SYNOPSISThermal expansion property at 288°C and methylene chloride resistance of poly (2,6-dimethyl-1,4-phenylene ether (PPE) /epoxy laminate were found to be affected by the functionality on PPE resin. Nonlofting PPE/epoxy laminates were prepared with the PPE grafted with fumaric acid or the PPE having (di-n-butylamino) methyl substituent on the polymer backbone. Employing vacuum-vented PPE extrudate or phenol-redistributed PPE was also effective in improving the PPE/epoxy laminate properties. Attempts to preparing a real PPE/epoxy interpenetrating network as the matrix material for the laminate were also made by incorporating both PPE crosslinker and epoxy curing catalysts in the same formulation.
Inhibition data (I50 values) have been obtained for inhibitors of the chorismate mutase activity of chorismate mutase-prephenate dehydrogenase from Aerobacter aerogenes. Several 1-substituted adamantane derivatives were investigated; the order of decreasing inhibitory activity with the various substituents was -PO32- much greater than -P(OCH3)O2- greater than -CO2- greater than -CH2CO2- greater than -SO2- greater than SO3-. 3-Chloroadamantane-1-acetic acid was slightly less effective than adamantane-1-acetic acid. 2-(1-Carboxy-1,4-dihydrobenzyl)acrylic acid (19), an analogue of prephenate, was an effective inhibitor. Other substances investigated, including 2,4,10-trioxaadamantane-1-acetic acid (15), 5-enolpyruvylshikimic acid (20), and 1-(carboxyethyl)-1,4-dihydrobenzoic acid (18), failed to inhibit chorismate mutase activity under the conditions investigated.
mixing. The tube was then stoppered, shaken vigorously, and plunged into a Dewar flask containing liquid nitrogen. After 1 min the tube was removed and placed in the ESR spectrometer in a liquid nitrogen bath. An ESR spectrum was then detected (gyromagnetic ratio 2.0025). The spectrum obtained in this way suffered from poor resolution, so no information about the structure of the radical was able to be obtained. Attempts to obtain a solution spectrum in dimethylformamide at room temperature were unsuccessful. Solvent Isotope Effects. Kinetic studies in Me^O-D^(4:1 v/v) were carried out as described above except that NaOD in D20 was substituted for Ba(OH)2 in water.
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