Journal of Applied Research in Chemical-Polymer Engineering

Abstract Research subject: Poly (vinyl chloride) (PVC) is non-biodegradable, and the widespread use of conventional plasticizers, particularly phthalates, in its formulation poses significant risks to human health and the environment. In this research, various blends of PVC and poly (lactic acid) (PLA) with different ratios were prepared in an internal mixer. The effect of PLA content, as well as the influence of various plasticizers including dioctyl phthalate (DOP), dioctyl adipate (DOA), epoxidized soybean oil (ESO), and chlorinated paraffin wax, on the mechanical and biodegradability properties was investigated. Furthermore, the role of a compatibilizer in improving the distribution of the PLA phase and increasing the compatibility between the polymers was evaluated.
Research approach: Tensile testing and dynamic mechanical analysis (DMTA) were performed to study the mechanical behavior. Scanning electron microscopy (SEM) imaging was used to examine the morphology and the distribution of the PLA phase. In addition, a biodegradability test was carried out to analyze the degradation behavior of samples in the environment.
Main results: The results indicated that the PVC/PLA(90/10)-DOP blend exhibited a suitable distribution of the PLA phase within the PVC matrix, whereas a poor distribution of PLA in PVC was observed in the PVC/PLA(80/20)-DOP blend. The addition of a compatibilizer to the PVC/PLA(80/20)-DOP sample led to increased uniformity in the PLA phase distribution and improved tensile strength. Samples with higher PLA content showed greater biodegradability behavior, suggesting the role of PLA as a degradability-enhancing agent. The comparison of different plasticizers indicated that several of the ones used in this research exhibit properties comparable to DOP and may be considered as effective substitutes for it. The findings suggest that the simultaneous use of PLA and appropriate plasticizers such as ESO, along with the application of a compatibilizer, is an effective method for producing PVC samples with enhanced mechanical and biodegradability properties.

Abstract Research subject: Biodegradable compounds with high mechanical and thermal properties are one of the intersting research topics. Polylactic acid is an aliphatic polyester with high biodegradability and flexibility. It, however, suffers from several weaknesses such as high permeability to water vapor and gases, low glass transition temperature, poor thermal stability and brittleness which can be improved by the incorporation of nano-scale fillers giving rise to bionanocomposites. The aim of this study was to investigate the effect of the simultaneous incorporation of cellulose nanocrystals and nanosilver on the mechanical, thermal and water vapor permeability behavior of polylactic acid-based films.
Research approach: Polylactic acid films and their bionanocomposites containing different levels of cellulose nanocrystals (0.01, 0.03 and 0.05 g) and nanosilver (0.01 g) were prepared by solution casting method. To improve compatibility and miscibility of the polymer, cellulose nanocrystals were reacted with acetic anhydride and modified. FTIR spectroscopy, tensile test, thermal properties (DSC), migration test and antibacterial properties were used to study the properties of the samples. The water vapor permeability of the samples were also measured.
Main results: The addition of cellulose nanocrystals, increased the glass transition temperature (T_g) and melting point (T_m) of the samples. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the bionanocomposite relative to pure polylactic acid. With the addition of cellulose nanocrystals, permeability was reduced by about 25%. As the amount of cellulose nanocrystals increased, the swelling and water absorption of the samples increased significantly. The migration rate of the samples also decreased after the addition of nanocellulose.