Determination of dn/dc values for ethylene–propylene copolymers

Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

“…Linear PE standards (Polymer Standard Service GmbH, Mainz, Germany), isotactic PP standards (American Polymer Standards, Mentor), linear PE with M w 260 kg/mol, iPP 200 kg/mol, and EP copolymers were dissolved in 1-decanol at a concentration of 1-2 mg/mL at 160 C. Samples of EP copolymers were prepared by Suarez 51,52 and described by Coto et al 53,54 The copolymerization reactions were carried out in a stirred tank reactor operating in semicontinuous mode at 70 C and 5 bar. Their molecular characterization data obtained with high-temperature SEC and NMR spectroscopy are summarized in Table I.…”

Purification and structural characterization of an α-glucosidase inhibitory polysaccharide from apricot ( Armeniaca sibirica L. Lam.) pulp

“…The molecular weight and molecular weight distribution of the sample were measured using GPC/MALLS (Coto, Suárez, & Caballero, 2007;Liu, Bo, Zhang, & Zhu, 2003;Suárez, Caballero, & Coto, 2010). This process was performed on an infusion system (Waters 515 HPLC Unit Pump) fitted with one gel column (Shodex SB-806M) and the combined detectors (Wyatt-DAWN HELEOS ® eighteen-angle laser light scattering and Wyatt-Optilab rex refractive index detector).…”

Broadening of polymer chromatographic signals: Analysis, quantification and correction through effective diffusion coefficients

“…Temperature was also set at 145 • C. The DAWN EOS photometer system was calibrated with toluene, the detectors were normalized with a standard monodisperse PS (M w = 30 kg mol −1 ) which was also used to determine interdetector volume [20]. The differential refractive index increments dn/dc of the polymers and copolymers were determined following a procedure previously described [21]. Constant dn/dc values of 0.053 mL g −1 and 0.101 mL g −1 were used for PS and EP polymers, respectively.…”

“…Constant dn/dc values of 0.053 mL g −1 and 0.101 mL g −1 were used for PS and EP polymers, respectively. dn/dc values for EP copolymers were considered composition independent according to previous work [21]. The software used was ASTRA V 5.1.9.1, from Wyatt Technology.…”