TY - JOUR
T1 - Conformational Asymmetry in Poly(vinylcyclohexane) Containing Diblock Copolymers
AU - Gehlsen, Mark D.
AU - Bates, Frank S
PY - 1994/6/1
Y1 - 1994/6/1
N2 - Three types of compositionally symmetric and nearly monodisperse diblock copolymers, poly(1,2-butadiene)-poly(styrene) (1,2-PB-PS), poly(cis-1,4-isoprene)-poly(styrene) (1,4-PI-PS), and poly(1,4-butadiene)-poly(styrene) (1,4-PB-PS), were anionically synthesized and subsequently catalytically saturated, yielding poly(vinylcyclohexane)-poly(ethylethylene) (PVCH-PEE), poly(ethylenepropylene)-poly(vinylcyclohexane) (PEP-PVCH), and poly(ethylene)-poly(vinylcyclohexane) (PE-PVCH). The order-disorder transition temperature, TODT, was determined for the unsaturated and saturated diblock copolymers using dynamic mechanical spectroscopy. Changes in TODT with saturation are dependent on the resulting polyolefin microstructure. PVCH-PEE has a much lower TODT, while PEP-PVCH and PE-PVCH display higher ones, relative to the unsaturated precursor materials. Group contribution analysis qualitatively anticipates the PVCH-PEE behavior but fails to account for the PEP-PVCH and PE-PVCH results. Entropic arguments based on differences in the conformational characteristics of each block appear to be correlated with the associated variations in the segment-segment interaction parameter, χ. These findings support earlier speculation regarding the role of conformational asymmetry in the thermodynamics of polymer-polymer systems.
AB - Three types of compositionally symmetric and nearly monodisperse diblock copolymers, poly(1,2-butadiene)-poly(styrene) (1,2-PB-PS), poly(cis-1,4-isoprene)-poly(styrene) (1,4-PI-PS), and poly(1,4-butadiene)-poly(styrene) (1,4-PB-PS), were anionically synthesized and subsequently catalytically saturated, yielding poly(vinylcyclohexane)-poly(ethylethylene) (PVCH-PEE), poly(ethylenepropylene)-poly(vinylcyclohexane) (PEP-PVCH), and poly(ethylene)-poly(vinylcyclohexane) (PE-PVCH). The order-disorder transition temperature, TODT, was determined for the unsaturated and saturated diblock copolymers using dynamic mechanical spectroscopy. Changes in TODT with saturation are dependent on the resulting polyolefin microstructure. PVCH-PEE has a much lower TODT, while PEP-PVCH and PE-PVCH display higher ones, relative to the unsaturated precursor materials. Group contribution analysis qualitatively anticipates the PVCH-PEE behavior but fails to account for the PEP-PVCH and PE-PVCH results. Entropic arguments based on differences in the conformational characteristics of each block appear to be correlated with the associated variations in the segment-segment interaction parameter, χ. These findings support earlier speculation regarding the role of conformational asymmetry in the thermodynamics of polymer-polymer systems.
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U2 - 10.1021/ma00091a024
DO - 10.1021/ma00091a024
M3 - Article
AN - SCOPUS:0028445152
SN - 0024-9297
VL - 27
SP - 3611
EP - 3618
JO - Macromolecules
JF - Macromolecules
IS - 13
ER -