Yuanyuan Dou,Nan Tian,Zhenbo Ning,Ni Jiang,Zhihua Gan
Polyesteramides have attracted much attention due to their intriguing properties. However, the synthesis of di- or triblock polyesteramides based on polyamide 6 (PA6) remains challenging owing to their harsh reaction conditions. In this work, we introduced a new strategy to synthesize poly(ε-caprolactone)-block-PA6-block-poly(ε-caprolactone) (PCL-b-PA6-b-PCL) in a mild way. A series of well-designed copolymers were characterized by gel permeation chromatography, 1H, DOSY, and 13C NMR, and their crystallization and melting behavior, degradation rate, and compatibilization effect on PA6/PCL blends were found to be strongly composition dependent. Interestingly, the copolymers exhibited diverse spherulite morphologies, including curving stems and banded spherulites, which also correlated with the different relative content of PA6. Besides, PA6 nanodomains could act as physical cross-linking points to improve the tensile strength and Young’s modulus of PCL. This work fills the synthesis gap of well-defined PA6-based triblock polyesteramides, providing new materials for material modification and elucidation of some basic scientific questions.
The preparation of polyesteramides (PEAs) with regular block structure has long been a challenge, owing to the occurrence of the ester-amide exchange during the polymerization at high tempereture. In this work, we report a simple and green method to prepare polyamide 6 (PA6) based triblock PEA whose structure is poly(ε-caprolactone)-block-PA6-block-poly(ε-caprolactone) (PCL- b -PA6- b -PCL) using tetraphenyl tin as catalyst without solvent. The first segment PA6 was synthesized via cationic ring-opening polymerization (ROP) of ε-caprolactam (CPL), later, ROP of ε-caprolactone (CL) was involved to extend polycaprolactone (PCL) segments by using tetraphenyl tin as catalyst. By varying the proportion of CPL and CL, series PA6-based PEAs was prepared and characterized by gel permeation chromatography, 1 H, DOSY, and 13 C NMR. The results showed that PEA containing more proportion of CL presented a higher molecular weight with narrow polydisperse index. In particular, the lower water absorption and lower oligomers content infers that the PEA could have a prospective application in processing precision electronic devices.
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