Study On The Component Of Recycled PE, PP By Infrared Image System And Thermal Analysis

With the development of the industry of high polymer material industry, plastic has been widely used in every walk of life and a number of sophisticated technology field, and it has become an important part in people’s life, especially polyethylene (PE) and polypropylene (PP), they are widely used in packaging food, medicine, etc. Plastic bring great convenience to people, at the same time, the waste also cause serious environmental pollution. The recovery and utilization of waste plastic has important and practical significance for saving energy、reducing the damage to the environment. Now, there exist scotoma in the regulation of the recycled plastic. In this context, the recognition for recycled plastic, especially the composition analysis has important significance. But it is difficult to determine the composition of recycled plastics by single method. Therefore, combining several testing methods to analysis the composition of recycled plastic is very necessary.Raw PE and recycled PE, raw PP and recycled PP, the additives in the recycled materials can be identified by the combine of4test methods of FTIR, DSC, TG and UV. The results show that the main component of recycled PE-1is PE and a small amount of stearic acid salt; There has not only PE but also a certain amount of PP and a small amount of stearic acid salt in recycled PE-2; Recycled PE-3was the blend system of LDPE and HDPE, and it has the component of stearic acid salt; Four kinds of recycled PE bottles were all the blend system of recycled HDPE and PP. Recycled PP-1and recycled PP-2were both made of recycled PP and recycled PE and a small amount of stearic acid salt; The main component of recycled PP-3is PP and a small amount of stearic acid salt; The main component of recycled PP bottle-1and recycled PP bottle-2is PP; The main component of recycled PP bottle-3and recycled PP bottle-4are the blend system of recycled PP and HDPE, but the main component is PP.Infrared image system is a microcosmic analysis technology developed on the basis of FTIR microscope and the scanning interferometry technology. It can scan the mixed samples on the level of molecular quickly and widely for getting valuable spectral information in the infrared image. The distribution of the component in the recycled PE, recycled PP, recycled PE bottle and recycled PP bottle was studied by the infrared image system. The composition of recycled materials was explain further.The blend system of HDPE and PP was build, and the content of PP or PE in the recycled materials was calculated through the S curve fitting and linear fitting, the deviation less than3%, so the fitting method has certain accuracy and provides the reference value of quantitative analysis for the component determination in the blend. This method can be used for the quantitative analysis of the component in other blend system.The method of the combination of FTIR, DSC, TG, UV and infrared image system has the character of high accuracy and small sample.Especially the infrared image system can detect the trace impurity in a complex mixture, and it provides a new, powerful technology for plastic.