APERIODlC CRYSTAL STRUCTURE IN VEGETABLE FIBRES. Nguyen Van Tri, Pham The Vung, Le Hai Hung and Nguyen Van Thang, Institute of Technical Physics, Hanoi University of Technology, Hanoi Vietnam

The particular molecular-electronic microstructure and related properties of many different genera of vegetable fibers (such as cotton, jute, pineapple, sisal) have been studied with ESR in combination with other methods. The partner radicals C^* and O^*, and especially a new (2Fe-2S) exchange complex in the fibred structure were revealed. The measurement data indicate that the stable solid partner radical group R^*(C^*O^*) is mainly by the end of two cellulose macromolecule chains. The physical local structure coupled by fivefold (2Fe-2S) rhombic combinations diagonally bonding a macromolecule chain with five neighbouring ones is based on a pentagon created by five sulfur atoms whose plane is perpendicular to the axis of the elementary fibre. A practical fiber is constituted from numerous elementary fibres spiraling about its axis by an angle [[Theta]]_[[omicron]]= 54,7deg.. The important roles of this structure in the formation of the elementary fibres and in specific features of the material (such as the strength, the tensility, the torsional module) have been partly discovered. Some physical and biological technological treatments to improving fibre properties have been also efficiently examined.

This publication is completed with financial support from the National Basic Research Program in Natural Sciences and the Textile Research Institute.