Environmentally friendly soybean protein concentrate adhesives with enhanced microbiological stability

A. LARREGLE; J. F. MARTUCCI; E.M. CIANNAMEA; F. FANGIO; P.M. STEFANI; R.A. RUSECKAITE

Congreso; 16 Congreso Internacional en Ciencia y Tecnología de Metalurgia y Materiales SAM ? CONAMET; 2017

For several years our group has developed soy protein based adhesives with competitive properties to synthetic adhesives for particleboard and wood laminates use. The biggest limitation in the use of these adhesives is their susceptibility to moisture, which promotes the development of fungi. One way to overcome this difficulty is to develop active adhesives formulations capable of preventing or limiting microbial growth. With this objective, soy protein concentrate based adhesives (SPC) with anti fungal activity were prepared. The minimum inhibitory concentration (MIC) of the active natural agents (carvacrol, cinnamic aldehyde, vanillin) were evaluated against Aspergillius terreous. From these results, a concentration above the MIC was established for each active agent and incorporated into distilled water with different modifiers, and in the presence and absence of emulsifier. The evolution of the average size and distribution of dispersed particles was analyzed using a Nanosizer 90 in order to establish the proportions of active and emulsifying agents that provide a stable emulsion. From these results, stable active SPC based adhesives were prepared. Thermal stability was tested by differential scanning calorimetry and thermogravimetry and rheological behavior was analyzed on each formulation. Preliminary results indicated that the addition of low levels of active and emulsifying agent did not significantly alter the thermal properties and rheological dispersions SPC. Studies in vitro against Aspergillius terreous are ongoing.