Polymer scientists have developed a siloxane (silicone) polymer that stretches to 5000 percent of its original length and then returns to its unstretched size when released. The scientists presented their work at the 250th National Meeting & Exposition of the American Chemical Society in Boston, Massachusetts (August 2015). The new material was developed by researchers at Gelest—a Pennsylvania-based company that specializes in research and production of silane, silicone, and metal-organic materials for advanced technology applications. See also: Polymer; Silicone resins

To make the stretchy (elastic) polymer, the scientists first produced macromonomers from cyclic siloxane monomers using a reaction know as ring-opening polymerization. The macromonomers were then polymerized using a condensation (step-growth) reaction, a typical reaction for producing siloxane polymers. The researchers found that increasing the molecular weight of the macromonomers improved the elasticity of the polymer. See also: Macromolecular engineering; Organosilicon compound; Polymerization; Ring-opening polymerization

Elastomeric siloxane polymers typically can be stretched to about 500 percent of their original length in part because chemical bonds (cross-links) between the polymer chains help to prevent the polymer from being pulled apart. So far, analytical testing of the new stretchy polymer has produced a suprising finding; that is, it has a linear structure without detectable cross-links. Further testing and molecular modeling is needed to confirm this, however. See also: Analytical chemistry; Molecular modeling of polymers and biomolecules

Silicone elastomers are used in medical and surgical devices because they are compatible with body tissues. Gelest is hopeful that its new material will be useful for medical-implant and flexible-electronic applications. See also: Printable semiconductors for flexible electronics