Biodegradable silica rubber core-shell nanoparticles and their stereocomplex for efficient PLA toughening

Publication date: 3 May 2018 Source:Composites Science and Technology, Volume 159 Author(s): Zibiao Li, Joseph K. Muiruri, Warintorn Thitsartarn, Xing Zhang, Beng Hoon Tan, Chaobin He In the effort to overcome the shortcomings such as brittleness and poor mechanical stability, and increase the competitive edge of renewable poly(lactic acid) PLA over conventional petroleum-based thermoplastics, silica rubber core-shell nanoparticles for effective PLA toughening were successfully synthesized by sequential ring opening polymerization (ROP). The core-shell structure was designed with silica as inner core, P(CL-mLA) as ‘rubber’ middle layer and terminal PDLA chains (SiO2-r-PDLA), to facilitate the stereocomplex formation with PLLA matrix for enhanced interface control. The PLLA/SiO2-r-PDLA nanocomposites were fabricated through solution blending-injection molding process. Nuclear magnetic resonance (1H NMR and 13C NMR) results confirmed the presence of grafted ’rubber’ and PDLA chains from the surface of silica particle. In addition, PLLA/SiO2-r-PDLA nanocomposites showed tremendous improvement in thermal and mechanical properties using differential scanning calorimetry (DSC) and tensile testing, respectively. Besides the formation of stereocomplex in the nanocomposites, a detailed study on the melt stability of these stereocomplex nanocomposites revealed a ‘memorized’ stereocomplex behavior, i.e., having the ability to perfectly reassemble after re-crystalliza...
Source: Composites Science and Technology - Category: Science Source Type: research