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Title: Structural characterization of polycarbonates for membrane applications by atomic level simulation

Journal Article · · Industrial and Engineering Chemistry Research
; ;  [1];  [2]
  1. ETH-Zentrum, Zuerich (Switzerland). Inst. fuer Polymere
  2. Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering

Polycarbonate polymers are desirable for use in membrane applications for separating gas mixtures due to their unique properties. Two commercially important membrane polymers, the tetramethyl (TMPC) and tetrabromo (TBPC) derivatives of Bisphenol A polycarbonate, were studied with computer simulation. The volume available to various gas diffusants in these polymers was characterized by calculating the volume of clusters of Delauney tetrahedra between the atoms of an ensemble of bulk molecular mechanics models of the polymer. The inverse of this available volume correlated with the diffusivity of various gases in these polymers. This correlation was able to qualitatively reproduce the gas diffusion consistent with the superior diffusivity and superior selectivity of TMPC and TBPC, respectively. Analysis of the structure of the two polymers suggests a more ordered packing of the TMPC chain which is consistent with the experimentally observed trend in which inhibited packing leads to increased selectivity for gas diffusion in polymers. Despite the model`s neglect of the thermal motion of the polymer, it has potential for use as a tool to suggest other perturbations in polycarbonate structure that may produce superior properties.

Sponsoring Organization:
USDOE
OSTI ID:
183081
Journal Information:
Industrial and Engineering Chemistry Research, Vol. 34, Issue 12; Other Information: PBD: Dec 1995
Country of Publication:
United States
Language:
English