標題: Effects of molecular structure of modifiers on the thermodynamics of phenolic blends: An entropic factor complementing PCAM
作者: Wu, HD
Chu, PP
Ma, CCM
Chang, FC
應用化學系
Department of Applied Chemistry
公開日期: 4-五月-1999
摘要: Different thermodynamics in phenolic blends with different polymeric modifiers, i.e., phenoxy, poly(decamethylene adipate), poly(ethylene oxide), and poly(vinyl alcohol), calculated by the Painter and Coleman association model (PCAM) are examined. The thermodynamics is calculated based upon the equilibrium constants derived experimentally from infrared spectroscopies of low molecular weight analogues with similar hydrogen-bonding formation. The discrepancies between the PCAM predictions and the experimentally observed T-g and free volume variation with blending composition are attributed to the additional entropic effects introduced by the long repeated units of modifiers. The structural characteristics and hydrogen-bonding heterogeneity as derived from solid-state NMR and IR spectra support the notion that the length and size of the modifier repeated unit are responsible for such discrepancies. These observed nonidealities can be interpreted as competition between inter- and intraassociations (Delta H-m favored), which depend on the entropy rise associated with the amount of increase of the breaking off of the self-association in phenolic and modifiers within blends. While PCAM is based on "true" miscibility, however, minor modification is required to better describe the thermodynamics for "real" blends where microdomain heterogeneity with size greater than that defined by thermodynamic criteria may be present.
URI: http://dx.doi.org/10.1021/ma9812377
http://hdl.handle.net/11536/31344
ISSN: 0024-9297
DOI: 10.1021/ma9812377
期刊: MACROMOLECULES
Volume: 32
Issue: 9
起始頁: 3097
結束頁: 3105
顯示於類別:期刊論文


文件中的檔案:

  1. 000080179200039.pdf

若為 zip 檔案,請下載檔案解壓縮後,用瀏覽器開啟資料夾中的 index.html 瀏覽全文。