L Rajabi - aDepartment of Chemical Engineering, College of Engineering, University of Razi, Kermanshah-۶۷۱۴۹, Iran.
Z Mohammadi - Department of Chemistry, College of Science, University of Razi, Kermanshah-۶۷۱۴۹, Iran.
M . R Panahi - Department of Mechanical Engineering, College of Engineering, University of Razi, Kermanshah-۶۷۱۴۹, Iran.
Sh Ghorabi - Department of Chemical Engineering, College of Engineering, University of Razi, Kermanshah-۶۷۱۴۹, Iran.

This research work focuses on the performance optimization of composites containing both micro and nano size TiO2 particles separately in various concentrations and to understand the role of each on the thermal stability and moduli of the composites. Thermal stability of the particle-reinforced composites increased on increasing the concentration of TiO2 both in nano- and micro- filled cases, except for the 2.5wt% nano-filled composite. Storage modulus (E') increased on adding micro-TiO2 to the epoxy hardener resin system from 1 - 2.5 - 5 wt% respectively and decreased dramatically on further increasing the micro-TiO2 content to 7.5 and 10 wt% respectively. Nano-TiO2 particlereinforced composites showed an increasing trend of storage modulus for 2.5 – 5 - 7.5 wt% TiO2 filled composites with respect to the neat resin system. Presence of both micro and nano-TiO2 particles increased the Tg of the composites.

Polymer matrix composites (PMCs); Mechanical properties; Thermal analysis; Nano/Micro TiO2