Study Of Degradation And Shrinking Of Plastics By Natural Volatile Constituents

The degradation of polypropene plastics (PP) and shrinking of expanded polystyrene (EPS) were studied in this paper. The extraction of volatile oil in Ledum palustre by supercritical CO2 extraction was compared to the vapor refluence extraction. Analytical conditions of gas chromatography (GC) for 4 kinds of volatile oil, from Ledum palustre, ginger, peels of orange and leaves of pine tree, were set up, and their chromatograms were attained. The effect of volatile oil of Ledum palustre on degradation of PP plastic and the shrinking of EPS plastic by different solvent were investigated. The experimental results showed that the supercritical CO2 extraction can get more components in volatile oil than the method of vapor refluence, but most of the components were the same. As to the degradation of PP plastics, oxygen and light can affect the process, and the existence of oxygen was an important factor and the ultraviolet ray can also accelerate the degradation. The maximum tensile strength of PP samples treated with oil and plasma decreased significantly. Due to the detection of free radicals, a mechanism of degradation was postulated to be a series of free radical reactions. The free radicals were produced from the volatile oil under some given conditions, and could react with PP, accordingly lead the degradation of plastic. The results of shrinking of EPS showed that the volatile oil of Ledum palustre as a solvent was better than the others and it had no toxicity, so it can replace the other chemical reagents for the shrinking of EPS plastic. The research of this paper may provide some new ways for the degradation and recycle use of plastics.