Materials produced and used in society are diverse and evolving. (For eg. there are approximately 75,000 chemicals now used commercially). Sustainable materials have a key role to play in a more sustainable world.
Two strategies have been identified to support a sustainable materials economy.
- A process known as dematerialization, involves developing ways to use less material to provide the same service in order to satisfy human needs.
- Detoxification of materials used in products and industrial processes.
The design of such materials is a component of the growing field of green chemistry, which links the design of chemical products and processes with their impacts on human health and the environment in order to create sustainable materials.
Some of the sustainable materials discussed below are – Bioplastics, Biopolymers, Sustainable chemicals, Sustainable paper and Sustainable wood.
Bioplastics are made from biopolymers which are living green cells. They are made from a compound called polyhydroxyalkanoate, or PHA. Bacteria accumulate PHA in the presence of excess carbon source. Poly 3-hydroxy butyric acid (PHB) is the most common microbial PHA.
There are two ways fermentation can be used to create biopolymers and bioplastics:
- Lactic Acid Fermentation- In this process, after the lactic acid is produced, it is converted to polylactic acid using traditional polymerization processes.
- Bacterial Polyester Fermentation- It is the process by which bacteria can be used to create polyesters. Bacteria like Ralstonia eutropha, Bacillus megaterium, Pseudomonas putida, Pseudomonas spp., Bacillus mycoides, Alcanivorax borkumensi, Rhodococcus ruber etc. use the sugar of harvested plants, such as corn, to fuel their cellular processes. The by-product of these cellular processes is the polymer. The polymers are then separated from the bacterial cells.
There has been recent commercialization of bio-derived plasticizers for polyvinyl chloride, polyester resins for coatings and inks, biopolyols for urethane foams and others based on vegetable oil and carbohydrate renewable sources.
Market status and growth
In 2009, world bioplastics production is heavily concentrated in the developed countries of North America, Western Europe and Japan. This will change dramatically by 2013 when Brazil will become the world’s leading producer of bioplastics. Bioplastics demand in Japan will advance nearly six fold to 178,000 metric tons in 2013. Furthermore, China plans to open over 100,000 metric tons of new bioplastics capacity by 2013, making that country a major player in the global industry.
The bioplastics market in Southeast Asia is in its nascent stage and in the preliminary development phase. The large population in this region provides an impetus to producers to explore opportunities here. Producers are encouraged by the huge market potential of the region, which primarily stems from the market's novelty and current low penetration in target applications. The market is expected to grow at a compounded annual growth rate of 129.8% in the next 5-7 years until 2015 as per a report by Frost & Sullivan.
For instance, Biodegradable plastics, such as starch based resins, polylactic acid and degradable polyesters, accounted for the vast majority (nearly 90 percent) of bioplastics demand in 2008. Double-digit gains are expected to continue going forward, fueled in part by the emergence of polyhydroxy alkanoates (PHAs) on the commercial market. However, non biodegradable plant-based plastics will be the primary driver of bioplastics demand.
According BCC research, the market for biodegradable plastics reached 541 million pounds in 2007, and is expected to reach 1.2 billion pounds by 2012.
A claim that a biodegradable, environmentally friendly product can replace almost all plastics definitely gets attention, but must be taken with a grain of salt. The bioplastics industry is advancing technologically and continues to increase its share of the plastics market, yet it still has an insignificant market share and substantial issues to resolve. Regardless, few would fault an industry with such capacity to benefit the environment for setting ambitious goals.
While production of most bioplastics results in reduced carbon dioxide emissions compared to traditional alternatives, there are some real concerns that the creation of a global bio-based economy could contribute to an accelerated rate of deforestation if not managed effectively.
There are associated concerns over the impact on water supply and soil erosion. There are also fears that bioplastics will damage existing recycling projects.
One of the major problems for biopolymers development is related to their cost. Even if according to European Bioplastics Association biopolymers prices are decreased 5 times in the last 10 years, Biopolymers prices are still high. They could be estimated today between 1.3 and 4 Euro/kg.
Bio-based and biodegradable plastics are a very promising innovation for both industry and the economy. The entire value added chain is involved:
Cultivation of renewable raw materials
Use of products such as agricultural film (mulch film), packaging (agricultural products) composting in organic farming (fertilizer substitute).
