Impregnation modification of sugar palm fibres with phenol formaldehyde and unsaturated polyester

This study investigated the effects of impregnation modification via vacuum resin impregnation on physical and mechanical properties of sugar palm (Arenga pinnata) fibres. The fibre was evacuated at a constant impregnation pressure of 1000 mmHg impregnation times (0, 5, 10, 15, 20 and 25 min) with two different impregnation agents: phenol formaldehyde (PF) and unsaturated polyester (UP). A notable improvement in the physical properties of sugar palm fibres was observed after they were impregnated with PF and UP for 5 min, shown by the reduction of their moisture content (91 % and 89 %, respectively) and water absorption (43 % and 41 %, respectively) compared to the control sample. However, no significant improvement (p≤0.05) in the physical properties of fibre was observed when the impregnation time was extended (from 10 to 25 min) using both impregnation agents. As for the mechanical properties of the fibre, significant improvement was observed after they were impregnated for 5 min. The fibres impregnated with UP resulted in better fibre toughness and improved mechanical properties as shown in their higher tensile strength and elongation at break compared to the fibres impregnated with PF. Both the physical and mechanical properties showed no significant improvement (p≤0.05) after time for impregnation was extended (from 10 to 25 min) using both impregnation agents. Therefore, it can be concluded that the physical and mechanical properties of sugar palm fibre could be enhanced by impregnating the fibre with thermosetting polymer (PF and UP) for 5 min. It was shown that impregnation with unsaturated polyester (UP) showed better improvement than phenol formaldehyde (PF). In addition, this study also concluded that the unsatisfactory enhancement of the properties of sugar palm fibre even after the impregnation time was extended from 10 to 25 min was due to the use of low impregnation pressure of 1000 mmHg.