Amorphous and crystalline phase interaction during the Brill transition in nylon 66

Wolanov, Y.; Feldman, Alexander Y.; Harel, H.; Marom, G.

doi:10.3144/expresspolymlett.2009.55

Cited by 26 publications

(26 citation statements)

References 23 publications

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“…14). In addition, at temperature close to 100 C is evident a peak in loss factor tand that may be attributed to the polymorphic phase Brill transition [41]. Moreover, from comparison of Fig.…”

Section: Mechanical and Thermo-mechanical Propertiesmentioning

confidence: 94%

Study of the effect of atmospheric pressure air dielectric barrier discharge on nylon 6,6 foils

Kuzminova

Shelemin

Kylián

et al. 2014

Polymer Degradation and Stability

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Section: Mechanical and Thermo-mechanical Propertiesmentioning

confidence: 94%

Study of the effect of atmospheric pressure air dielectric barrier discharge on nylon 6,6 foils

Kuzminova

Shelemin

Kylián

et al. 2014

Polymer Degradation and Stability

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“…It is worth mentioning that the structure of conventional nylons has usually a continuous evolution with temperature towards a pseudohexagonal packing that is achieved at the so-called Brill transition temperature [28][29][30][31][32][33][34]. Unfortunately, low resolution or ambiguous X-ray diffraction data do not provide a good understanding of this transition.…”

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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“…Because both PA66 matrix and glass fibers possess positive thermal expansion coefficient, the increase of strain during heating process is mainly due to the expansion of the dimension. When the temperature is higher than the T g of PA66, which value is about 50 °C obtained from DSC measurement, chain segments begin to move, and residual stress releases with the reduction of free volume and densification through the movement and configurational rearrangement of PA66 segments, resulting in the reduction of strain. Reduction of strain in holding stage is due to the release of residual stress in composite, and the reduction of strain in cooling stage is attributed to the shrinkage of dimension and generation of new residual stress.…”

Section: Resultsmentioning

confidence: 96%

“…It is because that glass fiber provide lower energy condition for heterogeneous nucleation and accelerate the crystallization rate of PA66. The spherocrystals near fiber surface collide each other because of high nucleation density, so that they can only grow along one direction vertical to the surface of glass fiber and form the transcrystallization region eventually . Besides, the width of transcrystallization region is approximately 15 μm similar to the diameter of glass fiber.…”

Section: Resultsmentioning

confidence: 99%

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Annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66

Meng

Luo

et al. 2017

J of Applied Polymer Sci

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Generally, annealing is one of the important post-processing methods used to obtain injection molding products coupled with excellent comprehensive performance. Based on a series of experimental studies in this work, a systematic investigation was performed to research the annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66 (LGF-PA66) composite. The composite was prepared by injection molding, using LGF-PA66 pellet with 50 wt % fiber content and 12 mm length. Composite samples were annealed in 120 8C to 200 8C range and then subjected to various tests at room temperature. Besides, the releasing strain during a specific temperature cycle was also investigated. Our results suggest that annealing treatment had a neglected impact on the crystallinity and crystal morphology of LGF-PA66 composite. However, with the increasing of processing temperature, annealing could strikingly promote the phase transition from g to a and the further growth of a 2 crystal in (010)/(110). In addition, annealing of LGF-PA66 composite resulted in a drastic increase in tensile and flexural properties and a reduction in impact strength, along with the transition of failure mode. The changes in mechanical properties were attributed to the crystal transition, strengthening of matrix performance, and the release of residual stress.

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Amorphous and crystalline phase interaction during the Brill transition in nylon 66

Cited by 26 publications

References 23 publications

Study of the effect of atmospheric pressure air dielectric barrier discharge on nylon 6,6 foils

Study of the effect of atmospheric pressure air dielectric barrier discharge on nylon 6,6 foils

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

Annealing effect on crystalline structure and mechanical properties in long glass fiber reinforced polyamide 66

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