Studies on using cellulosic natural fibers as reinforcement for composites are rapidly growing. The aim of this study is using a raffia-based woven fabric as reinforcement for composites that are grown in the Mediterranean Zone of Turkey. These fabrics benefit from their mechanical performances, low density and their biodegradability. However, it is necessary for the fabrics to form adhesion in the matrix. Therefore, chemical processes should be applied onto the surface of the raffia-based woven fabrics. In this study, three different formulations (different concentrations of maleic anhydride, formic acid and acetic acid) were applied by using conventional and microwave energy on the raffia fabrics. At the end of the application, composite structures were formed by using the fabric as the reinforcement layer and isophtalic polyester as the matrix by the vacuum infusion method. The composite structures were characterized by attenuated total reflectance scanning electron microscope analysis and their mechanical tests were performed through tensile testing. Considering all results, the combination of acetic acid with the microwave process was found to modify the raffia fabric surfaces.

Producing composites from natural fibers is known to be common. These fibers benefit from their mechanical performances, low density, and their biodegradability. However, it is necessary for the fibers to form adhesion in the matrix. Therefore, it is necessary to apply a chemical process to the surface of the fibers. In this study, four different processes in conventional and ultrasonic energies were applied on luffa cylindrical fibers. At the end of the application, a composite structure was formed on the fibers that were obtained by using unsaturated polyester resin. The changes in the characteristics of the composite structure were recorded by mechanical tests, Fourier transform infrared, X-ray diffractometer, and their morphological characteristics by means of scanning electron microscopy. Considering all the results, formic acid and acetic acid process results were found to adequately modify the fiber surfaces.

This work aims to obtain reinforced composites of natural fibers that obtained from their agricultural wastes of and conductive polymers to develop an innovation and alternative materials. By the use of natural fibers contributes to the recycle of agricultural wastes, sustainability and further the resulting composite becomes alternative to the metals. Here, flexible conductive composites were obtained from artichoke(A), banana(B) and luffa(L) stem waste fibers(F) by the in-situ polymerization of 3,4-ethylene dioxythiophene (EDOT), pyrrole, and carbazole in the presence of cerium ammonium nitrate, iron nitrate, and iron chloride. Fibers were coated with the conductive polymers mentioned above by the in-situ chemical(C) polymerization and optimum coating conditions were investigated. Effect of EDOT concentration, oxidant concentration was performed to determine the optimum conditions for AF/PEDOT(C). FT-IR, SEM, thermal analysis supported the formation of composite and from the mechanical measurements, modulus of AF/PEDOT(C) was obtained. The highest conductivity of 12.8 S/cm was obtained from AF/PEDOT(C) composite using FeCl₃ as an oxidant. Further polymerization of EDOT by electrochemical(E) method was continued on the AF/PEDOT(C) and the electroactivity of resulting electrochemical composite, AF/PEDOT(C)/PEDOT(E) was characterized accordingly. Detailed characterization showed that to use of this composite as a capacitor, one should use 0.03 M EDOT and 0.9 M FeCl₃ for chemical polymerization and then continued by electropolymerization by applying 10 cycles in 0.03 M EDOT. All results showed that AF waste could be converted to the valuable AF/PEDOT(C)/PEDOT(E) conductive composites which is potentially suitable material for several electronic applications as charge storage, biosensor, electronic devices.

In this research, polyurethane (PU) foam composites were prepared by using various agricultural waste (rice husk, corn silk, artichoke stem) particles. In order to enhance the compatibility and adhesion between the waste particle and PU matrix, alkali treatment was employed. The alkali treated particles were chemically and morphologically characterized by Fourier transform infrared (FTIR) spectroscopy, cellulose determination instrument, and scanning electron microscopy (SEM), respectively. The effects of the alkali treatment on the structural, morphological, mechanical, and acoustic properties of the overall PU foam composites were all examined. Due to the differences in chemical compositions of the agricultural wastes, the alkali treatment affected the acoustic and mechanical properties of the PU foam composites in varying ratios. The PU foam composite reinforced with alkali treated artichoke stem waste particles showed the highest tensile strength value of 265 kPa, whereas the highest sound absorption value of 40.5% as an enhancement on the acoustic properties compared to the blank PU foam composite was recorded in corn silk waste particle loaded sample.