Water absorption and tensile strength degradation of Petung bamboo (Dendrocalamus asper) fiber—reinforced polymeric composites

Bamboo fibers have attracted great interest and are believed to have the potential as natural fiber for reinforcing polymer composites. This research aims to study water absorption behavior and its effect to tensile strength of the composites made from petung bamboo fiber, which is one of the most grown bamboo species in Indonesia. Unidirectional (UD) and random composites were manufactured using wet hand lay-up method. Examinations were carried out by means of boiling water immersion test, tensile test, scanning electron microscopy and Fourier transform infrared spectroscopy. Water absorption of UD petung bamboo fiber/polyester composites is higher than that of random composites, i.e. 3.6% compared to 2.2%. This was due to higher fiber volume fraction of the UD composites. Water absorption caused irreversible tensile strength degradation on the composites. The initial properties of the composites were not recovered even after drying. The absorbed water decreased the tensile strength by 6% in UD composites and 38% in random composites. This was most likely to occur due to the permanent interfacial degradation.