Revistes Catalanes amb Accés Obert (RACO)

El tiempo crítico de disolución de hilos de fibras acrílicas.

Joaquín Gacén Guillén, J. M. (José María) Canal Arias

Resum


Critical disolution time technique (TCD) for acrylic fibres has been developed as a means of detecting structural fibre differences which can give rise to defects of different value in the articles manufactured from them. Dimethylformamide, (DMF), dimethylsulphoxide, (DMSO), and DMSO/DMA binary mixtures were used as solvents. There exists a linear correlation between log TCD and testing temperature and also for log (1/TCD) and 1/T (K^_1) which permit us to deduce apparent activation energy of breakup process to the fibre
structure that occurs during TCD measurement. On the other hand the DMSO concentration in the mixture with DMA is related to TCD according to an exponential law: TCD = A + B . ee^_cx. TCD evolution has been studicd for
100 % relax, 100 % retractable and High Bulk (HB) yarns. Use of 15/85 mixture of DMSOIDMA in weight is suggested, and for the determination o£ TCD of acrylic fibres temperatures between 35 and 60°C are recomended. In order to know the sensitivity of the technique in detecting structural variations during industrial handling of some of acrylic fibre articles, the variation in TCD, of different HB acrylic fibre yarns subjected to industrial treatments (steaming and dyeing) to develop bulkiness, has been studied. The technique is very sensitive in detecting structural fibre differences.

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