Characterization by light scattering of butadiene-acrylonitrile copolymers with microgel content

Francuskiewicz, Frieder; Dautzenberg, H.

doi:10.1016/0014-3057(85)90124-7

Cited by 5 publications

(7 citation statements)

References 14 publications

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“…Very likely the chain behavior that becomes noticeable at large q values is not solely caused by free chains alone, but a marked fraction belongs to the structure of the aggregate, a result that was reasonable to expect. Apparently, the observed aggregate system can be classified in the above-mentioned framework between a one-component heterogeneous structure and a two-component system (14) n agg,1 ) [n agg exp -(1 -m)]/m (15) …”

Section: Discussionmentioning

confidence: 99%

“…Several research groups, including us, [11][12][13][14] employed an empirical procedure for mathematical separation of the two components. Such a treatment requires reasonable assumptions on the architecture of the high molar mass aggregate component and mostly also of the other component.…”

Section: Introductionmentioning

confidence: 99%

“…To some extent, a selective precipitation could give valuable information, but a complete separation was not possible also with other sytems and cannot be expected on the basis of common fractionation theories. , In any case the high concentration phase after partial precipitation always contains a certain amount of short chains, and vice versa, the dilute phase contains a small fraction of high molar mass particles. Another way of separation consists of a mathematical analysis of the scattering curves from such a two-component system. − However, if linear chains are attached to the first component and are not independently moving, differentiation between the two possibilities of attached or free chains will be difficult or may not even be feasible without data from other independent measurements. Separation of the two components is commonly achieved by size exclusion chromatography.…”

Section: Introductionmentioning

confidence: 99%

“…The main difficulties in the description of aggregates, in particular of a polymer two-component system, arise from the fact that the architecture of the aggregates is not known, and this problem becomes further involved by a large size distribution. Several research groups, including us, − employed an empirical procedure for mathematical separation of the two components. Such a treatment requires reasonable assumptions on the architecture of the high molar mass aggregate component and mostly also of the other component.…”

Section: Introductionmentioning

confidence: 99%

“…Another way of separation consists of a mathematical analysis of the scattering curves from such a two-component system. [11][12][13][14] However, if linear chains are attached to the first component and are not independently moving, differentiation between the two possibilities of attached or free chains will be difficult or may not even be feasible without data from other independent measurements. Separation of the two components is commonly achieved by size exclusion chromatography.…”

Section: Introductionmentioning

confidence: 99%

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Uncommon Solution Behavior of Poly(N-vinylimidazole). Angular Dependence of Scattered Light from Aggregates in Ethanol

Савин

Burchard

2004

Macromolecules

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Static light scattering measurements from high molar mass poly(N-vinylimidazole) (PVI) in ethanol displayed strikingly different angular dependencies from the PVI samples below Mw ) 8 × 10 5 g/mol. The high molar mass particles were considered as aggregates. A classification of the aggregate structure became possible by comparison with different, well-understood models. The shapes of the curves were examined, on one hand, on the basis of one-component models, with heterogeneity in segment density, and on the other, on the assumption of a two-component system. The observed scattering curves show behavior similar to the soft-sphere model and in another aspect to star-branched macromolecules with stiff arms. Also, a two-component analysis of the scattering data was successful with a globular architecture for the aggregates and coil behavior for nonattached linear chains. The analysis gave evidence to clustering of segments. A large number of the linear mass density was found combined with a considerable chain stiffness. Indications were found that the fraction of free chains was overestimated. A significant part of the chains appeared to be attached to the aggregates. Sterical stabilization in the course of dissolution of the glassy material, combined with hydrogen bonding, are suggested as the reason for the incomplete dissolution.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%