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.

Cellulose fibers obtained from waste pineapple leaves were chemically treated with acid hydrolysis for reduction to nanoscale size. Once the cellulose nanofibers were obtained, they were used as a reinforcing material (0.3%–1.0%) of a chitosan-starch matrix. Transmission and scanning electron microscopy was used to check the morphology and reduction of the fiber, with which it was demonstrated that the chemical structure of cellulose was not damaged. Once the composites were obtained, thermal tests were carried out through a thermogravimetric analysis and differential scanning calorimetry, in which it was observed that the thermal stability was not affected by the use of the reinforcement. Fourier transform infrared (FTIR) analysis confirmed interactions between hydroxyl groups and amino groups of polysaccharides. Finally, a dynamic mechanical analysis was performed, in which the increase in the storage module of up to 90% was observed with only 0.7% of the nanofiber reinforcement. Through the results obtained in this research, the use of pineapple leaves as raw material for obtaining cellulose nanofibers is verified, which can be an alternative as a use of matrix reinforcement, suggesting an alternative for the replacement of synthetic reinforcements.