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末端带有羟基的聚醚、聚酯预聚物是制备聚氨酯橡胶和塑料重要起始材料,而羟基终止的聚异戊二烯及聚丁二烯则可用以制备结构材料及火箭固体推进剂中的粘合剂。这些预聚物中羟基的含量是决定交联后形成网状结构聚合物性质的重要参数,需要建立准确测定的方法。最常用的测定方法是化学滴定法,但缺点是反应时间长,样品需要量大,预聚物不溶于水时用KOH滴定困难以及预聚物中如含有对碱敏感的基团不能应用。用IR测定预聚物中羟基,一般多用二硫化碳或四氯化碳为溶剂,使用厚的吸收池(如10厘米)测定3640cm~(-1)附近自由羟基的伸缩振动。但这种方法即使在羟基浓度很低时也
Hydroxy-terminated polyether, polyester prepolymer is an important starting material for the preparation of polyurethane rubber and plastics, and hydroxyl-terminated polyisoprene and polybutadiene can be used to prepare structural materials and rocket solid propellant Of the adhesive. The content of hydroxyl groups in these prepolymers is an important parameter that determines the properties of the network-forming polymer after crosslinking. It is necessary to establish an accurate measurement method. The most commonly used method is chemical titration, but the disadvantage is that the reaction time is long, the sample needs a large amount, the titration with KOH when the prepolymer is insoluble in water is difficult, and the prepolymer can not be used if it contains alkali-sensitive groups. The hydroxyl groups in the prepolymer were determined by IR. The general use of carbon disulfide or carbon tetrachloride as the solvent, the use of thick absorption cell (such as 10 cm) Determination of free hydroxyl near 3640cm -1 stretching vibration. But this method even when the hydroxyl concentration is low