Maleated trans-1,4-polyisoprene from Eucommia ulmoides Oliver with dynamic network structure and its shape memory property

We developed a bio-based shape memory polymer with dynamically crosslinked network structure from trans-1,4-polyisoprene (TPI) derived from Eucommia ulmoides Oliver. Grafting of maleic anhydride onto TPI was performed in 1,2-dichlorobenzene, and the subsequent hydrolysis gave maleated trans-1,4-polyisoprene (MTPI). Increasing trend of the grafted maleic moiety was observed with increasing the concentration of maleic anhydride in the grafting reaction. With increase in maleic content, the glass transition temperature (T-g) of the resulting polymer increased, whereas the crystallinity decreased. The maximum stress of the MTPI with carboxylates was larger than that of the protonated MTPI. Above the melting temperature, the Young's modulus of MTPI with carboxylates was higher than that of neat TPI and the protonated MTPI, due to dynamically crosslinked network structure. Furthermore, the MTPI with 1% carboxylate content exhibited excellent shape memory-recovery properties, exploiting the combination of the physical crosslinking and the melting of the crystal. The resulting materials are expected to contribute to the development of bio-based intelligent materials. (C) 2014 Elsevier Ltd. All rights reserved.