Unsaturated Polyester Resin/Aluminum Tri-hydroxide Added with Short Glass Fiber for Battery Box

Abstract

A battery box made of polymer material must consider mechanical strength
and flame retardancy. One solution to increase the flame retardancy of polymers is to
add a flame retardant filler. However, sometimes adding a flame retardant filler can
cause degradation of mechanical strength compared to neat polymers. The combination
of more than one type of filler or hybrid fillers can produce the optimal combination of
flame retardancy and mechanical strength. An experimental study was carried out to
characterize several composite polymer samples of unsaturated polyester (UP) resin
combined with fillers of aluminum tri-hydroxide (ATH) to increase flame retardancy
and short glass fiber (G) to improve mechanical strength. The DSC results show that
the maximum endothermic of all samples occurred at a temperature of around 70 ºC.
The TGA results prove that ATH and G can maintain the thermal stability of UP so that
the composite samples were degraded at higher temperatures by reducing the rate of
weight degradation due to a temperature of around 0.1%/ºC. The burning test also
shows that samples with ATH and G have a lower burning rate value than neat UP. For
mechanical characterization, the tensile strength of the samples with ATH and G was
lower than that of neat UP. However, UP/ATH/G2 showed an optimal composition
compared to other filler compositions with a tensile strength of 41.5 MPa. This sample
also produces an optimal bending strength of 68.9 MPa and even higher than neat UP.
These results were confirmed by SEM observations, in which filler G was exfoliated in
the UP. The broken G particles on the fracture surface observation prove the good
interlock bonding between UP and G, which contributes to increasing the mechanical
strength of the UP composite.