Mixed Matrix Membranes Containing a Biphenyl-Based Knitting Aryl Polymer and Gas Separation Performance

Novel mixed matrix membranes (MMMs) were prepared using Matrimid (M), polysulfone (PSF) or polyphenylene oxide (PPO) as the continuous phase and a porous biphenyl-based knitting aryl polymer as a filler, synthesized through the Friedel–Craft reaction. The filler had little influence on the thermal and morphological properties of the membranes but affected the mechanical and gas transport properties, which were different depending on the type of matrix. Thus, in the case of MMMs based on Matrimid, the filler increased considerably the permeability to all gases, although no improvements in selectivity were achieved. A PSF-based MMM showed minor permeability increases, but not in all gases, while the selectivity was particularly improved for hydrogen separations. A PPO-based MMM did not exhibit variation in permeability nor in permselectivity with the addition of the filler.

Antioxidant activities of two novel synthetic methylbenzenediol derivatives

2-(tert-Butyl)-5-methylbenzene-1,4-diol and 3-(tert-butyl)-5-methylbenzene-1,2-diol were synthesised by Friedel-Craft reaction of 2-methylbenzene-1,4-diol and 4-methylbenzene-1,2-diol, respectively, with tertiary butanol providing reasonable yields. The antioxidant activities of these two products, mother compounds and 2-(tert-butyl)benzene-1,4-diol were investigated and compared by means of 2,2-diphenyl-1-picrylhydrazyl radical and Rancim at test; 3-(tert-butyl)-5-methylbenzene-1,2-diol is the most potent antioxidant tested by using Rancimat test experiment. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging abilities of 2-methylbenzene-1,4-diol, 4-methylbenzene-1,2-diol and 2-(tert-butyl)benzene-1,4-diol are almost equal and more than twice as strong as 2-(tert-butyl)-5-methylbenzene-1,4-diol and 3-(tert-butyl)-5-methylbenzene-1,2-diol. The antioxidant activities of the five compounds evaluated by Rancimat test mainly depend on their steric synergist effects between the two phenolic hydroxyl groups in their molecules. The antioxidant activities of the five compounds mainly depend on how many 2,2-diphenyl-1-picrylhydrazyl radicals can be scavenged by one mole of them in 2,2-diphenyl-1-picrylhydrazyl test. One mole of 2-methylbenzene-1,4-diol, 4-methylbenzene-1,2-diol and 2-(tert-butyl)benzene-1,4-diol can scavenge four moles of 2,2-diphenyl-1-picrylhydrazyl radicals, but one mole of 2-(tert-butyl)-5-methylbenzene-1,4-diol or 3-(tert-butyl)-5-methylbenzene-1,2-diol can only scavenge two mole 2,2-diphenyl-1-picrylhydrazyl radicals because 2,2-diphenyl-1-picrylhydrazyl radicals are very bulky.