solution first increased and then decreased with the increase of nano-calcium carbonate content,reached a maximum at 15%,and the second platform and the shear thinning phenomenon weakened.