| 摘要 |
The invention is directed to a pycnometer designed to measure the density of particulate porous polymer samples, particularly polymer samples having hydrocarbons and/or air absorbed in the pores thereof. The apparatus includes a sample cell of fixed volume fitted with a sample container of fixed weight, a gas reservoir of fixed volume, a valved line providing gas communication between the sample cell and the gas reservoir, a linear variable differential transducer to measure the weight of the polymer sample in the sample cell, a variable capacitance quartz crystal for measuring gas pressure in the gas reservoir, and a computer which calculates the density of the sample from the sample weight, and the volume of the sample determined by measurement of a super-atmospheric gas pressure in the gas reservoir when isolated from the sample cell and the equalized pressure established when the gas reservoir is placed in open communication with the sample cell. An output signal from the computer indicative of the sample's density can be fed to a light-emitting diode or a printer, or to a process control computer to make any required adjustments in a polymerization reactor to produce polymer within a preselected range of polymer density.
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