BASIC RESEARCH ON NATURAL FIBRES AND RESULTING COMPOSITES Ramakrishna and Sandararajan (2005b) investigated the effect of variation in chemical composition on tensile strength of four natural fibres (coir, sisal, jute and H. cannabinus fibres), when subjected to alternate wetting and drying, and continuous immersion for 60 days in three mediums (water, saturated lime and sodium hydroxide). Chemical composition of all fibres changed for tested conditions (continuous immersion was found to be critical), and fibres lost their strength. But coir fibres were reported best for retaining a good percentage of its original tensile strength for all tested conditions. Sisal retained 60 to 70% of their initial tensile strength after exposure in fresh water only.
Agopyan et al. (2005) studied the selected fibres (coir,