Advanced polymer composites have obtained great application interest in a number of demanding aerospace, wind energy, automotive, infrastructure, and consumer applications. Great varieties of curing methods are investigated to develop low-cost and high-efficient fabrication of advanced polymer composites, which still remains as a great challenge and thorny issue. Especially, the autoclave curing process, which is widely used for curing of high performance advanced polymer composites, is labor- and capital-intensive, with costs increasing exponentially with part size and limiting increased use of advanced polymer composites. Researchers and industries have long desired to explore and develop low-cost and high-efficient curing methods for fabrication of advanced polymer composites and investigated different radiation and thermal curing alternatives. In this paper, current development status of the radiation curing (gamma ray, x-ray, ultraviolet, accelerated electron beams) and thermal curing (radiation heating (infrared, laser and microwave), convection and conduction heating (hot gas, flame, oven and hot shoe), induction heating, ultrasonic heating, resistance heating and thermal additives (magnetic particles, NIR absorbent particles) based heating methods applied for the curing of advanced polymer composites are reviewed. The curing mechanism and current application status of the different curing processes for fabrication of advanced polymer composites is discussed, and main advantages and disadvantages of these methods are comparatively analysed and evaluated according to the material, cost, feasibility and power criteria for successful curing application of advanced polymer composites.

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Natural fibers are increasingly being used as composite reinforcement for both thermoplastic and thermoset resin, mainly for automotive application. Due to their hydrophilic nature, natural fibers have certain limitations during composite manufacture especially owing to their poor resin wettability, weak fiber–polymer interface, high moisture absorption, and being affected by high temperature in case of thermoplastic resin. This work investigates the impact of sisal fiber modification techniques on moisture absorption, thermal, and mechanical properties of the fiber. Four sisal fiber samples were prepared; untreated, alkaline treated, acetylated, and a combined alkaline-treated/acetylation samples. The samples were evaluated for their hygroscopic nature, thermal stability, and tensile properties. It is found that acetylation resulted in a reduction of moisture absorption of sisal fiber as the acetylated and alkaline-treated/acetylated samples recorded a decrease of 42% and 28%, respectively. Alkaline treatment increased the absorbency owing to the removal of hemicellulose and lignin. The thermogravimetric result revealed that alkaline treatment improved the thermal stability as the alkali-treated and alkali-treated/acetylated samples showed improvement in thermal properties. The acetylated sample resulted in a significant reduction in tensile strength. But, the results from tensile tests of the alkaline-treated samples showed an insignificant decrease in tensile strength and improvement in the modulus for all treated samples. Fourier-transform infrared and scanning electron microscopic analysis were included in the study to supplement the results with structural and microstructural changes. The effect of those treatments on the sisal–PET composite properties was studied and will be submitted in part 2 of the study.

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A proposed modeling approach to calculate the mechanical properties of thermoplastic matrices reinforced with natural fibers is suggested. This model aims to solve the great deviation trends observed in the fiber content especially out of the range 10–40% volume fraction vf. The model considers the transfer of fiber load hand over from fibers pull out to fiber load bearing. Different cases of the matrices are studied. Namely, matrix with either elastic or elastic plastic behavior, matrix with either brittle or ductile failure strain in comparison with the reinforcing fiber. Length and orientation efficiency factors for stiffness and strength are exploited. Another factor describing the even distribution of the fibers and the amount of corresponding matrix in adhesion is developed. This factor gives insight to the compounding process. Experimental plan is carried out to investigate the fiber loading of 0–50% vf and different matrices namely polypropylene PP and maleated anhydride polypropylene MAPP. The suggested model is tested versus both the current experimental data and the literature results. The model shows good matching with the experimental results in a big domain of the fiber vf. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

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Rice straw is causing in many countries severe environmental problems in terms of black clouds caused by the incineration process. Hence, among other reasons, the incorporation of ground rice straw as a filler and reinforcement material for polymers is of advantageous. In this study, Egyptian rice straw was used to reinforce commercial polypropylene and laboratory prepared maleic anhydride-grafted PP with the fill grades between 5wt% and 30wt%. Rice straw PP composites show an improved Young's modulus at increased fill grades, against a decrease in tensile strength. The addition of 1% maleic anhydride per I g of rice straw as a compatibilizing agent caused further amelioration of the fiber/matrix bonding leading to improved mechanical behavior, which was also assessed using scanning electron microscopy. Additional assessments were made via thermographic analysis and density measurements.