New method developed to solve plastics sustainability problem

Date:
August 17, 2021
Source:
University of Akron
Summary:
A research group is developing polymers that can be broken
down into their constituent parts; thus, when the catalyst for
depolymerization is absent or removed, the polymers will be highly
stable and their thermal and mechanical properties can be tuned
to meet the needs of various applications.



FULL STORY ========================================================================== Plastics sustainability has come a long way in recent years thanks in
large part to scientific advances. But even as plastics become more and
more environmentally friendly, the world continues to be polluted as
many industries rely on them for their widely used products.


==========================================================================
The latest research from Dr. Junpeng Wang, assistant professor in UA's
School of Polymer Science and Polymer Engineering has a solution to
reduce such waste and clear a scientific pathway for a more sustainable
future that can appeal to the rubber, tire, automobile and electronics industries. Although this work is supported by UA, Wang recently earned
a National Science Foundation CAREER Award that will support future developments from this research.

The problem at hand: Synthetic polymers, including rubber and plastics,
are used in nearly every aspect of daily life. The dominance of synthetic polymers is largely driven by their excellent stability and versatile mechanical properties. However, due to their high durability, waste
materials composed of these polymers have accumulated in the land and
oceans, causing serious concerns for the ecosystem.

In addition, since over 90% of these polymers are derived from finite
natural resources, such as petroleum and coal, the production of these materials is unsustainable if they cannot be recycled and reused.

A promising solution to address the challenges in plastics sustainability
is to replace current polymers with recyclable ones in order to
achieve a circular use of materials. Despite the progress made thus
far, few recyclable polymers exhibit the excellent thermal stability
and high-performance mechanical properties of traditional polymers. The recyclable materials Wang and his team have developed are unique in the superior thermal stability and versatile mechanical properties. Their
article explaining the research, "Olefin Metathesis-Based Chemically
Recyclable Polymers Enabled by Fused-Ring Monomers," was published last
week by Nature Chemistry.

"We are particularly interested in chemically recyclable polymers that
can be broken down into the constituents (monomers) from which they are
made," says Wang. "The recycled monomers can be reused to produce the
polymers, allowing for a circular use of materials, which not only helps
to preserve the finite natural resources used in plastics production, but
also addresses the issue of unwanted end-of-life accumulation of plastic objects." The key in the design of chemically recyclable polymers is to identify the right monomer. Through careful computational calculation,
the researchers identified a targeting monomer. They then prepared
the monomer and polymers through chemical synthesis, using abundantly
available starting materials.

Wang's research group, including polymer science graduate students and
a postdoctoral scientist, aims to address those challenges by developing polymers that can be broken down into their constituent parts. When the catalyst for depolymerization is absent or removed, the polymers will be
highly stable and their thermal and mechanical properties can be tuned
to meet the needs of various applications.

"The chemically recyclable polymers we developed show excellent thermal stability and robust mechanical properties and can be used to prepare
both rubber and plastics," says Wang. "We expect this material to be
an attractive candidate to replace current polymers. Our molecular
design is guided by computation, highlighting the transformational
power of integrating computation and experimental work. Compared to
other recyclable polymers that have been demonstrated, the new polymers
we demonstrate show much better stability and more versatile mechanical properties. When a catalyst is added, the polymer can be degraded into
the constituent monomer for recycling." Next for Wang's research group
is to expand the scope of the chemically recyclable polymers and to
develop carbon-fiber reinforced polymer composites.

The team will also analyze the economic performance of this industrial
process and life-cycle analysis for commercialization of the polymers.

========================================================================== Story Source: Materials provided by University_of_Akron. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Devavrat Sathe, Junfeng Zhou, Hanlin Chen, Hsin-Wei Su, Wei Xie,
Tze-Gang
Hsu, Briana R. Schrage, Travis Smith, Christopher J. Ziegler,
Junpeng Wang. Olefin metathesis-based chemically recyclable polymers
enabled by fused-ring monomers. Nature Chemistry, 2021; 13 (8):
743 DOI: 10.1038/ s41557-021-00748-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210817193022.htm

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