Bio-Based Silica Reinforced Aliphatic Bio-Epoxy Composites

Published in: Global Partnerships for Development and Engineering Education: Proceedings of the 15th LACCEI International Multi-Conference for Engineering, Education and Technology
Date of Conference: July 19-21, 2017
Location of Conference: Boca Raton, FL, United States
Authors: Andres Rigail, PhD. (ESPOL, EC)
Maria Olivia Aviles, Eng. (ESPOL, EC)
Rodrigo Perugachi, MS. (ESPOL, EC)
Full Paper: #299

Abstract:

Composites of bio-based aliphatic polyfunctional epoxy resin reinforced with high concentration of bio-silica were prepared by a solvent free method. The unmodified bio-silica (BS) was obtained from rice husk. Two amine hardeners were used: one was based on polyethylene oxide (PEO) and the other on polypropylene oxide (PPO). The epoxy-amine systems were reinforced with 10, 20, 30 and 40% weight fraction to the unfilled epoxy resin. The structure and morphology of the BS was analyzed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. These techniques were also used to determine the silica dispersion degree in the polymer matrix. Thermal characterization was carried out using a Dynamic Scanning Calorimetry (DSC) and Thermogravimetric Analyses (TGA). The glass transition temperature, Tg, increased significantly for both polyetheramine cured systems incorporating 10 wt% and 20 wt% of the BS; nevertheless, the best performance was observed in PEO networks. The thermal stability at 5% of weight loss temperature, increased consistently with filler concentration up to ~ 21% and ~ 10% compared to neat PEO and PPO cured networks, respectively. Tensile strength and Young modulus for PEO systems showed similar results up to 30 wt% of BS, while for PPO systems they decreased relentlessly at 20 wt% of BS. PEO composites showed an overall increase in the Shore D hardness testing. Water swelling experiment illustrated greater hydrophilicity of PEO compared to PPO filled and unfilled cured systems. The water absorption remains unaltered up to 20 wt% of BS, revealing a good interaction between both networks and filler. A better compatibility and good correlation between mechanical and thermal properties were observed in 10 wt% of BS in both polyetheramine cured networks.