화학공학소재연구정보센터
Journal of Materials Science, Vol.56, No.1, 886-901, 2021
The enhanced II-I transition behaviors of an isotactic polybutene-1 alloy by a TAB-3
Polymer crystallization and crystal transition mechanisms are charming but elusive long-lasting questions in polymer physics due to theoretical and industrial importance. Interestingly, after a TAB-3 incorporated into an isotactic polybutene-1 (iPB-1) alloy, its II-I transition was sharply enhanced at room temperature, whereas the "nucleation" was inversely inhibited at low temperaturesT(low)s around - 10 degrees C or almost kept fixed at room temperature. Moreover, with II-I transition preceding, the peak melting pointT(m,peak)of the remained form II decreased, while theT(m,peak)of the resulting form I increased inversely. And the crystallinity increase of the neat iPB-1 alloy during II-I transition turned as decrease after TAB-3 incorporation. All the results were difficult to be interpreted according to the traditional solid-solid nucleation-growth II-I transition mechanism with nucleation as the rate-determining step. We looked back and reconsidered the II-I transition mechanism and preferred a "form II"-"form-II-favored packed mesophase"-"form I" process with crystals reorganized. Formation of the intermediate form-II-favored packed mesophase from form II crystals promoted by TAB-3 incorporation controls the entire II-I transition and accounts for the characteristic "growth-controlled" II-I transition kinetics of the iPB-1 alloy. The results are triggering to deep theoretical understanding to the II-I transition for further extended industrial applications of iPB-1.