Study On Modification Of Poly(Propylene Carbonate) And Its Application Properties In Packaging Field

With the people`s living standard improving, as the main force of packaging industry, plastic packaging is playing the role which can not be substituted in the field of commodity, food and so on. However, many plastic packaging products are so difficult to handle and hard to degradation that resulted in increasing serious environmental pollution.Poly(propylene carbonate)(PPC), as a kind of new biomaterial, was prepared via polymerization of carbon dioxide(CO2) and propylene oxide, is one of the most promising green plastic. This material is not only the full use of "greenhouse gases" carbon dioxide, converted into environmentally friendly degradable plastic, but also to avoid secondary pollution problem of plastics on the environment. It also extends the application of plastic, to a certain extent, ease the depletion of oil resources. Nano-cellulose is a new functional materials which has wide source of raw materials, and low cost, meanwhile it has broad prospects in the field of functional materials.In this paper, nanocellulose(NCC) was prepared from microcrystalline(MCC) by acid hydrolysis method, then prepared PPC/NCC nanocomposite. Researched its performance in the field of packaging, provided some basis for future research.The best preparation condition of NCC are ensured that sulfuric acid concentration of 64%, hydrolysis temperature of 45℃, and hydrolysis time of 1.5h. The XRD pattern show the NCC is characteristic of the cellulose I crystal form. The TEM images show he diameter is about 200-380 nm, with the length of 20-40 nm. NCC still keep with the basic chemical structure of cellulose analysed by FTIR.And then, composite comprised of poly(propylene carbonate)(PPC) and NCC were prepared via melting blending. The results show that, the best preparation condition of composite were evaluated that as follows: the concentration of MA of 1%, blending temperature of 135℃, blending time of 15 min. FTIR show that PPC and NCC not produce chemical reaction, they still keep with the basic chemical structure. SEM show that with the addition of NCC, the composite changed into fibrous structure from the sea-island structure.At last, package performances of composite were examined. When the NCC percentage is 1.5%, the tensile of the composite is increased by 288%, and the elongation at break is 1.6% compare to PPC, the impact strength of the composite is increased by 4 times. The composite has a better thermal stability, when the NCC percentage is 2.5%, T5%, T50%, Tmax of the composite is increased by 31,13,17℃. NCC could help the degradation of PPC, and the degradation rate increases with the NCC. PPC/2.5%NCC composite could be degraded 69% within 100 days. NCC improve age resistance stability of PPC, and the age resistance stability of the composite would better if it had more NCC in it.This topic used NCC as a modifier for PPC to prepare the PPC/NCC nanocomposite. It has so excellent general properties that can be applied in packaging field. The result have important meaning to deal with environment and achieve sustainable development.