爆珠水分含量测定方法比较研究

Comparation of Determination Methods for Moisture Content in Capsules

分别用直接干燥法、减压干燥法,以及低温绝干氮气吹扫法,测定爆珠的水分含量(质量分数),测得水分含量分别为(1.018±0.00473)%、(0.915±0.0255)%、(0.851±0.0147)%。采用低温绝干氮气吹扫法测得的爆珠水分含量与直接干燥法和减压干燥法测得结果均具有显著性差异(P<0.05),水分含量不仅直接影响爆珠壁材性能,也直接影响着爆珠芯材的逃逸路径与储存稳定性。直接干燥法测定爆珠的水分含量时,样品有破裂漏油现象;真空干燥法测定时,样品有少量破裂漏油现象。直接干燥法和真空干燥法测定过程中由于样品破裂,导致爆珠中易挥发香味油性物质的挥发,造成水分含量测定结果偏离真实值。采用低温绝干氮气吹扫法测定爆珠水分含量时,样品无破坏,样品干燥前后形貌无变化,测定结果更接近真实值,可以判定低温绝干氮气吹扫法测得结果较直接干燥法、减压干燥法更准确可靠。

The moisture content of a capsule was tested by direct drying method,vacuum drying method,low temperature dry nitrogen purge method with results(mass fraction)of(1.018±0.00473)%,(0.915±0.0255)%,and(0.851±0.0147)%,respectively.The moisture content of the capsule measured by low temperature dry nitrogen purge method was significantly different from that measured by the direct drying method and vacuum drying method(P<0.05).Not only did moisture content affect properties of capsule wall material,but also it directly had an influence on the escaping paths and storage stability of capsules.A mass of rupture and oil leakage of the capsules occurred when the direct drying method was applied,which may result from high drying temperature.A small number of rupture and oil leakage of the capsules occurred while the vacuum drying method was applied,which may be caused by the pressure difference between the inside and the outside of the capsule.Both methods lead to the loss of volatile oily substances because of sample rupture,resulting in the measured results of moisture content of samples deviated greatly from the real values.When the moisture content of the capsule was determined by low temperature dry nitrogen purge method,its appearance was intact and no destruction occurred,therefore,the measured results were more accurate and reliable than the results obtained by direct drying method and vacuum drying method.