Premium
Influence of plasticizers suggests role of topology in polymer solidification at high cooling rates
Author(s) -
Piccarolo Stefano,
Poulose Anesh Manjaly,
Luzio Alessandro
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.36564
Subject(s) - crystallization , materials science , polymer , crystallization of polymers , quenching (fluorescence) , plasticizer , nucleation , microscale chemistry , polyethylene terephthalate , topology (electrical circuits) , thermodynamics , composite material , physics , mathematics , mathematics education , quantum mechanics , fluorescence , combinatorics
Abstract Although solidification in processing determines short‐ and long‐term properties, methods for understanding polymer crystallization mostly rely on real time experiments. Their evidences being drawn on time scales farther apart with respect to those experienced in processing. Nor significant outcomes have been so far drawn with approaches mimicking the typical processing times, the Continuous Cooling Transformation methods. Use of these techniques has indeed been limited to a heuristic interpretation of the structure developed under extreme solidification conditions without suggesting alternative routes to the understanding or even clues to the many open questions on polymer crystallization under realistic solidification conditions. If the mechanisms inferred from realtime methods cannot in principle be translated to processing conditions the oxymoron is not overcome. In this work, we compare the influence of a plasticizer on the density drop with cooling rate, and therefore on the disappearance of any long range order crystalline phases, observed after fast controlled quenching of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). The plasticizer enhances significantly the maximum cooling rate at which PET still shows long range order crystalline phases, whereas barely modifies the situation for PBT. On the basis of a series of concurrent clues, we suggest that the complex inherent topology of macromolecular melts introduces a timescale on polymer crystallization lying in the range of the solidification conditions experienced in processing. Although melt topology is known to determine in many instances polymer solidification, all approaches so far proposed to describe the development of polymer crystallization overlook or even neglect any explicit dependence of such mechanisms on parameters like the molecular weight between entanglements. Albeit the arguments are feeble they all concur to raise several questions even on the contradictory role of nucleating agents under the extreme conditions experienced in processing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012