Synthesis and Characterisation of Potentially Biodegradable Polyurethane Adhesives from Soybased Polyols

Abstract

Vegetable oils are one of the most important renewable raw materials because of their high availability and low price. Their use as a reagent for the synthesis of polymers represents many advantages such as biodegradability, low toxicity, sustainability, etc. The design of polymers from renewable resources is subject to increasing interest, specifically the development of biodegradable materials in order to reduce the dependence on petroleum and its negative impact on the environment. On the other hand, thanks to the versatility of polyurethane adhesives, they can be formulated by designing their properties through the selection of their reagents.

This work focused on the development of potentially biodegradable polyurethane adhesives containing polyols from renewable resources, such as soy-based vegetable oils. Moreover, they were synthesised with 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol as chain extender.

The potentially biodegradable polyurethane adhesives were characterised by Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric tests (TGA), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). Finally, the adhesion properties were measured from a T-peel test of leather/polyurethane adhesive/SBR rubber joints, in order to establish the amount of polyol based on soybean oil that could be incorporated to synthesise polyurethane adhesives satisfactorily and meet the quality requirements for footwear.