| 摘要 |
<p>1,236,143. Photo-electric absorption measurement. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. April 23, 1969 [April 25, 1968], No.20695/69. Heading G1A. [Also in Divisions B1, C3 and G2] A process for monitoring the concentration of living polymer chains in a homogeneous solution polymerization reaction mixture comprises removing a stream therefrom, treating a portion of the stream with a de-activating agent to produce a de-activated reference portion, and comparing the light absorbance characteristics of the reference portion with those of a second, active portion of the stream at the same narrow band wavelength of transmitted radiation. The results may be shown graphically or used to control and modify the polymerization process, particularly in relation to molecular weight and-distribution. In the preferred procedure, samples are removed from polymerization zone 10 and passed in part via line 18 to cell 30 and in part via line 16 to cell 28. Light from source 34 passes via filter 36 to cells 28 and 30, and thence via filters 42 and 44 to photo-tubes 46 and 48, the output from which is fed to control or record station 50. The sample portion flowing in 18 is de-activated from store 20 via line 22. Partial de-activation of the sample portion flowing in 16 may also be effected via line 26. The process may also be applied to monitoring the purification of reactants prior to polymerization. In examples, polybutadiene, polyisoprene, butadiene-styrene random and block copolymers are prepared using butyl lithium initiator in cyclohexane or cyclohexaneisopentane mixture. Analogous monomers, solvents and initiators are-stated in one example to give similar results.</p> |
