| Popis: |
As carbon dioxide (CO2) is an inexpensive, abundant, sustainable and green carbonyl resource, its utilization to produce value-added chemicals and polymeric materials has attracted much more attention. In this work, a novel CO2 route polyurea (PUa) was synthesized. The chemical composition, molecular structure, and aggregation structure of polyurea has been confirmed by 1H-NMR, HMBC-NMR, DSC, TG, MALDI-TOF MS and POM. The result from POM shows that polyurea gives out a spherulitic morphology, exhibited a typical black cross pattern formed by many concentric circles with different light and shade. Moreover, shape memory polymers of polyurea-multiblock-poly(propylene carbonate) (PUa-mb-PPCs) with a Mn nearly 4.72 × 104 Da and a polydispersity index (PDI) of 1.51–1.64 were synthesized by chain extension of the polyurea with CO2 derived poly(propylene carbonate) diols (PPC-OH). The PUa-mb-PPCs possess high strength and elasticity because the crystallinity formed by polyurea and amorphous region from PPC. Notably, excellent shape memory effect (SME) is observed in shape thermomechanical testing. The present work provides a simple and renewable process for the synthesis of CO2-copolymer with multiblock structure, opening a new route for preparation of functional polymeric materials from carbon dioxide conversion. Keywords: Carbon dioxide utilization, Thermoplastic elastomer, PUa-mb-PPC, Polyurea, Shape memory effect |
