Anionic Nylon 612/TiO2 Composite Materials: Synthesis, Characterization and Properties

Abstract

Two novel series of composites have synthesized in situ by simultaneous anionic ring-opening copolymerization-rotational molding fast environment-friendly process using e-caprolactam (CL) with laurolactam (LL) as starting comonomers and TiO2 as filler. The type of filler (with surface treated or not) differentiates the two series. Aminopropyl triethoxysilane (APTES) coupling agent was used. By adjusting the TiO2 in the range 0.0–8.0 wt.% in the feed monomers mixture, various composites were obtained. The characterization of samples was performed, in the context of filler type and content variation by combined use of ATR–FTIR spectroscopy, X-ray spectroscopy, DSC, TGA/DTG, SEM and mechanical measurements. In addition, degree of conversion, intrinsic viscosity and water absorption were evaluated. Introduction of the long methylene sequences through the second monomer into the nylon 6 chains improved especially the water uptake of the composites. The melting temperature (Tm), crystallization temperature (Tc), degree of crystallinity (αDSC) and the interface interactions between filler and nylon 612 matrix prove to be improved by treatment of filler surface. The same trend was recorded for tensile strength, tensile modulus, elongation at break and impact strength. The results related to composites were compared with those obtained for neat nylon 612 copolymer synthesized in the same conditions.