A new instrument for preparative gel permeation chromatography

Abstract

SynopsisA preparative liquid-phase chromatograph w&s built for the purpose of obtaining sufficiently large quantities of very narrow fractions of different polymeric species, such as polystyrene, PVC, polybutadiene, and polyethylene. This apparatus allows the fractionation of approximately 20 g of polymer per day; the fractions so obtained have polydispersities of about 1.1 over a very wide range of molecular weights. Polydispersities of less than 1.01 were obtained after recycling of the sample. DESCRIPTION AND CHARACTERISTICS OF THE PREPARATIVE CHROMATOGRAPHA preparative chromatograph can be divided into five components ( Fig. 1) which are (1) the pumping system; (2) the sample injector; (3) the columns; (4) the detector; (5) the fraction collector. We shall not describe in this paper the pumping system and the detector, which are directly based on the Waters analytical instrument.

Growth Kinetics of Polyethylene Single Crystals. I. Growth of (110) Faces of Crystals from Dilute Solutions in Xylene

“…The surface free energy product has often been estimated by using the well-known relation G G q exp -4( Aht)kT(AT). (9) where G is the growth rate (cm sec-1), Go contains factors not strongly dependent on temperature, b is the thickness of a layer on a growing strip of a crystal (4.55 X 108 cm19), Ahf is the heat of fusion (2.80 X 109 erg cm-319), Td°i s the equilibrium dissolution temperature (when considering crystallizations from the melt T¿°i s replaced by Tm°, the equilibrium melting temperature), and AT = Td°-T where T is the crystallization temperature. The slope of the plot In G us.…”

Facile Synthesis of Unimodal Polymethacrylates with Narrow Dispersity via NIR LED Light‐Controlled Bromine–Iodine Transformation Reversible‐Deactivation Radical Polymerization

“…[ 4 ] However, the precision synthesis of this type of polymers is of great significance but huge challenge up to now, especially synthesizing by simple radical polymerization method. Usually, the synthetic strategies for narrow Đ polymers can be divided into physical separation [ 5 ] and chemical synthesis. The chemical synthetic methods mainly include anionic polymerization, [ 6 ] ring‐opening polymerization (ROP), [ 7 ] and reversible‐deactivation radical polymerization (RDRP).…”

Fractionation of Poly(vinyl chloride)s by Preparative Scale Gel-Permeation Chromatography

“…The fractionation of polymers by the preparative-scale GPC (gel-permeation chromatography) has been attempted with several polymers/-11 but a report by Peyrouset, et a/., 6 is the only example reported in regard to PVC. They fractionated a PVC sample with a weight-average molecular weight (Mw) of 8.97 X 10\ using silica beads (Spherosil) and obtained fractions with a polydispersity (the ratio of Mw to number-average molecular weight Mn) of 1.1-1.2.…”