Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reli...Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reliable experimental evidence is needed to fully understand the process,and the catalytic mechanism remains elusive.To address this issue,we proposed a reactant-modulated catalytic depolymerization strategy involving a pre-mixing of alcohol or polylactic acid(PLA)with an organic base catalyst.Through systematic experimental and theoretical investigations,we have confirmed that different intermediates are formed during pre-mixing the catalyst with PLA or methanol,which can either slow down or accelerate the subsequent alcoholysis reaction.By employing the methanol-modulated depolymerization technique,we successfully achieved PLA alcoholysis at temperatures as low as–40℃.We further investigated the solubility and reactivity of different polyesters,including PET,PC,PBS,PBAT,PCL,and PLA,revealing an efficient recycling method for PLA.By optimizing reaction conditions in a continuous flow reactor,we recovered 127.3 g of methyl lactate from 100 g of plastic cups in just 4 h at room temperature.These findings greatly improve our grasp of polyester solvolysis processes and create new opportunities within the plastics sector recycling.展开更多
文摘Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reliable experimental evidence is needed to fully understand the process,and the catalytic mechanism remains elusive.To address this issue,we proposed a reactant-modulated catalytic depolymerization strategy involving a pre-mixing of alcohol or polylactic acid(PLA)with an organic base catalyst.Through systematic experimental and theoretical investigations,we have confirmed that different intermediates are formed during pre-mixing the catalyst with PLA or methanol,which can either slow down or accelerate the subsequent alcoholysis reaction.By employing the methanol-modulated depolymerization technique,we successfully achieved PLA alcoholysis at temperatures as low as–40℃.We further investigated the solubility and reactivity of different polyesters,including PET,PC,PBS,PBAT,PCL,and PLA,revealing an efficient recycling method for PLA.By optimizing reaction conditions in a continuous flow reactor,we recovered 127.3 g of methyl lactate from 100 g of plastic cups in just 4 h at room temperature.These findings greatly improve our grasp of polyester solvolysis processes and create new opportunities within the plastics sector recycling.