- Biotechnology, chemical and plastic-producing industries:
Manufacture of monomers, additives und polymers
- Plastics-processing industry:
Manufacture of semi-finished and finished products
- Sales and marketing
- Users in both food and non-food sectors (brandowners)
- Disposal and recovery
Biodegradable polymers are a growing field. A vast number of biodegradable polymers have been synthesised or are formed in nature during the growth cycles of all organisms. Some microorganisms and enzymes capable of degrading them have been identified.
Depending to the evolution of the synthesis process, different classifications of the different biodegradable polymers have been proposed. Figure 1 shows an attempt at classification. We have 4 different categories. Only 3 categories (1 to 3) are obtained from renewable resources:
1. Polymers from biomass such as the agro-polymers from agro-resources (e.g., starch, cellulose),
2. Polymers obtained by microbial production, e.g., the polyhydroxy-alkanoates,
3. Polymers conventionally and chemically synthesised and whose the monomers are obtained from agro-resources, e.g., the poly (lactic acid),
4. Polymers whose monomers and polymers are obtained conventionally, by chemical synthesis.
We can also classify these different biodegradable polymers into two main families: the agro-polymers (category 1) and the biodegradable polyesters (categories 2 to 4).
The current state of Biopolymers and their potential future
Non-biodegradable plastics and polymers have become the material of choice in the modern world, and there is evidence of vigorous R&D activities to discover, develop, and commercially produce degradable biopolymers to replace them. But the reality is that biopolymers are still in the early stages of development and considering them as an alternative for the current commercial products is too improbable. Because biopolymers originate from plants, they can be utilized in sectors where they come in contact with the human body, such as personal hygiene/grooming, cosmetics, medical implant/devices, textile, and food markets.
The use of plastics in our everyday life is nearly boundless. Due to its low cost of production and versatility, no alternate emerging product is likely to replace the nearly ubiquitous presence of plastics. The current global production level is about 250 million tons and its growth will continue to be robust globally. Plastics are preferred as they are light, durable, resist deterioration, and the markets they cater to are extensive: food, textiles, furniture, electronics, vehicle parts, photography/videography, coatings, construction, enclosures, bottles/containers, and many more.
The most commonly used types of plastics are PO, PP, PS, PVC, PET, PC, PET, PU, polyacrylates, polyvinyl acetates, and polyamides. These synthetic polymers are typically made from the naphtha fraction of petroleum or natural gas; and are heavy pollutants as they are not biodegradable. We are living in a "throw away" society and as a result, millions of tons of plastics end up in landfills, the ocean, and the shores. Even if this practice were to stop today, plastic waste would continue to wash upon our shores for hundreds of years. This has significantly eroded the marine life, as millions of marine animals die each year; and there is clear evidence that this trend will escalate because the global thirst for these materials is on the rise.
Burning plastic wastes has not been an option either, as toxic gases such as hydrogen cyanide and hydrogen chloride are emitted. Attempts to accelerate biodegradation via additives such as chemicals, oxygen, and UV additives have not resulted in meaningful measurable reduction.
Thus, there is a dire need for the discovery of totally biodegradable polymers and it is not surprising to see that biotechnology has been the global focus. Biotechnology has been referred to as a series of enabling technologies that involve the applications of organisms to manufacturing and service industries to achieve environmental sustainability and stability. Touted as the major technology of the 21st century, one can observe that biotechnology is highly multi-disciplinary, since it umbrellas many scientific fields such as biology, microbiology, biochemistry, molecular biology, genetics, chemistry, chemical engineering, and biomedical engineering.
The total sunk-in capacity for biopolymers in 2009 was around 500 million lbs. These include polylactide acid [PLA] (NatureWorks, Galactic, Hycail BV); polyhydroxyalkanoates such as PHAs, PHB, and PHBH (Biomer, Procter&Gamble); polymers based on bio-based PDO (DuPont); cellulose polymers (Innovia Films); epoxy polymers from bio-glycerol; and starch polymers and blends (AkzoNobel [National Starch Chemical] and several other players). NatureWorks (Cargill Dow) is the major commercial player with a PLA capacity of 280 million lbs; and Novamont is the major producer of starch polymers and blends, with a capacity of 120 million lbs.
The total capacity of biopolymers is expected to reach 1.3 billion lbs, if Braskem's 400 million lbs/year of bio-polyethylene production and Braskem's/Nova Zymes's 400 million lbs/year of bio-polypropylene production materializes in Brazil. At these levels, the biopolymer's share of the total global production of synthetic polymers will be a meager 0.26%! If biopolymers were to replace all of the polymer products, the amount of biopolymer production would need to put a strain on our planet's ecosystem and require massive deforestation.
