Investigation of the Physical and Thermodynamic Properties of Polymer Lactic Acid (PLA) Biodegradable Polymer

Polycarboxylic acid is one of the largest bioplastics consumed in the world and has a wide range of applications in the medical and industrial sectors and has many interesting properties such as biodegradability, biocompatibility, high strength, and more. Poly-lactic acid, as a renewable and stable source, has a high potential for reducing oil dependence for economic and environmental development. Based on the molecular weight of the polylactic acid, it is divided into two groups: low molecular weight and high molecular weight. The physical and structural properties of the molecular chains of polymers are influenced by the molecular weight of the polymers. Therefore, by changing the size of the molecule, the properties of the polymer also change. The melting point, strength, and other physical properties of the polymer also depend on the size and dimensions of the molecule (polymeric chain length). In this study, the effect of the degree of polymerization on the physical and thermodynamic properties of biocompatible and biodegradable polylactic acid polymers was investigated using molecular dynamics simulation technique at ambient temperature and pressure. And parameters such as solubility, density, free volume, etc. were calculated and the results of the simulation were compared with the available experimental data and were well-matched with each other. The results also show that the increase in the degree of polymerization reduces the solubility parameter and does not show any significant changes in the PLA solubility parameter after 30 degrees of polymerization, and the amount of FFV does not change much and is close to 18.2%.