蒸气压渗透计的结构对仪器常数的影响

<正> 蒸气压渗透计(VPO)依其结构不同,分为探头下垂式蒸气室和探头站立式蒸气室两类。关于仪器常数K是否随溶质的分子量范围的不同而变化的问题,已引起人们的注意,但报道的结果并不一致。因仪器、标样及纯度、操作方法的不同,难以判断其误差。为了便于比较,本文选用VPO仪中具有代表性二类仪器,对同一标样进行了标定。

THE EFFECT OF THE STRUCTURE OF VPO ON THE INSTRUMENT CALIBRATION FACTOR

In order to check the effect of structure of VPO on the instrument calibration factor two kinds of VPO, one with stand-up type thermistor and the other with hang-down type, have been calibrated with a number of identical standard samples. Including nine organic compounds, with molecular weight ranging from 178 to 1089 and six polystyrene samples from 2.82×10³ to 4.42×10⁴. The results show that the calibration factor of the instrument with hang-down thermistors is dependent on the molecular weight of solute while that of the instrument of stand-up thermistors is inde-pendent on the molecular weight of solute. Some factors including the concentration and viscosity of the solution the quantity and shape of the liquid on the thermistors have been discussed.