화학공학소재연구정보센터
Polymer, Vol.52, No.13, 2877-2882, 2011
Substituent effect on structure and physical properties of semicrystalline Diels-Alder network polymers
Semicrystalline cross-linked polymers were synthesized using the Diels-Alder (DA) reaction between furyl-telechelic poly(E-caprolactone) prepolymers (PCLF2-x. x (substituent in the vicinity of furan) = A (amide), E (ester) and U (urethane)) and a tris-maleimide linker (M-3). The equilibrium of the thermoreversible DA reaction shifted by changing the substituent, that is, the dissociation of PCLF2-x and M-3 during the retro-DA reaction was significant in the order of PCLF2-E-M-3 > PCLF2-U-M-3 > PCLF2-A-M-3, while the association during the DA reaction was effective in the reversed order. This can be attributed not only to the difference in electron density in furan rings (PCLF2-A approximate to PCLF2-U > PCLF2-E) but also to the presence of hydrogen-bonding between C=O in maleimide and N-H in the amide or urethane bond in the vicinity of furan and its strength (PCLF2-A-M-3 > PCLF2-U-M-3) and the absence for PCLF2-E-M-3. The shift of reaction equilibrium resulted in effective modulation of structures and physical properties of crystallization-first (CRY1st) and cross-linking-first (CL1st) network polymers. (c) 2011 Elsevier Ltd. All rights reserved.