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Structural dependence of density in high molecular weight esters

Shobha, Hosadurga K and Kishore, Kaushal (1992) Structural dependence of density in high molecular weight esters. In: Journal of Chemical & Engineering Data, 37 (4). pp. 371-376.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/je00008a001


The effect of molecular structure on density has been examined in high molecular weight esters (molecular weight 300-900), having varying degrees of branching. Densities were calculated from an empirical equation, which agrees well with the experimental values (error +/-1.5%), irrespective of branching. Since density is related to molecular packing and hence to the molecular rotation, in n-alkanes, the glass transition temperature (T(g)) and density both increase with molecular weight, and hence T(g) is directly related to the density. The esters exhibit a complex behavior. In linear esters the T(g) decreases with molecular weight which is explained from group contribution and molecular interactions. In the +-branched esters, however, T(g) decreases with molecular weight until the molecular weight reaches 600 and increases sharply thereafter. The Y-branched esters show an intermediate behavior. The dependence of T(g) on molecular weight has been explained from the segmental motion.

Item Type: Journal Article
Publication: Journal of Chemical & Engineering Data
Publisher: American Chemical Society
Additional Information: Copyright of this article belongs to American Chemical Society.
Department/Centre: Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited: 30 May 2011 08:04
Last Modified: 30 May 2011 08:04
URI: http://eprints.iisc.ac.in/id/eprint/37658

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