Cotton pulp testing is a quality assessment process for cellulose pulp derived from cotton raw materials. Crucial to the textile, pharmaceutical, and specialty paper industries, this testing effectively controls raw material purity, fiber properties, and chemical safety, ensuring products meet international environmental standards and industry application requirements.
The testing scope encompasses over 20 types of cotton pulp, including textile-grade pulp, acetate-grade pulp, nitrocellulose-base pulp, pharmaceutical excipient-grade pulp, refined cotton pulp for filter paper, specialty paper-grade pulp, and etherified cotton pulp.
Key testing parameters include cellulose content, alpha-cellulose purity, ash content, degree of polymerization distribution, whiteness and color, water absorbency, viscosity characteristics, residual resin content, heavy metal content, iron ion concentration, moisture content, fiber length distribution, dirt count, swelling degree, pH value, carboxyl content, cuprammonium solution rheology, ignition residue, chlorine-containing compounds, and biodegradability.
Common testing methods and standards include the GB/T 744 titration method for determining the degree of polymerization; the ISO 5351 viscosity method for evaluating pulp dissolution characteristics; the TAPPI T413 ash method for analyzing high-temperature ignition residue; the GB/T 1545 acid-base titration for measuring the pH of water extracts; the ISO 2470 blue-light reflectometer method for quantifying whiteness; the Soxhlet extraction method for determining organic solvent residues; ICP-MS spectrometry for trace heavy metal detection; microscopic image analysis for fiber morphology characterization; the GB/T 12658 electron microscopy method for counting dirt and impurities; UV-Vis spectrophotometry for iron ion concentration; the Karl Fischer method for precise moisture content testing; the GB/T 9107.5 swelling degree method for testing fiber swelling properties; gas chromatography for separating trace resin components; infrared spectroscopy for functional group structural identification; and X-ray diffraction for crystallinity analysis. In addition, there are specialized testing methods and patent applications concerning cotton pulp concentration; the purity of the cotton pulp directly affects the quality of products such as paper and rayon.
Testing instruments include Ubbelohde viscometers, muffle furnaces, electronic balances, whiteness meters, fiber analyzers, pH meters, Soxhlet extractors, ICP mass spectrometers, scanning electron microscopes, UV-Vis spectrophotometers, Karl Fischer moisture titrators, gas chromatographs, Fourier-transform infrared (FTIR) spectrometers, X-ray diffractometers, and dirt count testing stations.
