Performance Evaluation of Alkali and Acrylic Acid Treated—Untreated Jute Composites of Mixed Epoxy—Phenolic Resins

Abstract

Hydrophilic character of jute fibers was reduced by acrylation of alkali treated fibers. Jute (treated and untreated) composites of mixed matrix material (25 wt% epoxy resin of bisphenol-C (EBC) and 25 wt% bisphenol-C-formaldehyde (BCF) of jute fibers) were prepared by hand lay-up technique at 150°C under 7.6 MPa pressure for 2 h. Tensile strength was found to increase from 44.3 to 63 MPa (42.2%) and flexural strength was found to increase from 56.2 to 64 MPa (13.9%) on alkali treatment and acrylation. Similarly electric strength was found to increase from 0.18 to 0.72 kV/mm (400%) and volume resistivity was found to increase from 4.13 × 10¹⁶ to 5.1 × 10¹⁶ Ω-cm (123.5%). Water absorption of the composites was carried out at room temperature in distilled water and 10% each of aq. HCl and aq. NaCl solutions, and also in boiling water. The equilibrium water uptake is reduced drastically from 17.3—12.3% to 8.8—4.9% on acrylation. Similarly diffusivity was also found to reduce from 5.7—3.9 × 10^-12 m² s^-1 to 4.8—2.2 × 10^-12 m² s^-1. Drastic reduction in water uptake and diffusivity are due to replacement of hydrophilic hydroxyl groups to hydrophobic vinyl ester groups. No effect of boiling water was observed on the stability of the composites. Saturation time in boiling water was reduced to about 34 and 30 times without any damage to the JEBCF-50 and TJEBCF-50 composites, respectively.