Synthesis and characterization of rigid water-blown, palm oil-based polyurethane/organically-modified clay nanocomposite foam

Abstract

Despite the superior enhancement it could impose, incorporation of montmorllonite (MMT) nanoclay in polymer-matrix composites is still limited due to miscibility issues with its host matrix; which could be alleviated with surface-modification of the nanoclay. In this paper, diamino methylpentane-modified montmorillonite (DAMP-MMT) nanoclay was incorporated into a bio-based polyurethane (PU) foam at different weight loadings. Characterization tests were then carried out to investigate the influence of included organoclay on the mechanical properties, thermal stability, foam morphology, and foaming kinetics. MMT modification effect could clearly be observed with exfoliated microstructure at lower loadings, compared to pristine clay at similar loading. Presence of organic modifier tethered on the surface of nanoclay was found to act as catalyst which induced accelerated curing, affecting cellular size and structure of foam, which in return cascades into influencing mechanical and thermal properties of the foam. Compressive strength improved with addition of 1 wt.% clay, and deteriorated beyond this point; believed due to clay agglomeration at higher clay loadings. However, thermal stability showed improvement parallel with its clay content, believed owed to additional bonds formed between amine -NH2 from organoclay and – NCO from diisocyanates. Incorporation of organoclays in rigid bio-based PU foam shows great potential in moderate load-bearing applications while upholding “green chemistry” practice.