Kinetics of homogeneous crystal nucleation of polyamide 11 near the glass transition temperature. Issue 1 (29th August 2020)

• Record Type: Journal Article
• Authors: Jariyavidyanont, Katalee; Zhuravlev, Evgeny; Schick, Christoph; Androsch, René
• Is Part Of: Polymer crystallization. Volume 4:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-29
• Subjects: crystal nucleation -- crystallization -- fast scanning chip calorimetry -- polyamide 11; Crystalline polymers -- Periodicals; Crystallization -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pcr2.10149
• Languages: English
• ISSNs: 2573-7619

Abstract

Abstract: In this work, the kinetics of formation of homogeneous crystal nuclei of polyamide 11 (PA 11) near the glass transition temperature ( T g ), which is slightly above ambient temperature, has been analyzed using fast scanning chip calorimetry (FSC), employing Tammann's two‐stage crystal nuclei development method with non‐isothermal and isothermal nucleation and growth stages. The critical cooling rate above which formation of an ordered phase (crystals or mesophase) is suppressed is around 1000 K/s. Formation of nuclei, in contrast, can only be prevented by cooling the melt faster than about 30, 000 K/s to far below T g . The temperature of fastest formation of crystal nuclei is about 10–15 K higher than T g, with first detection of nuclei within less than a millisecond. As such, the onset‐time of nuclei formation is about one order of magnitude shorter than the time of first observation of crystals/mesophase. Furthermore, annealing experiments performed below T g revealed glass‐crystallization, with the stability of the formed ordered phase limited to temperatures near T g . Since rapid cooling and solidification of the melt of PA 11 at low temperatures often occurs in processing of this material, this work provides new insights into processing‐controlled structure formation, eventually being beneficial for tailoring the property profile. Abstract : Polyamide 11 is a crystallizable bio‐based polymer with its semicrystalline morphology, and therefore properties, controlled by the nucleation path. Fast scanning chip calorimetry and application of Tammann's two‐stage development method allow quantification of the kinetics of homogeneous crystal nucleation near the glass transition temperature. The data reveals that nucleation is fastest at around 60 °C, beginning after few milliseconds. It is expected that the performed study contributes to further understanding of homogeneous crystal nucleation in polymers as well as crystallization at processing‐relevant cooling conditions/supercooling.