Oak Ridge National Laboratory, Tenn., reports that a team of researchers from ORNL, Washington State University, and the University of Idaho, have developed shape-memory polymers that exhibit triple-shape-memory behavior, meaning that the polymers can transform from one temporary shape to another at one temperature, and then back to a permanent shape at a different temperature.
Dr. Orlando Rios of Oak Ridge explains that although researchers have been interested in shape-memory polymers, managing the shape-shifting behavior has been a struggle. “One big issue is controlling the transformation temperatures and their properties,” he says. “We give a recipe where you can adjust the transformation temperature and shift the performance of the material.”
Changing the ratio of ingredients allows the researchers to control the overall properties. The team’s method is based on off-the-shelf chemicals that can be easily scaled up to manufacture the material in bulk. “We’ve taken it from something of a scientific curiosity or fundamental research material, to something that can be produced in larger volumes,” Dr. Rios says.
Mixing the shape-memory polymers with other materials could produce stronger and stiffer composite parts that can later be recycled or reprocessed. Recyclable carbon fiber and glass fiber composites, for instance, are in high demand in the automotive industry.
“The ability to control the shape-memory behavior of the material provides great design flexibility,” says Dr. Yuzhan Li of Washington State.
The material could also be used as binding glue for new types of rare-earth-free magnets made from powders. The team is already experimenting with 3-D printing powder-based magnets with shape-memory polymers.
“The applications for these materials are very broad, since the shape-shifting temperatures for these materials can be finely tuned by controlling the ratio of the chemicals used in their synthesis,” says Prof. Michael Kessler of Washington State.
The study, published in the journal Macromolecules, is featured on the current issue’s cover.
https://www.ornl.gov/news/shape-shifting-plastic
https://news.wsu.edu/category/research/
