Phenolic Thermoset Matrix Reinforced with Sugar Cane Bagasse Fibers: Attempt to Develop a New Fiber Surface Chemical Modification Involving Formation of Quinones Followed by Reaction with Furfuryl Alcohol

Abstract

Summary: A new chemical modification of sugar cane bagasse fibers for phenolic thermoset composites is presented. It consists in creating quinones in the lignin portions of fiber and react them with furfuryl alcohol to create a coating around the fiber more compatible with the phenolic resins used to prepare polymeric matrix. Sodium periodate was used in suitable conditions to oxidize mainly phenolic syringyl and guaiacyl units of the lignin polymer to create quinones, which were characterized by UV‐visible diffuse reflectance spectroscopy by comparison with model compounds. The reactivity of furfuryl alcohol (FA) with fibers was greatly enhanced after they were oxidized: 13% weight percent gain compared to 2% without oxidation. Chemical analysis of unmodified and FA‐modified fibers have shown an important degradation of hemicelluloses and a slight one of cellulose which almost maintains its crystallinity. A 25% decrease of strength and length properties of the fibers after FA chemical treatment was measured by dynamic mechanical analysis. The lignin‐like proportion of the fiber was greatly enhanced after the FA‐treatment. This was confirmed by thermal analysis, DSC, and TGA experiments, on unmodified and FA‐modified fibers. SEM analysis of the fibers and of phenolic composites with modified fibers have confirmed the FA grafting and shown a better compatibility at the interface between the chemically modified fibers and the phenolic matrix. Nevertheless, the chemical treatment of the fibers decreased the impact strength of the composite, which could be caused by the fiber damage suffered during the chemical modification and for the more intense adhesion at the interface, which in some cases decrease somewhat the impact strength.Cross photomicrography of FA‐modified sugar cane bagasse fiber (600×).magnified imageCross photomicrography of FA‐modified sugar cane bagasse fiber (600×).

Renewable Resources as Reinforcement of Polymeric Matrices: Composites Based on Phenolic Thermosets and Chemically Modified Sisal Fibers

“…[7] The use of lignocellulosic materials as replacements for synthetic fibers in the production of composites has gained significant importance in technical applications, such as in the automotive, as well as in the packaging industries. [8][9][10] Unfortunately, several disadvantages of natural fibers such as mechanical and thermal degradation during processing can make them undesirable for certain applications. Thermal degradation of the fibers occurs above 200 8C, resulting in gaseous products, which can cause high porosity and lower mechanical properties of the composites.…”

“…In a series of papers, [9][10][11][12] we have applied a new way of chemically modifying the surface of lignocellulosic fibers. This method involves a selective modification of the lignin polymer partly preserving the cellulose.…”

Utilization of Recycled Polypropylene for Production of Eco-Composites

“…In fact, either partial degradation of PP occurs, or the extent of the reaction between maleic groups of the compatibilizer and hydroxyl groups of cellulose is increased. In this latter case, a better interfacial adhesion could be obtained as a result of the recycling process of the matrices, and this phenomenon could explain the improvement of the thermal stability and the interesting mechanical response of recycled matrices-based composites [23][24][25] . dispersion but also of the filler/matrix adhesion level after applying an external load.…”

Photodegradation of sugarcane bagasse fibers: influence of acetylation or grafting UV-absorber and/or hindered nitroxide radical on their photostability

“…29,30 Our present research interest concerns ways to transform sugarcane bagasse fibers into useful materials, such as board and composites. 31,32 For board materials in outdoor uses, their photostability might be questionable and the photochemical behavior of these fibers to UVVisible irradiation needs basic knowledge. Very recently, 33 we have shown that acidolysis lignins of peroxide bleached and unbleached bagasse fibers present a high content in p-hydroxyphenylpropane units compared to hardwood and softwood.…”