Roy Raharjo

Graduate Student - Chemical Engineering
The University of Texas at Austin

Location: PRC Building 133, 1.308A
Phone (512) 232 2802
Email: Roy Raharjo

B.S. Chemical Engineering
Purdue University 2002

See Roy Raharjo's CV.

Research Areas:

Mixed Gas n-Butane/Methane Sorption and Transport in Poly(dimethylsiloxane) and Poly(1-trimethylsilyl-1-propyne)

Solubility selective polymers are important for a number of separation processes requiring selective removal of larger gas or vapor molecules that constitute the minority components in a gas stream. Traditionally, membrane separation performance is estimated from pure gas permeation measurements. However, in certain cases, the mixed-gas selectivity of vapor over a permanent gas can actually be higher than the pure gas selectivity. For example, Pinnau et al. [1] observed a significant decrease in hydrogen permeability in poly(1-trimethylsilyl-1-propyne) (PTMSP) due to the presence of propane in the gas mixture, thus increasing the selectivity of propane over hydrogen. The hydrogen permeability decreased from 20,000 x 10-10 cm3(STP).cm/cm2.s.cmHg for pure gas to 1000 x 10-10 cm3(STP).cm/cm2.s.cmHg in a mixture with a relative propane pressure of 0.8. The propane permeability doubled as the relative propane pressure increased from 0 to 1. Consequently, the selectivity of propane/hydrogen increased from about 1, based on pure gas measurement, to approximately 25 in a mixture with high relative propane pressure. They attributed this unusual observation to the high solubility of propane in the polymer, which effectively blocks hydrogen permeation.

The goal of this project is to develop a fundamental understanding of the competitive effects in vapor/gas permeation through solubility selective polymers like poly(dimethylsiloxane) (PDMS) and PTMSP. n-butane/methane will be used as the model vapor/gas mixture. Mixed-gas permeability and solubility in PDMS and PTMSP will be measured as a function of temperature and pressure to determine the diffusion and sorption-related contributions to this phenomenon. This study should aid in developing high-performance solubility selective polymers for vapor/gas separations.

References
[1] Pinnau, I.; Casillas, C. G.; Morisato, A.; Freeman, B.D. Hydrocarbon/Hydrogen Mixed Gas Permeation in Poly(1-trimethylsilyl-1-propyne) (PTMSP), Poly(1-phenyl-1-propyne) (PPP), and PTMSP/PPP Blends. Journal of Polymer Science: Part B: Polymer Physics, 1996. 34, 2613 - 2621.

Publications:

Raharjo, R.D., H. Lin, D.F. Sanders, B.D. Freeman, S. Kalakkunnath, D.S. Kalika, “Relation Between Network Structure and Gas Transport in Crosslinked Poly(propylene glycol diacrylate)”, Journal of Membrane Science, 283, 253-265 (2006).

Wang, X-Y, F.T. Willmore, R.D. Raharjo, X. Wang, B.D. Freeman, A.J. Hill, and I. Sanchez, “Molecular Simulation of Physical Aging in Polymer Membrane Materials,” Journal of Physical. Chemistry B., 110, 16685-16693 (2006).

Wang, X-Y, R.D. Raharjo, H.J. Lee, Y. Lu, B.D. Freeman, I.C. Sanchez, “Molecular Simulation and Experimental Study of Substituted Polyacetylenes: Fractional Free Volume, Cavity Size Distributions and Diffusion Coefficients”, Journal of Physical Chemistry B, 110, 12666-12672 (2006).

Jansen, J.C., M. Macchione, R. Raharjo, B.D. Freeman, and E. Drioli, “Pure and Mixed Gas Transport Properties of Novel Asymmetric Poly(ether ether ketone) Membranes with Different Morphologies”, Desalination, 199(1-3), 461-463 (2006).

Lin, H., E. Van Wagner, R. Raharjo, B.D. Freeman, I. Roman, “High-Performance Polymer Membranes for Natural-Gas Sweetening”, Advanced Materials, 18, 39-44 (2006).

Prabhakar, R.S., Raharjo, R., Toy, L.G., Lin, H., and Freeman, B.D., “Self-Consistent Model of Concentration and Temperature Dependence of Permeability in Rubbery Polymers,” Industrial & Engineering Chemistry Research, 44, 1547-1558 (2005).

R. D. Raharjo, H. J. Lee, B. D. Freeman, T. Sakaguchi, and T. Masuda, "Pure gas and vapor permeation properties of poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] (PTMSDPA) and its desilylated analog, poly[diphenylacetylene] (PDPA)", Polymer, 46 (2005) pp. 6316-6324.

Raharjo, R.D., H. Lin, D.F. Sanders, B.D. Freeman, S. Kalakkunnath, D.S. Kalika, "Relation Between Network Structure and Gas Transport in Crosslinked Poly(propylene glycol diacrylate)", Journal of Membrane Science, submitted.

Lin, H., E. Van Wagner, R. Raharjo, B.D. Freeman, I. Roman, "High-Performance Polymer Membranes for Natural-Gas Sweetening", Advanced Materials, 18, 39-44 (2006).