CMS Membranes AFPM EXAM III

What does CMS stand for

Carbon molecular sieves

What doe CMS result from

the high temperature pyrolysis of some polymers at controlled conditions

in general, what do CMS consist of

highly disordered graphene-like carbon sheets, with very little long-range order (amorphous phases)

What does the CMS phases display

open micropores connected by rigid slit-like ultramicropores to provide high sorption and diffusion coefficients

What do CMS exhibit

distributions of micropores and ultramicropores

What happens during the conversion process of CMS

reorganization of polymer main chains occurs, with small gas molecules released and free radicals formed. Those free radicals can form crosslinking leading to a 3D network with graphene-like structure. With increasing temperature, these networks can form ordered structures

What can form ‘slit-like’ pore structure, combined with a bimodal pore distribution

The packing imperfections between ordered regions

What are the main challenges of CMS

First you need to start with a high quality MOF membrane. High temperature needed to convert the MOF in CMS may be an issue to preserve membrane integrity. Control over pore size may be quite challenging…. Lots of trial error experiments. Once you (hopefully) get a continuous CMS membrane, STABILITY may be an issue