Gope, P. C.Chauhan, Sonika2024-08-052024-08-052023-05Theses of Ph.Dhttps://krishikosh.egranth.ac.in/handle/1/5810212852The ecological pressure due to growing population and need of structural materials have triggered the need for new materials which can perform equivalently to the conventional structural materials, and are cost effective, easily available and sustainable. This thesis is an investigation of the properties of Grewia Optiva natural fiber reinforced composites (G.O. NFRC). Grewia Optiva is a natural fiber extracted from a wild tree abundantly available in Uttarakhand. It was concluded by Taguchi method that 30 fiber weight %, 45mm fiber length, and fiber orientated normal to the loading axis are optimum for fabricating G.O. NFRC. The mode-I fracture toughness at optimum condition was found as 2.122±0.094 MPa√m . The tensile, flexural, and impact strength corresponding to optimum fiber, and composite processing conditions are 336.32%, 136.93%, and 308.28% higher as compared to pure epoxy. Scanning electron micrographs of the fractured surfaces indicate good bonding of fiber and matrix and show the major fracture mechanisms such as fiber pull-out and fiber-matrix debonding. The effect of humidity, NaOH, and Benzoyl Peroxide (BP) treatment on the mechanical preperties of G.O. NFRC was also studied using Response Surface Methodology (RSM) and ANOVA. The results revealed that the fibre treatment with BP on NaOH pretreated fiber shows optimum results at 90% relative humidity. The corresponding experimental results of the tensile strength (MPa), % elongation, flexural strength (MPa), impact strength (kJ/m2), and fracture toughness (MPa√m) are 260.895±3.619, 5.230±0.221, 52.572±2.550, 33.226±1.838, and 2.565±0.355 respectively. The RSM yielded the optimum tensile strength, % elongation, flexural strength, impact strength, and fracture toughness as 271.42 MPa, 5.163 %, 52.76 MPa, 32.96 kJ/m2, and 2.408 MPa√m respectively. The D-optimal value is 0.768. The mechanical properties indicate that G.O. NFRC can have potential applications like wallboard, window frames, doors, flooring, cubicle walls, ceiling panels.EnglishThesis