Avaliação das propriedades da blenda de poli(3-hidroxibutirato)/quitosana após esterilização térmica ou radiolítica

Abstract

AesumoNesse trabalho foi desenvolvido filme de PHB/quitosana com aplicação promissora em embalagens de alimentos e medicamentos. Esses filmes foram preparados via casting solution e após esterilização térmica ou radiolítica suas propriedades foram avaliadas a partir da microscopia eletrônica de varredura, ensaio de tração, calorimetria exploratória diferencial e análise termogravimétrica. Foram constatadas alterações na morfologia dos filmes de PHB/quitosana após os processos de esterilização. As propriedades mecânicas da blenda se mantiveram aproximadamente constantes após esterilização térmica. Porém, após irradiação as blendas apresentaram-se quebradiças. As propriedades térmicas da blenda foram alteradas apenas para as doses de 50 e 75 kGy, em que foi observado uma redução no valor da entalpia de cristalização, grau de cristalinidade, cristalinidade relativa e taxa de cristalização da blenda. Foi observado que a degradação térmica dos filmes de PHB e das blendas, antes e após os processos de esterilização apresentaram um único estágio (250-300 °C). Palavras-chave: blendas poliméricas, esterilização térmica, esterilização radiolítica, PHB, quitosana. AbstractIn this work was developed PHB/chitosan film with promising application in food and medicine packaging. These films were prepared by the casting solution and after radiolytic or thermal sterilization their properties were evaluated by scanning electron microscopy, tensile testing, differential scanning calorimetry and thermogravimetric analysis. PHB/chitosan films changed their morphology after sterilization processes. Mechanical properties of the blend remained approximately constant after thermal sterilization. But, after irradiation the blends presented brittle. Thermal properties of the blend were changed only for the doses of 50 and 75 kGy, in which case was observed a reduction in the crystallization enthalpy value, the degree of crystallinity, relative crystallinity and crystallization rate of the blend. It was observed thermal degradation of the PHB films and blends, before and after sterilization processes presented a single stage (250-300 °C).

Effect of Chitosan Addition in Whey-based Biodegradable Films

“…According to Le Tien and coauthors [54], whey proteins have the capacity to crystallize during heating in film preparation. Abdelwahab and coauthors [55] and Souza and coauthors [56] also reported the influence of chitosan on the morphological characteristics of films based on biopolymers, with similar results.…”

Development of active PHB/PEG antimicrobial films incorporating clove essential oil

“…This combination can be an option to reduce the demand for degradable packaging Polyhydroxybutyrate (PHB) is a well know biodegradable polymer used worldwide due to its crystalline structure, superior characteristics of aroma barrier, and water vapor permeability [9] . PHB is a thermoplastic polymer obtained from renewable natural sources that shown characteristics of biodegradability, biocompatibility, UV resistance and properties similar to the synthetic polypropylene [12][13][14] . However, the high crystallinity of PHB makes it very rigid and brittle, limiting its applications [15,16] .…”

Gamma irradiation effects on polycaprolactone/zinc oxide nanocomposite films

“…Conventional synthetic polymers are widely used in our society due to characteristics such as low density, low cost of production, and facility for molding, among others. Due to their chemical constitution, however, they have a low rate of degradation, leading to environmental problems [1][2][3] . An alternative to these materials are the polymeric materials constituted by poly (α-hydroxy acids), which are biodegraded by microorganisms in CO 2 , water, and cellular components among other materials [4,5] .…”