Multifunctional Polymeric Nanocomposites Based on Cellulosic Reinforcements

Debora Puglia, Elena Fortunati, José M. Kenny

• Publisher: William Andrew
• Year: 2016
• eBook ISBN: 9780323417396
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Multifunctional Polymeric Nanocomposites Based on Cellulosic Reinforcements introduces the innovative applications of polymeric materials based on nanocellulose, and covers extraction methods, functionalization approaches, and assembly methods to enable these applications. The book presents the state-of-the-art of this novel nano-filler and how it enables new applications in many different sectors, beyond existing products. With a focus on application of nano-cellulose based polymers with multifunctional activity, the book explains the methodology of nano-cellulose extraction and production and shows the potential performance benefits of these particular nanostructured polymers, for applications across different sectors, including food active packaging, energy-photovoltaics, biomedical, and filtration. The book describes how the different methodologies, functionalization, and organization at the nano-scale level could contribute to the design of required properties at macro level. The book studies the interactions between the main nano-filler with other active systems and how this interaction enables multi-functionality in the produced materials. The book is an indispensable resource for the growing number of scientists and engineers interested in the preparation and novel applications of nano-cellulose, and for industrial scientists active in formulation and fabrication of polymer products based on renewable resources. - Provides insight into nanostructure formation science, and processing of polymeric materials and their characterization - Offers a strong analysis of real industry needs for designing the materials - Provides a well-balanced structure, including a light introduction of basic knowledge on extraction methods, functionalization approaches, and assembling focused to applications - Describes how different methodologies, functionalization, and organization at the nano-scale level could contribute to the design of required properties at macro level

Chapter 1

Extraction of Lignocellulosic Materials From Waste Products

E. Fortunati, F. Luzi, D. Puglia and L. Torre, Civil and Environmental Engineering Department, UdR INSTM, University of Perugia, Terni, Italy

Abstract

The need to both avoid waste production and find new renewable resources has led to new and promising research based on the possibility of revalorizing the biomass producing sustainable chemicals and/or materials. This may play a major role in replacing systems traditionally obtained from non-renewable sources. Most of the low-value biomass is termed lignocellulosic, referring to its main constituent biopolymers: cellulose, hemicellulose, and lignin. Different extraction methods were optimized over the years for the extraction of these components from natural fibers and sources, and most of these techniques have been adapted for the extraction of lignocellulosic components from agricultural and forest wastes.

This chapter reviews the characteristics, applications, and especially, the extraction methods for lignocellulosic materials (cellulose, hemicellulose, and lignin), focusing on their advantages and drawbacks in terms of technical issues and environmental impact. Also reported and discussed are a number of recent advances developed in our laboratories.

Keywords

Agricultural wastes; forest wastes; raw materials; cellulose; lignin; extraction methods; green chemistry; sustainability

