Brill transition and melt crystallization of nylon 56: An odd–even polyamide with two hydrogen-bonding directions

Morales-Gámez, Laura; Soto, David Presa; Franco, Lourdes; Puiggalı́, Jordi

doi:10.1016/j.polymer.2010.09.074

Cited by 90 publications

(78 citation statements)

References 39 publications

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“…It was reported by Kinoshita [7] that these nylons seems to primarily crystallize into the -form, in which amide groups tilt with respect to the chain axis and form complete hydrogen bonds in the molecular sheets. While, the existence of the crystalline phase similar to the -form have been reported for various aliphatic nylons containing methylene segments with odd numbers, such as nylon-5,6 [8,9], nylon-5,10 [10], nylon-9,2 [11], nylon-6,5 [12], nylon-12,5 [13], and even-odd nylons derived from undecanedioic acid [14]. The wide-angle X-ray diffraction (WAXD) patterns of these nylon crystals give two strong Bragg reflections at d-spacings ca.…”

Section: Introductionmentioning

confidence: 86%

Polymorphism of poly(nonamethyleneoxamide) crystal

Nakagawa

Nozaki

Maeda

et al. 2015

Polymer

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The crystal structures of poly(nonamethyleneoxamide) (nylon-9,2) were investigated by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry. Nylon-9,2 shows a polymorphism with two different structures depending on the conditions of sample preparation.Monoclinic form I is the dominant crystalline phase for the solution-crystallized sample. For melt-crystallized samples, form I and new monoclinic form I′ coexist. Variable-temperature WAXD measurements were used to investigate the stability of each crystal form and the phase transition. Form I does not undergo any phase transitions prior to melting, although the orthorhombic molecular chain packing in form I at low temperature comes close to the quasihexagonal one during the heating process. Form I′ shows no phase transition on heating until its melting, too. The crystal lattice simply expands due to the thermal expansion. Form I is believed to be more stable, because the melting temperature of form I is higher than that of form I′.

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Section: Introductionmentioning

confidence: 86%

Polymorphism of poly(nonamethyleneoxamide) crystal

Nakagawa

Nozaki

Maeda

et al. 2015

Polymer

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“…More complex geometries have been postulated for the room temperature structures of polyamides containing glycine units [14] and also of several odd-even and even-odd 4 nylons [8,[15][16][17][18][19][20][21][22][23][24][25][26]. These structures were characterized by the establishment of hydrogen bonds along three and two directions as a consequence of the conformational preferences of glycine residues and the inability to establish a saturated intrasheet hydrogen bonding scheme when an all-trans molecular conformation was assumed and odd diamine or diacid units were involved (Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Reversible changes induced by temperature in the spherulitic birefringence of nylon 6 9

Murase

Casas

Martínez

et al. 2015

Polymer

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Spherulitic morphologies of nylon 6 9 as an example of an even-odd nylon were studied by optical microscopy. A well-defined dependence on crystallization temperature was found. In particular, positively birefringent spherulites were characteristic for temperatures higher than 232 ºC, low birefringence spherulites developed between 232 and 225 ºC, positive ringed spherulites were found between 225 and 220 ºC, and finally negative fibrillar spherulites were formed at temperatures lower than 220 ºC. These optical properties were clearly different from those observed with even-even nylons (e.g., negative and positive birefringence for high and low temperatures, respectively), and may derive from the peculiar crystalline structures determined for even-odd nylons.Furthermore, low birefringence spherulites were characterized by a flat-on lamellar disposition and reversibility of the birefringence sign in the 80-120 ºC temperature interval (positive and negative values at high and low temperatures, respectively).Real time WAXD profiles taken during heating and cooling processes demonstrated that different crystalline structures (named I, II and III) developed depending on the temperature and crystallization procedure of samples (e.g., from solution or from the melt state). Crystalline structures were characterized by the formation of hydrogen bonds along two crystalline directions in all cases, a peculiar arrangement that may account for the development of positive and negative spherulites in a more simple way than formulated for conventional polyamides having a single hydrogen bonding direction. DSC and FTIR data also showed a complex structural behavior with structural transitions in the 80-120 ºC range, a region that corresponds to birefringence sign reversibility.

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“…The continuous smooth spinning with no bristles under the experimental spinning conditions for 72 hours suggested that PA56 is spinable and spinning smoothly under the experimental spinning conditions .Performance test results of PA56 filament fibers are as shown in Table 1.It is worth mentioning that elongation at break and boiling water shrinkage is too large and strength needs to be improved [13].Therefore, as a new polymer material, related polymer synthesis, preparation and other basic research and technology of PA56 are still in infancy and starve for further study. 3.9 42 17 Molecular weight and its distribution have a greater impact on the processing performance, mechanical properties, crystallization properties and heat resistance of fiber.…”

Section: Resultsmentioning

confidence: 92%

“…At the same time we made a breakthrough in the blended yarn and textile processing of International Conference on Materials, Environmental and Biological Engineering (MEBE 2015) polyamidefiber, and laid the foundation for the production and development of bio-based polyamidefiber. Bio-based polyamide56 fiber is expected to be advanced materials used in clothing and industrial textiles [9][10][11][12]. This paper discusses on several basic performances closely related to applications of textile and apparel.…”

Section: Introductionmentioning

confidence: 99%

Study on the Structure and Properties of Novel Bio-based Polyamide56 Fiber Compared with Normal Polyamide Fibers

Hao¹,

Guo²,

Li³

et al. 2015

Proceedings of the 2015 International Conference on Materials, Environmental and Biological Engineering

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Abstract. The new kind of bio-based polyamide56 fiber has been synthesized by adipic acid and 1,5-pentanediamine, which was prepared by fermenting a variety of starch. The spin ability, physical and thermal properties of bio-based PA56, PA 6 and PA 66 were evaluated through systematic investigation and measurement. Bio-based polyamide56 resin has been proved to have good spin ability. PA56 have more concentrated distribution of molecular weight than other nylons, which indicated more stable viscosity beneficial for spinning and higher fiber strength. The infrared spectrum showed characteristic amide and methylene absorption peaks of PA56 but different vibration intensities with conventional nylon, which demonstrates different molecular structure. Differential scanning calorimetry combined with thermal gravimetric revealed good heat resistance (the thermal decomposition temperature is 403.7 °C) and high melting-point (254.1 °C) of polyamide56. X-ray diffraction of these fibers were proposed and showed that slightly higher crystallinity of polyamide56 so as to have more regular arrangement of molecular.

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Brill transition and melt crystallization of nylon 56: An odd–even polyamide with two hydrogen-bonding directions

Cited by 90 publications

References 39 publications

Polymorphism of poly(nonamethyleneoxamide) crystal

Polymorphism of poly(nonamethyleneoxamide) crystal

Reversible changes induced by temperature in the spherulitic birefringence of nylon 6 9

Study on the Structure and Properties of Novel Bio-based Polyamide56 Fiber Compared with Normal Polyamide Fibers

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