Date of Award

Fall 5-12-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Dr. Ram Gupta

Second Advisor

Dr. Khamis Siam

Third Advisor

Dr. Pawan Kahol

Fourth Advisor

Dr. Anuradha Ghosh

Abstract

Structural fire is one of the most catastrophic issues related to human safety observed from reports of National Fire Protection Association of United States in past years. Polyurethanes are one of the important structural material used as thermal insulation in housing. They are also used in automotive, construction, medical, packaging, furniture, thermal, electrical, and vibration insulation. Considering this, we have synthesized bio-based polyurethane foams using limonene-based polyol, isocyanates, and other compounds. Flame retardancy was imparted using reactive flame retardant polyols. Firstly, flame retardancy test was performed on the foams using two novel aliphatic and two novel aromatic bromine-based synthesized reactive flame retardant polyols in different concentration in foams. It was observed that bromine acts in gas as well as a condensed phase to provide flame retardancy. Moreover, it required 6% concentration of bromine in final foam to impart desired flame retardancy. Secondly, flame retardancy was studied using phosphorus-based synthesized reactive flame retardant polyol in different concentration. We observed that foams containing only 1.5% phosphorus are sufficient to provide better flame retardant properties. The study was further analyzed using cone calorimeter test. Results showed excellent flame retarding properties compared to many reported values. Lastly, another phosphorus-based novel flame retardant polyol was synthesized. This study was generalized by using soybean and castor oil-based polyols which are also widely used bio-based polyols, as a comparison to limonene-based polyol used during synthesis of the polyurethane foam. Castor oil-based foams showed the best result in flame retardant properties. Hence, thorough analysis on castor oil-based foams was performed as a representative study to understand peak heat release, total heat release, and smoke release rate of the foams. From the overall study, the addition of reactive flame retardant polyols showed improved mechanical properties and maintained their cell structure. Higher close cell content (95-100%) throughout the study was maintained by all the foams containing reactive flame retardant polyols. This suggests excellent thermal insulation properties of the foams for the desired application. Results obtained from this study can serve as an important function to overcome structural fires and assist in providing human safety.

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