High energy ball milling and sonofragmentation were used successfully to reduce the crystallite size of calcium carbonate extracted from the eggshell. The ceramic was milled using either deionized water or stearic acid and then subjected to a subsequent size reduction by means of a tip horn. The thermal degradation of particles was influenced by the presence of stearic acid in milling process because it acts as a protective layer around eggshell particles. It was found that the reduction in crystallite size diminishes the degradation temperature and the presence of the surfactant may lead to a change in particle shape by trough a superplasticity phenomenon. Tubes, fibers and a rectangular prism were observed in Transmission Electron Microscopy.

Abstract Over five million tons of chicken feathers (CF) are generated all over the world by the poultry industry, with an immense potential to exploit. Keratin is an abundant protein found in chicken feathers that offers excellent thermal properties and it is durable, insoluble in organic solvents and chemically unreactive. Elastomers are materials with a wide application range, for instance, adhesives, shoe soles, plastic modifiers, tire industry, sealants, among others. However, it is necessary to improve their properties and mechanical performance at elevated temperatures. A good path to do so is to combine the elastomer with CF to obtain materials with enhanced properties. In present work, a composite based on styrene-butadiene (SB) elastomer and CF was prepared by means of melt mixing. Composites were characterized by FTIR, DSC, DMA and X ray diffraction techniques. The results show that there is an increase in stiffness of SB/CF composites compared with pure elastomer.

The mixture of synthetic and natural materials yields a material with improved physical-chemical properties. One way of obtaining this kind of material is through graft copolymerization. Some natural materials have been used in graft copolymerization with synthetic monomers. In this work, graft copolymerization of butyl acrylate (BA) onto starch using a redox initiator system was carried out. The graft yield was evaluated for different reaction conditions. The graft copolymer was characterized by infrared spectroscopy, thermal analysis and scanning electron microscopy (SEM).