Lignocellulosic Fibers and Nanocellulose as Reinforcing Filler in Thermoplastic Composites (original) (raw)
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Composites Made from Lignocellulosics and Thermoset Polymers
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Composites made from a stryrene/unsaturated polyester thermoset matrix and woodflours from different wood species have been prepared and tested. Pine (Pino Eliottis), eucaliptus (Eucaliptus Saligna) and marmelero (Ruprechia Laxiflora), a softwood and two semihard woods respectively, were selected for this study because of the availability and local abundance. The particles were used untreated and chemically modified with maleic anhydride (MAN). Thermogravimetric analysis and analytical techniques were used in the characterization of untreated and treated flours. Dispersion of the fibrous particles, as well as maximum filler concentration (accompanied by complete wetting of the wood fibers) was dependent on the treatment and on the wood species utilized. Bending and compression tests indicated some improvement in the performance of the composites, if the woodflour was previously esterified. Scanning electron microscopy (SEM) allowed to observe changes in the fracture surfaces due to MAN treatment of the fibers.
SURFACE TREATMENTS OF LIGNOCELLULOSIC FIBERS IN THE PRODUCTION OF COMPOSITES FROM DIFFERENT MATRIXES (Atena Editora), 2024
Lignocellulosic natural fibers have been used in the production of composites, whether for reasons of lower production costs, good availability of natural fibers, environmental issues, among others. Improving the characteristics of the new material produced is generally achieved by combining the isolated physical and mechanical characteristics of each material. However, given the importance of ensuring good physical and mechanical properties of composites in industry, there is a need to increase adhesion between fibers and matrices to obtain more resistant and durable composites. Thus, the study aims to explore different surface treatment techniques to reinforce the adhesion between fibers and matrices, and to evaluate the effectiveness of these techniques, by comparing the results obtained with different types of composites with different fibers used as reinforcements. To this end, a bibliographical review was carried out, with the aim of obtaining information about natural lignocellulosic fibers, which are most used as reinforcement in composites, in addition to methods of extraction and processing of lignocellulosic fibers, as well as information about the chemical composition of fibers, physical and mechanical properties, such as density, tensile strength, modulus of elasticity, among others. Furthermore, the research investigates composites reinforced with and without fiber treatments. Surface treatments significantly improve adhesion between fibers and matrices, resulting in composites with better physical and mechanical properties than untreated raw fibers.
Journal of Materials Research and Technology, 2012
Environmental, economic, and technical reasons justify research efforts aiming to provide natural materials with possibility of replacing synthetic ber composites. Commonly known lignocellulosic bers, such as jute, sisal, ax, hemp, coir, cotton, wood, and bamboo have not only been investigated as reinforcement of polymeric matrices but already applied in automobile components. Less common bers, such as curaua, henequen, que, buriti, olive husk, and kapok are recently being studied as potential reinforcement owing to their reasonable mechanical properties. The relatively low thermal stability of these bers could be a limitation to their composites. The works that have been dedicated to analyze the thermogravimetric stability of polymer composites reinforced with less common lignocellulosic bers were overviewed.
BioResources
Wood flour (WF) of poplar, acid hydrolysis residue (AHR) of corn cob from xylose production, and cellulose fibers (CF) from bleached eucalyptus pulp were compared as functional fillers of lignocellulosic-plastic composites (LPC) in terms of tensile strength and thermal stability. WF showed a negative effect on tensile strength of LPC. AHR-filled LPC at 10% of filling level exhibited an improvement by 8.9%, whereas higher filling level led to a decrease of tensile strength due to poor interfacial compatibility, as revealed by SEM analysis. Remarkably, tensile strength achieved a maximum of 25.8 MPa for CF-filled LPC at 2.5% of filling level, which was an approximately 76.7% improvement compared to the control. Dependence of LPC thermal stability on chemical compositions of fillers was revealed. WF-filled LPC showed a lower onset decomposition temperature compared to the control due to the presence of xylan, while thermal stability of AHR-filled LPC was enhanced due to the presence of...
