1
High-performance Materials from Bio-based Feedstocks: Introduction and Structure of the Book

Kaewta Jetsrisuparb1, Jesper T.N. Knijnenburg2, Nontipa Supanchaiyamat3 and Andrew J. Hunt3

1 Department of Chemical Engineering, Khon Kaen University, Khon Kaen, Thailand

2 International College, Khon Kaen University, Khon Kaen, Thailand

3 Materials Chemistry Research Center (MCRC), Department of Chemistry, Centre of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand

1.1 Introduction

The overexploitation of the Earth's resources over the last century has led to a decrease in natural resources, a loss of natural habitat, climate change, and degradation of the environment, resulting in the extinction of several species [1]. The recovery of global economics after COVID-19 is also driving lifestyle changes, leading to increased high-performance materials production. As a result, a large number of nonrenewable resources are being utilized, which inevitably contributes to the generation of waste and may lead to detrimental effects to both environment and health. In addition, the scarcity of fossil resources and finite elements with potential global supply chain vulnerabilities are global concerns. Concerns over the supply of natural resources and potential damage to the environment have compelled governments to implement policies that mitigate the risk of further damage. The formation of the World Commission on Environment and Development (WCED) in 1983 and their report called "Our Common Future" in 1987 (also called "Brundtland report") was one of the catalysts for the move toward a sustainable future for humankind [2]. The definition of sustainable development is the development that "meets the needs of the present without compromising the ability of future generations to meet their own needs" [3]. Importantly, sustainability is a complex balance between societal, economic, and environmental needs, where this must be achieved in unison [4]. Implementation of a bio-based circular economy including minimizing the waste by recycling materials and utilization of replenishable resources is key to sustainable development.

Historically, chemistry goes hand in hand with innovation, thus promoting a positive image of this industry. However, the perception of the industry can be tarnished with media reports of life-threatening accidents and environmental pollution [5]. Anastas and Warner pioneered the concept of green chemistry, "the invention, design and application of chemical products and processes to reduce or to eliminate the use and generation of hazardous substances" [6]. Today, green chemistry is recognized and widely accepted to pursue sustainable development. The 12 principles of green chemistry (stated next) are regarded as a blueprint for achieving the aims of green chemistry. Moreover, green chemistry can aid in the development of sustainable bio-based chemicals and importantly also high-performance materials.

The 12 principles of green chemistry as stated by Anastas and Warner [6] are:

1. Prevention

   It is better to prevent waste than to treat or clean up waste after it has been created.

2. Atom Economy

   Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.

3. Less Hazardous Chemical Syntheses

   Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.

4. Designing Safer Chemicals

   Chemical products should be designed to effect their desired function while minimizing their toxicity.

5. Safer Solvents and Auxiliaries

   The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used.

6. Design for Energy Efficiency

   Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.

7. Use of Renewable Feedstocks

   A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.

8. Reduce Derivatives

   Unnecessary derivatization (use of blocking groups, protection/deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible because such steps require additional reagents and can generate waste.

9. Catalysis

   Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

10. Design for Degradation

    Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.

11. Real-time Analysis for Pollution Prevention

    Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.

12. Inherently Safer Chemistry for Accident Prevention

    Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires. [6]

By examining the 12 principles of green chemistry, the use of waste biomass and bio-based products to produce high-performance materials is in agreement with the seventh principle, which encourages the use of renewable feedstocks. The utilization of renewable resources has an added benefit as they can potentially lead to the development of carbon-neutral products.

According to the Kirk-Othmer Encyclopedia of Chemical Technology, bio-based materials refer to "products that mainly consist of a substance (or substances) derived from living matter (biomass) and either occur naturally or are synthesized, or it may refer to products made by processes that use biomass" [7]. Strictly speaking, this also includes traditional materials such as paper, leather, and wood, but these traditional uses are outside the scope of this book. It is important to note that bio-based materials are different from biomaterials (which involve biocompatibility), and being bio-based does not always mean the material will be biodegradable or safe.

The use of bio-based materials seems to be an appropriate approach to minimize the negative impact on the environment while harnessing the unique properties they offer. The development application of high-performance advanced bio-based materials through green synthetic approaches (i.e. application of the 12 principles of green chemistry) can aid in developing sustainable circular economies, while still minimizing environmental impacts. High-performance bio-based materials can be applied in catalysis, energy materials, polymers, medical devices, and even construction materials to name but a few.

A significant source of biomass which is ripe for exploitation into high-performance materials comes in the form of waste or agricultural residues. These include residues from food (e.g. corncob, sugarcane bagasse, rice husk, rice straw, and wheat straw) and non-food production (e.g. cellulose and lignin), forest residues, industrial by-products (e.g. ashes from biomass power generation), animal wastes (e.g. manure) as well as municipal wastes [7, 8]. These resources offer a complex mixture of polymers, inorganics, and chemicals, which can include but are not limited to polysaccharides, lignin, proteins, and ash, all of which are attractive alternative feedstocks to replace nonrenewable fossil-based resources. Exhaustion of fossil fuels and other finite resources is a driver for bio-based materials for high-performance applications. The structural diversity of biomass constituents and their unique properties are also promising for new applications including high-performance products.

Despite the great potential, some of the biggest challenges in using biomass as feedstock for high-performance applications are its heterogeneity, seasonal variation, and complexity regarding separation. In many cases, biomass needs to undergo some form of processing prior to being used as high-performance materials. Typically, the processing of biomass can be performed using chemical, biochemical, and thermochemical processes. These challenges are being tackled as part of the growth in holistic biorefineries, and such approaches that generate no waste are vital for maximizing the value of biomass.

However, unlike petrochemical feedstocks that require significant functionalization, bio-based feedstocks are blessed with an abundance of functionalities. As such, the development of high-performance materials from biomass requires different chemistries compared to those from fossil resources. The benefits of biomass utilization for industrial-scale production of high-performance materials are that they can potentially reduce waste and production costs, in addition to being carbon neutral, low cost, versatile, and renewable.

1.2 High-performance Bio-based Materials and Their...