Bedeutung und Verwendung

These test methods measure the amount of carboxyl groups present in wood or lint pulp. The carboxyl group represents the surface charge of the pulp, which is a very important amount used in the paper industry.

ASTM D1926-2011 Standardtestmethode für den Carboxylgehalt von Cellulose

Schritt 1: Umfang

1.1 These test methods include the determination of the carboxyl content or ion exchange capacity of cellulose from any source. Two test methods, sodium chloride-sodium bicarbonate method (1) and methylene blue method (2), are described. Test methods need to be used within their limitations, and it needs to be recognized that the accuracy of any method for determining carboxyl groups cannot be determined. In the lower carboxyl group value range, the sodium chloride-sodium bicarbonate method is less accurate. The methylene blue method can be used for the whole range of carboxyl group values. It is particularly useful at low ranges. It is not suitable for the determination of carboxyl groups in soluble carbohydrate materials. Although these test methods can be used to determine the ion exchange capacity of unbleached pulp, residual lignin will lead to uncertain errors, especially sulfonic acid groups in unbleached sulfite pulp (3).

1.2 In SI-Einheiten ausgedrückte Werte gelten als Standardwerte. In dieser Norm sind keine anderen Maßeinheiten enthalten.

1.3 Diese Norm soll nicht alle Sicherheitsbedenken berücksichtigen, wenn überhaupt, mit seiner Verwendung verbunden. Es liegt in der Verantwortung der Benutzer dieser Norm, vor der Verwendung geeignete Sicherheits- und Gesundheitspraktiken festzulegen und die Anwendbarkeit behördlicher Beschränkungen zu bestimmen.