The degradation of polymeric materials is recognized as one of the goals to be fulfilled for the sustainable economy. In this study, a novel methodology was presented to synthesize multiple highly cross-linked polymers (i.e., hydrogels) through amine-thiol scrambling under mild conditions. Amine-terminated poly(ethylene glycol) (PEG-NH 2 ) was reacted with the representative conjugate acceptors to synthesize hydrogels in organic and aqueous solutions, respectively. The materials above exhibited high water-swelling properties, distributed porous structures, as well as prominent mechanical strengths. It is noteworthy that the mentioned hydrogels could be degraded efficiently in hours to release the original coupling partner, which were induced by ethylene diamine at ambient temperature through amine-amine metathesis. The recovered PEG-NH 2 reagent could be employed again to regenerate hydrogels. Due to the multiple architectures and functions in polymeric synthesis, degradation and regeneration, a new generation of “smart” materials is revealed.
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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