Lignocellulosic Composite Materials

Growing environmental concerns in recent years have led to finding new resources to replace the synthetic materials such as glass and carbon fibers in the development of polymeric and cementitious matrices-based composites. One such material is lignocellulosic fibers, due to their inherent characteristics such as abundant availability and renewability, low weight, biodegradability, interesting specific properties, etc. Studies have been carried out throughout the world in the utilization of these fibers particularly in the development of light weight, but high-performance composites. Some of their products are already in use in many applications. Although these fibers have been used even in sculptures or in arts in general, there is no report on the characteristics required for such applications. This chapter focuses on the exploration of these aspects particularly about the appearance of some plant fibers as well as their texture and potential use in polymeric sculptures or in arts. While doing so, the chapter will also present availability, methodologies used for the characterization as well as the reported properties (chemical, physical, mechanical thermal, electrical, environmental, and moisture absorption) of various Brazilian-based lignocellulosic fibers. It is hoped this will be applicable to fibers from other parts of the world to open up new areas of their utilization in a scientific manner enabling new value-added application for these agro-industrial byproducts, which may otherwise go waste.

The development of high-performance materials made from natural resources is increasing worldwide. Within this framework, natural fiber reinforced polymeric composites now experience great expansion and applications in many fields, ranging from the automotive to the construction sector. The great challenge in producing composites containing natural fibers and with controlled features is connected to the great variation in properties and characteristics of fibers. The quality of the natural fibers is largely determined by the efficiency of the treatment process and can dramatically influence the properties of the final composites. The overall fiber extraction processes, applied to vegetable fibers, is called retting and consists in the separation of fiber bundles from the cuticularized epidermis and the woody core cells. Today, many efforts are being made to optimize the retting methods in terms of fiber quality production, reduction of environmental issues and production costs. This chapter aims to provide a classification and an overview of the retting procedures that have been developed during years and are applied to extract mainly bast fibers.

The use of lignocellulosic fibers as reinforcement in polymer composites is attracting interest due to their properties such as mechanical properties and environmental benefits. Nevertheless, the hydrophilic character of lignocellulosic fibers reduces the compatibility with the hydrophobic matrices resulting in composites with poor mechanical properties. Therefore, in order to reduce the hydrophilic character of fiber and improve the fiber/matrix adhesion, is necessary to modify the fiber surface morphology. In this chapter, different lignocellulosic fiber treatments and the effect of these treatments on fiber properties as well as on composite mechanical performance were discussed. Even though chemical treatments are the most widely used, physical and biological treatments are environmentally friendly and promising alternatives.

Interest in the utilization of renewable resources is increasing because of depleting natural resources, environmental awareness and economic considerations. Natural fibre composites (biocomposites) have already attracted significant attention from the academic and industry (mainly automotive) fields. Natural fibres like kenaf, hemp, sisal, flax and jute have been the subject of extensive investigations for composite applications and therefore the focus of this chapter is on less common lignocellulosic fibres which are inexpensive and abundantly available at present. These fibres will be presented in terms of extraction methods, chemical, morphological, thermal and mechanical properties with a view to assessing their suitability as biofibres in composite applications. The introduction of these less common natural fibres in thermoplastic and thermosetting matrices is reviewed and compared with the traditional and much more common natural fibres, while the very last part of the chapter is dedicated to the development of cellulose-based nanocomposites, which is perceived as one of the most promising research fields related to lignocellulosic-based products.

Due to the biodegradability, renewability and important specific properties, the lignocellulosic fibres become a celebrity in the composite materials fields. This interest is essentially forms elements of the strategic outline of sustainable development and environmental respect. In this context, this chapter is obviously focused on thermoset composites reinforced by lignocellulosic fibres. We present in this chapter the different thermoset matrices and a deep depiction of lignocellulosic fibres from their morphological structures to their mechanical properties. Then, we present a review of the largest part of an eloquent work of literature that have paid attention to the exploration of the mechanical and rheological properties of composite lignocellulosic fibres and realm of application of this new category of materials.

