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image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Polymer Engineering ...arrow_drop_down
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
Polymer Engineering & Science
Article . 1999 . Peer-reviewed
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Rheokinetical behavior of melamine‐formaldehyde resins

Authors: P.‐O. Hagstrand; C. Klason; L. Svensson; S. Lundmark;

Rheokinetical behavior of melamine‐formaldehyde resins

Abstract

AbstractThe effects of cure temperature and amount of catalyst on the rheokinetical behavior of a melamine‐formaldehyde (MF) thermosetting system is investigated using a dynamic mechanical technique similar in nature to Torsion Impregnated Cloth Analysis (TICA) and Torsional Braid Analysis (TBA). The proposed name of the used technique is Torsional Substrate Analysis (TSA). Isothermal cures of the resin are carried out from 115°C to 160°C for varying amounts of catalyst. Each TSA measurement exposes several transitions. First, a glass‐to‐liquid transition during the heatup procedure is seen, indicated by sharp peaks of the loss shear modulus, G″, and loss tangent, tanδ. Later, vitrification is seen, indicated by a second G″ maximum. Finally, a completion of shift to a diffusion controlled cure reaction occurs, shown as a storage shear modulus, G′, plateau. The rheokinetical data is used to construct Time‐Temperature‐Transformation (TTT) cure diagrams, for each level of catalyst. High pressure differential scanning calorimetry (HPDSC) measurements are carried out in order to estimate the fractional conversion of samples that have been cured isothermally for times corresponding to a second tanδ maximum, the second G″ maximum, and the G′ plateau. The fractional conversion is determined by the residual entalphy technique. The HPDSC measurements do not give a clear answer whether the second tanδ maximum corresponds to gelation or not. It is therefore likely that TSA, like similar techniques, is not capable to detect gelation. A glass transition temperature of 130°C and 150°C is found to correspond to a fractional conversion of 0.65 and ∼0.80, respectively. Preliminary measurements suggest that the maximum glass transition temperature, Tg ∞, of the investigated MF resin is at least 180°C.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
19
Top 10%
Top 10%
Average
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