3,4-dichlorobenzyl methacrylate and ethyl methacrylate system: monomer reactivity ratios and determination of thermodynamic properties at infinite dilution by using inverse gas chromatography

Copolymers with various contents of 3,4-dichlorobenzyl methacrylate (BzMA) and ethyl methacrylate (EMA) were prepared in 1,4-dioxane solution using 2, 2 ' -azobisisobutyronitrile (AIBN) as initiator at 60 degreesC. The copolym er compositions were determined by H-1 NMR analysis. The monomer reactivity ratios were calculated by both Fineman-Ross, and Kelen-Tudos methods. The monomer reactivity ratios were found to be r(BMA) = 0.521 +/- 0.019, r(EMA) = 0.847 +/- 0.221 (Kelen-Tudos) and r(BMA) = 0.677 +/- 0.008 r(EMA) = 1.11 7 +/- 0.209 (Fineman-Ross). The FT-IR, C-13 NMR spectra of the copolymers h ave been discussed. In all other samples thermal degradation proceeded in a single step. A slight increase in thermal stability of the copolymers was observed with increase in BzMA content. Some thermodynamic quantities such as the specific retention volumes, V-g(0), weight fraction activity coeffic ients of solute probes at infinite dilution, Ohm (infinity)(1), Flory-Huggi ns intereaction parameters, chi (infinity)(12), between polymers and solven ts, the partial molar free energy, DeltaG(1)(infinity) the partial molar he at of mixing, DeltaH(1)(infinity), at infinite dilution were determined fro m the interactions of poly(BzMA-co-EMA) with alcohols, ketones, acetates, a romatics and n-alkanes by inverse gas chromatography method at 130-150 degr eesC. All probes are non-solvent for poly(BzMA-co-EMA) (7:93%) and poly(BzM A-co-EMA) (87:13%) at 130-150 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.