Curing behaviour of unsaturated polyester resin and interfacial shear stress of sugar palm fibre

Abstract

Studies on the effect of cobalt of unsaturated polyester resin and the effect of treated sugar palm fibre with sodium hydroxide on single fibre strength and interfacial shear strength (IFSS) are presented in this paper. 1% of methyl ethyl ketone peroxide was used as the initiator, while cobalt of variable percentages (0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8% and 1%) was used as the hardener. The effects on glass transition and exothermic reaction of unsaturated polyester were studied for post curing temperature determination using differential scanning calorimetry by heating the samples at 10ºC/min heating rate from 30ºC to 120ºC with flowing of purge nitrogen gas atmosphere. For the single fibre test and IFSS, the treatment was carried out using sodium hydroxide solution with 1% concentration for one hour soaking time. Based on the optimisation percentage of cobalt, it was found that the higher the percentage of cobalt, the faster the sample tested to gel and cured. Treated sugar palm fibre exhibited better single fibre strength and IFSS between the matrices compared to untreated fibre due to the effectiveness of the alkali treatment. This can be attributed to the rearrangement of fibrils along the direction of tensile force and the removal of the coating layer and impurities after the alkaline treatment.

Effect of fiber orientation and fiber loading on the mechanical and thermal properties of sugar palm yarn fiber reinforced unsaturated polyester resin composites

“…Initially, 1 wt % of MEKP as the initiator was mixed well with the unsaturated polyester resin, followed by mixing with 0.2 wt % of cobalt naphthanate. Then, the mixed resin was poured over the fiber and compressed using a hot press machine at 70 °C and 8 MPa for 30 minutes [23,24]. A mold was prepared by spraying with silicone mold release agent to avoid any stacking with the composites.…”

Mechanical properties of sugar palm yarn/woven glass fiber reinforced unsaturated polyester composites: effect of fiber loadings and alkaline treatment

“…Then, the chemical constituents (Table 1) of the untreated and treated sugar palm fiber were analyzed according to the following standard methods: ethyl-benzene extractive (TAPPI T 204 CM-97), lignin (TAPPI T 222 OM-98), holocellulose [20] and alfa cellulose (TAPPI T 203 CM-99). Table 1 shows also the tensile properties of untreated and treated single sugar palm fiber [21].…”

“…A certain amount of glass fibers was placed inside the mold, followed by a placement of all the quantity of sugar palm fiber and final-ly the rest of glass fiber. After each placement, a small amount of mixed unsaturated polyester resin was poured over the fibers in order to improve the absorption of resin and to minimize the formation of voids and finally compressed using hot press machine with at 70 °C and 8 MPa for 30 minutes [21]. Table 2 shows the summary of the formulation of hybrid composites between the matrix and fibers.…”

Effect of Fibre Length and Sea Water Treatment on Mechanical Properties of Sugar Palm Fibre Reinforced Unsaturated Polyester Composites

“…Indeed, by removing the impurities and waxy substance from the fibre surface and the creation of a rougher surface after the treatment, the mechanical interlocking and thus the interface quality will have promoted. Hence leads to higher strength of the composites structure [31]- [32]. Fig.…”