Warasan Witthayasat Lae Theknoloyi Mahawitthayalai Mahasarakham (Oct 2019)
Characterization of Poly(L-lactide) and Poly(D-lactide) blends by solution casting process
Abstract
Polylactide is the most widely used biodegradable polymer. The high thermal stability and mechanical properties of polylactide makes permit a wide range of industrial applications. Polylactide has two isomers; Poly (L-lactide) (PLLA) and Poly (D-lactide) (PDLA). Blended PLLA and PDLA forms in a stereocomplex have melting points around 220-230°C higher than pure PLLA or PDLA 50°C. In this experiment, PLLA and PDLA were blended by a solution casting process using dichloromethane as solvent. The ratios of PLLA:PDLA were 100:0, 90:10, 70:30, 50:50, 30:70, 10:90 and 0:100. The blended films were then tested for their mechanical properties and thermal stability. The results showed that PLLA:PDLA at 50:50 had only one melting point around 225°C while the melting temperatures of neat PLLA and PDLA were about 172-175°C. Moreover, the blend materials also had higher tensile strength than pure PLLA or PDLA 55% as well as higher thermal stability than pure PLLA or PDLA.
