Kinetic Analysis of Poly(-caprolactone)/poly(lactic acid) Blends with Low-cost Natural Thermoplastic Starch

Abstract

Non-isothermal thermogravimetry in an inert atmosphere was used to investigate the thermal stability of poly(e-caprolactone) (PCL), polylactide (PLA), thermoplastic starch (TPS) and their binary (PCL/PLA,PCL/TPS andPLA/TPS) and ternary (PCL/PLA/TPS) blends. All investigated blends were prepared by Brabender kneading chamber. A two-stage degradation pattern is seen in the case ofPCL, whilePLAexhibits only single stage degradation. On the other hand, the degradation of neat TPS proceeds through three degradation stages. It was found that addition ofPLAaffects the degradation ofPCL/PLAblends indicatingPLA’s destabilising effect onPCL. TPS addition thermally destabilizes both,PCLandPLA, but notably thePCLsample. Likewise, that addition of TPS thermally destabilized all investigated ternary blends. The obtained data were used for the kinetic analysis of the degradation process. By using the isoconversional Friedman method and the multivariate nonlinear regression method kinetic analysis was performed. Kinetic analysis revealed the complexity of the thermal degradation process for neat samples and all investigated blends. Kinetic parameters (activation energy, pre-exponential factor and kinetic model) for each degradation stage of neat samples and all investigated blends were calculated.

Keywords

• kinetic analysis
• poly(e-caprolactone)
• polylactide
• hermogravimetric analysis
• thermoplastic starch