Synthesis and characterization of poly(L-lactide)-block-poly(epsilon-caprolactone)-grafted titanium dioxide nanoparticles via ring-opening in situ grafting polymerization

摘要

The synthesis of nanocomposites via in situ grafting polymerization due to its ability to produce polymeric materials with promising microscopic and macroscopic characteristics is becoming very attractive. In this paper, different poly(L-Lactide)-block-poly(epsilon-caprolactone) (PLLA-b-PCL) copolymers were in situ synthesized in the presence of modified titanium dioxide (TiO2) nanoparticles (mTNP) as the initiator and stannous octoate as the catalyst. The surface of TiO2 was modified by grafting aminopropyl trimethoxy silane to improve initiator efficiency. Copolymers with 90/10, 70/30, and 50/50 mass ratio of L-lactide/ epsilon-caprolactone and 5 wt% of mTNP (proportional to epsilon-caprolactone) were synthesized. The samples were characterized by HNMR, CNMR, FTIR, GPC, TGA, TEM, and DSC, confirming the successful formation of PLLA-b-PCL on the surface of mTNP. Tensile test results showed the synthesized nanocomposite with mass ratio of LLA/CL = 70/30 had optimum mechanical properties among other nanocomposites and also in comparison with the neat PLA.