Enhancement of Gas Permeability in HPC, CTA and PMMA under Microwave Irradiation

Abstract

ABSTRACT:Gas permeability in hydroxypropyl cellulose (HPC), cellulose triacetate (CTA), and poly(methyl methacrylate) (PMMA) membranes under microwave irradiation was investigated in comparison with permeability obtained without microwave (conventional method). Permeability coefficients for several gases in HPC, CTA and PMMA under microwave were higher than those obtained by conventional methods. That is, the enhancement of gas permeability (microwave irradiation effect) by microwave was made clear, additionally it was suggested that accelerated molecular motion of -OH and -COO-moiety in side chains contribute to the enhancement under microwave irradiation. The degree of the enhancement of gas permeability depended on the combination of polymers and gases. Consequently, the size of gas molecule, polar groups and free volume spaces in polymer are assumed to affect the microwave irradiation effect.

Implementation of antireflection layers for improved efficiency of carbon nanotube–silicon heterojunction solar cells

“…63 Barrer for PS versus 800 Barrer for PDMS). [25][26][27] However, it should be noted that the thickness of the various polymer layers…”

A helicopter view of microwave application to chemical processes: reactions, separations, and equipment concepts

“…It has been postulated that the selective interaction of microwaves with polar functional groups of polymeric membranes and/or with the feed mixture components can accelerate diffusivity and permeability through the membrane. Nakai et al (2006) investigated gas permeability through hydroxypropyl cellulose (HPC), cellulose triacetate (CTA), and poly(methylmethacrylate) (PMMA) membranes under microwave irradiation in comparison with the permeability obtained with conventional heating. They found higher permeability coefficients for several gases under microwave irradiation.…”

Chemical and Biological Resistant Clothing

“…Effective personal protection against exposure to toxic chemical agents in vapor form is critical in the military and in civilian defense due to threats of chemical-biological agents and industrial toxins. 1 Earlier technology was based on butyl rubber (i.e., linear poly(methylpropene-co-2methyl-1,3-butadiene)), working on the principle of total blockage. 2 The lack of breathability of butyl rubber, however, results in fatigue and exhaustion due to heat stress and ineffective evaporative cooling.…”

“…2 The lack of breathability of butyl rubber, however, results in fatigue and exhaustion due to heat stress and ineffective evaporative cooling. 1,3 To reduce the heat load, permeable clothing was developed implementing PBI Saratoga carbon pellet technology, 4,5 a carbonaceous-sorbent technology. 6 In this type of permeable clothing, a layer of finely distributed active carbon, either bound in polyurethane foam or as particles of carbon, is dispersed between two layers of textile.…”

“…The U. S. Department of Defense currently uses protective garments (Military JSLIST suit) made with three layers of open-cell polyurethane loaded with activated carbon. 1 These garments are bulky and heavy (PBI Saratoga weighs approximately 460 g/m 2 ). 5b Therefore, lighter membranes are considered a high priority.…”