Mechanical properties of a polyurethane hybrid composite with natural lignocellulosic fibers
TL;DR: In this article, a simplex-centroid mixture design model was used to evaluate the effects of the added fibers on composite properties such as resilience, elastic modulus and deformation under permanent compression.
Abstract: Several low-cost hybrid composites composed of polyurethane and renewable natural fibers were developed and analyzed for their mechanical and physical properties. Composites were fabricated by replacing up to 20% w/w of the polyethylene glycol present in conventional polyurethane foams with one and the mixture of three natural fibers: sugarcane bagasse, sisal or rice husk. Prior to composite production, fibers were mercerized with sodium hydroxide and hydrogen peroxide to remove lignin and hemicellulose. A simplex-centroid mixture design model was used to evaluate the effects of the added fibers on composite properties such as resilience, elastic modulus and deformation under permanent compression. Obtained hybrid composites demonstrated up to 32% of resilience, 0.1 GPa of elastic modulus, and 7.32% of permanent deformation. In order to optimize these properties, fiber amounts were adjusted using a quadratic mathematical model, indicating that formulations containing only the rice husk or an 82/18 (% w/w) rice husk/sugarcane bagasse mixture will perform best. The obtained composite is a unique low cost material because is environmentally friendly and has a high potential for applications in shock absorption and padding materials, due its proven good resilience and elastic modulus.
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TL;DR: The fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented.
Abstract: Polymeric foams can be found virtually everywhere due to their advantageous properties compared with counterparts materials. Possibly the most important class of polymeric foams are polyurethane foams (PUFs), as their low density and thermal conductivity combined with their interesting mechanical properties make them excellent thermal and sound insulators, as well as structural and comfort materials. Despite the broad range of applications, the production of PUFs is still highly petroleum-dependent, so this industry must adapt to ever more strict regulations and rigorous consumers. In that sense, the well-established raw materials and process technologies can face a turning point in the near future, due to the need of using renewable raw materials and new process technologies, such as three-dimensional (3D) printing. In this work, the fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented. Then, the strategies for the improvement of PUFs sustainability, including recycling, and the enhancement of their properties are discussed.
330 citations
Cites background from "Mechanical properties of a polyuret..."
...Others authors used cellulose and lignocellulosic fibers [138,139], egg shell wastes [140], date palm particles [141], walnut and hazelnut shells [142], or esparto wool [143], just to mention a few, as reinforcing materials in the production of PUFs, as will be discussed later....
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...Different types of fillers and nanofillers, such as cellulose and lignocellulosic fibers [138,139], glass wool, glass microspheres or glass fibers [180–182], egg shell wastes [140], date palm particles [141], walnut and hazelnut shells [142], and esparto wool [143], just to mention a few, can be used to improve the structural and mechanical properties of PUFs....
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TL;DR: In the recent decade, the growth of the natural fiber reinforced polymer (NFRP) composite has made a considerable impact on the polymer composite research and innovation as mentioned in this paper, and this rapid growth warranted their properties over low-cost synthetic fiber composites and reduced environmental impacts.
186 citations
TL;DR: In this article, the preparation, properties and prospects of flax fibres and its composites are discussed, and open issues and ideas for further improvement are also analyzed, and more emphases are given for the development of environment-friendly bio-inspired material.
145 citations
TL;DR: In this article, a composite of rigid polyurethane (PU) and hemp fiber (H.F) was used as reinforcement in the preparation of partially biodegradable green composites.
92 citations
TL;DR: In this paper, natural fiber-based materials are gaining a revival popularity to replace synthetic fiber in the composites in the recent trend and increasing awareness toward sustainable product design, and natural fiber based materials are becoming more and more popular.
Abstract: Owing to the recent trend and increasing awareness toward sustainable product design, natural fiber-based materials are gaining a revival popularity to replace synthetic fiber in the compos...
90 citations
Cites background from "Mechanical properties of a polyuret..."
...Several natural hybrid composites have been developed and the purposes are mainly to improve mechanical resistance (Aji et al. 2011; Otto et al. 2017; Shahzad 2011)....
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01 Jan 1963
TL;DR: In this paper, a sequence of procedures for identifying an unknown organic liquid using mass, NMR, IR, and UV spectroscopy is presented, along with specific examples of unknowns and their spectra.
Abstract: Presents a sequence of procedures for identifying an unknown organic liquid using mass, NMR, IR, and UV spectroscopy, along with specific examples of unknowns and their spectra,
11,753 citations
TL;DR: A comprehensive review of literature on bio-fiber reinforced composites is presented in this paper, where the overall characteristics of reinforcing fibers used in biocomposites, including source, type, structure, composition, as well as mechanical properties, are reviewed.
3,074 citations
TL;DR: A review of the literature on the various aspects of cellulosic fibres and biocomposites can be found in this paper, where the pros and cons of using these fibres are enumerated in this review.
1,908 citations
TL;DR: In this article, the thermal properties, crystallinity index, reactivity, and surface morphology of untreated and chemically modified fibers have been studied using differential scanning calorimetry (DSC), X-ray diffraction (WAXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), respectively.
Abstract: Plant fibers are rich in cellulose and they are a cheap, easily renewable source of fibers with the potential for polymer reinforcement. The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for reinforcement of polymeric materials. Hemp, sisal, jute, and kapok fibers were subjected to alkalization by using sodium hydroxide. The thermal characteristics, crystallinity index, reactivity, and surface morphology of untreated and chemically modified fibers have been studied using differential scanning calorimetry (DSC), X-ray diffraction (WAXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), respectively. Following alkalization the DSC showed a rapid degradation of the cellulose between 0.8 and 8% NaOH, beyond which degradation was found to be marginal. There was a marginal drop in the crystallinity index of hemp fiber while sisal, jute, and kapok fibers showed a slight increase in crystallinity at caustic soda concentration of 0.8–30%. FTIR showed that kapok fiber was found to be the most reactive followed by jute, sisal, and then hemp fiber. SEM showed a relatively smooth surface for all the untreated fibers; however, after alkalization, all the fibers showed uneven surfaces. These results show that alkalization modifies plant fibers promoting the development of fiber–resin adhesion, which then will result in increased interfacial energy and, hence, improvement in the mechanical and thermal stability of the composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2222–2234, 2002
1,396 citations