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Handbook of Size Exclusion Chromatography and Related ...

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Table 1 Cellulose Content <strong>of</strong> Some<br />

Common Natural Sources<br />

Source Cellulose (%)<br />

S<strong>of</strong>twood 33–42<br />

Hardwood 38–51<br />

Cotton 83–95<br />

Flax (unretted) 63<br />

Flax (retted) 71<br />

Hemp 70–74<br />

Jute 61–72<br />

Ramie 69–76<br />

Sisal 67–78<br />

Source: Refs. 3–5.<br />

Plant fibers are generally classified as seed-hair, bast, or leaf fibers. Seedhair<br />

fibers, such as cotton, aid in the wind dispersal <strong>of</strong> the seed. Cotton lint<br />

fibers are used in the textile industry <strong>and</strong> the shorter fuzz fibers (linters) are<br />

mainly transformed into cellulose derivatives. The bast fibers (for example,<br />

ramie, hemp, flax, <strong>and</strong> jute), <strong>and</strong> leaf fibers (for example, sisal) have a<br />

supportive function. The bast fibers are strings <strong>of</strong> many individual cells <strong>and</strong> are<br />

used for manufacturing coarse textiles <strong>and</strong> textile-related products. Leaf fibers<br />

are coarser than bast fibers <strong>and</strong> are used as cordage <strong>and</strong> for rugs rather than for<br />

making clothes.<br />

Today, wood is the main source <strong>of</strong> the cellulose used for industrial<br />

production <strong>of</strong> paper <strong>and</strong> board; highly refined wood pulps are the major raw<br />

material for regenerated fibers <strong>and</strong> films or manufacture <strong>of</strong> cellulose derivatives.<br />

Because cellulose is biodegradable, biocompatible, <strong>and</strong> derivatizable there is<br />

also a growing interest in extending the use <strong>of</strong> bi<strong>of</strong>ibers. Besides common<br />

derivatives like ethers <strong>and</strong> esters, efforts are made to find new applications<br />

through new derivatives, for example, graft copolymers <strong>and</strong> products with high<br />

net value such as composites (6–9). <strong>Size</strong> exclusion chromatography (SEC) is an<br />

invaluable tool to characterize cellulose, whether the interest is to study native<br />

cellulose fibers or to control <strong>and</strong> develop common or new cellulose-based<br />

products. In the present chapter, application <strong>and</strong> development <strong>of</strong> SEC for<br />

characterization <strong>of</strong> cellulose is reviewed. This will essentially include the main<br />

topics described in the corresponding chapter in the first edition <strong>of</strong> this<br />

h<strong>and</strong>book (10). The first edition covered the literature from 1970 to 1991, <strong>and</strong><br />

the present review will give special attention to the literature published during<br />

the past decade.<br />

© 2004 by Marcel Dekker, Inc.

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