Irradiation of poly(l-lactide) biopolymer reinforced with functionalized MWCNTs†
Radiation sterilization processes by high energy radiation are successfully utilized for modification and sterilization of sensitive biodegradable and biocompatible polymer composites. The effect of γ-irradiation on mechanical and thermal properties of poly (L-lactide) (PLLA) biodegradable polymer reinforced with PLLA grafted from multiwalled carbon nanotubes (MWCNT-g-PLLA)s was characterized. For this purpose, the PLLA chains covalently grafted from the sidewall of aminated MWCNTs. Then, the MWCNT-g-PLLAs/PLLA composite films are prepared by solution casting using chloroform as solvent. The prepared composites were γ-irradiated and characterized by differential scanning calorimeter (DSC), SEM and tensile test instruments. It is found that the γ-irradiation increases the tensile modulus and tensile strength, while decreases the elongation at break. The melting point of composites decreases by irradiation, while the melting enthalpy increases. Additionally, It is found that if the γ-irradiation of composites increases to higher than 50 kGy, the rigidity and brittleness of composites, that have more concentrations of functionalized MWCNTs, increase gradually.