Method for testing looseness of reinforced fibers in chlor-alkali ionic membrane

The invention discloses a method for testing the relaxation degree of reinforced fibers in a chlor-alkali ionic membrane, which comprises the following steps: (1) measuring the hydrolysis swelling ratio of a chlor-alkali ionic membrane precursor without reinforced fibers, the swelling ratio (TD or MD) = 100% * (size after membrane hydrolysis-size before membrane hydrolysis)/size before membrane hydrolysis; (2) calculating the limit displacement of the to-be-tested chlor-alkali ionic membrane precursor sample containing the reinforced fibers, and obtaining the tensile force at the limit displacement through the tensile curve, the limit displacement = the effective length of the tensile sample * the swelling ratio; and (3) calculating the fiber looseness in the to-be-tested sample of the chlor-alkali ionic membrane precursor containing the reinforced fibers, wherein the fiber looseness is equal to (1/the drawing force at the limit displacement) * 100%. The method provided by the invention solves the problem tha