Dielectric Breakdown Strength and Flammability Properties of Flame Retardant Filler/PLLA-PLA Microsphere/Kenaf Fiber Composites

Poly(L-lactic acid) (PLLA) is well known as biodegradable polymer and it is used in many applications since its strength and modulus are comparable with another commercial polymers. However, PLLA exhibits brittle fracture, thus blending of PLLA with other polymer is carried out to improve the toughness of PLLA. In addition, Kenaf fiber is a natural fiber which commonly been used to reinforce the biodegradable composites. However, uses of biodegradable composites is limited in some applications for example appliances, textile, and fabric applications due to low compatibility, low thermal stability at blending temperature and flammability. Therefore, addition of flame retardant filler in PLLA-PLA microsphere/KF composite is to prevent or slow down the ignition of composites which are used in many application such as consumer applications and appliances. A phosphorus-based non-halogenated flame retardant or trade name of NP-100 is used in this study to reduce the flammability of the biocomposites. Generally, this flame retardant filler will react with hydrogen and form water, and reduces the rate of combustion. The dielectric breakdown strength of PLLA-PLA microsphere/KF/NP-100 composites at 0, 2 and 4 wt% of NP-100 loading was investigated in this study. It was observed that addition of NP-100 loading at 2 and 4 wt% in composites improved dielectric breakdown strength from 21.09 kV/mm to 23.71 kV/mm and 21.60 kV/mm, respectively.