纤维乙酰化对提高硬质纤维板性能的作用

<正>本文研讨乙酰化可否显著提高硬质纤维板的性能。试验时所用纤维浆料为25％(体积比)醋酐的二甲苯溶液,在125℃下进行乙酰化。结果如下:(1)纤维乙酰化导致硬质纤维板厚度显著增加。尺寸稳定性的增加主要是由于增积的结果。(2)乙酰化纤维板在调湿后,含水率增加很小。纤维素羟基变换成憎水性乙酰基减少了纤维吸水量。(3)浸水厚度膨胀显著减小。乙酰化使硬质纤维板具较大的尺寸稳定性。(4)乙酰化对干弯曲强度无显著影响。

EFFECTS OF ACETYLATION OF FIBER ON THE IMPROVEMENT OF PROPERTIES OF THE HARDBOARD

This study was undertaken to determine whether acetylation of fiber could bring about marked improvement in properties of the hardboard. The pulp was acetyla; ted with 25 per cent (in volume) solution of acetic anhydride in xylene at 125C. The results obtained are as follows: (i) The acetylation of fiber resulted in a obvious expansion in the thickness of the hardboard and the increased dimensional stability is mainly due to the bulking effect. (2) After conditioning.the moisture content of the acetylated hardboard increased slightly. The conversion of cellulosic hybroxyl groups to less hydrophilic acetate groups reduces the amount of water absorbed by the fibers. (3) Swelling in thickness of the specimens in liquid water was cousiderably reduced. The acetylation imparts greater stability to the dimensions of the hardboard. (4) The acetylation does not significantly affect the dry bending strength of the hardboard.