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

Abstract

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 .

Biobased Thermoplastic Polyamide Elastomers: Preparation, Properties, and Applications

“…Based on the one-pot method, Dong and colleagues also prepared BTPAEs with PA1012 as the HS. 48 Each of the two synthetic methods has its own advantages. The low initial viscosity of the one-step method makes the ratio of the reaction groups easier to regulate and results in BTPAEs with stable properties, diverse regulation, high efficiency, and low cost.…”

“…The current widely used synthetic method for BTPAEs is melt polymerization, They can be further classified according to the reaction steps into two-step polymerization and one-pot polymerization. , The two-step method is to react under vacuum and high temperature to obtain polyamide prepolymer, then add SS for reaction (the specific temperature and pressure are adjusted according to the specific situation), and finally obtain BTPAEs. For example, Dong and co-workers have synthesized a series of BTPAEs through a two-step method route. − For example, Figure a presents the typical synthesis of PA1012-PTMG-based BTPAEs, in which PA1012 serves as HS and poly­(tetramethylene ether glycol) (PTMG) serves as SS. The structure of the obtained BTPAEs can be determined by 1 HMR spectroscopy, as shown in Figure b.…”

“…The structure of the obtained BTPAEs can be determined by 1 HMR spectroscopy, as shown in Figure7b.The one-pot method involves adding all of the monomers at the initial stage and reacting under high temperature and vacuum to directly obtain the product. Based on the one-pot method, Dong and colleagues also prepared BTPAEs with PA1012 as the HS 48. Each of the two synthetic methods has its own advantages.…”

Intermolecular ═C–H···O═C Hydrogen Bonding and Conformational Preference in Crystalline Poly(butylene 2,5-furandicarboxylate)

“…bands in IR relative to those of the amorphous state. − Recently, Sato has summarized such an C–H···O interaction as the weak hydrogen bonding in biodegradable polymers, unlike the truly strong hydrogen bonding in X–H (X = O, N, etc.) systems such as the N–H···OC hydrogen bonds in polyamides. − Yet, the stretching modes of C–H in PEF also displayed a red-shift after crystallization . Furthermore, apart from the IR evidence reported by Sousa and Sbirrazzuoli et al in crystalline PEF, , the presence of intermolecular C–H···OC hydrogen bonding in FDCA-based polyesters is not yet well elucidated.…”

Robust and Transparent Polyamide 1012 Membranes for Biogas Purification Controlled by the Degree of Hydrogen Bonding Order

“…The γ form has one single characteristic reflection in its WAXD pattern, produced by the diffraction of the (100)/(010)/(110) γ planes, where the interchain distance is equal to the intersheet distance. Under external fields, such as heating − or stretching, the α form can be reversibly converted to the γ form.…”