Sustainable Thermoplastic Elastomers with Ionic Interactions

Thermoplastic elastomers (TPEs) are widely used in electronics, clothing, adhesives and automotive components due to their high processability and flexibility. ABA triblock copolymers, in which A represents glassy end-blocks and B a rubbery midblock, are commercially available TPEs. commercial TPEs are derived from petroleum whose manufacturing and disposal have undesired environmental impacts, motivating the development of TPEs from sustainable sources. However, polymers with bulky constituents, such as the long alkyl side-chains of vegetable oil-derived polymers, exhibit poor mechanical performance due to lack of entanglements in the rubbery matrix. Transient networks were incorporated into the midblock through either hydrogen bonding or ionic interactions to improve mechanical performance. ABA triblock copolymers were synthesized with poly(n-butyl acrylate – ran – acrylic acid) or poly(lauryl methacrylate – ran – methacrylic acid) copolymer midblocks and poly(methyl methacrylate) endblocks. Characterization of these systems indicates that relaxation time of the rubbery midblock is the controlling parameter for enhancement of mechanical properties.