Preparation And Study On Performance Of Ultrafine Oyster Shell Powder/PP Composites

Polypropylene (PP) is one of the five most generally used plastics, which is usually toughed by inorganic filler (such as CaCO3). Abandoned oyster shell has brought about serious environmental problems to costal cities; nevertheless, ultrafine oyster shell powder probably can be regarded as a substitute for industrial inorganic fillers.This thesis is divided into three parts, the preparation of ultrafine oyster shell powder, the modification of ultrafine oyster shell powder and the preparation versus property tests of ultrafine oyster shell powder/PP composite. The result shows as follows:(1) Ultrafine oyster shell powder obtainable using airstream pulverization, EDTA titration method, XRD, SEM, FTIR and Thermal Analysis (TG/DTA) are introduced to characterize oyster shell and its powder. And the result shows:the mass fraction of CaCO3 in oyster shell is 94.9% and generally of aragonite state, aragonite converts into calcium oxide and calcite after heating in an hour above 700℃; alkane and carboxylic acid are detected by FTIR in oyster shell; as is shown in SEM image, the outer surface of the oyster shell is made up of stratum corneum and distributed with tiny pores, and the inner surface of the oyster shell is nacre of orderly structure, the ultrafine oyster shell powder is mainly of flaky state, the rest is of Columnar and granulous state.(2) Ultrafine oyster shell powder is modified by titanate 201 coupling agent. As we can see from the activation curve of shell powder, the activation index of which reaches the highest when the mass fraction of the coupling agent is around 2%and modification temperature is 90℃, when the ultrafine oyster shell powder is modified, a 2933.39cm-1 peak is shown in FTIR spectra image, which is the characteristic peak of the alkyl in the coupling agent, furthermore, a 320℃ exothermic peak is shown in DTA curve, the decomposition of the alkyl is responsible for that, and it manifests that the ultrafine oyster shell powder and the coupling agent are chemically bonded.(3) The modified ultrafine oyster shell powder is added into PP with mass fraction of 0%、1.5%,3%、4.5%、6%、8%、10% and 12%, the mixed material is granulated and molded, then, the related properties are tested using various equipments. The result shows:the impact toughness of ultrafine oyster shell powder/PP composite reaches the maximum value of 10.18KJ/m2 and increased by 64.9% compared with that of PP when the mass fraction of ultrafine oyster shell powder is 8%; the tensile strength of the composites decreases with the increase of content of ultrafine oyster shell powder; in comparison with PP, the melt flow index of ultrafine oyster shell powder/PP composite is a bit higher when the content of the ultrafine shell powder is in certain range; The melting temperature and melting enthalpy show no great fluctuation according to DSC data; the ultrafine oyster shell powder distributes uniformly among PP and has great compatibility when mass fraction is under 8%, and appears even better after modification.Conclusions can be drawn that it is feasible to add ultrafine oyster shell powder instead of calcium carbonate into PP for it is cost effective and help alleviate pollution, most importantly; it can enhance the combination property of PP and have huge potential economic value.