Algae-Inspired, Sulfur-Based Polymer with Infrared Transmission and Elastic Function

This study prepared an elastic material with an infrared (IR)-transmitting property based on the structural features of algae oils. The bulk copolymerization of elemental sulfur and unsaturated hydrocarbons yields sulfur-based polymeric products, in a process termed inverse vulcanization. The inverse vulcanization of algal oils, such as squalene and botryococcene, forms highly cross-linked products owing to the multiple reaction sites along the long unsaturated backbone. Based on this structural feature, a combination of the algal oils and plant-based short-chain monoterpene compounds (d-limonene and β-myrcene) was investigated to provide a suitable cross-linking density for achieving an elastic function. Inverse vulcanization of squalene and β-myrcene produced an elastic material with an IR-transmitting property. The developed material served as a varifocal lens in the IR region that responds to external elongation forces. From the viewpoint of sustainability, it is meaningful that the material was produced from sustainable feedstocks (algae and plant oils) and a surplus feedstock (sulfur).