Aliphatic polyamides (nylons): Interplay between hydrogen bonds and crystalline structures, polymorphic transitions and crystallization

Puiggalı́, Jordi

doi:10.1002/pcr2.10199

Cited by 14 publications

(13 citation statements)

References 88 publications

(95 reference statements)

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“…The Brill transition has been widely studied in the polyamide family, ,,− and recently, a Brill-like transition has been reported for poly(octamethylene carbonate) (PC8) and poly(hexamethylene dithiocarbonate) (PC6-D) . In PC8, Zhao et al reported the convergence, upon heating, of the d 110 = 0.43 nm and d 200 = 0.38 nm, observed at low temperatures (in the denoted α phase), into a single d -spacing at 0.41 nm at ∼42 °C (in the denoted β phase).…”

Section: Introductionmentioning

confidence: 99%

Using Successive Self-Nucleation and Annealing to Detect the Solid–Solid Transitions in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

et al. 2021

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Solid−solid transitions in poly(hexamethylene carbonate) (PC6) and poly(octamethylene carbonate) (PC8), denoted the δ to α transition, have been investigated, using selfnucleation and the successive self-nucleation and annealing (SSA) technique. The SSA protocol was performed in situ for thermal (differential scanning calorimetry (DSC)), structural (wide-angle X-ray scattering (WAXS)), and conformational (Fourier transform infrared spectroscopy (FT-IR)) characterization. The final heating after SSA fractionation displayed an enhanced (compared to a standard second DSC heating scan) endothermic and unfractionated peak signal at low temperatures corresponding to the δ to α transition. The improved (i.e., higher enthalpy and temperature than in other crystallization conditions) δ to α transition signal is produced by annealing the thickest lamellae made up by α and β phase crystals after SSA treatment. As thicker lamellae are annealed, more significant changes are produced in the δ to α transition, demonstrating the transition dependence on crystal stability and, thus, on the crystallization conditions. The ability of SSA to significantly enhance the observed solid−solid transitions makes it an ideal tool to detect and study these types of transitions. In situ WAXS reveals that the δ to α transition corresponds to a change in the unit cell dimensions, evidenced by an increase in the d-spacing. This implies a more efficient chain packing in the crystal, for both samples, in the δ phase (lower d-spacing at low temperatures) than in the α phase (higher d-spacing at high temperatures). The chain packing differences are explained through in situ FT-IR measurements that show the transition from ordered (δ phase) to disordered (α phase) methylene chain conformations.

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Section: Introductionmentioning

confidence: 99%

Using Successive Self-Nucleation and Annealing to Detect the Solid–Solid Transitions in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

et al. 2021

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“…At present, two possibilities are considered for explaining the existence of two different α-phases: First, a more stable H-sheet structure is induced during the annealing in the PAE38 sample to prevent the chain conformation from changing from all-trans to gauche until 150 °C. Although the all-trans conformation is considered the lowest-energy and most stable conformation in the even–even PAs, the researchers evaluated the presence of an intermediate phase ,, based on the experimental results of PA46 and PA66. Moreover, Li et al have demonstrated that the chain conformation could be affected under stretching, inducing the new crystal phase (denoted α′) in PA46.…”

Section: Resultsmentioning

confidence: 99%

Brill Transition in Polyamide 1012 Multiblock Poly(tetramethylene oxide) Copolymers: The Effect of Composition on Hydrogen-Bonding Organization

et al. 2022

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The effect of composition on the Brill transition of polyamide-based copolymers was systematically investigated with the synthesized polyamide 1012 (PA1012) multiblock poly(tetramethylene oxide) (PTMO) copolymers. By using the X-ray scattering and infrared spectroscopy techniques, it was found that the amorphous PTMO segments accelerated the reorganization of hydrogen sheet (H-sheet) structures of PA1012 segments during rapid cooling from the melt, resulting in an α-phase with a higher crystal perfection index (CPI) for a lower PA1012 content (W PA ) copolymer. For low-W PA copolymers, the α-phase is completely transformed to the γ-phase at a lower Brill temperature (T B ) at a given CPI, which is attributed to the enhanced chain mobility by the PTMO segments. All the studied samples (W PA in the range of 1.00 to 0.32) are superimposed to form a master curve of T B / T B,CPI=1 = 0.9 × CPI + 0.08, where T B,CPI=1 is the theoretical T B for each sample at its corresponding perfect H-sheet structure. The results imply that the thermodynamic mechanism of Brill transition in the PA1012 homopolymer and PA1012-PTMO copolymer is equivalent. Moreover, this master curve can be used to quantitatively estimate the T B of PA1012-PTMO copolymers with a given composition and is expected to be applied in polyamide-based copolymers composed of different comonomers by determining their own characteristic parameter of T B,CPI=1 .

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“…Polymers containing aromatic rings are more polarized and these polymers have strong intermolecular forces. Hydrogen bonds between amides in polyamides help to stabilize them [ 38 ].…”

Section: Synthetic Polymersmentioning

confidence: 99%

Upgrading of bio‐separation and bioanalysis using synthetic polymers: Molecularly imprinted polymers (MIPs), cryogels, stimuli‐responsive polymers

Aslıyüce

İdil

Mattìasson

2022

Engineering in Life Sciences

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Bio-separation plays a crucial role in many areas. Different polymers are suitable for bio-separation and are useful for applications in applications in both science and technology. Besides biopolymers, there are a broad spectrum of synthetic polymers with tailor-made properties. The synthetic polymers are characterized by their charges, solubility, hydrophilicity/hydrophobicity, sensitivity to environmental conditions and stability. Furthermore, ongoing developments are of great interest on biodegradable polymers for the treatment of diseases.Smart polymers have gained great attention due to their unique characteristics especially emphasizing simultaneously changing their chemical and physical property upon exposure to changes in environmental conditions. In this review, methodologies applied in bio-separation using synthetic polymers are discussed and efficient candidates are focused for the construction of synthetic polymers.

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Aliphatic polyamides (nylons): Interplay between hydrogen bonds and crystalline structures, polymorphic transitions and crystallization

Cited by 14 publications

References 88 publications

Using Successive Self-Nucleation and Annealing to Detect the Solid–Solid Transitions in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

Using Successive Self-Nucleation and Annealing to Detect the Solid–Solid Transitions in Poly(hexamethylene carbonate) and Poly(octamethylene carbonate)

Brill Transition in Polyamide 1012 Multiblock Poly(tetramethylene oxide) Copolymers: The Effect of Composition on Hydrogen-Bonding Organization

Upgrading of bio‐separation and bioanalysis using synthetic polymers: Molecularly imprinted polymers (MIPs), cryogels, stimuli‐responsive polymers

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