DETERMINATION OF EVAPORATION RATE AND VAPOR-PRESSURE OF ORGANIC MONOMERS USED FOR VAPOR-DEPOSITION POLYMERIZATION

Thermogravimetry (TG) and the Langmuir equation have been employed for the determination of the temperature dependence of the evaporation ra te and saturated pressure of monomers used in vapor deposition polymer ization (VDP). The measuring process utilizes the evaporation of monom ers in vacuum. The ranges of the evaporation rate and saturated pressu re of monomers as determined by the TG technique are from 10(-2) to 10 (-5) mol/M2.s and from 1 to 10(-3) Pa, respectively. Comparison of the evaporation rate vs temperature relation and the melting point of mon omers determines whether the evaporation involves sublimation from a s olid surface or evaporation from a liquid surface.