1. Introduction to Natural Cellulose Fibers from Renewable Resources

For centuries, mankind has been clothed using natural cellulose and protein fibers that have been almost entirely derived from dedicated sources. Cultivation of fiber crops and rearing of silkworms and sheep have been the traditional methods of obtaining cellulose and protein fibers, respectively. However, fiber crops were not just sources for clothing, but the by-products generated were major sources for food and means for substantial income. For instance, cotton seeds have been used as a source for oil and also as animal feed. Among the different types of fibers, natural cellulose fibers, mainly cotton, have been the most common source for fibers. Recently, the cultivation of cotton and other natural fibers has been declining due to the difficulties in growing cotton, better profits from biofuel crops such as corn and soybeans, and limited technological improvements in processing and using cotton-based textiles. Similarly, the supply of petroleum resources required for synthetic fibers at affordable prices could be questionable in the near future. At any given time, it can be expected that fuel needs would predominate the use of petroleum resources for textile fibers. In addition, increasing consumption, especially in the developing countries, constraints on the natural resources required to produce fibers, and inability to increase the supply proportionate to the demand are expected to make most of the current fibers either too expensive or unavailable for commodity applications. This scenario is neither unrealistic nor unforeseeable. The production of natural fibers such as cotton is declining due to cotton farmers shifting to more profitable biofuel crops such as corn and soybeans. These biofuel crops are also less demanding in terms of resources required for cultivation, harvesting, and processing into final products. The decrease in cotton production could escalate further due to the demand for biofuels.