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Application of (1)H DOSY for Facile Measurement of Polymer Molecular Weights.

ABSTRACT: To address the practical issues of polymer molecular weight determination, the first accurate polymer weight-average molecular weight determination method in diverse living/controlled polymerization via DOSY (diffusion-ordered NMR spectroscopy) is reported. Based on the linear correlation between the logarithm of diffusion coefficient (log D) and the molecular weights (log Mw), external calibration curves were created to give predictions of molecular weights of narrowly-dispersed polymers. This method was successfully applied to atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT), and ring-opening metathesis polymerization (ROMP), with weight-average molecular weights given by this method closely correlated to those obtained from GPC measurement.

SUBMITTER: Li W

PROVIDER: S-EPMC3545650 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

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Application of (1)H DOSY for Facile Measurement of Polymer Molecular Weights.

Li Weibin W Chung Hoyong H Daeffler Christopher C Johnson Jeremiah A JA Grubbs Robert H RH

Macromolecules 20121204 24

To address the practical issues of polymer molecular weight determination, the first accurate polymer weight-average molecular weight determination method in diverse living/controlled polymerization via DOSY (diffusion-ordered NMR spectroscopy) is reported. Based on the linear correlation between the logarithm of diffusion coefficient (log D) and the molecular weights (log Mw), external calibration curves were created to give predictions of molecular weights of narrowly-dispersed polymers. This ...[more]

PMID: 23335819

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Project description:BackgroundThe disability weight is an essential factor to estimate the healthy time that is lost due to living with a certain state of illness. A 2014 review showed a considerable variation in methods used to derive disability weights. Since then, several sets of disability weights have been developed. This systematic review aimed to provide an updated and comparative overview of the methodological design choices and surveying techniques that have been used in disability weights measurement studies and how they evolved over time.MethodsA literature search was conducted in multiple international databases (early-1990 to mid-2021). Records were screened according to pre-defined eligibility criteria. The quality of the included disability weights measurement studies was assessed using the Checklist for Reporting Valuation Studies (CREATE) instrument. Studies were collated by characteristics and methodological design approaches. Data extraction was performed by one reviewer and discussed with a second.ResultsForty-six unique disability weights measurement studies met our eligibility criteria. More than half (n = 27; 59%) of the identified studies assessed disability weights for multiple ill-health outcomes. Thirty studies (65%) described the health states using disease-specific descriptions or a combination of a disease-specific descriptions and generic-preference instruments. The percentage of studies obtaining health preferences from a population-based panel increased from 14% (2004-2011) to 32% (2012-2021). None of the disability weight studies published in the past 10 years used the annual profile approach. Most studies performed panel-meetings to obtain disability weights data.ConclusionsOur review reveals that a methodological uniformity between national and GBD disability weights studies increased, especially from 2010 onwards. Over years, more studies used disease-specific health state descriptions in line with those of the GBD study, panel from general populations, and data from web-based surveys and/or household surveys. There is, however, a wide variation in valuation techniques that were used to derive disability weights at national-level and that persisted over time.

Dataset Information

Application of (1)H DOSY for Facile Measurement of Polymer Molecular Weights.

Publications

Application of (1)H DOSY for Facile Measurement of Polymer Molecular Weights.

Similar Datasets

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