Volume no :5, Issue no: 2, April (2012)

SYNTHESIS AND GAS PERMEATION PROPERTIES OF RING-OPENED POLYNORBORNENE DICARBOXIMIDES BEARING 2,2,6,6-TETRAMETHYLPIPERIDYL MOIETIES

Author's: JOEL VARGAS, ARLETTE A. SANTIAGO, JAVIER CRUZ-GÓMEZ, JORGE A. CRUZ-MORALES, MIKHAIL A. TLENKOPATCHEV, MARÍA I. LORÍA-BASTARRACHEA, JOSÉ LUIS SANTIAGO-GARCÍA and MANUEL AGUILAR-VEGA
Pages: [107] - [133]
Received Date: March 12, 2012
Submitted by:

Abstract

The N-2,2,6,6-tetramethylpiperidyl-norbornene-5,6-dicarboximide (2a), N-4-hydroxy-phenyl-norbornene-5,6-dicarboximide (2b), and N-pentafluorophenyl-norbornene- 5,6 -dicarboximide (2c) mixtures of exo and endo monomers were synthesized and polymerized via ring opening metathesis polymerization (ROMP) using bis(tricyclohexylphosphine) benzylidene ruthenium (IV) dichloride (I) and tricyclohexylphosphine [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene] [benzylidene] ruthenium dichloride (II) to produce the corresponding polynorbornene dicarboximides PTMPiNDI, PHPhNDI, and PPFPhNDI, respectively. The transport of five gases He, and across membranes prepared from these polynorbornenes were determined at 35°C by using a constant volume permeation cell. Gas permeability, diffusion, and solubility coefficients of PTMPiNDI classify it as a low permeability polymer for oxygen and carbon dioxide with possibilities of use in packaging applications. It was also found that gas permeation is lower in PTMPiNDI due to a lower fractional free volume (FFV), which difficulties the diffusion through it as compared to PHPhNDI and PPFPhNDI that present more open structures. The permeability coefficients for all gases in the fluorine-containing PPFPhNDI membrane are much more larger than those in the non-fluorinated PHPhNDI and PTMPiNDI membranes. The sorption process and not the diffusive step is responsible for this increase in the permeability of the PPFPhNDI membrane. A molecular dynamics simulation of each polynorbornene was performed to estimate the density value. The results are in good agreement with the experimentally measured densities and allow to corroborate FFV determinations.

Keywords

gas permeation, polynorbornene dicarboximide, ring-opening metathesis polymerization.