Polyamide‐6,6‐based blocky copolyamides obtained by solid‐state modification

Abstract

Copolyamides based on polyamide-6,6 (PA-6,6) were prepared by solid-state modification (SSM). Para-and meta-xylylenediamine were successfully incorporated into the aliphatic PA-6,6 backbone at 200 and 230 C under an inert gas flow. In the initial stage of the SSM below the melting temperature of PA-6,6, a decrease of the molecular weight was observed due to chain scission, followed by a built up of the molecular weight and incorporation of the comonomer by postcondensation during the next stage. When the solid-state copolymerization was continued for a sufficiently long time, the starting PA-6,6 molecular weight was regained. The incorporation of the comonomer into the PA-6,6 main chain was confirmed by size exclusion chromatography (SEC) with ultraviolet detection, which showed the presence of aromatic moieties in the final high-molecular weight SSM product. The occurrence of the transamidation reaction was also proven by 1 H nuclear magnetic resonance (NMR) spectroscopy. As the transamidation was limited to the amorphous phase, this SSM resulted in a nonrandom overall structure of the PA copolymer as shown by the degree of randomness determined using 13 C NMR spectroscopy. The thermal properties of the SSM products were compared with melt-synthesized copolyamides of similar chemical composition. The higher melting and higher crystallization temperatures of the solid state-modified copolyamides confirmed their nonrandom, block-like chemical microstructure, whereas the melt-synthesized copolyamides were random.

Poly(butylene terephthalate)/Glycerol-based Vitrimers via Solid-State Polymerization

“…Physical mixtures of PBT and glycerol were prepared from solution using a common solvent approach. − As a representative example, for the physical mixture containing 14.1 mol % of glycerol and 2 mol % Zn­(acac) 2 , the dried PBT powder (9.14 g, 41.55 mmol), glycerol (0.64 g, 6.92 mmol) and Zn­(acac) 2 (0.22 g, 0.83 mmol) as the transesterification catalyst were dissolved in 20 mL of HFiP at 55 °C. After complete dissolution of all compounds, the HFiP was distilled off.…”

Recent Advances in Solid-State Modification for Thermoplastic Polymers: A Comprehensive Review

“…In this kind of thermoplastic polymers, two studies in the field of polymer science focused on modifying polyamides through solid-state methods [49,50]. Jeyakumar et al studied the modification of polyamide-6,6 (PA-6,6) to prepare a comonomer by using p-Xylylenediaminepara-and m-Xylylenediamine [50]. This process was conducted under an inert atmosphere and initially resulted in a decrease in molecular weight due to chain scission.…”

Recent Advances in Solid-State Modification for Thermoplastic Polymers: A Comprehensive Review

“…In this kind of thermoplastic polymers, two studies in the field of polymer science focused on modifying polyamides through solid-state methods [57,58]. Jeyakumar et al studied the modification of polyamide-6,6 (PA-6,6) to prepare a comonomer by using p-Xylylenediaminepara-and m-Xylylenediamine [57]. This process was conducted under an inert atmosphere and initially resulted in a decrease in molecular weight due to chain scission.…”