Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticiz...Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.展开更多
基金This work was finacially supported by the National Key Research and Development Program of China(No.2017YFA0403103)the Key Programs of the Chinese Academy of Sciences(No.ZDRW-CN-2018-2)the Youth Innovation Promotion Association CAS(No.2018040).
文摘Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.
