The harsh synthesis conditions and lack of hard segments have long presented difficulties in the preparation of polyamide-based thermoplastic elastomers (TPAEs). In this work, a facile synthesis of TPAEs was developed using amide exchange. First, itaconic acid-polyoxypropylene diamine copolymer (IA-PPA) was synthesized by copolymerizing bio-based polyoxypropylene diamine (PPA D400) and itaconic acid (IA). The P2000 (IA-PPA with Mn ~ 2000) was then used as the soft segment of polyamide-6 based thermoplastic elastomers (PA6- b -P2000). Experimental results indicate that P2000 could directly initiate the ring-opening polymerization of caprolactam to form a prepolymer containing PA6 segments. PA6- b -P2000 thermoplastic elastomers were then obtained by the amide exchange reaction of PA6 segments. The structure and properties of IA-PPA and PA6- b -P2000 were further characterized in detail. The results demonstrate that the elastomers have good thermal stability and superior elasticity, which are highly dependent on the crystallinity and phase separation structure of the polyamide elastomer. Using this flexible approach, multifunction TPAEs can be designed and commercialized in a short time.
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.
He Tingwei,Liu Tao,Huang Junyao,Wang Xueli,He Yong,Ma Bomou
In this work, a novel poly(ester amide)s (PEAs) was designed and synthesized from dimethyl terephthalate (DMT), 3-amino-1-propanol (AP) and adipic acid (AA). Firstly, the aromatic diol monomer (BHTT) was synthesized by DMT and AP, it was characterized by 1 H NMR, 13 C NMR, FT-IR and DSC, respectively. Then, the BHTT and AA were used to synthesize the semi-aromatic PEAs with alternating structure by melt polymerization. The effects of polymerization temperature and time on the crystallization, thermal stability and amide transesterification of PEAs were fully investigated. It was found that the prepared PEAs are semi-crystalline polymer with melting point around 154–165 °C and decomposition temperature around 377–392 °C. Most important, the chemical structure of PEAs synthesized under different conditions was explored by 1 H NMR, 13 C NMR and DEPT spectra, which confirms the occurrence of amide transesterification during the melt polymerization process.
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