This thesis illustrates a comprehensive study on the PVT, solubility and surface tension properties of polylactic acid (PLA) with dissolved CO2 based on thermodynamic models. The solubility of CO2 in PLA melt was calculated by means of a gravimetric method, using a Magnetic Suspension Balance (MSB). The swelling volume of the polymer/gas mixture due to dissolution of gas was compensated for by direct measurement through a view cell or by theoretical models such as Simha Somcynsky (SS) - Equation of State (EOS) and Sanchez Lacombe (SL) - Equation of State (EOS). Three grades of PLA (i.e., PLA3001D, PLA8051D, and PLA4060D) were chosen. It was observed that the pressure, temperature, D-content and Molecular weight variance had an effect on the swelling and solubility. The surface Tension of PLA/CO₂ mixture was also calculated from the captured image using the Axsymmetric Drop Shape Analysis (ADSA). The effects of varying the pressure, temperature, and molecular weight on surface tension were investigated.

This thesis illustrates a comprehensive study on the PVT, solubility and surface tension properties of polylactic acid (PLA) with dissolved CO2 based on thermodynamic models. The solubility of CO2 in PLA melt was calculated by means of a gravimetric method, using a Magnetic Suspension Balance (MSB). The swelling volume of the polymer/gas mixture due to dissolution of gas was compensated for by direct measurement through a view cell or by theoretical models such as Simha Somcynsky (SS) - Equation of State (EOS) and Sanchez Lacombe (SL) - Equation of State (EOS). Three grades of PLA (i.e., PLA3001D, PLA8051D, and PLA4060D) were chosen. It was observed that the pressure, temperature, D-content and Molecular weight variance had an effect on the swelling and solubility. The surface Tension of PLA/CO₂ mixture was also calculated from the captured image using the Axsymmetric Drop Shape Analysis (ADSA). The effects of varying the pressure, temperature, and molecular weight on surface tension were investigated.