Poly(lactic acid)/polystyrene bioblends characterized by thermogravimetric analysis, differential scanning calorimetry, and photoacoustic infrared spectroscopy

Abstract

Bioblends are composites of at least one biodegradable polymer with nonbiodegradable polymer. Successful development of bioblends requires that the biodegradable polymers be compatible with other component polymers. Compatibility can be assessed by evaluating the intermolecular interactions between the component polymers. In this work, the interaction in binary bioblends comprising biodegradable poly(lactic acid) (PLA) and polystyrene (PS) was investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). The TGA studies indicated that incorporation of PLA in PS resulted in thermal destabilization of PS. The DSC studies showed that some parameters favored partial miscibility of PS in PLA, while others favored immiscibility, such as the existence of two glass transitions. The FTIR-PAS spectra revealed the presence of intermolecular n-p interactions between PLA and PS and indicated that the degree of interaction was dependent on the concentrations of the polymers in the bioblends. FTIR-PAS results computed via differential spectral deconvolution were consistent with, and therefore support, the results of TGA and DSC analyses of PLA/PS bioblends. The degradation kinetics, used to determine the degradation mechanism, revealed a two-or threestep mechanism.

Thermal degradation behavior and gas phase flame‐retardant mechanism of polylactide/PCPP blends

“…As DTG curves shown, at a constant heating rate, the first derivative of TGA weight loss curve of PLA has a single peak, which implies that there is only a single stage during the thermal degradation of PLA. 15,16 However, the DTG curves of PLA/15% PCPP show two stages degradation behavior, particularly at the 5 C/min heating rate. The first stage is belonging to the degradation of PCPP, and the second stage would be due to the thermal degradation of PLA.…”

Double percolation of multiwalled carbon nanotubes in polystyrene/polylactic acid blends

“…This effect is confirmed by the TGA analysis of PS2CNT and PLA2CNT masterbatches, with an increase of 11-15 °C recorded for both the polymers on both T d and T mdr . As concerning the blends, the sample PS/PLA 50/50 shows a two-step degradation mechanism, the first step attributed to the degradation of the PLA phase and the second one to the PS phase [59]. While a slight decrease of T d is recorded for this system, the temperatures corresponding to the maximum degradation …”

The effect of additives interaction on the miscibility and crystal structure of two immiscible biodegradable polymers

“…PLLA is immiscible with PHB [7] although a small amount of PHB is miscible with PLLA resulting in a lower Tg value [6] . PLLA is also immiscible with PPC [8.9] , butadiene-styrene copolymer (ABS) [10] , poly(-caprolactone) PCL [11] , low density polyethylene blends [12] , poly(vinyl acetate-co-vinyl alcohol) [13] , poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBco-PHV) [14,15] , starch [16,17] and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) PHB/HHx [18] , polystyrene (PS) [19] . Among the practical ways to overcome the problems of this improves immiscibility is the addition of a third polymer with certain amount miscible with the two other polymers to obtain a compatible and miscible polymeric system.…”