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Thermodynamic miscibility of polymer‐liquid crystal blends
Author(s) -
Patwardhan Ashutosh A.,
Belfiore Laurence A.
Publication year - 1988
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760281407
Subject(s) - miscibility , materials science , differential scanning calorimetry , unifac , polycarbonate , polymer , polymer blend , thermodynamics , liquid crystal , phase (matter) , polymer chemistry , chemical engineering , organic chemistry , copolymer , composite material , chemistry , phase equilibrium , physics , optoelectronics , engineering
The thermodynamic phase behavior of two polymer‐liquid crystal blends was investigated in both the solid and molten states. One of the blends (p‐hexyloxybenzoic acid and poly[ethylene glycol]) contains a semi‐crystalline polymer. The second example (p‐pentyloxycinnamic acid and bisphenol‐ A polycarbonate) contains a high‐impact‐resistant amorphous thermoplastic. Whereas, the former system is almost completely immiscible at ambient temperature, yet advantageous for applications in the microelectronics industry, the latter blend exhibits partial (concentration‐dependent) miscibility. Our multi‐technique assessment of miscibility/phase separation includes high‐resolution carbon‐13 solid state NMR spectroscopy, differential scanning calorimetry (DSC), and group‐contribution thermodynamics (Universal Quasi‐Chemical Functional‐Group Activity Coefficient formalism including a Free Volume correction for the small molecule activity, UNIFAC‐FV). Approximate temperature‐composition (equilibrium) phase diagrams are constructed for both blends in light of the results from NMR, DSC, and UNIFAC‐FV.