Colemanite: a fire retardant candidate for wood plastic composites

Abstract

The use of raw boron minerals (i.e. tincalconite, colemanite, and ulexite) was evaluated to increase the fire performance of wood plastic composites (WPCs) in comparison with commercially available fire retardants (FRs). Cone calorimetry and limited oxygen index tests were performed to evaluate the fire properties of WPC specimens. Artificial weathering and 3-point bending tests were also performed on the test specimens loadedwith the highest loading level of FRs. The most important decrease in theheat release rate values was 42% and 40% in the magnesium hydroxide- and colemanite-added WPCs at a loading level of 15% (w/w), respectively.Incorporation of colemanite and ulexite into the WPCs increased thelimited oxygen index levels by nearly 13% at the same loading level. Anincrease was observed in the peak heat release rate values in all of theWPC specimens after accelerated weathering. All of the FRs hadstatistically improved MOE values compared with the control WPCspecimens. In particular, the incorporation of zinc borate and boraxincreased the MOE values by approximately 48% and 42%, respectively.Similar to the effect on the MOE values, zinc borate and borax improvedthe modulus of rupture the most (approximately 18%).

Citation

Terzi, Evren; Kartal, Saip Nami; Piskin, Sabriye; Stark, Nicole; Figen, Aysel Kanturk; White, Robert H. 2018. Colemanite: a fire retardant candidate for wood plastic composites. BioResources. 13(1): 1491-1509.