Study of the miscibility of poly (lactic acid) / poly (butylene adipate-co-terephthalate) blends prepared by solvent-casting method

The production of PLA / PBAT blends aims to overcome the disadvantages that each polymer had individually, such as fragility, processability and cost limitations. In this study, we investigated the miscibility and properties of biodegradable films of PLA - Poli (lactic acid), PBAT-Poli (butylene adipate-co-terephthalate) and their blends with proportions of 95/5, 70/30, 30/70 and 5/95 PLA / PBAT, respectively, produced by the casting method. The blends produced were characterized by the techniques of Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TGA), scanning electron microscopy (SEM), diluted solutions viscosimetry and mechanical tensile testing. The Raman spectra, glass transitions temperature (Tg), and TGA analysis indicated that the polymers are immiscible in the compositions studied. Mechanical analyzes point to a decrease in the stiffness of the blend with the addition of PBAT. The interaction parameters, obtained by viscosimetry analysis of diluted solutions, suggest partial miscibility of the blend with 5% of PBAT. The study of the miscibility and properties of the PLA / PBAT blends obtained by solvent evaporation will enable the production of new materials by different techniques aiming at new applications for this material.