Abstract
Polyvinyl alcohol fibers (PVA) were treated with dimethyldichlorosilane (DMCS) in anhydrous condition and in air and nitrogen atmospheres. The effects of different reaction conditions and solvents on the extent of reaction were investigated. The percent weight gain of PVA increased as the molar ratio of silane to yarn was increased. An increase in the reaction temperature or time resulted in an increase in the weight gain. The percent gain in weight in air is slightly less than in nitrogen atmosphere, and in dimethylformamide (DMF) it is much higher than in benzene. The effect of these different reaction conditions on the extent of reaction has been explained in terms of accessibility of reaction sites. Physical properties of these chemically modified fibers were also investigated. Moisture regain, density, and bire fringence were reduced due to DMCS treatment. Compared to the parent fibers, the mechanical properties of the modified fibers were also impaired. The elastic recovery increased considerably, indicating the possibility of an inter moleculer crosslinking reaction. The thermal stability data revealed that at lower percent weight gain (<2%) the stability of the modified fibers was lower than that of the parent. However, above 2% weight gain an improvement in thermal stability behavior was observed.
Published Version
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