Hydrocarbon molecules may enter the polymer network, pushing molecular chains apart and causing the material to expand. The difference can arise from molecular rearrangements, delayed relaxation or changes in the interactions between polymer chains and absorbed molecules. The researchers will expose polymer samples to controlled concentrations of hydrocarbon vapors and track how the materials respond. The new measurements may help distinguish reversible molecular motions from more persistent structural changes and improve models used to predict polymer performance. Subject of Research: Elastomers, petroleum-derived polymers, polymer swelling, elasticity and hysteresisArticle Title: Ultrasonic Experiments Aim to Reveal Why Rubber Remembers Its HistoryWeb References: Gennady Gor’s NJIT profile; NJIT Laboratory for Materials InterfacesImage Credits: Courtesy of New Jersey Institute of TechnologyKeywordsElastomers, polymers, hysteresis, rubber, polymer swelling, ultrasonic sensors, materials science, chemical engineering, petroleum research, NJIT