Separation Process And Mechanism Study On Alcoholysis Of Waste Containing Polylactic Acid

In this paper,the alcoholysis recovery method and process flow of PLA,and the alcoholysis separation and mechanism of PLA-containing mixed waste were studied.The specific studies are as follows:?1?The methanol alcoholysis of PLA with Zn?OAc?₂ as catalyst was studied.The conversion rate of PLA at different temperatures and different times was investigated.Then,the better reaction temperature and reaction time were selected and the residue was characterized by SEM.on this basis,the reaction kinetics of methanol alcoholysis of PLA was investigated.The results showed that the reaction was a first-order reaction with the activation energy of 102.99 kJ.moL^-1.Then the mechanism of methanol alcoholysis reaction of PLA was preliminarily speculated.?2?Methanol alcoholysis separation of Zn?OAc?2 as catalyst containing PLA waste plastics was studied.It was found that PP,PS,PET,PE,ABS could be separated by methanol alcoholysis after mixing with PLA,PA6 and PVC will reduce some quality after reaction,at the same time,the morphology of PP,PS,PA6,PVC,PET,PE and ABS still changed to some extent.?3?The alcoholysis of colored PLA was studied.The effects of alcohol type?methanol,ethanol?,alcohol dosage,reaction temperature and reaction time on the conversion rate and product yield of colored PLA were investigated with Zn?OAc?₂ as catalyst.The alcoholysis products were identified as methyl lactate and ethyl lactate by FT-IR and ¹H-NMR,the results showed that the methanol alcoholysis reaction of red PLA was studied with Zn?OAc?₂ as catalyst.the optimum conditions were 140?,3.5 h,m[Zn?OAc?₂]:m[PLA]=2%,V?CH₃OH?=20 mL.Methanol alcoholysis of black PLA was studied with Zn?OAc?₂as catalyst.the optimum reaction conditions were 140?,3 h,m[Zn?OAc?₂]:m?PLA?=0.02,m?CH₃OH?:m?PLA?=2.72.The methanol alcoholysis reaction of colored PLA with zinc lactate as catalyst was also studied.The yield of methyl lactate was calculated by gas chromatography internal standard method.The effects of reaction temperature,reaction time,methanol dosage and catalyst dosage on the reaction were investigated.The optimal degradation conditions were determined as follows:130?,4 h,m?CH₃OH?:m?PLA?=3,m?zinc lactate?:m?PLA?=0.02.