RPE/Sand Powder Blends And The Study On Its Compatibilization

Recycle of waste plastics, especially the general-purpose plastics, is the emphasis on environmental protection and sustainable development. Currently, for recycling waste plastic, mixing of the plastic with polymer and filler is mainly applied to obtain the composite material with outstanding property. Based on the principle of waste recovery, low cost and multifunction, the composites of common sand and recycled polyethylene (RPE), which could be applied for structural and decorative plates, were firstly prepared via the method of melt blending.Since the great performance difference, RPE and inorganic filler are difficult to connect together, which results in a strong impact on the property of composites. In this paper, modifiers of PE-g-MAH and SEBS-g-MAH were made based on previous studies. Additionally, RPE/Sand composites were prepared via the method of melt blending and mechanical properties were tested. Then, the grafted production was introduced to modify the RPE/Sand composites, and the effect of modifiers content on mechanical properties of composites was investigated.In this paper, two methods, solution and melt graft, were used to make HDPE–g-MAH, and the effects of some conditions, such as initiator content, composition ratio of monomer, reaction temperature and time, on grafting percentage and grafting efficiency were studied. In addition, the grafted production was characterized by chemical analyze and FT-IR. The results showed that, initiator and monomer are the main factors on grafting reaction. For the solution method, the grafting percentage and efficiency were optimal at the ratio of HDPE: BPO: MAH=100: 2: 10(wt), while for the melt method, the optimal ration was HDPE: BPO: MAH=100: 3: 12(wt).DCP used as initiator, SEBS-g-MAH was obtained through torque rheometer by melt grafting. It was showed that the grafting percentage and efficiency were optimal at the ratio of SEBS: MAH: DCP = 100: 10: 1(wt), and if the content of MAH was more than 10(wt), the grafting efficiency would decrease.The RPE/Sand composites were prepared via melt blending and mechanical properties were tested. The results indicated that the addition of the sand is helpful to improve tensile-strength and bending property of the composite, however, impact strength decreases. If the composition ratio is RPE: Sand=100: 80(wt), the comprehensive mechanical properties is optimal. Furthermore, the adding of sand causes an increase of the surface hardness, the Vicat softening point, the water absorbing capacity, and the melt viscosity of the composites, and also causes the decrease of process ability.The grafted production was introduced to modify composites of RPE/Sand, and the effect of the content of modifiers on mechanical properties of composites was investigated. The results suggested that SEBS-g-MAH and PE-g-MAH are respectively optimal for toughening and reinforcement. While LDPE has toughened to some extent, but the comprehensive effect was not equal to the above two. In addition, modifiers improve the processing rheology to some extent, while the grafting percentage had little effect on mechanical properties and torque balance of the materials.SEM was used to observe the impact fracture of composites and the modified mechanism was also studied. The results showed that it forms strong interfacial bond between RPE matrix and sand powder which treated by silane coupling agent by used the modifiers. When the composite material is subjected to external forces, it can effectively use of rigid sand particles carrying load and transfer stress and could raised the material to resist damage force, so that the strength and toughness of composites are improved together.