Abstract:The performance as reinforcement of a fibrillar protein such as feather keratin fiber over a biopolymeric matrix composed of polysaccharides was evaluated in this paper. Three different kinds of keratin reinforcement were used: short and long biofibers and rachis particles. These were added separately at 5, 10, 15 and 20 wt% to the chitosan-starch matrix and the composites were processed by a casting/solvent evaporation method. The morphological characteristics, mechanical and thermal properties of the matrix and composites were studied by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical analysis. The thermal results indicated that the addition of keratin enhanced the thermal stability of the composites compared to pure matrix. This was corroborated with dynamic mechanical analysis as the results revealed that the storage modulus of the composites increased with respect to the pure matrix. The morphology, evaluated by scanning electron microscopy, indicated a uniform dispersion of keratin in the chitosan-starch matrix as a result of good compatibility between these biopolymers, also corroborated by FTIR. These results demonstrate that chicken feathers can be useful to obtain novel keratin reinforcements and develop new green composites providing better properties, than the original biopolymer matrix.

The objective of the study was to obtain a new biodegradable graft polymer by performing two chemical processes: first, a transesterification reaction between carboxylic acid’s salt and ethyl acrylate’s ester, followed by polymerization of the vinyl group from the ethyl acrylate monomer via free radicals. The copolymer’s FTIR shows an absence of ethyl bands, while the characteristic band of pyranose is maintained, which confirms the monomer’s graft. TGA analysis shows that sodium alginate had three decomposition temperatures: 103 °C due to dehydration, 212 °C associated with the destruction of glycosidic bonds, and 426 °C due to conversion of alginate into Na2CO3. The copolymer presents four processes at different temperatures, i.e., evaporation of alcohol at 65 °C, decomposition of ungrafted alginate at 220 °C, copolymer decomposition at 298 °C, and degradation of fragments into carbonate at 423 °C. The evaluation of the action of fungal growth on the copolymer was higher than 50%, which means it is an excellent material to be biodegraded.

modified ground quill, 2522% for composites with modified long fiber and 3206% for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73% for chitosan-starch matrix up to 16% for the composites with 5 wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiating chitosan-starch films with sustainable features.