Various kinds of plant natural fibers have been studied. Many of these are purposely grown for the fiber while some are derived from agricultural waste. A few types of plant natural fibers have been produced on a commercial scale. With various current problems facing us all today, the needs of plant natural fibers are even greater. There remains some fiber containing agricultural wastes which are underutilized. One of these is pineapple leaf waste. Pineapple leaf fiber (PALF) is known to possess high mechanical properties and can be obtained from pineapple leaf waste using different extraction methods. However, most of these methods are not suitable for large-scale production of the fiber for industrial uses. In addition, PALF produced with these methods is normally large in size, and this limits its applications. Recently, a novel method for the extraction of PALF has been presented. The method allows short and fine PALF to be produced. This PALF has diameter as small as 3 μm and with a cut length of 6 mm, the aspect ratio (length to diameter ratio) could be up to 2000. These characteristics make this PALF very suitable for the effective reinforcement of both plastics and rubbers. It will be demonstrated how to best utilize this PALF. This PALF could be surface treated or used in conjunction with compatibilizer or adhesion promoter as in other cellulose fibers. Recent progress will be presented and potential applications will be reviewed.

Wood composites are materials made by bonding together wood and adhesives into a large material that can be used for different purposes. Nowadays, lightweight materials play an important role in several industries: aerospace, building and furniture. The reduction of weight is desirable for economic reasons (materials and transportation costs) and environmental reasons (resources, eco-efficiency). Once wood composites are employed in these industries, low density is a desired property. There are several options in the market to reduce the weight of composites, such as the use of low-density wood species, lower compaction of the wooden mat, incorporation of light fillers in the core layer of the panel, or use of sandwich panels with honeycomb core. All these strategies have challenges with respect to manufacturing, machinability (connections and lamination of the edges) and performance (physico-mechanical properties).

Natural fibre is an emerging material that can help to reduce the dependency on non-renewable resources and sustains the ecological balance. This research focuses on the design and fabrication of a laptop table using kenaf fibre reinforced polymer composite. A composite portable laptop table was developed using standard design method and the manufacturing method used was hand lay-up. Market investigation, product design specification, conceptual design, detail design followed by fabrication were performed accordingly throughout this project. Stress distribution and deformation of the end product was tested using simulation software. This research has enabled to produce a strong, stable and aesthetic furniture which is made from composite material.

Cost-effectiveness, environment-friendly nature of lignocellulosic (LC) materials have been utilized for geotechnical engineering for value-added end uses, however, so far the efficacy of such LC materials has not been widely accepted by the engineers due to lack of their long-term durability. Durability of LC materials can be enhanced by altering fibre chemistry or by applying a degradation-resistant surface coating. This chapter will present an extensive overview of such potential processes for enhancement of durability of LC materials followed by a comprehensive discussion on designing and testing parameters of geotextiles and geocomposites using LC materials. A special emphasis has been given to erosion control system and stabilization of slopes using jute fibres as a potential LC material.

Current requests in the field of food packaging lead to the reasoned design of materials able to improve the global environmental balance of the food/packaging system by minimizing the negative environmental impact of the packaging material while improving its positive role in the food wastes and losses reduction that strongly impact our environment. This means to simultaneously control food degradation reactions while limiting undesirable migrations of additives from packaging towards in respect of our health and remaining economically competitive. The substitution of oil-based materials by ones issued from renewable and non-food resources (e.g. issued from bioconversion of agro-food wastes, for example) and furthermore, fully biodegradable in natural conditions is also a necessity and represents a significant breakthrough from the research in the field of food packaging. In this context, increasing attention is given to full-biocomposites, i.e. composite materials based on constituents all biosourced and biodegradable. Developing full-biocomposites for food packaging requires taken into account numerous factors, and this is even more important for complex biodegradable materials due to the gap in knowledge on their behaviour and potentialities in usage conditions. The objective of this chapter is to decipher the state of the art on full-biocomposites by considering the specific stakes relative to the food packaging application. After the first part of introduction, the second part will present the role of packaging to ensure food quality and safety and how it should be designed in such a way to reduce food waste and losses. The third part will present the window of mass transfer properties of full-biocomposites, which is the main functional property when considering the food packaging application. The fourth part will consider the economical competitiveness of full-biocomposites, the fifth part will treat the safety issues and the sixth of the different options of end of life and waste management.

In this chapter, an overview of various composites for sound absorption applications were reported. It includes composites made of a polymer matrix reinforced with synthetic fibres and natural fibres. New developments dealing with composites made of lignocellulosic fibre were discussed in detail and the merits and demerits of composite made of synthetic fibres and natural fibres have been discussed. In this chapter, procedures for estimating the sound absorption coefficients of various sound absorbing natural fibres were discussed with a mathematical model. Factors that may influence the sound absorption coefficients of porous materials, such as fibre size, porosity, flow resistivity, thickness, tortuosity and density were described. Empirical models to predict the flow resistivity and sound absorption coefficient were also discussed. This chapter also examines the critical issues and scientific challenges that require further research and development of polymer composite materials for their increased acceptance in the modern world for sound absorption purpose.