| In recent years,plastic pollution is a global focus issue,and the problem of contamination caused by abandoned one-time use plastics is particularly prominent.Production,sales and use of disposable non-biodegradable plastic products had become the recognized effective prevention measures.The"Forbidden Plastic List(first batch)"released by Hainan Province,which clearly prohibited 6 kinds of non-degradable polymer materials producing,selling and using such as polyethylene(PE),polypropylene(PP),polystyrene(PS),polyvinyl chloride(PVC),ethylene-vinyl acetate copolymer(EVA)and polyethylene terephthalate(PET),and it was necessary to implement a biodegradable plastic product in a field that must be used in disposable plastics.According to research,at present,the composite materials of biodegradable replacements were poly(butylene adipate-co-terephthalate(PBAT),polylactic acid(PLA)or starch(ST),wherein PBAT and PLA were the main substrates.With a large amount of bio-degradation replacements,it would inevitably add prohibited materials due to its huge economic interests or fack of material performance.This behavior of the prohibited materials for blending materials in the degradable materials may increase the performance of the disposable plastic article,but the micro-plastic produced after the material disintegration caused greater pollution.In order to support Hainan’s banned work and support market supervision with technical support for prison,PE was blended with PBAT and PLA in this study,respectively,according to the different mass percentage.EVA,PP,PS and PVC were also blended with PBAT and PLA with the same formula,respectively.These simulating samples were provided for qualitative and quantitative testing of forbidden plastics by Fourier transform infrared spectroscopy(FTIR)and chemometrics,and the quantitative results by FTIR of 9 systems were proof by the heat analysis methods(thermo gravimetric analyzer(TGA)and differential scanning calorimetry(DSC)).This study had established a fast qualitative and quantitative testing technology,which not only supported market supervision of plastic-related products,but also provided feasible screening technologies for new products of biodegradable products.Due to the melting temperature were too large between the components in PET-PBAT,PET-PLA,and PVC-PLA systems,it was difficult to melt blend without additives,therefore,these three individuals were not used as the research object of this thesis.The main contents were as follows:This study analysed 4 systems by FTIR with principal component analysis(PCA)such as PE-PBAT,EVA-PBAT,PE-PLA and EVA-PLA.The infrared qualitative characteristics of all systems were characterized.The clustering analysis model and infrared quantitative models of four physical systems such as EVA-PBAT,PE-PBAT,EVA-PLA and PE-PLA were established,and the number of primary components and qualitative features obtained by cluster analysis were 14,R~2X(cum)=0.997,Q~2X(cum)=0.992.The cross-validation of the quantitative model had an average residual value within±2.7%.In order to verify the reliability of the FTIR quantitative model,it was further adopted to prove that thermal analysis methods such as thermal loss analysis and differential scanning heat analysis methods were further used.Analysis of the quantitative models between the content and weight loss rate of EVA and PE were studied by TGA.The quantitative relationship of PE in PE-PBAT system material was“y=0.99x-0.97”,and linear correlation factor R~2was 0.962.The quantitative relationship of PE in PE-PLA system was“y=0.983x-0.927”,and linear correlation factor R~2was 0.995.The quantitative relationship of EVA in EVA-PBAT system was“y=0.99x-0.97”,and linear correlation factor R~2was 0.992.The quantitative relationship of EVA in EVA-PLA blend materials was“y=0.86x-0.0927”,and linear correlation factor R~2was 0.9996.After cross-verification,the average residual value was±5%.Analysis of the quantitative model of the content and heat flow or melt enthalpy were studied by DSC.The DSC semi-quantitative method was only applicable to the system of EVA-PBAT.The heat flow quantitative curve of the EVA-PBAT system was“y=0.321x-1.532(R~2was 0.983)”,the melt enthalpy curve was“y=-0.003x+0.0027(R~2was 0.997)”.After cross-validation,repetitiveness and precision indicated the average residual value was±3%.After analysis of the three quantitative models such as ATR-FTIR,TGA,and DSC,the quantitative model of ATR-FTIR had good reliability.After extending the above infrared qualitative and quantitative methods and thermal analysis quantitative method to PP,PS,and PVC,all systems in all systems were prohibited in the shaping components,but only some systems had a good thermal analysis quantitative linear relationship.The weight loss rate and PS content in the PS-PLA system had a linear relationship:y=0.9096x-0.915,and linear correlation factor R~2was 0.985.The weight loss rate and PVC of PVC-PBAT blend material had a linear relationship:y=0.6639x+3.0022,and linear correlation factor R~2was 0.998.The PP content had a good correlation with the melt enthalpy in the PP-PBAT system,and the linear equation was“y=-0.5895x+13.1499(R~2of 0.9937)”.The quantitative curve of the PP content in the PP-PLA system was“y=0.2831x+33.8596(R~2of 0.9874)”.As a result,this study established a fast,simple,reliable,and low-cost spectral legal qualitative and quantitative detection technology for the multi-component mixed systems,which provided more reliable technical support for the smooth advancement of plastic prohibition. |
PDF Full Text Request