【国外标准】 Standard Test Method for Stability of Cellulose Fibers in Alkaline Environments

5.1 This method is intended to provide a generalized procedure for determining the stability of cellulosic pulp fibers exposed to alkaline environments. Specifically, this method allows various pulp types to be compared with respect to the effect of exposure to alkaline conditions on the strength of individual cellulosic fibers based on a zero-span tensile test. The time intervals listed in the procedure are not critical, and more intervals of shorter or longer duration may be added. In addition, the procedure may be simplified by removing some of the intermediate intervals so long as a range of intervals is determined. An example of a simplified procedure would be to determine 4 intervals (for example, 1 day, 1 week, 2 weeks, 4 weeks; or 1 day, 3 day, 7 day, 14 day).5.2 The specified solution (1N NaOH) is strongly alkaline. Although this alkali concentration is higher than some environments that would be simulated by this test, the stronger pH provides better differentiation between different cellulose fiber types. Although alkaline stability based on other alkalis (for example, KOH, Ca(OH)2, etc.) at a different concentration could be determined by this method, 1N NaOH is to be considered the standard solution. Alkaline stability results from other treatments may be reported in addition to the standard solution if the additional solution(s) provide useful information.1.1 This test method describes a procedure for determining the effect of exposure to alkaline environments on the strength of cellulose fibers. An alkaline environment is defined to be any matrix in which the pH is greater than 8 for a period of 2 or more hours.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.