Characterization of low-density polyethylene by gel permeation chromatography—III. Study on the Drott method using a whole polymer
✍ Scribed by A. Cervenka; G.R. Williamson
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 308 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0014-3057
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✦ Synopsis
Two features of the Drott iterative procedure for the estimation of long-chain branching have been examined, viT. the proportionality between the number of long-chain branches n per molecule and its molecular weight M, and the exponent ~ relating the ratio of intrinsic viscosities of branched and linear polymers of the same weight-average molecular weight to n. The original Drott model describing the distribution of long-chain branches (LCB) has been replaced by a more general equation: n = const M s, and an examination of the effect of the exponents B and ~ on the molecular weight distribution (MWD) and LCB characteristics carried out. The analysis has revealed that, unless information on the LCB distribution is available, the method described by Drott for which B = 1 can hardly give meaningful information on MWD and LCB for commercial low-density polyethylenes.