Renewable Resources relative availability

The main purpose of this chapter was to emphasize the interest in considering cork and suberin, both cheap renewable resources, potentially available in very large amounts, as valuable precursors to novel macromolecular materials, particularly when exploited as by-products. Undoubtedly, the predominance of long aliphatic moieties in both these precursors, points to applications of the corresponding polymers associated with a relative softness and a highly hydrophobic character, but these obvious features should not be considered as exclusive since much more needs to be explored in this still young domain. 

The use of coal as an alternative raw material for some plastics materials is easier to see than that of agricultural (renewable) resources. Thus, polymers and copolymers of formaldehyde are well established commercial products. The primary raw material for these polymers, methanol, can be made from coal just as readily as from natural gas or oil. Certainly, in the case of a new plant for making methanol, the cost and availability of natural gas or petrolexun relative to coal must be weighed carefully. Even an operating plant might be converted from natural gas to coal as raw material much more easily than perhaps any other petrochemical operation. 

Two striking differences distinguish the essence of this chapter from most other chapters, namely (i) the fact that the furan compounds relevant to polymer synthesis are not found as such in nature but are instead obtained from parent renewable resources and (ii) it is possible in principle to envisage a whole new realm of polymer materials based on furan monomers and furan chemistry, covering a very wide spectrum of macromolecular structures. Concerning the first point, the massive availability of saccharidic precursors and their relatively sirt5)le conversion into furan derivatives, eliminate in fact any apparent problem of absence of such natural structures. As for the second point, its unique relevance has to do with the potential perspective of a viable alternative to the present reality based on polymer chemistry derived from fossil resources. In other words, the biomass refinery concept would be applied here to the synthesis of different furan monomers, simulating the equivalent petroleum counterpart. 

It has been estimated that worldwide, about 15 billion tons of raw materials are extracted from the Earth every year some of these are renewable and some are not. Over time, it is becoming more apparent that the Earth is virtually a closed system relative to its constituent materials and that its resources are finite. In addition, as societies mature and populations increase, the available resources become scarcer, and greater attention must be paid to more effective use of these resources relative to the materials cycle. 

Caution must therefore be observed before concluding that polymers based on fossil resources are less sustainable than bio-based polymers, particularly as they have not yet been shown to have better technological behaviour than the commodity synthetic polymers. Indeed, some properties are noticeably inferior. Moreover, if renewable energy is available cheaply in the future, many synthetic polymer feedstocks could be made from natural products. For example, ethene can be manufactured from ethanol, which may in turn be manufactured from carbohydrates. In the short term, polymer feedstocks from natural and fossil resources will co-exist and the primary determinant of the proportion of each utilised will depend on the relative ecological benefits and economics of each. Over the next decade the standards organisations will need to come to terms with the reality that end-of-life disposal is just one of the factors to be weighed in the ecological balance. 

At a time when the available resources are decreasing due to pollution and overfishing elsewhere in the United States, a consumer demand for shellfish products has created the conditions for an expanding and profitable market. Alaska, with its relatively uninhabited and unpolluted shoreline, with its many species of commercially harvestable shellfish, has a great potential for economic growth, if a renewed shellfish industry can be established. 

At the present time, due to lack of wood and petroleum resources, as well as increasing awareness of the environment and energy, the areas of application for new types of natural fiber functional materials are expanding. Natural fibers have the advantages of active surface, low density, low cost, worldwide availability, renewability, biodegradability, ease of preparation, low energy consumption and relative non-abrasive-ness over traditional reinforcing synthetic fibers [1-3]. Moreover, natural fibers are... 

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