Flexible Foams and Elastomers from Castor Oil

Date

2024-03-07

Authors

Shrestha, Maha L.

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Abstract

Self-transesterification of castor oil was employed to prepare higher molar mass polyols possessing interesting properties. Detailed structures of the polyols were studied using various standard techniques along with spectrometric analysis such as MALDI-TOF/MS. Polyurethane elastomers prepared from these polyols provided soft material with low Shore A hardness. These polyols were also tested in molded polyurethane foams and their polyurethane properties were compared with that of the commercial bio-polyols.

Description

Natural oils are excellent substitutes for various feedstocks used to synthesize polyol in the preparation of polyurethanes. Synthesis of polyols for polyurethanes directly from oils is possible by various methods such as thiol-ene addition of mercapto alcohols, hydroformylation/hydrogenation, metathesis, transesterification (glycolysis and glycerolysis), epoxidation and ring opening with alcohols, acids, hydrogen or inorganic acids, and ozonolysis/hydrogenation. Most of these methods yielded low molar mass polyols of around 1000, similar to the oils they are derived from. Typically, polyols with molar mass range 3000-6000 are required for flexible foams and elastomers which can be obtained by alkoxylation (propoxylation/ ethoxylation); however, this process lowers the bio-based content of the resulting polyols. We hereby focused on synthesis and structure elucidation of self-condensed polyols from castor oil containing ~ 2.7 hydroxyl groups per triglyceride. Our objective also involves obtaining a series of castor oil-based polyols that provide varying degrees of hydroxyl functionalization with suitable viscosity for flexible foam and elastomer formulation. Experimental techniques include wet chemistry (titration), viscosity measurements, size-exclusion chromatography combined with light scattering (SEC/LS), and spectroscopic techniques such as Fourier-transform infrared (FT-IR), Nuclear Magnetic Resonance (NMR) and matrix-assisted laser desorption/ionization coupled to time of flight (MALDI-TOF). The current study also involves the preparation and analysis of flexible polyurethane foams and elastomers. Data collection methodology is experimental analysis using various instruments such as FTIR, NMR, Maldi-Toff/MS etc...

Keywords

2024 Faculty and Student Research Poster Session and Research Fair, West Texas A&M University, College of Agriculture and Natural Science, Poster, Polyols, Flexible foams

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