Research Preparation And Absorption Properties Diatomite /polypropylene Porous Composite Material

With the improvement of living standards, people pays more and more attention to noise pollution. Sound absorption and noise reduction are becoming a hot spot research,polypropylene foam is a crystal type plastic, which has good mechanical properties,excellent heat resistance, and is friendly to the environment, therefore polypropylene foam is gradually replacing other foaming materials and widely used. But due to its own characteristic, the foaming process of polypropylene is not easy to control, thus affecting the industrialized production of polypropylene foam, so the modification of polypropylene is crucial. Diatomite is mainly composed of Si O2, has the characteristic of special porous structure. In recent years, it is continuously developed and applied in sound absorption materials and engineering plastics as a fine inorganic fillers. It can not only keep the pore structure of diatomite, but also ensure a certain strength, thus successfully preparing sound absorption material which has certain sound absorption ability.In this paper, for the purpose of developing diatomite/polypropylene porous composites which has a broad spectrum of sound absorption, orthogonal test method is used to choose the best preparing technology of diatomite porous/polypropylene composites. The effect of diatomite/polypropylene's foaming technology, such as foaming temperature, foaming time, cavity thickness of forming mold and so on, on the organization and compression performance of composite material is mainly investigated.The influence of the content of Aluminum coupling agent and soluble additives Na Cl on the sound absorption and compression properties of porous materials is also studied. The results show that the diatomite/polypropylene porous composite material has good strength and sound absorption characteristic, reaching the following conclusions:Diatomite/PP porous composite which has certain strength and highly efficient sound absorption properties is successfully prepared, which the compressive strength is up to12.46 MPa, and the peak value of sound absorption coefficient is 0.83. In order to achieve good compression property, the best molding process is that the foaming temperature is180 ?, the foaming time is 15 min, and the molding thickness is 16 mm.The best molding process of getting good elastic modulus is that the foaming temperature is 175 ?, the foaming time is 12 min, and the molding thickness is 16 mm. The most important factor of influencing density and elastic modulus is molding thickness, and the next influencing factors are foaming temperature and foaming time respectively, and the compressive strength increases with the increase of foaming temperature. The best molding process of getting higher sound absorption coefficient is that the foaming temperature is 175?, thefoaming time is 15 min, and the molding thickness is 18 mm. The modification of diatomite is the best when the content of the aluminum coupling agent is 1wt%, and when the contents of diatomite, aluminum coupling agent, foaming agent and open cell agent are30wt%, 1wt%, 10wt% and 2wt% respectively, it has higher sound absorption coefficient and effective sound absorption frequency width, and the highest sound absorption coefficient is 0.78. Diatomite/polypropylene porous composites prepared by adding 15wt%Na Cl show excellent sound absorption characteristic, the peak value of sound absorption coefficient is 0.83, increased by 6.41%, the efficient sound absorption frequency width is greater than 3437 Hz, increased by 27.29%.