Fibers from pineapple's crown (PCF), rice husks (RH) and cotton textile residues (RTF) were characterized by SEM, X-ray diffraction, FTIR and thermogravimetric analysis. Moisture content, water absorption, density and the distribution of the diameter of the fibers were also evaluated. RTF showed cylindrical microstructure with smooth surface, PCF showed cellular structure and the microstructure of RH is globular, showing cell pattern of the outer surface epidermis which is well organized and has a corrugate structure. PCF and RH showed crystallographic planes of cellulose I and RTF showed a mixture of cellulose I and cellulose II. RTF showed the highest degree of crystallinity and the lower moisture content and water absorption. These results occur because the RTF has no hemicellulose, as verified by FTIR. Comparing the three fibers, the RTF presented the lowest density and diameter. Furthermore, the onset degradation temperature of RTF was 40 °C higher than the PCF and the RH.

Solid municipal waste contains a large volume of polymers and its final disposal is a serious environmental problem. Consequently, the recycling of the principal polymers present in the solid waste is an alternative. In this review we describe the mechanical and chemical recycling of polymers and the energy recovery from plastic wastes. Polymer recycling involves not only the development of processing technologies, but also the solution of many chemical and analytical problems. The technological, economical and social aspects of polymer recycling are also considered.