Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties

Abstract

Protein macromolecules derived from plants have been considered as alternative resources for various applications, including adhesives, films, rubbers, and biocomposites. Plant protein polymers are pH sensitive and need to be modified to meet application performance. This study demonstrated interactions between polyamide-epichlorohydrin (PAE) and soy protein as affected by pH and temperature. PAE and soy protein molecules formed reversible ionic complexes at room temperature at a pH range of 4-9. The complexation interactions acted as physical crosslinking, which stabilized the soy protein structure and increased its denaturation temperature and enthalpy. The viscosity of adhesives derived from the interaction of PAE and soy protein was affected significantly by the complexation formation, denaturation, and pH. The complexation interactions improved the adhesion properties of the PAE/modified soy protein. pH also played an important role in the adhesion performance, which was attributed to the pH dependence of the protein conformation and PAE/soy protein complexation interactions.

Soy flour dispersibility and performance as wood adhesive

“…Interaction of PAE with soy protein prior to curing has been reported [11], but PAE's main attribute is reacting with the wood and proteins during curing. Like most soy adhesive research, the published studies have been carried out using soy protein isolate (SPI), but not with soy flour, which is now used for the commercial adhesives for economic reasons.…”

Formation of Poly(propylene)‐Based Biocomposite Films and Their Use in the Attachment of Methylene Blue

“…[1][2][3][4] The conjunction of both polymers type enhances the properties of the final material, broadening its application field. [5][6][7] Biocomposite materials have proved useful in such varied fields as biomedical materials, [8] controlled-delivery systems, [9] biological tissue engineering, and food packaging. [5,8] The biopolymer ''chitosan'' (CS) is a polysaccharide chemically composed of linkages b-(1,4)-2-amino-2-deoxy-D-glucose attained from the deacetylation of chitin, an abundant biopolymer present in the shell of shrimps, crabs, and crawfish.…”

Properties of soy protein isolate/poly(vinyl alcohol) blend “green” films: Compatibility, mechanical properties, and thermal stability

“…In recent years, the development of environment‐friendly and biodegradable materials based on nature polymers, especially from agriculture products including cellulose, starch, and protein materials, have received increasing attention in an attempt to substitute existing petroleum‐based polymers 1. Among these various natural materials, soy protein‐based plastics have been extensively studied as a potential replacement owing to their low cost, easy availability, and complete biodegradability 2. Especially, soy protein isolate (SPI) contains more protein than any other soy protein products, which leads it to hold a higher film forming ability for packaging films,3 edible films,4 and skin repair films 5.…”