Synthesisand Properties Of Polylactide/Layered Inorganic Intercalation Nanocomposites

The application prospect of polylactic acid material is promising becauseof its good biodegradable property which is beneficial to sustainabledevelopment of environment. In this paper, the polylactic acid and its layeredinorganic intercalation nanocomposite materials are researched. The polylacticacid materials are prepared by solution polymerization and ring-openingpolymerization respectively. The polylactide/montmorillonite and polylactide/graphene nanocomposites are obtained via situ polymerization of lactide withmontmorillonite and graphene on the basis of attained high molecular weightpolylactic acid materials. Additionally, the comparative study of polylactide/montmorillonite nano-composite materials prepared by melt blending and situpolymerization respectively is also taken. Since poor compatibility betweeninorganic material and polymer, the inorganic material is modified by POSS toimprove its compatibility in the polymer. All obtained materials arecharacterized by FT-IR, GPC, DSC, TEM, permeability testing andconductivity testing to research the properties of their structure, molecular weight, permeability, electrical conductivity, etc. The main contents are listedas below.1. The preparation of polylactic acid. Polylactic acid was prepared bysolution polymerization and lactide ring-opening polymerization, respectively.In this study, the effect of reaction time, catalyst and reaction temperature onthe molecular weight of polylactic acid were investigated. By GPC analysis,the weight-average molecular weight of polylactic acid was determined. Bycomparison, the best conditions for the synthesis of high molecular weightpolylactic acid were determined.2. On the basis of high molecular weight polylactic acid, polylactide/layered inorganic nanocomposites were synthesized by situ-polymerization,using MMT and graphene as inorganic material, respectively. The formationof intercalated structure was characterized by TEM and XRD.3. POSS modified MMT and graphene. The amide bond was formed bythe reaction between amino in POSS and carboxyl in inorganic layer, so thatPOSS could enter into the inorganic layer and increase the layer spacing,which was in favour of improving the compatibility between the inorganic andpolylactic.