Interaction of N Atoms Through Porous Membranes in Nitrogen Flowing Post Discharges

Abstract

Results of investigations conducted with membranes of several pore diameters are presented: nylon (5 µm), PDVF(1 µm), and polysulfones (1.2 and 3 µm) exposed to a N2 flowing (1 Ln · min−1) microwave (100 W) post discharge, produced at low gas pressure: 130 to 4 000 Pa (1 to 30 Torr). The transmissions of N atoms through these membranes were measured from the intensity variation of the N2, 1st position afterglow before and after the membranes. It appeared that N atoms penetrate and cross the membranes with a transmission factor varying from 20 to 50% for nylon and from 50 to 100% for PDVF and from 33 to 100% for polysulfones during the exposure time (<30 min). Such variations of transmission factors are the results of membrane etching by N atoms.

Active species in N2and N2-O2afterglows for surface treatments

“…Investigations with other membranes also found that T N increased after 30 min of post-discharge from 0.5 to 1 with PDVF (pores 1 m) and from 0.33 to 1 with polysulfones (pores 13 m) [20].…”

“…The interaction of N-atoms with nonwoven membranes was investigated on nylon (5 μm) made by cosolvent evaporation from a nylon extruded film and polypropylene (PP) prepared from polypropylene fibers by a melt-blown process, which were exposed as shown in figure 5 to the N 2 flowing (1 slm) microwave (100 Watt) post discharge produced at low gas pressures: from 1 to 30 Torr [19,20,21]. The N atoms transmission through these membranes was measured from the intensity variation of the N 2 (580 nm) afterglow, which results of N atom recombination (reaction (a)), before and after the membranes.…”

Transmission of N Atoms Through PP Membranes for Nitrogen Flowing Post Discharge Sterilisation Processes

“…Transmission of N-atoms through nylon, polyvinylidene fluoride (PDVF), polysulfone, and laboratory made and commercial PP porous membranes was previously reported [2,3] and discussed in terms of variations of the membrane porosity with the treatment time as a result of membrane etching, which is particularly efficient with nylon membranes. The previous results were obtained at a constant N 2 flow rate of 1 Slm.…”

“…In previous works, the effect of pore diameter and polymer properties on N transmission through different membranes was evaluated [2,3]. In the present work, we attempt to study the effects of varying the N 2 flow rate and gas pressure of a N 2 flowing microwave post discharge on the N atom transmission through three layered commercial polypropylene (PP) membranes (already used for conventional sterilisation processes) comprising an intermediate layer of fibres with diameters in the range of nanometres.…”

Modification of polymer membrane properties by low-temperature plasma

“…Treatment by a nitrogen-containing plasma (N 2 , NH 3 ) results, along with etching and polymer radical formation, in insertion of nitrogen atoms into the surface layers of membranes to form N-C bonds [39][40][41][42][43][44][45][46][47][48][49][50][51]. The wettability of membrane surface is therewith improved and their protein adsorptivity is decreased.…”