While the current R&D efforts look promising due to advances in bacterial and plant sciences, the reality is that the development of biopolymer products is in its infancy stage due to challenges involved in developing a truly biodegradable product. Finding the right bacterial system and then developing a process for commercial readiness is not a simple, but a daunting task.
Plant-based biopolymers are based on green sources and typically cost more in energy and processing than conventional polymers. Government subsidies, tax credits, and other incentives provided to farmers and end-users further obscures the real cost of production.
Although PLA was known as the first commercially available synthetic "biodegradable" polymer, it is now recognized as a "compostable" polymer (heat and moisture are needed to degrade it).5 In addition, infrared sensor devices are required to sort out PLA from other wastes. The portion of biopolymer waste in landfills is infinitesimal. Having waste management try to find biopolymer waste from a colossal pile of garbage is like finding a needle in a haystack. The current amount of plastics, glass, and paper that is recycled is small and most of these used products end up in landfills. One can expect the same trend for biopolymer wastes, and given that they would not undergo total biodegradation without heat and moisture, these products would also contribute to creating more landfills. Until a truly biodegradable product is developed, governments will need to improve public awareness and increase efforts for recycling/appropriate waste management from its current state. Germany has taken a lead towards this effort.
Also PLA and other biopolymers compete with bio-ethyl acetate and other bio fuels such as bio-ethanol and bio-diesel, which are also made from the same natural sources of corn, sugarcane, etc. These sources are the backbone of our food industry. Even if biopolymer production currently contributes only minimally towards food scarcity and its increase in costs, the potential to eventually further limit lands for food production will continue to raise public debate.
There are also other factors. Cultivation of land for biopolymers makes the land unavailable for other food crops, forcing the need for deforestation. Another issue is that bio-products, like food products, are at the mercy of Mother Nature. Just as floods, droughts, and unpredictable seasonal variations can impact the supply of crops for food, these environmental factors could impact the stability of biopolymer production as well. Finally, the environmental costs to convert marginal land into a fertile farm for production of corn or sugarcane is excessive, and involves the use of large amounts of agricultural machines (tractors, harvesters, tillage equipment, grinders, choppers, etc.) which are based on diesel, fuel, and gas. In addition, expensive chemical fertilizers are used to increase the harvest yield and frequency of harvests each year.The use of diesel, fuel, and gas will create more greenhouse gases; and the use of chemical fertilizers will reduce the organic matter of soil, further contributing to greenhouse gas emissions.
The inter-twining dichotomy of bio- and food products competing for the same resources, coupled with politically driven green initiatives has distorted the intrinsic potential value of biopolymers. Although these arguments are valid, they fail to highlight the potential niche for the biopolymer market.
No one can predict the future with certainty. When Dr. Kary Mullis, the 1993 Nobel Prize winner for his invention of the Polymerase Chain Reaction (PCR), was asked about the long term prediction on the future of his technology, he replied, "Who the hell knows?" The same response could possibly be given regarding the future of biopolymers.
However, by peeling away the misinterpretations, one will find that biopolymers potentially have an important role in shaping the future of the personal hygiene/grooming, cosmetics, medical implant/devices, textile, and food sectors, but are not substitutes for the conventional polymers that dictate our current way of living.
Biochemicals are chemicals produced from organic sources known as biomass. They are sometimes called bio-based chemicals, green chemicals, and plant-based chemicals, chemicals from biomass and biomass chemicals. It is expected that bioderived chemicals will come from three sources: direct production using conventional thermochemical and catalytic process, biorefining, and expression in plants.
Status and growth
A recent report (C&News, 2009) estimates over $100 billion of the current global chemicals market, about 3% (i.e., €51bn-77bn ($61bn-93bn)) are derived from either bio-based feedstock or fermentation or enzymatic conversion or combination of them. This report projected that the share of bio-derived chemicals would grow to about 15% of global chemical sales by 2025.
There are several drivers for the interest and growth of bio products in the marketplace. A few that are worth mentioning include the availability of cost effective technologies including novel functional building blocks and improved processes, concerns about long term sustainability and price volatility of fossil-based feedstock, a more benign footprint on the environment, and consumer interest in green products and public policy.
Many large and established chemical and biotechnology companies as well as numerous smaller startup and venture companies are actively involved in the development and commercialization of bioproducts from a variety of renewable biomass sources. For example, many chemical companies are teaming up with biotechnology companies to develop products based on biochemicals.
