Formulation designs and characterisations of whey-protein based API adhesives

摘要

Purpose - The purpose of this paper is to investigate the effects of the components of whey-protein based aqueous polymer-isocyanate (API)adhesives on the bond strength.Design/methodology/approach - The bond test (according to the JIS K6806-2003 standard), Fourier transform infrared spectroscopy (FTIR) and scanningelectron microscopy (SEM) were used to characterise the whey-protein based API adhesives with various formulations and processing technologies.Findings - The good bond strength of the optimised whey-protein based API adhesive was attributed to the formation of strong chemical bonds in thebondline and to the additions of polyisocyanate, polyvinyl alcohol (PVA) and nano-CaCO3 powder that improved adhesive cohesive strength by eitherchemical crosslinks or mechanical interlocking. The blending procedures of whey protein, PVA, polyvinyl acetate (PVAc) and p-p-MDI had great impactson the performances of the whey-protein based API adhesives.Research limitations/implications - SEM micrographs showed that the effects of blending processes on the bond strength, pot life and colour mightbe attributed to the particle size of hydrophobic p-MDI droplet and p-MDI distribution in the protein-PVA matrix.Practical implications - The study lays the foundations of the formulation design and the processing technology for preparing whey-protein basedAPI adhesives.Originality/value - The effects of the components of whey-protein based API adhesives and the effects of blending processes on the bond strengthwere investigated by means bond strength evaluation, FTIR and SEM analyses; whey protein is utilised successfully to prepare novel API adhesives forstructural uses.