The effect of flame retardant additive on the properties of kenaf/polyurethane foam composite

Abstract

This research is mainly focused on the preparation and characterization of polyurethane foam (PUF) with the addition of kenaf fiber and flame retardants, which are expandable graphite (EG) and aluminum hydroxide (ATH). Kenaf core fiber was ground into 63 μm in size and was used as the natural filler in the PUF at different amount which are 1, 3, 5 and 7 wt%. Various amount of EG (5, 10 and 15 wt%) and ATH (2, 4 and 6 wt%) was incorporated into the PUF. EG was milled for 1 hour and 30 minutes in a ball mill machine which in turn produces EG particles with 100 μm in size. The composites were prepared by the mixture of palm oil based polyol and isocyanate with the ratio of 1:1.1. The PUF composites were prepared through mixing process by using a mechanical stirrer with 2000 rpm speed. The effect of different amount of filler loading and flame retardant on the PUF was studied to determine the rising time, density, compression properties, flammability behavior, thermal analysis and morphological studies. From the results obtained, it showed that PUF filled with kenaf fiber takes shorter rise time compared to the PUF filled with flame retardants. While, density values were increased with the increasing amount of filler and flame retardant into the PUF matrix. For mechanical study, compression strength and modulus of the PUF composites was reduced as the amount of kenaf fiber and flame retardants were increased. The mechanical strength was improved for PUF/15EG and PUF/KF/15EG due to the large surface area provided by the pulverized EG particles. Based on LOI and flammability test, it was recorded that PUF with the highest amount of flame retardants and with the presence of kenaf fiber (PUF/KF/6ATH/15EG) shows excellent flame retardancy properties.