Cargill Dow currently makes polylactic acid from corn kernels but has plans to switch to cheaper feedstocks, such as corn stalks, wheat straw, rice hulls, and sawdust, so that biochemicals can be more competitive in the marketplace. Genomatica, a San Diego based producer of chemicals from renewable sources including sugar, raised $45 million in a new round led by VantagePoint Venture Partners, a fund that has committed $2.5 billion to cleantech.
Current research is also focused on developing genetically modified microorganisms for use in specific chemical productions. Asian countries like China, Singapore, Korea and others increase their investments every year to find their position and try to lead some developments.
The alcohol segment holds the largest market share, while the polymers segment is expected to have the highest growth rate due to the increasing applications of bio-polymers in the manufacture of biodegradable and compostable plastics and in consumer goods such as cell phones and laptops.
Sustainable paper & wood
Over the period 1980 to 2007, global wood consumption has been essentially stagnant, increasing by only 0.4% per year. In contrast over the same period, global consumption of wood products increased steadily, paper by an average 3.2% per annum and solid wood products (sawn timber and wood panels) by 0.8% per annum.
Wood and paper-based goods produced in a sustainable manner are at high need because:
- They come from a renewable resource –trees, the product of sunlight, soil, nutrients and water.
- They capture carbon – through photosynthesis, trees take carbon dioxide out of the atmosphere and replace it with oxygen, mitigating greenhouse gas emissions. In sustainably managed forests the carbon released through harvesting is offset by that stored through regeneration and regrowth, making these forests carbon neutral.
- They store carbon over the long term –solid wood, panel and other wood and paper-based products can effectively store carbon for decades or even centuries.
- They are recyclable – they can be reused, or converted into other products, extending their useful life and adding to the available resource pool of wood fiber.
Demand for sustainable paper products is on the rise worldwide as consumers increasingly switch to recycled paper or paper produced from sustainable resources in an effort to reduce their overall carbon footprint. Currently the global demand for ‘green’ paper is estimated to be around 16.8 million tonnes. This is set to grow at a CAGR of 6.6 % to reach 24.8 million tonnes by 2016.
Opportunities in the sustainable paper industry are exposed to Papermaker, Pulp manufacturers Raw material suppliers Equipment/Machinery manufacturers, Printers, Publishers, Sustainability organizations, Industry consultants and analysts.
Many leading publishers and printers in the US are increasing the recycled paper content of books to around 30 per cent, as part of an industry-wide move towards more sustainable and responsible development.
Wood finds its use in industries such as in building and construction, energy supply etc., For example, cork extracted from cork oak tree, is being currently used mainly in the bottling and interior decorating product applications. The reserves of the cork are increasing at a steady rate due to the growth of the cork plantation establishments. Though this fact is at odds with various wine manufacturers who need a reason to switch to alternate capping methods, the industry growth is profound and undeniable.
The future of cork, and the growth of the industry, is open to one’s imagination. The use of cork in the bottling industry will undoubtedly remain strong due to the “enthusiast” belief that cork is better than plastic or screw tops. For interior use, cork use will also grow, especially with the increase awareness in “sustainable” and “green” construction techniques, the desire for people to decrease toxins in indoor environments, and the life-cycle benefits afforded cork interior products.
Other sustainable materials in building and construction are: Icestone Tile, Maplex, Organic Concrete, Kirei Board,etc.
Woodfuel is a broad term covering the direct use of wood in cooking and heating, the use of charcoal (both for households and for industrial uses) and also recovered wastes in wood-using industries.
The demand for energy is rapidly increasing, but wood resources are finite. What was once regarded as a family business, i.e. the free gathering of fuelwood for daily needs - has rapidly become a major policy issue with far-reaching ramifications on vital social, economic and environmental sectors. Satisfying current and future wood-energy demand requires sound planning of the wood-energy sector and careful management of the resources in a perspective of economic and environmental sustainability.
Asia accounts for about 44 percent of all wood fuel use, Africa about 21 percent and South America and the Caribbean about 12 percent. In developing countries woodfuel makes up about 80 percent of total wood use and in a few countries it is almost the sole use of wood. Africa is the region where wood fuel plays its most critical role. Compared to other regions, Africa has by far the highest per capita consumption of wood fuel.
In addition to fuel wood, charcoal and solid fuel mixtures that include wood in one form or another, new wood energy technologies of outstanding potential for sustainable development are now emerging in developed and developing countries alike. They include wood-fired combined heat and power (CHP) systems and decentralized power plants that provide competitive and reliable electricity for household and other uses on a village scale, at a cost broadly comparable with that of unsubsidized grid power.