Thermal and mechanical properties of waste grass broom fiber-reinforced polyester composites

The main focus of this study is to utilize waste grass broom natural fibers as reinforcement and polyester resin as matrix for making partially biodegradable green composites. Thermal conductivity, specific heat capacity and thermal diffusivity of composites were investigated as a function of fiber content and temperature. The waste grass broom fiber has a tensile strength of 297.58 MPa, modulus of 18.28 GPa, and an effective density of 864 kg/m(3). The volume fraction of fibers in the composites was varied from 0.163 to 0.358. Thermal conductivity of unidirectional composites was investigated experimentally by a guarded heat flow meter method. The results show that the thermal conductivity of composite decreased with increase in fiber content and the quite opposite trend was observed with respect to temperature. Moreover, the experimental results of thermal conductivity at different volume fractions were compared with two theoretical models. The specific heat capacity of the composite as measured by differential scanning calorimeter showed similar trend as that of the thermal conductivity. The variation in thermal diffusivity with respect to volume fraction of fiber and temperature was not so significant. The tensile strength and tensile modulus of the composites showed a maximum improvement of 222% and 173%, respectively over pure matrix. The work of fracture of the composites with maximum volume fraction of fibers was found to be 296 Jm(-1). (C) 2012 Elsevier Ltd. All rights reserved.