Effect of Fiber Treatment and Fiber Content on Flexural Properties of Luffa Cylindrica-Reinforced Resorcinol Composites

The present paper investigates the flexural behavior of bio composites prepared using resorcinol-formaldehyde (RF) as matrix and natural fibers of luffa cylindrica (LC) as reinforcement. The reinforcement LC fibers were collected from local forest area. The poor adhesion between hydrophilic natural fiber and matrix is a common problem in natural fiber reinforced composites. To overcome this problem the LC fibers were exposed to chemical treatments like alkali treatment, bleaching and acid hydrolysis. The effects of fiber loading of chemically treated and untreated LC fiber on ultimate flexural stress, yield strength, breaking stress and modulus of the composites were analyzed. When both chemically treated and untreated LC fibers were reinforced, the modulus of the composites were increased compared to the pure RF matrix. However the modulus of composites with chemically treated LC fiber were enhanced compared to that of the composites having untreated fiber. Furthermore the values of ultimate stress, yield stress and breaking stress was more for composites with treated LC fiber. But with the incorporation of untreated LC fiber in the matrix, such values are decreased compared to that of the matrix.