Sustainable flame-retardant polyurethanes using renewable resources

• Published in: Industrial crops and products 2018-11, Vol.123, p.480-488
• Main Authors: Bhoyate, Sanket, Ionescu, M., Kahol, P.K., Gupta, Ram K.
• Format: Article
• Language: English
• Subjects: Castor oil; Flame-retardant; Mercaptenized oils; Orange peel oil; Polyols; Polyurethanes; Reactive-phosphorus; Smoke suppression; Soybean oil
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2018.07.025

[Display omitted] •Bio-resources were used to prepare flame-retardant polyurethane foams.•Diethyl allyl phosphonate was used to synthesize P-based flame retardant polyol.•Flame-retardant polyurethane foams showed improved compressive strength.•Horizontal burning test showed a drastic reduction in self-extinguishing time.•Cone calorimeter data showed a significant reduction in peak heat release rate. Renewable bio resources such as soybean, orange peel, and castor along with a novel phosphorous based polyol were used to prepare highly flame-retardant polyurethane foams. Diethyl allyl phosphonate (DEAP) and thioglycerol (TG) were used to synthesize phosphorous (P) based flame retardant polyol (DEAP-TG). Polyurethane (PU) foams having a various weight percentage of phosphorous were prepared using a varying amount of DEAP-TG (as a phosphorous source) and other bio-based polyols. Use of DEAP-TG polyol in polyurethane foams showed improved compressive strength without affecting closed cell content and morphology of the foams. The horizontal burning test showed a drastic reduction in self-extinguishing time and weight loss for the PU foams containing DEAP-TG polyol. For example, castor oil and DEAP-TG based PU foam which contains 1.5 wt% P showed significant reduction in self-extinguishing time (from 94s to 1.7s) and weight loss (from 48.5% to 3%) compared to neat castor oil based foams. Cone calorimeter data also showed a significant reduction in peak heat release rate, total heat release, total smoke release, and overall smoke production rate for the foam containing 1.5 wt% P compared to 0 wt% P in the foam. The improved flame retardancy was due to the formation of a protective char layer over the surface of the foam due to decomposition of a phosphorus compound. Our research provides a green alternative to prepare industrial grade flame-retardant polyurethane foams.