Creep Behaviour of Natural Fibre Reinforced Unsaturated Polyester Composites

Hemp fibre reinforced unsaturated polyester composites (HFRUPE) containing different fibre volume percentages (10, 15, 21 and 26%) were prepared and subjected to short term flexural creep tests to investigate creep behaviour. The tests were conducted at ambient and elevated temperatures and at low to medium stress levels. Strain versus time curves (of both hemp and glass fibre reinforced specimens) were plotted directly from the experimental results. These show that the process of flexural creep behaviour is greatly influenced by both stress level and temperature. Comparison with results obtained for glass fibre reinforced specimens reveal that the use of hemp fibre reinforcement results in improved creep resistance at ambient temperature. At low temperature, 3 layered hemp reinforced composite specimen showed similar creep resistance properties to CSM samples. From the characteristics of the resultant creep curves, it is obvious that creep strain of composite samples is significant at elevated temperatures. Creep performance deteriorates as temperatures increase above glass transition temperatures for unreinforced UPE specimens.