Crystalline transition of polyamide‐10,20 investigated by <i>in situ</i> Fourier transform infrared spectroscopy

Cui, Xiaowen; Yan, Deyue

doi:10.1002/polb.20266

Cited by 16 publications

(10 citation statements)

References 25 publications

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“…The bands at 1243 and 1263 cm -1 are the amide III bands coupled with the out-of-plane methylene motions, whereas the band at 946 cm -1 is the amide IV vibration. [24][25][26] Figure 6d shows the FTIR spectra for the homopolymer PApip,14 on heating from 30 °C to the melt. On heating from 30 °C, the bands at 1188 and 1305 cm -1 disappear between 100 and 110 °C, i.e., in the temperature region where the change in the lamellae thickness is observed in the SAXS patterns (see Figure 3h).…”

Section: Resultsmentioning

confidence: 99%

Influence of Hydrogen Bonding on the Conformational Changes, the Brill Transition, and Lamellae Thickening in (Co)polyamides

et al. 2006

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Copolyamides, based on 1,12-dodecanedicarboxylic acid and different ratios of 1,2-ethylenediamine and piperazine, i.e., PA2,14-co-pip,14 as well as the homopolymers PA2,14 and PApip,14 are studied. Incorporation of the piperazine component in the homopolymer PA2,14 reduces the number of hydrogen bonds. This provides a unique opportunity to investigate the influence of hydrogen bonding on the origin of the Brill transition and chain mobility within polymer crystals. Time-resolved conformational, structural, and morphological changes during heating are followed by FTIR spectroscopy, WAXD, and SAXS. The findings are that from 0 to 62 mol % of piperazine the Brill transition occurs in the same temperature region. The transformation is triggered by the conformational changes in the methylene sequences of the main chain, followed by twisting in the methylene sequences next to the amide group. This results in enhanced chain mobility along the c-axis, causing lamellar thickening. For 80 mol % of piperazine and higher, no Brill transition is observed. However, conformational changes in the methylene sequences of the main chain occurs, triggering lamellar thickening.

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Section: Resultsmentioning

confidence: 99%

Influence of Hydrogen Bonding on the Conformational Changes, the Brill Transition, and Lamellae Thickening in (Co)polyamides

et al. 2006

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“…The Brill transition, either involving the gradual crystallographic changes from the triclinic crystalline phase into a pseudohexagonal phase upon heating, or vice versa on cooling, is a common behavior in many even–even nylons, such as PA66, PA610, and PA1010. − Numerous pioneering investigations have been reported, but the corresponding Brill transition mechanism is still controversial. However, a large amount of evidence demonstrates that the conformational change of the methylene units at elevated temperatures leads to identical intersheet and interchain distances, which also becomes the most acceptable viewpoint. − …”

Section: Introductionmentioning

confidence: 99%

Self-Associated Polyamide Alloys with Tailored Polymorphism Transition and Lamellar Thickening for Advanced Mechanical Application

Wang

Dong

Huang

et al. 2017

ACS Appl. Mater. Interfaces

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Long chain polyamides with various number of methylene units in recurring amide groups, PA1012 and PA612, were blended to combine their unique advantages. The Brill transition and accompanied lamellar thickening were investigated by in situ wide angle X-ray scattering (WAXS) and small angle X-ray scattering. From WAXS patterns, the transformation from the α- to γ-crystalline phase, known as "Brill transition", can be independently observed in the constituent phases of the long chain polyamide alloys (LCPAs) during heating. A constant T (ca., 100 °C) irrespective of the blend composition and proportional variations of the phase content was obtained. Additionally, with elevated temperature, a gradual increase in both the crystalline layer (L) and amorphous layer (L) was detected in constituent polyamides. The compositional independence of the Brill transition in LCPAs and similar lamellar thickening originate from the complete immiscibility of both polyamides, which share stronger intramolecular rather than intermolecular hydrogen-bonding interaction and hence exhibit self-association. Contributed by the γ phase, with less extended structure and increased lamellar thickness with compact stacking, LCPAs with controlled strength and flexible features can be achieved, which can be utilized in advanced mechanical applications, particularly for hoses of automobiles. The unusually linear compositional dependence of mechanical parameters makes it possible to tailor the polymorphic and tensile properties.

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“…The strong band at 1718 cm −1 can be assigned to the carbonyl stretching mode of the carboxylic groups, signifying the existence of free carboxylic groups. The absorption band at 1625 cm −1 is due to the carbonyl stretching vibration of the amide group (amide I band), whereas the band at 1579 cm −1 is associated with the vibrational mode of the N–H amide bond (amide II band) . The bands at 1200–1000 cm −1 are ascribed to the asymmetric vibrations of the siloxane groups (Si–O–Si), which were formed during the condensation reaction of APTES .…”

Section: Resultsmentioning

confidence: 99%

“…The absorption band at 1625 cm −1 is due to the carbonyl stretching vibration of the amide group (amide I band), whereas the band at 1579 cm −1 is associated with the vibrational mode of the N-H amide bond (amide II band). 20 The bands at 1200-1000 cm −1 are ascribed to the asymmetric vibrations of the siloxane groups (Si-O-Si), which were formed during the condensation reaction of APTES. 21,22 A comparison of Figs.…”

Section: Figures 1a-1dmentioning

confidence: 99%

Ladder-Like Aromatic Imide-Functionalized Poly(silsesquioxane): Preparation and Characterization via the Sol-Gel Route

Schramm

Rinderer

Tessadri

2015

Adv. Polym. Technol.

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ABSTRACT:A ladder-like polysilsesquioxane (PSSQ) has been synthesized by reacting pyromellitic acid anhydride (PMDA) with (3-aminopropyl)triethoxysilane (APTES), yielding the corresponding poly(amic acid) (PAA). The as-prepared PAA was converted to an imide-functionalized PSSQ by thermal treatment at 220°C. The material was characterized by means of Fourier transform infrared spectroscopy, 13 C and 29 Si solid-state magic angle nuclear magnetic resonance spectroscopy, X-ray powder diffraction, thermogravimetric analysis, and differential thermogravimetric analysis. The findings give evidence that a ladder-like PSSQ is formed when PMDA reacts with APTES in a molar ratio of 1:1. Kinetic studies of the adsorption of methylene blue (MB) reveal that PMDA/APTES (molar ratio = 1:1) is capable of adsorbing MB whereas PMDA/APTES (molar ratio = 1:2) shows almost no MB adsorption capacity. C

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Crystalline transition of polyamide‐10,20 investigated by in situ Fourier transform infrared spectroscopy

Cited by 16 publications

References 25 publications

Influence of Hydrogen Bonding on the Conformational Changes, the Brill Transition, and Lamellae Thickening in (Co)polyamides

Influence of Hydrogen Bonding on the Conformational Changes, the Brill Transition, and Lamellae Thickening in (Co)polyamides

Self-Associated Polyamide Alloys with Tailored Polymorphism Transition and Lamellar Thickening for Advanced Mechanical Application

Ladder-Like Aromatic Imide-Functionalized Poly(silsesquioxane): Preparation and Characterization via the Sol-Gel Route

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