Rheology of starch and gum chañar brea mixtures

MARTIN MASUELLI AND ROMINA POSTEMSKY

Las Vegas

Congreso; 8th Edition of Biopolymers & Bioplastics Polymer Science and Engineering Conferences; 2018

8th Edition of Biopolymers & Bioplastics Polymer Science and Engineering Conferences

In this work, the interaction of a mixture between soluble starch and gum chañar brea (GChB) is evaluated by rheologicaldeterminations. The objective of this study is to analyze the interactions between starch and GChB in order to establish thefeasibility of link power, a parameter obtained by verifying viscosity variation and viscous flow activation energy with biopolymerconcentration. The solutions were prepared in the following proportions: 2.5, 3.5 and 7% by weight of starch, mixed with GChBfrom 0.5-2.5% by weight. The soluble starch solutions were prepared at boiling for 5 min, to produce the imbibition of their structureand their partial solubilization. Next, the GChB was incorporated and the suspensions were cooled. The suspensions were evaluatedat different temperatures (25, 30 and 40°C). The starch used was Biopack, the GChB was extracted in the Salteño forest and waspurified with ethanolic extractions. The pure solutions of starch and GChB have Newtonian behavior as well as their mixtures, exceptwhen the concentration of starch is 5% and the rubber pitch of 2.5%, where a small deviation occurs. The increase in temperature,from 25 to 40°C, causes a decrease in viscosity of 34% for starch, 30% for GChB and 25% for the mixture. With the increase in theconcentration of GChB from 0.5 to 2.5% in the mixture, the viscous flow activation energy decreases for the same concentration ofstarch by an average of 22%. These results indicate a strong interaction when the biopolymer concentration is increased.