CAN/CGSB-4.2 No. 14.6-M91

1.1 This method describes a procedure for the quantitative analysis of binary mixtures of acrylic with modacrylic fibres, by removal of the modacrylic component. 1.2 If the types of fibres present in the mixtures are not known, they must be identified before quantitative analysis is undertaken (par. 10.1). 1.3 The accuracy of the results obtained with this method will be decreased by the presence of nonfibrous finishes that cannot be removed. 1.4 Certain modacrylics will not dissolve in cyclohexanone at 93 degrees C, but will dissolve at the boil. Others (for example Monsanto SEF products) do not dissolve even at the boil. When acrylic/modacrylic blends are analyzed, the analyst should proceed as follows: a. Check the solubility of the modacrylic fibre at 93 degrees C. If soluble, use this method (CAN/CGSB-4.2 No. 14.6-M91). b. If insoluble or only partially soluble following a., check solubility at the boil. When soluble, perform this method (CAN/CGSB-4.2 No. 14.6-M91) in boiling cyclohexanone. c. If the modacrylic is insoluble at the boil, analyze using microscopic count (CAN/CGSB-4.2 No. 14.9-M). Acrylics are unaffected by cyclohexanone at the boil. Where other fibres are present, their solubilities should be checked prior to analysis.