Investigation of Brill Transition in Nylon 6 and Nylon 6,6 by Infrared Spectroscopy

Vasanthan, Nadarajah; Murthy, N. Sanjeeva; Bray, R. G.

doi:10.1021/ma980935o

Cited by 175 publications

(164 citation statements)

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“…Besides the stable a-phase, the high temperature pseudohexagonal structure c-phase also can be found when PA66 is heated up to the Brill transition temperature. [42][43][44] The characteristic of the c-phase is that it exhibits only one strong reflection at ca. 2h = 21.8 8.…”

Section: Crystallization Behavior and Crystal Structurementioning

confidence: 99%

Polyamide 66/Clay Nanocomposites via Melt Intercalation

Liu¹,

2002

Macromol. Mater. Eng.

107

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Section: Crystallization Behavior and Crystal Structurementioning

confidence: 99%

Polyamide 66/Clay Nanocomposites via Melt Intercalation

Liu¹,

2002

Macromol. Mater. Eng.

107

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“…2 Many studies on the Brill transition for nylon have been carried out by XRD, NMR, FT-IR, and DSC. [2][3][4][5][6][7][8][9] Multiple melting is commonly observed in the nylon-66 sample crystallized from solution in methanol. 5 Several mechanisms of multiple melting are proposed such as independent melting of polymorphism of nylon-66, melt and re-crystallization of unstable crystallites and reorganization of amorphous parts.…”

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confidence: 99%

Phase Transition Behavior of Nylon-66, Nylon-48, and Blends

Zhang

Watanabe

Yoshida

et al. 2003

Polym J

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ABSTRACT:Phase transitions, including α-β phase transition and melting, of nylon-66, nylon-48 and blends were measured by simultaneous DSC-XRD and DSC-FT-IR. The molecular mechanism of α-β transition and melting of nylon-66 and blends were estimated from DSC-XRD and DSC-FT-IR. On the broad endothermic peak between 100 and 200• C, spacing of (010/110) of α-form expanded from 0.36 nm to 0.40 nm, and spacing of (100) of α-form changed from 0.44 nm to 0.41 nm, then (100) of β-form appeared. The triclinic ab plane changed to the rhombohodral ab plane from 100 to 200• C. The slide of hydrogen bonded sheet induced transition to the hexagonal β-form. Double melting peaks on DSC heating curve were due to the melting of two types of β-form consisted with weak and strong hydrogen bonded molecules. Nylon-66 is an important semicrystalline polymer. Nylon-66 shows solid-state transition called as the Brill transition, 1 and multiple melting 2-5 on heating from the room temperature to 280 • C. At the Brill transition, the triclinic α-form changes to a pseudohexagonal β-form. The temperature of the Brill transition has been reported variously from 100 to 240 • C, which appears sensitive to crystallization, annealing and deformation of the sample. 2 Many studies on the Brill transition for nylon have been carried out by XRD, NMR, FT-IR, and DSC. 2-9 Multiple melting is commonly observed in the nylon-66 sample crystallized from solution in methanol. 5 Several mechanisms of multiple melting are proposed such as independent melting of polymorphism of nylon-66, melt and re-crystallization of unstable crystallites and reorganization of amorphous parts. The mechanism of transitions is not fully understood owing to the complexity in multiple transitions.Thermal analysis, especially DSC is convenient to observe phase transition, however, DSC gives only total thermodynamic information of samples. Other measurements are necessary to obtain structural information. We have reported that the simultaneous DSC-FT-IR and DSC-XRD methods give not only thermal information but also conformational and structural information on real time of transitions such as crystallization, melting and solid-state transition. [10][11][12] Applications of the simultaneous DSC-FT-IR and DSC-XRD were reported to analyze the mechanism of α-γ transition of † To whom correspondence should be addressed.PVDF. 13,14 In the present work simultaneous DSC-FT-IR and DSC-XRD methods were used to analyze the molecular mechanism of phase transitions of nylon-66, nylon-48 and blends during heating. EXPERIMENTALNylon-66 (Scientific Polymer Products) and nylon-48, prepared using the interface polymerization of chloro octanedioyl and butanediamine, were used in this study. The relative viscosity of nylon-66 and nylon-48 is η rel = 1.79 and 1.90 respectively (measured at 25 • C in m-cresol). Nylon-66 and nylon-48 were dissolved in m-cresol at room temperature. Blend content of nylon-66 (φ Nylon-66 ) was 0-1.0 in weight fraction (φ Nylon-66 = 0.8 indicates blend of composition nylon-4...

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“…On heating, the two strong reflections at 0.37 nm and 0.44 nm are found to move together and merge to a single reflection with a spacing of 0.42 nm. Brill transition has also been observed by other techniques, such as NMR spectroscopy, [12] IR, [13,14] SAXS, [15] etc.…”

Section: Introductionmentioning

confidence: 83%