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Gel Permeation and Size Exclusion Chromatography
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Gregorio R. Meira, Jorge R. Vega, Mariana M. Yossen
SEC is the main technique for determining the molar mass distribution (MMD) of both synthetic and natural polymers. Other SEC applications include the determination of copolymer chemical composition, of chain branching, of polymer additives, and the pretreatment of biopolymers.
Polymer Testing Methods for Conventional and Technical Textiles
Published in Sheraz Ahmad, Abher Rasheed, Ali Afzal, Faheem Ahmad, Advanced Textile Testing Techniques, 2017
Usman Zubair, Sheraz Ahmad, Abher Rasheed, Ali Afzal, Faheem Ahmad
Moreover, the different chain lengths impart a distribution of molar masses over a range called the molar mass distribution. The latter, which can only be determined by GPC, is an important parameter in polymer science for controlling the reaction kinetics of polymerization and the physical properties of polymers.
Adhesives in the Wood Industry
Published in A. Pizzi, K. L. Mittal, Handbook of Adhesive Technology, 2017
The molecular characterization of formaldehyde-based resins comprises the determination of: The concentration and the molar ratios of the main components; for example, F:U, F:(NH2)2, F:P:NaOH.The content of reactive sites and functional groups and their distribution in the resin, including the type of bridges between the aromatic rings of the phenol molecule, as well as branching sites; analysis can be done by infrared (IR) spectroscopy, 1H-nuclear magnetic resonance (NMR) spectroscopy, 13C-NMR, or 15N-NMR.The degree of condensation and the molar mass distribution, investigated by gel permeation chromatography (GPC), also called size exclusion chromatography (SEC).The monitoring of the condensation process by diluting the resin with water, taking the water tolerance as measure for the degree of condensation or the increase in molar masses (shift of the molar mass distribution). Still an unsolved task is the prediction of board properties based on the analysis results of the resins used. A few correlation equations between chemical structures of various resins with different compositions and various board properties (dry or wet internal bond [IB] strength, subsequent formaldehyde emission) have been described in the literature (see Section 20.4.4), but a general correlation for various resins and various panels does not exist. The definition of the main parameters, however, is valuable, even though the numbers in individual correlation equations might differ.
Improvements on the use of GPC to measure large-size microstructures in aged asphalt binders
Published in International Journal of Pavement Engineering, 2022
GPC is a commonly used method to measure the distribution of molecules or microstructures in artificially-aged or recycled asphalt binders. Information on molar mass distribution can be used directly as a performance indicator, or as a parameter to predict other engineering properties. This study examined a critical issue in using GPC to measure aged asphalt binders. It was found that large molecules or microstructures formed in RTFO- and PAV-aged asphalt binders can mostly pass the filter membrane before GPC analysis, even for those binders subjected to three times of standard PAV treatments. However, much larger and greater amount of asphaltene agglomerates are found in field-aged, recycled asphalt binders. A significant portion of such agglomerates are blocked during the filtration process. Experiments in this study revealed that while about 1% by mass of the PAV-aged asphalt binders is blocked by GPC membrane, the blocked content for recycled asphalt binders ranges from 6% to more than 10%.
Relationships between the chemistry and the physical properties of bitumen
Published in Road Materials and Pavement Design, 2018
Sandra Weigel, Dietmar Stephan
Size exclusion chromatography (SEC) was carried out for each whole bitumen sample and its constituting fractions allowing the determination of the molar mass distribution. For these investigations, the instrument Malvern Viscothek GPCmax was used, including a RI detector and LT5000L-GPC columns (300 × 7.8 mm; filling material: styrene-divinylbenzene-copolymer). To analyse the samples, the bitumen as well as the fractions were solved in tetrahydrofuran.