الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In Egypt, we suffer from large quantities of different agricultural wastes which already deposed by burning in air causing great environmental hazards and aggravation of the annual phenomenon of ”black cloud”. The industrial applications of these wastes can fulfill our demand for their safe deposal. In this thesis, we tried to exploit some agricultural wastes through studying the effect of using bagasse and rice straw fibers for reinforcement of unsaturated polyester resin in making wooden-polymer composites (WPC). Bagasse and rice straw fibers were chemically treated with sodium hydroxide and sulfuric acid and then silane was added as coupling agent to obtain silanated fibers. In this work, different WPC were prepared through filling polyester by untreated and treated fibers as 5, 10 and 15% by weight. The curing reaction was then performed using peroxide initiator.
The effect of chemical treatment of bagasse and rice straw fibers on their microstructural properties was studied. TEM images confirmed that chemical treatment of fibers led to formation of nanocellulose particles with high aspect ratio. FTIR indicated that most of non-cellulosic content of fibers was disposed after chemical treatment and the obtained treated fibers were chemically bonded with polyester matrix. XRD indicated the increase of crystallinity of the treated fibers. The flexural behavior of the prepared WPC was studied. In addition, water absorption was examined. Young`s modulus of elasticity and flexural strength increased with silanated bagasse-polyester and silanated rice straw-polyester composites compared with either neat polyester or other composites. Alkali treated fibers-polyester composites had higher water absorption percentages compared with untreated fibers-polyester composites. However, silanated fibers-polyester composites recorded the least water absorption percentages.
Dynamic mechanical analysis was conducted on WPC to study the effect of exposure to water on the mechanical behavior these composites. The results indicated that the storage modulus increased after filling polyester with silanated fibers. The exposure to water slightly reduced the storage modulus of composites filled by bagasse, alkali treated bagasse, rice straw and alkali treated rice straw fibers. However, the silanated bagasse-polyester and rice straw-polyester composites achieved higher storage modulus even after exposure to water.
The chemical resistance of the prepared WPC to sodium hydroxide and hydrochloric acid was evaluated. Alkali treated fibers-polyester composites recorded lower chemical resistance against both reagents than untreated fibers-polyester composites. However, the silanated fibers-polyester composites achieved the highest chemical resistance to both chemical reagents. Generally, the exposure to chemicals did not cause any weight loss regarding the absence of any erosive effect.
TGA was conducted to find out the effect of fiber treatment on the thermal behavior of the prepared WPC. The results indicated that silanated bagasse-polyester and silanated rice straw-polyester composites have more enhanced thermal stability compared with composites filled by alkali-treated fibers or neat polyester. This enhancement in thermal stability was confirmed by measuring Tg. Actually, WPC composites filled by silanated bagasse and silanated rice straw fibers showed higher values of Tg than polyester or alkali treated fibers-polyester composites. Actually, enhanced mechanical and physical characteristics were achieved after filling polyester with silanated bagasse and silanated rice straw fibers. Consequently, the cheap eco-friendly WPC with their superior characteristics can be used in many industrial applications.