Weight not an issue for novel polymerization technique

“Our novel polymerization method could control both the chirality and the molecular weight of polybenzofuran, leading to unique optically active polymer materials with highly controlled structures.”Mineto Uchiyama, Nagoya University

Researchers in Japan have developed a new technique for creating polymers, which could lead to the development of plastics that are more environmentally friendly, heat-resistant and transparent.

One way to produce polymers is via a technique called asymmetric cationic polymerization, but this technique cannot control the molecular weight of the polymers. Being able to control the molecular weight of polymers, especially those used in the engineering of plastics, is important because it affects many of the properties of the plastics. Stiffer-flowing, high-molecular-weight polymers offer the best performance as they are tougher and more resistant to chemical and environmental damage.

Now, a group that includes Mineto Uchiyama and Masami Kamigaito of the Graduate School of Engineering at Nagoya University, and Kotaro Sato of the Tokyo Institute of Technology, has developed a novel technique called asymmetric living cationic polymerization, which allows them to synthesize optically active polymers with controlled molecular weight.

The researchers developed the technique by combining two existing polymerization techniques: living cationic polymerization and asymmetric cationic polymerization. The new technique creates polymers with controlled molecular weight and high optical activity that can be chemically controlled. They report their new technique in a paper in the Journal of the American Chemical Society.

Monomers are the building blocks of polymers and come from various sources. To test their new technique, the group used it to convert the monomer benzofuran, which can be derived from natural resources, into the polymer polybenzofuran. Benzofuran forms rigid polymers with a high glass-transition temperature and high transparency, and is also chemically recyclable.

The high glass-transition temperature of benzofuran allows polybenzofuran to maintain its hard shape, even at extreme temperatures. This means benzofuran is useful for the creation of sustainable transparent thermoplastics.

“Our novel polymerization method could control both the chirality and the molecular weight of polybenzofuran, leading to unique optically active polymer materials with highly controlled structures,” says Uchiyama. “This research is expected to lead not only to the development of new precision polymerization reactions but also to the development of new functional polymer materials. Since polybenzofuran has the properties of a highly heat-resistant plastic, it is expected to become a new material as a heat-resistant resin with optical activity.”

Uchiyama sees numerous uses for this polymer. “Polybenzofuran has a structure similar to polystyrene, which is one of the main plastics used daily for various products, such as plastic containers, cases and packaging,” he says. “While polybenzofuran is not used as a commercially available plastic, it has a stiffer molecular structure and a higher glass-transition temperature than polystyrene. We see it being used as a new plastic with good thermal properties. Furthermore, its unique optical properties could give additional functionalities.”

This story is adapted from material from Nagoya University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.