SM01.03.02 : Soft, Moldable Thermoplastic Elastomers

5:00 PM–7:00 PM Apr 3, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Thomas Kodger1

1, Wageningen University and Research, Wageningen, , Netherlands

Man-made rubbers, have excellent mechanical toughness but are inherently stiff due to topological constraints known as entanglements, which prevent polymer chains from crossing and act as crosslinks. Thus, entanglements place a physical lower bound on how soft elastomers can be made without adding liquid fillers. As such, soft materials with Young’s moduli, E<0.2MPa are composed of multiple components and are not chemically pure substances. By introducing liquid fillers to polymeric materials, the stiffness may be decreased, however this swollen material is mechanically brittle and leaks the filler material upon deformation inhibiting their use in many applications. Additionally, swelling with solvent hindering their ability to be formed or molded into structures. I will discuss the synthesis of soft, programmable elastomers using controlled polymerization techniques to fabricate triblock co-polymers with a middle block of silicone polymers in a ‘bottlebrush’ architecture which eliminates entanglements making the material soft without the necessity for solvent. The triblock polymer includes functional end blocks composed of a thermoplastic, polystyrene, which undergoes a glass transition upon cooling, allow this material to thermoset reversibly, i.e. 3D printed. I will present the synthesis and mechanical characterization of this material, with some preliminary data on high resolution 3D printing of finely detailed soft structures.