Acidity constants of benzamide and seven ortho‐substituted derivatives were determined. Except for o‐nitrobenzamide, all the amides exhibit medium effects. The data were treated by vector analysis. o‐Aminobenzamide displays two protonation equilibria. The second acidity constant was determined by vector analysis and by the excess acidity function, since the acid strength provided by perchloric acid is insufficient for complete protonation. Different acidity functions and the ortho substituent effect on ionization of the amide group are compared.
University of Manchester 8r UMIST, Grosvenor Street, Manchester, M17HS.
United KingdomA range of diacetylene-containing polyesters have been prepared by polycondensation of terephthaloyl chloride with diacetylene diols of structure HO-(CHz)n~C-GC~CH2)n-OH, where n = 1, 2, 3, 4 and 9. The results from characterization of the polyesters by DSC and Raman spectroscopy are presented. The polyesters from the diols with n = 3 and n = 9 have melting points (T, , , ) of 186 and 88 "C, respectively, and cross-polymerise under irradiation, but not thermally . These polyesters were blended with isotactic polypropylene (Tm = 167 "C) and the blends compression-moulded into dumbbell specimens, which then were exposed to 6oCo y-radiation to effect cross-polymerization of the polyester phases. The dumbbell specimens were subjected to simultaneous tensile testing and resonance Raman spectroscopy, and the shift in wavenumber of the CaC stretching band of the polydiacetylene crosslinks used to determine the local stress in the polyester phases independent of the overall applied stress, thereby facilitating determination of the efficiency of stress transfer in the blends. 0 1997 Huthig & Wepf Verlag, Zug CCC 1022-1360/97/$04.00 J 4 with PP to give materials which can PE(n=2) J J J be moulded without simultaneous PE(n=3) X d d PE(n=4) X (dl 'd' thermal cross-polymerization of the PE(n=9) X J d diacetylene units. Polyester Method for Cross-Polymerization Thermal UV light y-radiation
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