Renewable materials

The fermentation industry is based almost exclusively on renewable materials in the form of molasses, starch, etc. Most products are of very high value and relatively low volume such as antibiotics (qv) (23). 

Although chemistry as an emperical fundamental didpline has a long history, its application in industry gained importance after the introduction of the use of fossil energy sources during the industrial revolution. The chemical industry withdraws non-renewable materials, mainly fossil oil, from the earth s reserves to use as an energy source and as fossil oil a source of raw materials for production processes. The products so produced are rather... 

Additionally, corn cobs correspond to an abundant and low-cost renewable material in several coimtries worldwide and their recycling plays a very important role in the reduction of waste products. Consequently, such approach would lead to a relevant increase in the sustainability of agriculture around the world. 

Guhathakurta et al. reported the use of waste natural gum (Bahera) as a MFA in NR and brominated isobutylene-co-paramethyl styrene (BIMS) [38]. The authors found that this renewable material not only acted as an accelerator activator but also as an antioxidant. 

Starch and cellulose are potentially important renewable resources for chemical production. Glucose (a component of starch) is relatively easy to obtain from plant material and is used to synthesize existing chemicals. While this is so, the production of such renewable materials, a full fife-cycle assessment of the requirements for their production suggest that much fossil-soiuced energy and material would stiU be employed in the growing, harvesting and processing of biomass. 

As an example of good choice of starting materials, NEC were interested in making wide use of biopolymers instead of petrochemically derived plastics and composites in their consumer electronics. There is a desire to use renewable materials to reduce reliance on non-renewables and to avoid the predicted rising cost of petrochemically derived materials. A range of biopolymers already exist, but they lack the performance required for products such as mobile phones, portable entertainment devices and mobile computers. 

The expected contribution of catalysis in this area will derive both from the availability, at low processing costs, of new monomers obtained from biomasses and from the development of an optimized combination of biotechnology processes with classical and new biocatalytic processes. Research priorities for catalysis in the area of polymers from renewable materials for packaging, furniture, domestic water purification and recycling include the need to develop novel catalysts, e.g., for functionalization of polymeric and dendrimeric materials, with side-chain photoactive molecular switches (to be used as smart materials), or the development of multifunctional materials, combining, for example, nanofiltration with catalytic reactivity. 

The challenge for mankind in the 21st century is to design our industrial processes so that they become integrated with natural metabolic processes. This is why the study of renewable materials is becoming so important. 

Timber can be viewed as a classic renewable material. Trees absorb carbon dioxide and utilize water and sunlight to produce a material that can be used in construction, to produce paper or to provide chemical feedstocks, with the production of oxygen as a byproduct. Furthermore, at the end of a product life cycle, the material constituents can be combusted, or composted to return the chemical constituents to the grand cycles . In essence, timber use represents a classic example of a cyclic materials flow, mimicking the flows of materials through natural cycles. Provided that we manage our forests well and do not harvest beyond the capacity of the planet to provide timber, we have at our disposal an inexhaustible resource available in perpetuity. 

The purpose of this chapter is to briefly consider the environmental credentials of timber utilization and the changes that are now affecting the way in which timber is used. It is not intended to comprehensively cover the topic, which would require an entire book, but it serves to outline the case for timber as a renewable material and to illustrate how environmental considerations are changing the way in which the material is being used. In particular, the use of wood preservatives, which have ensured that this renewable material has continued to remain competitive against nonrenewables, will be discussed. Finally, the importance of wood modification as an emerging technology will be briefly considered. 

The replacement of timber products by nonrenewable materials is an unfortunate development, since it has been repeatedly shown that the use of timber does have associated environmental benefits compared with the use of nonrenewables (e.g. Marcea and Lau, 1992 Hillier and Murphy, 2000 Bowyer etal., 2003 Lippke etal., 2004). Timber has a lower embodied energy content (and hence a more favourable carbon emission profile) compared to most other building materials and can provide other benefits, such as improved thermal properties. It and the products made from it (in common with other renewable materials) can be used as a repository for atmospheric carbon dioxide. Wood is derived from a renewable resource, albeit potentially an exhaustible one unless it is managed correctly. Disposal of wood can be readily achieved with little environmental impact (subject to how the wood has been treated prior to disposal). 

Renewable raw materials are made or derived from short-term renewable sources (one to a few years or a few tens of years) such as plants, trees, wood wastes and other agricultural products. Not all these materials are necessarily biodegradable. Natural rubber, for example, comes from the latex of a tree (Hevea brasiliensis) and is not biodegradable. Renewable materials are often considered as opposites to fossil sources such as petroleum that are not renewable on a human timescale. On the other hand, some synthesized plastics such as certain polyesters are biodegradable. 

Blends of polymers from renewable resources with Ecoflex (see Fig. 4), however, show very beneficial properties with respect to processability and mechanical characteristics. Thus, Ecoflex is used as a performance enabler for biopolymers, making it possible to apply bio-based polymers to a certain extent in applications for which the pure renewable materials are not suitable. 

In the last few years, biodegradable polymers like PLA have been established in different nonbiodegradable applications. PLA is processed into fibers (e.g., for textiles) or is used for durable parts in electronics. The driver for these applications is the content of renewable materials and not the polymer s biodegradability. 

Moreover, telomers of glycerol or saccharides, i.e. made from renewable materials, can be used for biodegradable applications. Owing to their skin- and eco-friendli-ness, they have potential interest as additive in the cosmetic industry. Alternatively, telomers of polysaccharides might find applications in the paper industry. 

Basic research areas related to enzymatic processing of renewable materials include ... 

The integrated processing of renewable materials can lead to the generation of a wide range of products. Some examples of known and potential biorefinery products are [4] ... 

Vigneshwaran et al. (2006) s mthesized stable silver nanoparticles by using soluble starch as both the reducing and stabilizing agents. The use of environmentally benign and renewable materials like soluble starch offers numerous benefits of eco-friendliness and compatibility for pharmaceutical and biomedical applications. 

Based on the Renew materials, a system of instant shelter - From Shelter to House to Home - for the homeless everywhere is currently being designed by the RUBACON architectural design team. Two styles of construction are being designed, both with high resistance to storm and earthquake. 

Clean Technology, Utilization of Renewable Materials, Sustainable Engineering. 

Just as several principles of green chemistry are encompassed in a single process, sometimes these two areas overlap and a green chemical technology is simultaneously used in the processing and transformation of a renewable material e.g. sub-and supercritical water oxidation of biopolymers. 

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