Contents

1.1 Introduction 1

1.2 Cellulosic-Based Material Structure and Properties 7

1.2.1 Methods for Cellulose-Based Material Extraction From Agro-waste Products 12

1.3 Hemicellulose Structure, Properties, and Applications 15

1.3.1 Hemicellulose Extraction From Agro-waste Products 18

1.4 Lignin Structure, Properties, and Applications 24

1.4.1 Methods for Lignin Extraction From Agro-waste Products 28

1.5 Conclusions 30

References 31

1.1 Introduction

Lignocellulosic materials are the most promising feedstock as they are natural and renewable resources essential to the function of modern industrial societies (Pérez, Muñoz-Dorado, de la Rubia, & Martínez, 2002). Lignocellulose is the term used to describe the three-dimensional polymeric composites formed by plants as structural material. It consists of variable amounts of cellulose, hemicellulose, and lignin, besides other minor compounds. The high heterogeneity of this feedstock mainly depends on its origin, but also on other less manageable factors related to growing, harvesting, and storage conditions. A considerable amount of such materials as waste by-products is being generated through agricultural practices, mainly from various agro-based industries (Pérez et al., 2002). Sadly, much of the lignocellulosic biomass is often disposed of by burning, a practice that is not restricted to only developing countries. Recently, lignocellulosic biomasses have garnered increased research interest and special importance because of their renewable nature (Asgher, Ahmad, & Iqbal, 2013). Therefore, the huge quantities of lignocellulosic biomass can potentially be converted into different high-value products, including biofuels, value-added fine chemicals, and cheap energy sources for microbial fermentation and enzyme production (Iqbal, Kyazze, & Keshavarz, 2013). In the last few years, the use and revalorization of lignocellulosic biomass have represented a strategic solution to reduce natural wastes. At the same time, the use of these materials has represented a significant reduction in the volume of wastes accumulated in soil after cultivation and the pruning of trees (Gencer, 2015), or accumulated on marine coastal regions by the presence of algae such as Zostera seagrass and Posidonia oceanica (Davies, Morvan, Sire, & Bale, 2007; Ferrero, Boronat, Moriana, Fenollar, & Balart, 2013; Fortunati et al., 2015; Khiari, Marrakchi, Belgacem, Mauret, & Mhenni, 2011; Puglia et al., 2014), thereby minimizing the creation of residues and the use of raw materials (Dos Santos et al., 2013). Every year more than 24 million tons of processed vegetable wastes are produced from the agro-food industry, generating an enormous amount of residues without any application or revalorization (Bayer et al., 2014). The biomass obtained from agro-food industries is composed of essentially cellulosic components. These materials are considered an important resource for the extraction of biofuels (Singh, Kuila, Adak, Bishai, & Banerjee, 2012), for other applications as a component to realize composites (Jamil, Ahmad, & Abdullah, 2006), or for the extraction of cellulosic nanostructures (Hsieh, 2013; Johar, Ahmad, & Dufresne, 2012) to use as the reinforcement phase in the production of biodegradable nanocomposites, as previously described in the literature (Battegazzore, Bocchini, Alongi, Frache, & Marino, 2014; Fortunati et al., 2012, 2015). Most of the agricultural lignocellulosic biomass is comprised of about 10–25% lignin, 20–30% hemicellulose, and 40–50% cellulose (Kumar, Barrett, Delwiche, & Stroeve, 2009). As just indicated, cellulose is the major structural component of plant cell walls, while hemicellulose macromolecules are often repeated polymers of pentoses and hexoses. Lignin contains three aromatic alcohols (coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol) produced through a biosynthetic process, and it forms a protective seal around the other two components (ie, cellulose and hemicelluloses; Calvo-Flores & Dobado, 2010; Menon & Rao, 2012).

In general, the composition of lignocellulosic material highly depends on its source, whether it is derived from hardwood, softwood, or grasses. Agro-industrial wastes are generated during the industrial processing of agricultural or animal products. Those derived from agricultural activities include materials such as straw, stem, stalk, leaves, husk, shell, peel, lint, seed/stones, pulp or stubble from fruits, legumes or cereals (rice, wheat, corn, sorghum, barley, etc.), bagasses generated from sugarcane or sweet sorghum milling, spent coffee grounds, brewer spent grains, and many others. These wastes are generated in large amounts throughout the year, and are the most abundant renewable resources on earth. They are mainly composed of sugars, fibers, proteins, and minerals, which are compounds of industrial interest. Due to their high availability and composition rich in compounds that could be used in other processes, there is a great interest in the reuse of these wastes, both from an economic and environmental point of view (Table 1.1). The management of these wastes effectively and economically must be given major priority to ensure not only a reduction of the detrimental impact of wastes on the environment, but most importantly, transformation of these wastes into useful raw materials, or the production of value-added products with industrial and commercial potential. Due to the large variations of the chemical compositions of agro-residues, especially polysaccharides and lignin, it is important to choose an appropriate method of biomass fractionation for their effective biotechnological utilization (Howard, Abotsi, Van Rensburg, & Howard, 2003). The cell wall consists of three main components: cellulose microfibrils (with characteristic distributions and organization), hemicellulose, and lignin. There are also smaller amounts of pectin, protein, extractives, and ash. The structure of these materials is complex, and native biomass is generally resistant to chemical and enzymatic hydrolysis (Saha, 2003). During dilute acid hydrolysis of agro-residues, parameters such as temperature, time, acid concentration, and solid-to-liquid ratio play critical roles in obtaining optimum sugar recovery and minimum generation of inhibitors (Taherzadeh & Karimi, 2007). Establishment of these parameters is fundamental to defining optimal conditions for hydrolysis to ensure the success of the process.

