Irradiation of Henequen Natural Fibers for Micromorphilogical Improvements.

[NNadir]

In the area of materials science, natural fibers still constitute an extremely important raw material and turn up in surprising places.

For instance, a major component of many forms of highly stress resistant concrete are formulated with lignocellulose, a product that can be derived from woody plants. If the woody plants are grown with a suitable near sustainable way, they can represent a method of defacto sequestration of carbon, although the calcium carbonate component of concrete will probably overwhelm such fibers if dangerous fossil fuels are used to produce lime. Still, no matter how expensive in dangerous fossil fuel waste dumping terms terms lime is, a fiber reinforcement can certainly natural fiber reinforncement use represent a partials offset of environmental damage from it. Also the use of natural fibers competes with dangerous fossil fuel derived fibres like polyethylene, the long term of stability of which represents a significant wast problem around the world.

The properties of fibres in use can be improved by surface modification or by removal of some plant components, such as non-celluosic species like waxes and in some cases lignins.

Often this modifications involve a risk in themselves, in terms of solvents and the like.

Recently fibers from the cultivated plant Henequen have been treated with electron beam radiation to improve mechanical properties. The work, by Korean Scientists, Hae Young Choi, Seong Ok Han, Jung Soon Lee, at the Korea Institute of Energy Research, and the Department of Clothing and Textiles at Korea's Chungnam University evaluated ways to improve its properties through irradiation with electron beams.

The abstract of a paper reporting it is here: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THY-4T54289-3&_user=10&_coverDate=12%2F30%2F2008&_alid=1071840542&_rdoc=2&_fmt=high&_orig=search&_cdi=5295&_sort=r&_docanchor=&view=c&_ct=102&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4fc45e42585ee9d246b9726f254b8803">Applied Surface Science 255 (2008) 2466–2473

Some excerpts:

1. Introduction
Cellulose is the most abundant natural polymer and has been used as a renewable raw material in a wide range of applications, such as paper, wood, and textile manufacturing <1>. Cellulosic fibers, such as flax, hemp, jute, and henequen, have been applied for composites as fiber reinforcements in recent years. Natural fibers have the advantages of low density, low cost, recyclability,biodegradability, and good mechanical properties compared with traditional reinforcement material such as glass fiber. In spite of the advantages of these natural fibers, the processing of polymer composites with natural fibers has not been considered due to various limiting issues, e.g., poor surface properties for association with the polymer matrix and the degradation of mechanical properties. These problems can be overcome by chemical or mechanical processing of the natural fibers <2–6>.

The advantages of modifying fibers by using electron beam irradiation are that no chemicals are used, the process can be done at room temperature, and the reactions that occur are nonpolluting(solvent-free) <7,8>. Because of these advantages, research on the application of electron beam irradiation in fiber and textile technologies has been conducted on the modification of cellulose<9>. High dose electron beam irradiation of cellulose resulted in the dehydrogenation and destruction of anhydroglucose, while cross-linking was occurred at low irradiation dose <10–12>.

4. Conclusion
The effects of different doses of electron beam irradiation on the surfaces of henequen fibers were investigated. The cell wall layers of the henequen fibers were found to have a concentric amella structure built up of individual cellulose fibril aggregates. The surface morphology of henequen fiber was changed by electron beam irradiation resulting from the removal of pectin, axy and P layer at a low intensity of 10 kGy. From 0 kGy to 30 kGy, the RMS values were increased and show the highest value at the 30 kGy. It means that the exposure of S2 by electron beam irradiation shows the distinctive striation. With increasing of dose of electron beam irradiation, RMS values decreased due to the degradation of the S2 layer. The uneven surface esulting from electron beam irradiation may play a significant role for the adhesion between henequen fibers and the polymer matrix of the composite

There is no reference to gamma irradiation.

Hennequin is not as wildly used as sisal, of which about 240,000 MT, about half of which is raised in Brazil. While every little bit helps, it doesn't compare in scale to the 27 billion tons of dangeros fossil fuel waste dumped into the atmosphere each year.