Porosity determination of poly(trimethylolpropane trimethacrylate) gels

Abstract

Trimethylolpropane trimethacrylate (TRIM) was suspension-polymerized with toluene as poreforming agent. The concentration of the monomer (TRIM) in the porogen was varied between 20 and 50 v01.-' 4' 0 of the organic phase. The poly(TR1M) particles had narrow particle-size distributions. The porosity of the dry gels was studied with scanning electron microscopy, nitrogen adsorption/desorption and mercury porosimetry. All gels had bimodal pore-size distributions.The size distribution of large pores (r > 50 A) of solvent free poly(TR1M) broadened when the amount of TRIM was decreased. The pore-size distributions of the swollen poly(TR1M) gel particles were calculated from size-exclusion chromatography (SEC) results. The separation range for poly(TR1M) particles of polystyrene standards varied with the monomer concentration. A relationship between the pore-size distributions of dry poly(TR1M) gels and those of swollen gels is proposed. Whether or not the structure of poly(TR1M) gels could be described as fractals is discussed. 100 (V(swo1len gel) -V(dry gel) S = gel) CCC 0025-1 16X/91/$03.00 0 1991, Hiithig & Wepf Verlag, Basel 1224 A. Schmid, L.4. Kulin, P. Flodin P A K D Partition coefficient Skeletal density of the dry polymer Area beneath the differential pore-size distribution curve, proportional to the percentage of the total separating volume vR -vR2700000 vR 250 -vR 2700000 K D = R S P Specific resolution R ,Resolution of two peaks HETP Height equivalent to a theoretical plate *) Systematic IUPAC nomenclature: 2-Ethyl-2-hydroxymethyl-1,3-propanediol.

Preparation and Porosity Characterization of Highly Cross-Linked Polymer Resins Derived from Multifunctional (Meth)acrylate Monomers

“…Comparing the N 2 sorption Brunauer, Emmett, and Teller (BET) surface areas 31 of the TRIM resins 1 − 12 (Table ) with the analogous data for the polymer gels described by Flodin et al, − very similar values, 300−600 m 2 g -1 , are apparent. The Swedish group reported that changes in the pore structure led in some cases to linear, but in others to nonlinear, relationships between the surface area and the concentration of monomer in the porogen. , The BET surface area and corresponding pore volume as a function of monomer concentration in the porogen for our TRIM resins are shown in Figures and , respectively.…”

Molecularly Imprinted Polymer Beads: Suspension Polymerization Using a Liquid Perfluorocarbon as the Dispersing Phase

“…Such hollow beads have also been reported for conventional suspension polymerizations in water . The morphology of the beads is typical of beads made by suspension polymerization with a slightly denser and smoother surface layer covering a more open porous structure in the interior. , The beads made using acetone as porogenic solvent (Figure d) differed from the others. They were larger and had much rougher surface morphology and more “debris” on their surfaces than those prepared using chloroform or toluene.…”

Transparent Macroporous Polymer Monoliths

“…Transparency is judged, however, in the swollen state. Flodin et al compared dry-state techniques with swollen-state techniques, such as size exclusion chromatography (SEC). To correlate pore sizes and pore size distributions between the swollen and the dry states, the shape of pores was approximated to spherical and pore sizes of the swollen state were therefore calculated by multiplication of the pore size in the dry state by the swelling factor to the power of 1 / 3 (pore size swollen = pore size dry × (swelling factor) 1/3 ).…”