Synthesis and Properties of Waterborne Polyurethane Modified with Guar Gum Polysaccharide

Guar gum modified waterborne polyurethane (GWPU) was synthesized by the prepolymerization method using guar gum (GG) as an internal crosslinking agent. The influence of the GG content on emulsion and film properties was investigated. The Fourier transform infrared (FT-IR) results showed GG was successfully introduced into the polyurethane. The emulsion particles presented spherical morphology with an average diameter of about 40 nm characterized by transmission electron microscopy (TEM). The particle size increased with the increase of the amount of GG using dynamic laser scattering (DLS). The tensile strength of GWPU film was increased by 31.8% when the incorporated content of GG was only 0.3 wt%. With increasing GG content, the elongation at break and crystallinity of GWPU film decreased. The thermal stability increased initially as GG content increased, then decreased. Furthermore, the water resistance of GWPU was observably improved.