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pps proceeding
Symposium: S10 - Polymer nanocomposites and nanotechnology
Oral Presentation
 
 

Elastomeric Bio-based Epoxy / Clay Nanocomposites

Rigail-Cedeņo Andres (1), Schmidt Daniel F (2)*, Chavez Monica (3), Vera Grave (3), Alava Mercedes (4), Pacheco Yesenia (5)

(1) ESPOL Polyethnic University Escuela Superior Politecnica del Litoral - Guayas - Ecuador, (2) Department of Plastics Engineering - Massachusetts - USA, (3) ESPOL Polyethnic University Escuela Superior Politecnica del Litoral. - Guayas - Ecuador, (4) ESPOL Polyethnic University Escuela Superior Politecnica del Litoral - Guayas - Ecuador - Guayas - Euador, (5) ESPOL Polyethnic University Escuela Superior Politecnica del Litoral - Guaquil,Ecuador - Guayas - Ecuador

The focus of this research was to develop a fully bio-based elastomeric epoxy and its clay nanocomposites. Blends of sorbitol glycidyl ether (SGE) and epoxidized castor oil (ECO) were cross-linked with a dimer diamine (DDA) as curing agent in a solvent-free procedure. Blends of SGE and ECO (0/100, 30/70, 50/50, 70/30 and 90/10, w/w) were cured with stoichiometric amounts of DDA alone or following the addition of 5 wt% of one of two organically modified montmorillonite (OMMT) nanoclays, Cloisite 20A and 30B. Pure SGE was immiscible with DDA, but SGE/ECO blends were compatible. All networks were cured at 60°C for 6 hours, with crosslinking kinetics monitored via near-infrared (NIR) spectroscopy. Epoxy conversion increased with increasing ECO content due to improved compatibility with DDA. The greatest concentration of unreacted primary and secondary amine groups was observed with a 90/10 SGE/ECO blend. Nanoclay dispersion and affinity for the matrix was assessed via wide angle x-ray diffraction (WAXD), and confirmed an intercalated structure regardless of nanoclay type or epoxy formulation. Mechanical properties were also investigated. A broad range of Young Moduli (~0.7-4.8 MPa) and hardness values (30-81 Shore A) were obtained, with the greatest stiffness and hardness observed in the best 90/10 SGE/ECO blend reinforced with Cloisite 30B. Indeed, these results support the existence of a synergistic effect between increases in chemical crosslink density and reinforcement due to nanoclay addition as far as enhanced mechanical properties are concerned. Based on these studies, SGE/ECO/DDA clay nanocomposites show promise as versatile elastomeric networks whose hydrophobicity and mechanical properties may be adjusted for a range of industrial applications.