Alternative Solutions for Reinforcement of Thermoplastic Composites from : Natural Fiber Composites
2018
Natural Fiber Composites environmental advantages compared with traditional inorganic reinforcements and fillers. As a result of these advantages, natural fiber-reinforced thermoplastic composites are gaining popularity in automotives, garden decking, fencing, railing, and nonstructural building applications, such as exterior window and door profiles, as well as siding. The combination of interesting physical, mechanical, and thermal properties together with their sustainable nature has triggered various activities in the area of green composites. This chapter aims at providing a short review on developments in the area of natural fibers and their applications in fiber-based industries such as wood-plastic composites (WPCs). 3.2 CELLULOSE-BASED FIBERS 3.2.1 natural fibers Fibers can be classified into two main groups: man-made and natural. The term "natural fibers" is used to designate various types of fibers, which naturally originate from plants, minerals, and animals [1]. All plant fibers are composed of cellulose, hemicelluloses, and lignin whereas animal fibers consist of proteins (hair, silk, and wool). To clarify our case, the word "plant" might be cited as "vegetable," "cellulosic," or "lignocellulosic." Natural fibers offer the potential to deliver greater added value, sustainability, renewability, and lower costs compared with man-made fibers [2]. Plant fibers can be subdivided into nonwood fibers and wood fibers. Nonwood fibers can be classified according to which part of the plant they originate from. These include bast (stem or soft sclerenchyma) fibers, leaf, seed, fruit, root, grass, cereal straw, and wood [3]. Some of the important plant fibers are listed in Table 3.1 [4]. Agricultural residuals such as wheat straw, rice straw, bagasse, and corn stalks are also sources of natural fibers, although they have a lower cellulose content compared with wood [5]. Reddy and Yang [6] reported that velvet leaf (Abutilon theophrasti), which is currently considered a weed and an agricultural nuisance, could be used as a source for high-quality natural fibers. The fibers of the velvet leaf stem have properties similar to those of common bast fibers such as hemp and kenaf. The availability of large qualities of such fibers with well-defined mechanical properties is a general prerequisite for their successful use, namely in reinforcing plastics.
Polyethylene Composites with Lignocellulosic Material
Visakh/Polyethylene-Based, 2015
The aim of this chapter is to describe in detail the advances in polyethylene reinforced with lignocellulosic material. Indeed, the successful employment of natural based materials to reinforce/improve the properties of polyolefins has been growing in a wide range of applications. Firstly, basic concepts and terminology adopted in the lignocellulosic composite materials are reviewed. The objective is to bring the reader's attention to important issues that must to be taken into account when working in this subject as well as by providing the most appropriate references for those with interest to delve into the topic. In the context of polyethylenelignocellulosic composites, ongoing research is then summarised mainly focussing on (i) the main aspects related to the selection of the commonly used lignocellulosic materials and the potential of its main chemical constituents, (ii) the principal methods used for the improvement of interfacial adhesion and (iii) the main adopted processing routes and the composite properties. Finally, applications, new challenges and opportunities of these polyethylene-lignocellulosic composites are also discussed.
Natural Lignocellulosic Fibers as Engineering Materials—An Overview
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science
Recent investigations on the tensile properties of natural cellulose-based fibers revealed an increasing potential as engineering materials. This is particularly the case of very thin fibers of some species such as sisal, ramie, and curaua. However, several other commonly used fibers such as flax, jute, hemp, coir, cotton, and bamboo as well as less known bagasse, piassava, sponge gourde, and buriti display tensile properties that could qualify them as engineering materials. An overview of the strength limits attained by these fibers is presented. Based on a tensile strength vs density chart, it is shown that natural fibers stand out as a relevant class of engineering materials.
Effect of nanofillers as reinforcement agents for lignin composite fibers
Journal of Applied Polymer Science, 2000
Biobased nanocomposites and composite fibers were prepared from organosolv lignin/organoclay mixtures by mechanical mixing and subsequent melt intercalation. Two organically-modified montmorillonite (MMT) clays with different ammonium cations were used. The effect of organoclay varying from 1 to 10 wt % on the mechanical and thermal properties of the nanocomposites was studied. Thermal analysis revealed an increased in T g for the nanocomposites as compared with the original organosolv lignin. For both organoclays, lignin intercala-tion into the silicate layers was observed using X-ray diffraction (XRD). The intercalated hybrids exhibited a substantial increase in tensile strength and melt processability. In the case of organoclay Cloisite 30B, X-ray analysis indicates the possibility of complete exfoliation at 1 wt % organoclay loading.