Handbook of Composites from Renewable Materials, Design and Manufacturing

Vijay Kumar Thakur, Manju Kumari Thakur, Michael R. Kessler, Vijay Kumar Thakur, Manju Kumari Thakur, Michael R. Kessler

• Publisher: Wiley-Scrivener
• Year: 2017
• ISBN:
  9781119224273
• Edition: 1
• Topic: Technik & Maschinenbau
• Subtopic: Chemie- & Biochemietechnik

This unique multidisciplinary 8-volume set focuses on the emerging issues concerning synthesis, characterization, design, manufacturing and various other aspects of composite materials from renewable materials and provides a shared platform for both researcher and industry.

The Handbook of Composites from Renewable Materials comprises a set of 8 individual volumes that brings an interdisciplinary perspective to accomplish a more detailed understanding of the interplay between the synthesis, structure, characterization, processing, applications and performance of these advanced materials. The Handbook comprises 169 chapters from world renowned experts covering a multitude of natural polymers/ reinforcement/ fillers and biodegradable materials.

Volume 2 is solely focused on the Design and Manufacturing of renewable materials. Some of the important topics include but not limited to: Design and manufacturing of high performance green composites; manufacturing of high performance biomass-based polyesters by rheological approach; components design of fibrous composite materials; design and manufacturing of bio-based sandwich structures; design and manufacture of biodegradable products from renewable resources; manufacturing and characterization of quicklime filled metal alloy composites for single row deep groove ball bearing; manufacturing of composites from chicken feathers and poly (vinyl chloride); production of porous carbons from resorcinol-formaldehyde gels: applications; composites using agricultural wastes; manufacturing of rice wastes-based natural fiber polymer composites from thermosetting vs. thermoplastic matrices; thermoplastic polymeric composites; natural fiber reinforced PLA composites; rigid closed-cell PUR foams containing polyols derived from renewable resources; preparation and application of the composite from alginate; recent developments in biocomposites of bombyx mori silk fibroin; design and manufacturing of natural fiber/ synthetic fiber reinforced polymer hybrid composites; natural fiber composite strengthening solution for structural beam component for enhanced flexural strength; high pressure resin transfer molding of epoxy resins from renewable sources; cork based structural composites; the use of wheat straw as an agricultural waste in composites for semi-structural applications and design/ manufacturing of sustainable composites.

Chapter 1
Design and Manufacturing of High-Performance Green Composites Based on Renewable Materials

Katharina Resch-Fauster¹, Andrea Klein¹, Silvia Lloret Pertegás² and Ralf Schledjewski^2*

¹Chair of Materials Science and Testing of Polymers,

²Chair Processing of Composites, Department Polymer Engineering and Science, Montanuniversität Leoben, Leoben, Austria

^*Corresponding author: [email protected]

Abstract

Fiber reinforced polymers offer high mechanical performance in combination with low weight. Besides conventional composites such as glass fiber reinforced petrochemical-based polymers, new concepts fully based on renewable materials are getting more and more attention. The present chapter delivers an overview about bio-based epoxy resin systems, discusses the challenge regarding curing and proposes an ecological approach regarding curing of bio-based epoxy resin systems. Furthermore, reachable mechanical performance of some bast fiber types is presented in more detail, effects of different processing routes are summarized, and high performance components based on renewable materials are discussed.

Keywords: Natural fibers, bio-resin, epoxidized hemp oil, resin curing, fiber strength, composite processing

1.1 Introduction

Already from the beginning mankind has learned to use materials delivered by nature. Combining materials to reach unique properties is something well known for a very long time. In modern times the knowledge about composite materials, how to select the right constituents and how to combine them to reach superior component properties is well developed. Bledzki et al., (2012), presents a good overview about the history of biocomposites. An early example is linoleum, a mixture of linseed oil, powdered cork and a natural fiber based backing. After more than 150 years linoleum is still a very important and widely used material (Schulte & Schneider, 1996). In the nineteenth and early twentieth centuries many different types of composites based on renewable sources have been developed and used in many different fields of application. One very important area is automotive applications. In 1941 Henry Ford demonstrated the mechanical performance of a rear deck lid by trying to crack it with a sledge hammer. This deck lid was made of paper and soybean resin. Based on the knowledge gained by using natural materials, synthetic materials have been developed and used more and more often. Polymeric matrix systems based on petrochemicals and reinforcing materials like glass fibers and carbon fibers are predominately used for composite materials today. In recent years, materials based on renewable sources, sometimes also called green composites, are getting more and more attention (Evans et al., 2002, Gurunathan et al., 2015; Koronis et al., 2013). Comprehensive reviews concerning biocomposites with a focus on lignin-based types have been published by the group around Thakur (Thakur & Thakur 2014; Thakur et al. 2014a,b).

Materials based on renewable resources do have several advantages. They are available all over the world. At the nova-Institut in Germany basic data is available (Raschka & Carus, 2012). Today, data collected for 2008, only 100*10⁶ ha of the 13.4*10⁹ ha total land area, i.e., less than 1%, is used for the production of renewable resources for material use. “Material use” means, the biomass serves as raw material for the production of all kinds of goods as well as their direct use in products, and excludes the use of biomass where it serves purely as energy sources (Carus et al., 2010). In total 1.65*10⁹ tonnes of biomass have been used in 2008 of which 26*10⁶ tonnes are natural fibers and 24*10⁶ tonnes are plant oils. Approximately 14% of these natural fibers, i.e., 3.6*10⁶ tonnes, are flax, hemp, jute, kenaf, sisal, and related fibers (Raschka & Carus, 2012). All these fibers are plant fibers (Figure 1.1), mainly bast fibers, only sisal is a leaf fiber.

Figure 1.1 Opposite to mainly uniform synthetic fibers, natural fibers are non-uniform and there final shape depends on treatment methods they have been applied to; depicted here are hemp fibers.

Joshi et al. (2004) summarized the reasons why natural fiber composites are environmentally superior as compared to glass fiber composites:

• Lower environmental impact during fiber production
• Typically higher fiber content if natural fibers are used (to reach comparable performance)
• Lower density results in better light-weight performance and reduces fuel consumption and emissions, for example, in automotive applications
• End of life incineration results in carbon credits and recovered energy

Although green composites cover a wide range of different materials, e.g. starch-based resins with feather-based reinforcement (Flores-Hernández et al., 2014) or spent coffee ground powder as reinforcement (García-García et al., 2015), this contribution is focusing on plant fiber reinforced composites. Bio-based epoxy matrix systems are of special interest.

1.2 Bio-Based Epoxy Matrix – State-of-the-Art

In today’s society, demand for environmentally-friendly yet well-performing products (and hence materials) is growing vigorously and consistently. Next to the employment of natural fibers, the production of resins based on renewable resources (plant oil) increasingly becomes the center of attention for researchers as well as (composite) manufacturing companies. Plant oils can be gained from numerous different origins, such as a wide range of cereal grains or seeds (Ebnesajjad, 2013). Typically the derived oil is a triglyceride, which means that it consists of glycerol combined with three fatty acids. The structure of the fatty acids is different from crop to crop and defines the property portfolio of the plant oil (Meier et al., 2007). In order to transfer the triglyceride to a polymerizable/hardenable substance, the fatty acids are functionalized. Since epoxy resins are well established in the electronics, aerospace and marine industries, among others (Vaskova et al., 2011), the most commonly used way of functionalization is the epoxidation of fatty acids. Generally, epoxidation of fatty acids requires the presence of double bonds in the plant oil. There are various methods of epoxidation; however, the most (industrially) frequently used option is the so-called conventional method (Baumann et al., 1988). Simplified, a carbox...