Biocomposites reinforced with natural fibers: 2000–2010

The use of natural fiber reinforcements for the production of ecofriendly composites has arisen considerable interest both in thermoplastic and thermoset based materials. In the latter case, the matrix is often an epoxy based polymer, which allows remarkable performance, but that cannot be considered eco-friendly since it is non-biodegradable and is produced from non-renewable sources. This strongly impairs the environmental friendly character of the resulting composite material. The aim of this work was to study the characteristics and performance of a thermoset bioepoxy resin, which is partly based on natural components, to be used in hemp reinforced laminates. The permeability of the hemp fabric as well as the rheological and thermal behavior of the resin were studied in view of their fabrication by resin infusion techniques. The results showed that laminated composites could be easily obtained with a vacuum assisted resin transfer molding process. Static, dynamic and vibration-damping tests were performed to evaluate limits and potentials of such biocomposites.

Composites with hemp reinforcement and bio-based epoxy matrix

In this project, free vibration testing and dynamic mechanical analysis methods were used to study the damping properties of noil hemp fibre-reinforced polypropylene composites with varying fibre contents (0 to 60 wt%) and compatibilizers (maleic anhydride-grafted polypropylene and maleic anhydride-grafted polyethylene octane) under applied frequencies of 1 to 200 Hz. The storage modulus of the composites was increased by the increase in hemp fibre content.
However, the maximum damping ratio was obtained from the composite with 30 wt% noil hemp fibre. The addition of coupling agents reduced the damping capacity of all composites. However, 30 wt% noil hemp fibre-reinforced polypropylene coupled with 2.5 wt% anhydride-grafted poly ethylene octane revealed the highest damping ratio among coupled composites. Damping properties of the composites were relatively constant over the frequency range, except at frequencies which the material–instrument system began to resonate and peaks were observed in the curves.

Vibration damping characteristics of short hemp fibre thermoplastic composites

Increasing scientific interest has occurred concerning the utilization of natural fiber-enhanced hybrid composites that incorporate one or more types of natural enhancement. Annual natural fiber production is estimated to be 1,783,965 × 103 tons/year. Extensive studies have been conducted in the domains of natural/synthetic as well as natural/natural hybrid composites. As synthetic fibers have better rigidity and strength than natural fibers, natural/synthetic hybrid composites have superior qualities via hybridization compared to natural composites in fibers. In general, natural fiber compounds have lower characteristics, limiting the use of natural composites reinforced by fiber. Significant effort was spent in enhancing the mechanical characteristics of this group of materials to increase their strengths and applications, especially via the hybridization process, by manipulating the characteristics of fiber-reinforced composite materials. Current studies concentrate on enhancing the understanding of natural fiber-matrix adhesion, enhancing processing methods, and natural fiber compatibility. The optimal and resilient conceptions have also been addressed due to the inherently more significant variabilities. Moreover, much research has tackled natural fiber reinforced hybrid composite costs. In addition, this review article aims to offer a review of the variables that lead to the mechanical and structural failure of natural fiber reinforced polymer composites, as well as an overview of the details and costings of the composites.

Critical Review of Natural Fiber Reinforced Hybrid Composites: Processing, Properties, Applications and Cost

Thin kenaf/polypropylene (PP) composite sheets were manufactured via extrusion. The effects of kenaf and maleated PP (MAPP) proportions, fibre length, PP melt flow index (MFI) and die temperature on tensile, flexural, in-plane and out-of-plane shear properties were analysed by conducting experiments through ‘design of experiments’ methodology. Higher kenaf content and lower die/barrel temperatures resulted in composite sheets with higher average mechanical properties in various modes of testing. Matrix MFI appeared to significantly affect all mechanical properties. It is interesting to note that the properties of the very short-fibre composites produced are comparable to those reinforced with longer discontinuous fibres and long-fibre mats.

Factorial study of material and process parameters on the mechanical properties of extruded kenaf fibre/polypropylene composite sheets

Static and Dynamic Properties of Thermoplastic Matrix/Natural Fiber Composites

Problems related to the recycle of conventional composite materials are becoming always more relevant for many industrial fields Natural fiber composites (NFC) have recently gained much attention due to their low cost, environmental gains (eco‐compatibility), easy disposal, reduction in volatile organic emissions, and their potential to compete with glass fiber composites (GFC) Interest in natural fibers is not only based over ecological aspects NFC have good mechanical performances in relation to their low specific weight and low price A characterization of mechanical properties, dynamic behavior, and moisture absorption is presented

W. Lorenzi

Papers

Static and Dynamic Properties of Thermoplastic Matrix/Natural Fiber Composites

Natural fiber or glass reinforced polypropylene composites