Fingerprints of homogeneous nucleation and crystal growth in polyamide 66 as studied by combined infrared spectroscopy and fast scanning chip calorimetry

Anton, Arthur Markus; Zhuravlev, Evgeny; Kossack, Wilhelm; Andrianov, Ruslan; Schick, Christoph; Kremer, Friedrich

doi:10.1007/s00396-020-04666-9

Cited by 14 publications

(11 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since Brill first reported the reversible crystal transition of PA66 from the triclinic phase into a pseudohexagonal phase under heating in 1942, which is known as the Brill transition, numerous investigations into this phenomenon have been reported for various PAs, for example, PA6, − PA1010, and PA1012. , The Brill transition can be monitored by various means such as variable-temperature WAXD, ,,, Fourier transform infrared spectroscopy (FTIR), ,− and Raman spectroscopy . Under heating, the two reflection peaks of the α-phase in the WAXD patterns completely merge into a single peak of the γ-phase (and vice versa during cooling) at a specific temperature; this is defined as the Brill temperature ( T B ).…”

Section: Introductionmentioning

confidence: 99%

The Brill Transition in Long-Chain Aliphatic Polyamide 1012: The Role of Hydrogen-Bonding Organization

et al. 2021

View full text Add to dashboard Cite

The effect of hydrogen-bond (H-bond) organization, evaluated by the crystal perfection index (CPI), on the Brill transition of long-chain polyamide 1012 upon heating was investigated with variable-temperature wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and Fourier transform infrared spectroscopy (FTIR). A sufficiently high cooling rate was required to prepare samples with randomly distributed H-bonds (i.e., a low CPI) because this inhibits the reorganization of the 2-D hydrogen sheet structure during cooling from melts. The Brill temperature (T B) values of the T210 and T270 samples, which were prepared by cooling from 210 and 270 °C at a rate ranging from 5 to 100 °C/min, were determined. The T B values of the T270 samples determined by WAXD and FTIR show a significant linear decrease with the decreasing CPI, whereas that of the T210 samples remains constant because its CPI is independent of the applied cooling rate. Both the T210 and the T270 samples quenched by a liquid nitrogen bath are γ-phase at ambient temperature, suggesting that the critical cooling rate required to reduce the CPI depends on the content of hydrogen-bonded H-bonds at each temperature for the melts. The T B gap between the T210 and T270 samples with a similar lamellar thickness is caused by the content of randomly distributed H-bonds.

show abstract

Section: Introductionmentioning

confidence: 99%

The Brill Transition in Long-Chain Aliphatic Polyamide 1012: The Role of Hydrogen-Bonding Organization

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Tammann's nuclei development method implies formation of homogeneous nuclei at high supercooling of the melt, or in the glass, and their development to crystals at higher temperatures. This scheme, so far, has been applied for analysis of the kinetics of nuclei formation of PCL, 16,27 poly(L-lactic acid) (PLLA), [28][29][30] poly(ethylene terephthalate) (PET), 31 poly(butylene isophthalate) (PBI), 32,33 polyamide 66 (PA 66), 34,35 or polyamide 6 (PA 6). 36 For PA 11, data are not available.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of homogeneous crystal nucleation of polyamide 11 near the glass transition temperature

Jariyavidyanont

Zhuravlev

Schick

et al. 2020

Polymer Crystallization

Self Cite

View full text Add to dashboard Cite

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 processingcontrolled structure formation, eventually being beneficial for tailoring the property profile.

show abstract

“…No bands associated with degradation were found in the spectra collected after sample preparation. Similar sample preparation has been reported by Anton et al in their work on PA66 …”

Section: Methodsmentioning

confidence: 99%

“…Similar sample preparation has been reported by Anton et al in their work on PA66. 41 For obtaining kinetics information, the PA6 sample was initially heated to 300 °C (higher than reported T m,0 of PA6, 260 °C10 ) for 0.5 s to erase thermal history. Then, the melt was cooled to the crystallization temperature (T c ) at a rate of 2000 K/s.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Probing Three Distinct Crystal Polymorphs of Melt-Crystallized Polyamide 6 by an Integrated Fast Scanning Calorimetry Chip System

et al. 2021

View full text Add to dashboard Cite

Isothermal crystallization of polyamide 6 (PA6) was studied using a state-of-the-art modified fast scanning calorimetry (FSC) chip over a wide temperature range. Microfocus FTIR spectroscopy was carried out to collect temperaturedependent spectra of PA6 directly on the FSC chip. The changes observed in amide-and methylene-related bands provide direct evidence of three crystalline modifications in PA6 from melt crystallization. The melt-crystallized PA6 was found to develop the mesomorphic β-phase below 105 °C and the α-phase above 150 °C. It has been confirmed that the γ-phase coexists with the βor αphase in the temperature region between 105 and 150 °C. Isothermal crystallization kinetics of PA6 in a wide temperature range were extracted directly from exothermic peaks and indirectly using the interruption method. A peculiar discontinuity in crystallization kinetics has been found in the transition region between the βand γ-phases. In the same temperature region, a sudden transition from crystal aggregates to spherulitic morphology was captured by AFM. PA6 was cooled at rates from 10 to 2000 K/s before isothermal crystallization to mimic a full range of processing relevant conditions. A time−temperature−transformation diagram was built based on kinetic data to illustrate that the isothermal crystallization of PA6 is sensitive to the crystallization pathway. The novel platform built on a modified FSC chip is a powerful tool for the comprehensive study of polymer crystallization at processing-relevant conditions.

show abstract

Fingerprints of homogeneous nucleation and crystal growth in polyamide 66 as studied by combined infrared spectroscopy and fast scanning chip calorimetry

Cited by 14 publications

References 42 publications

The Brill Transition in Long-Chain Aliphatic Polyamide 1012: The Role of Hydrogen-Bonding Organization

The Brill Transition in Long-Chain Aliphatic Polyamide 1012: The Role of Hydrogen-Bonding Organization

Kinetics of homogeneous crystal nucleation of polyamide 11 near the glass transition temperature

Probing Three Distinct Crystal Polymorphs of Melt-Crystallized Polyamide 6 by an Integrated Fast Scanning Calorimetry Chip System

Contact Info

Product

Resources

About