Influência do uso de diferentes concentrações de agente reticulante na produção de filmes biodegradáveis à base de soro de leite e gelatina

Abstract

Synthetic polymeric materials are necessary in the structuring of products due to their mechanical characteristics and low. However, they may be derived from petroleum, a non-renewable source with limited reserves, thus the need arises for the development of biodegradable polymers obtained from biomass. Whey powder, a waste product of the dairy industry, is an alternative in the substitution of raw material of fossil origin by giving the final product flexible characteristics and absence of color and odor. The objective of this work is to evaluate films of different formulations produced based on whey protein and gelatin by casting technique. The results obtained were compared with a synthetic polymer based on PCW used in female external absorbent packaging. For the formulation of the films produced, in addition to whey powder and gelatin as the main and secondary raw materials, respectively, distilled water (solvent), glycerol (additive) and chitosan (additive) were also used in equal amounts and citric acid (crosslinker) in different proportions of 10%, 20%, 30% and 40% on a mass basis. The addition of citric acid resulted in the increase in the thickness of the films in addition to the increase in the solubility of the films with the gradual addition of citric acid. The contact angle test revealed that only the formulations with higher concentration of citric acid are hydrophilic. The elongation of the sample AC20 10 (14.99 %) showed the closest result compared to the standard (40.13 %). The morphological analysis showed that the produced films have uniform and dense structures, regardless of the composition. The FTIR spectra of the films produced revealed similar behaviors, with the presence of characteristic whey bands only in the finger print region, and the addition of citric acid highlighted the increase in the degree of esterification as the crosslinker concentration increased. The films produced showed lower thermal stability compared to the standard (-93.65 % mass loss), and the increase in the concentration of citric acid resulted in a decrease in the mass loss in the films produced, between 74.85 % and 79.81 %. The glass transition temperatures of the films produced (between 19.75 ºC and 22.35 ºC) were close to the standard (23.27 ºC). The characterization revealed that the films produced with 10 % and 20 % (m/m) of citric acid have the potential to be used as packaging for feminine sanitary napkins and the films with 30 % and 40 % (m/m) of citric acid were discarded as an option for this application, mainly due to the high degree of solubility presented, which could generate future problems. The study of the proposed application for films produced based on whey and gelatin is promising, since there is little literature regarding the suggested application. [resumo fornecido pelo autor]