Comparing crystallization rates between linear and cyclic poly(epsilon-caprolactones) via fast-scan chip-calorimeter measurements. (20th April 2015)

• Record Type: Journal Article
• Authors: Wang, Jing; Li, Zhaolei; Pérez, Ricardo A.; Müller, Alejandro J.; Zhang, Boyu; Grayson, Scott M.; Hu, Wenbing
• Is Part Of: Polymer. Volume 63(2015)
• Page Start: 34
• Page End: 40
• Publication Date: 2015-04-20
• Subjects: Fast-scan chip-calorimeter -- Cyclic PCL -- Linear PCL; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2015.02.039
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The vital role of chain ends in the crystallization of linear polymers can be understood by unraveling the mechanisms of crystallization of cyclic polymers. A commercial chip-calorimeter Flash DSC1 was employed to compare the nucleation and overall crystallization rates between linear and cyclic poly(epsilon-caprolactones) (PCL) with similar molar masses of around 2 kg/mol. In the high temperature region, faster overall crystallization of cyclic PCL relative to linear PCL is consistent with previously reported results employing conventional DSC. In the low temperature region, the cyclic PCL exhibits a lower onset temperature of homogenous nucleation when compared to linear PCL analogs. This result was attributed to a higher mobility of free chain ends in the linear PCL as compared to cyclic PCL. A simplified data-treatment method on the nucleation half-time has been proposed. Graphical abstract: Highlights: Fast-scan chip-calorimeter studies polymer nucleation at low temperatures. A simplified data-treatment method for nucleation half time has been proposed. Crystal nucleation of cyclic PCL unravels the role of chain ends in linear PCL. Measured crystallization rates at high temperatures agree with previous report.