| Nucleation of nucleating agents on polylactide（PLA） was studied in this paper.Firstly, four kinds of Montmorillonites（MMT） and three kinds of organic nucleatingagents（TX, TP, LBPA） were selected and added into the PLA melt matrix respectively,and Differential Scanning Calorimetry（DSC）, Polarizing Microscope（POM）, X-RayDiffraction（XRD）, Thermal Gravimetric（TG） were used to study the nucleation andthermal performance of inorganic and organic nucleating agents on PLA. Fourcomposite nucleating agents were made with two kinds of MMTs, which had betternucleation effects on PLA, and two kinds of organic nucleating agents, TX and TP.Same analysis methods were used to study the nucleation of composite nucleatingagents on PLA.There were significant effects of PLA on melting enthalpy, melting temperatureand crystallinity degree after adding MMTs, wherein MMT2and MMT4had greatereffect, the crystallinity degree increased8%compared with pure PLA. Three kinds oforganic nucleating agents, i.e. TP, TX and LBPA, had good effect of nucleation onPLA（crystallinity degree increased8.5%compared with pure PLA）. Compositenucleating agents had greater effect on PLA, the crystallinity degree increased13%compared with pure PLA.PLA crystals were spherulites, of which the size would decrease after addingMMTs or organic nucleating agents, and the crystallization time would be shortened.It would take5hours for the growth of pure PLA spherulites to be completed, while2hours for PLA with MMTs or organic nucleating agents. Adding TP nucleating agentsinto PLA would give larger size of spherulites compared with other nucleating agents,while composite nucleating agents have same effect compared with single componentnucleating agents. Adding composite nucleating agents into PLA matrix would reducethe size of PLA spherulites and shorten the time of crystallization significantly, whichtook only40minutes for the growth of spherulites.It had little effect for PLA polymorphs transition with the adding of nucleatingagents. No new peaks were shown on the diffraction patterns. Adding nucleatingagents led to stronger peaks as the2θ is16.4°and19.2°, with higher crystallizationdegrees, compared with pure PLA. There were same effects of composite nucleatingagents, compared with single component ones.Adding MMTs into PLA matrix would raise the initial decomposition temperature(T-5%) and the temperature of maximum rate of weight loss(TMax), whichled to a raising of5-17℃for T-5%, and MMT2had bigger effect（17℃compared withpure PLA）. However, adding organic nucleating agents would lower the T-5%and TMax,and TX has the biggest effect(about50℃of T-5%). Adding composite nucleatingagents would lower the T-5%and TMax, but had smaller effects compared with organicones. |
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