Study of Thermal and Rheological Properties of Polylactic acid/Chain Extender/Nanoclay Nanocomposites

In order to produce modified poly(lactic acid) (PLA) nanocomposites for applications requiring high meltstrength, a commercial PLA product was modified in melt by adding Lauroyl peroxide (LP) and Tris (nonylphenyl)phosphite (TNPP) as chain extenders and modified montmorillonite as nanoparticle. They were then investigated by TGA(Thermal gravimetric analysis) and RMS (rheometric mechanical spectroscopy). Their thermal, rheological, and meltviscoelastic properties were investigated and compared along with unmodified PLA. The results indicated that themechanism of stabilization is most likely chain extension that leads to the formation of longer linear chains in the TNPPmodifiedsamples, and a long chain branched (LCB) structure in LP-based samples. The samples with increased molecularweights showed enhanced melt viscosity and elasticity. Thermogravimetric analysis showed an increase up to 17 °C inthe onset temperature for thermal degradation after incorporation of 0.6 wt% TNPP.

کلیدواژه ها:

Polylactic acid ، Melt strength ، Thermal degradation ، Rheological properties ، Molecular weight