Table 1.1

Chemical composition of common agricultural residues and wastes

Types of biomass	Lignocellulosic substrate	Cellulose (%)	Hemicellulose (%)	Lignin (%)
Agriculture waste	Corncobs	45	35	15
	Rice straw	32.1	24	18
	Wheat straw	30	50	15
	Barley straw	33–40	20–35	8–17
	Corn stover	39–42	22–28	18–22
	Nut shells	25–30	25–30	30–40
	Swine waste	6	28	-
Energy crops	Empty fruit bunch	41	24	21.2
	Switch grass	45	31.4	12
Forestry waste	Hardwood stems Softwood stems Leaves	40–55	24–40	18–25
		45–50	25–30	25–35
		15–20	80–85	0
Industrial waste	Waste papers from chemical pulps	60–70	10–20	5–10
	Organic compound from wastewater solid	8–15	0	0

Source: Reprinted from Lee, H. V., Hamid, S. B. A., Zain, S. K. (2014). Conversion of lignocellulosic biomass to nanocellulose: Structure and chemical processes. Scientific World Journal. Article ID 631013, http://dx.doi.org/10.1155/2014/631013.

Moreover, the need to both avoid waste and find new renewable resources has led to a new and promising avenue of research: the use of food supply chain waste (FSCW) as a renewable biorefinery feedstock. FSCW could be defined as “the organic material produced for human consumption discarded, lost, or degraded, primarily at the manufacturing and retail stages.” Our food supply chain (FSC) has recently been recognized as being inefficient, producing large and accumulative quantities of waste. The European Union (EU) each year produces just under 90 million tonnes of food waste (FW), 38% of which is directly produced by the food manufacturing sector (Pfaltzgraff, De bruyn, Cooper, Budarin, & Clark, 2013).

In this scenario, the revalorization of different wastes from the agro-food industries (Fig. 1.1A and 1.1B), and the reuse of cellulosic sea wastes (eg, algae) (Fig. 1.1C and 1.1D) or agro-forest (wood and soft wood sources) (Fig. 1.1E and 1.1F) cellulosic wastes, represent a valid strategy for reducing petr...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Preface
• Chapter 1. Extraction of Lignocellulosic Materials From Waste Products
• Chapter 2. Production of Bacterial Nanocellulose From Non-Conventional Fermentation Media
• Chapter 3. Grafting of Cellulose Nanocrystals
• Chapter 4. Tensile Properties of Wood Cellulose Nanopaper and Nanocomposite Films
• Chapter 5. Nanocellulose-Based Polymeric Blends for Coating Applications
• Chapter 6. Multifunctional Applications of Nanocellulose-Based Nanocomposites
• Chapter 7. Nanocellulose-Based Polymeric Blends for Food Packaging Applications
• Chapter 8. Nanocelluloses as Innovative Polymers for Membrane Applications
• Chapter 9. Smart Nanocellulose Composites With Shape-Memory Behavior
• Chapter 10. Computational Modeling of Polylactide and Its Cellulose-Reinforced Nanocomposites
• Chapter 11. Nanocellulose Alignment and Electrical Properties Improvement
• Index