Characterization and properties of unsaturated polyester-Donax grandis hypodermal fiber composite

In this study, the investigation was conducted to develop the utilization of Donax grandis hypodermal fiber (DGHF) through composite using unsaturated polyester resin (UPR) as the matrix and titanium dioxide (TiO2) as the filler. There is shortcoming on the uses of natural fibers than synthetic substance as it hydrophilic properties which tend to decrease composite mechanical properties. In order to minimize the problem, DGHF was prepared with and without alkaline treatment. The UPR/DGHF composites were fabricated with different DGHF compositions (0wt%, 20wt%, 25wt% and 30wt%) and the addition of 1wt% TiO2 for UPR:DGHF:TiO2 composites. Hand lay-up mixing and compression moulding were used for the composites fabrication. They were tested for morphology, density, water absorption, thickness swelling, tensile and flexural tests. The results showed that the chemical composition of DGHF were consists of cellulose, hemicelluloses and lignin (52.9%, 30.4% and 31.2%, respectively) similar to that of common natural fibers used in composite fabrication. The water absorption and thickness swelling has shown better performance in treated 74:25:1 composite due to the addition of TiO2 and treated DGHF. The increment of composite’s density was higher for treated composite as a result of effective surface area for fiber-matrix contact. The mechanical properties showed an improvement with the addition of TiO2 and treated DGHF with better result was in treated 74:25:1 composite. This is due to having the highest crystallinity as confirmed by XRD analysis and morphological study. The role of TiO2 addition makes the DGHF dispersion less agglomerated and more homogenous in the composite which later improves the compatibility between matrix, reinforcement and inorganic filler. Thus, based on these results the DGHF is recommended as a potential natural fiber in composite industry.