Study On Mechanical Preparation Of Micro-Foaming Polypropylene

Micro foamed polyolefin composite materials is based on polyolefin material as base, by introducing the microcellular foaming technology in polymer inside the introduction of a large number of small cell, is designed to keep the polymer materials some of the excellent performance of the original at the same time, improvement of its performance, in order to reduce the cost, improve the performance of the objective. Micro foamed polymer is a kind of high performance composite model, compared with common foamed polymer, the former has lower foaming rate, cell size smaller, cell density greater, cell size distribution more uniform and better comprehensive performance advantages. As a structural material in transportation, automotive, military, aerospace and other fields have a wide range of applications. However, foamed polymer material internal from the single phase interface of fiber- resin increased to three kinds of interface of fiber – resin, fiber – gas, gas – resin. At present, the research of strengthening and toughening of foam composite materials, three-phase coexistence, has become a hot and difficult foaming industry research.Moreover, due to the reduction of effective bearing area after foaming, resulting in comprehensive mechanical properties have a certain decline, the realization of strengthening and toughening of micro foamed polymer is a difficult technical problem urgently needs the breakthrough in theoretical research. At present, the ways to improve the comprehensive performance of micro foamed polymer material mainly in the following two aspects: first, adding reinforcement to improve the comprehensive mechanical properties in micro foamed polymer material, this method can greatly improve the performance and the cost is low; second, to improve the foaming quality by adjusting the process conditions, thus improving the mechanical properties of foam materials, but this method improve the performance of the amplitude is limited.In this paper, using the two methods to improve the mechanical properties, selection of polypropylene resin as matrix material, preparation of sample by release press process in chemical foaming injection molding technology. On the one hand, filled with inorganic particles, fiber reinforced mechanism as the foundation, systematic study of the strengthening and toughening mechanisms of reinforcing phase enhanced melt in the presence of gas. On the other hand, by adjusting the process conditions for preparing composite foaming masterbatch to improve foaming quality, so as to explore the rule of cell size effects on micro mechanical foaming properties of composite materials. Providing important basis theoretical and method of micro foamed polyolefin composite materials for development of the better comprehensive performance. This paper achieves the following main results:1, CF reinforced PP composite foaming material effect is the best, and the best of AF toughening effect. Compared with PP, PP/CF composite foaming material, which stretch, compression, bending strength increased by 100.9%,80.4%, 126.5%. PP/AF composite foaming material, which impact strength increased by 151.2%.2, The fiber-resin interface proportion is more conducive to the promotion of mechanical properties. Fiber reinforced resin mainly rely on the plastic flow and bonding with resin transfer stress, the use of high strength fiber to withstand stress. The resin of fiber-resin interface can play the role of stress transfer. And the gas of fiber-gas interface cannot play the role, resulting in the fiber unable to enhance, play the role of defect.3, The case of the same porosity, cell size is smaller, the better mechanical properties.In ensuring the effective bearing area of the specimen under the same conditions, the larger cells as defects present in the material, and the smaller cells are beneficial to thpassivation crack expand.4, The better mechanical properties of banburying than extrusion. Its tensile strength, impact strength, flexural strength and compression strength were increased by 18.6%、22.1%、18.3%、18.1%.