ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Heterogeneous network polymers were prepared from poly(D-glutamic acid) (PGA) and poly(oxyethylene glycol) (PEG). The content of PGA was systematically varied: 30%, 40%, 50%, 60%, 65%, and 70% by weight. The molecular weights of the crosslinking PEG were 300, 600, 900, and 1800. The plots of the dynamic mechanical tan δ peak temperatures, the PGA interhelical distances (x-rays) and the densities against PGA contents showed a distinct break between 50% and 60%. The photographs under polarizing microscope also indicated an occurrence of phase inversion in the above content region. PGA containing small amounts of PEG and PEG containing small amounts of PGA were found to constitute the continuous phases, respectively, above and below the phase inversion region, while a well-mixed phase is always the dispersed phase. The glass transition was ascribed to the micro-Brownian motions of PGA, PEG, and PEG above and below the phase inversion region, respectively.
Additional Material:
23 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1977.070211216
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