new upcycling system for commercial polyesters
Scientists have developed a one-shot process to transform commonly available polymeric plastics, such as polyesters into highly functional materials called “vitrimers” that can be easily recycled into useful products while retaining enhanced thermo-mechanical properties of the original polymer. Credit: Dr. Mikihiro Hayashi and Nagoya Institute of Technology, Japan

While plastics or synthetic polymers have many useful properties, their mismanagement has resulted in widespread pollution that chokes up our ecosystems. As a solution to this, many synthetic polymers are sent for reprocessing and recycling; polyethylene terephthalate (PET) is one of the most common products frequently seen in the recycling loop in many countries. However, recycling has its own set of problems. During plastic recycling, partial fractions of the polymer chains are decomposed resulting in structurally weak, downgraded polymers. These sub-standard recycled plastics have much reduced properties and are only good for use as solid fuels. This leaves manufacturers with little choice other than to make new plastic products with fast-depleting petroleum feedstocks.

As such, researchers across the world are engaged in developing sustainable cross-linked polymer materials that can be recycled efficiently and cost-effectively. Adding to the growing body of knowledge, Dr. Mikihiro Hayashi, Assistant Professor at Nagoya Institute of Technology, Japan, and his colleague Mr. Takahiro Kimura have developed a simple method to recycle polyester, a common plastic material, into a cross-linked polymer that retains its strength and properties when recycled. Their method centers around transforming polyesters into vitrimers—a new class of polymers possessing dynamic covalent bonds that can reversibly break and reform to create new cross-links. The dynamic covalent bonds render the vitrimer with desirable properties, such as recyclability, reprocessability, and healing capabilities, which are characteristics of high-value functional materials. The study was published on August 1, 2022 in the Journal of Materials Chemistry A.

Dr. Hayashi says, “Our research demonstrates a one-shot upcycling process of commercial polyesters into cross-linked vitrimers with enhanced thermo-mechanical properties and sustainable functions.” He and his colleague created the vitrimers by simply mixing polyester with a cross-linker molecule— tetra-epoxy, along with the chemical compound 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a catalyst in the presence of tetrahydrofuran as the solvent. The solvent was later evaporated, and the remaining mixture was heated at 200°C for 24 hours, producing a film of vitrimer.


Researchers from Nagoya Institute of Technology, Japan, demonstrated that ordinary polyester can be easily converted into a versatile type of material known as vitrimers. Credit: Mikihiro Hayashi from Nagoya Institute of Technology (NITech), Japan

With this method, the cross-linking for producing vitrimer occurs in three quick sequential stages—hydrolysis (breaking of the polyester bonds), epoxy-opening reaction, and intermolecular transesterification. Discussing the superior mechano-elastic properties of the produced vitrimers, Dr. Hayashi says, “The highly cross-linked and recyclable vitrimer exhibits a 60-fold increase in tensile modulus or Young’s modulus and a 10-fold increase in the maximum endurable stress when compared with the original polyester. It also has a gel fraction of nearly 100%.” Moreover, the vitrimer was observed to retain its properties even after being ground into fractured pieces and pressed into a flat sheet, which reaffirms its recyclability.

Plastics are essential materials with many benefits and useful properties because they are lightweight, cheap, non-toxic, and easy to produce. However, at the same time, it is necessary to acknowledge and limit the environmental damage they cause. Improving the recyclability of plastic polymers will encourage recycling programs and reduce the use of petroleum, a non-renewable resource. As Dr. Hayashi rightly observes, “The world needs versatile options for recycling synthetic polymers. The method we propose will not only eliminate the use of petroleum-derived chemicals, but it could also be the first step towards a practical and sustainable upcycling system for the future, which adheres to the principles of circular economy and helps realize the SDGs.”

As a step forward, the researchers are now planning to devise a more direct transformation of polyesters into vitrimer without using any solvents and are also looking into using their method to transform commercial PET into other highly recyclable materials. If successful, the developed method could lead to a closed loop of plastic production and avert any further environmental crises caused by excessive plastic production. More information: Takahiro Kimura et al, One-shot transformation of ordinary polyesters into vitrimers: decomposition-triggered cross-linking and assistance of dynamic covalent bonds, Journal of Materials Chemistry A (2022). DOI: 10.1039/D2TA04110C Journal information: Journal of Materials Chemistry A

Provided by Nagoya Institute of Technology Citation: New upcycling system for commercial polyesters (2022, September 27) retrieved 27 September 2022 from https://phys.org/news/2022-09-upcycling-commercial-polyesters.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

TECH NEWS RELATED

Apple: Most iCloud data can now be end-to-end encrypted

As part of an ongoing privacy push, Apple said Wednesday it will now offer full end-to-encryption for nearly all the data its users store in its global cloud-based storage system. That will make it more difficult for hackers, spies and law enforcement agencies to access sensitive user information. The ...

View more: Apple: Most iCloud data can now be end-to-end encrypted

Apple iOS 16.2 RC Update Brings iPhone 5G Connection to India

Apple debuts the new iOS 16.2 Release Candidate (RC) update, which brings new much-awaited features to iPhone users. The RC update offers a 5G connection to iPhone users in the second most populated country in the world, India. It also provides new features to built-in apps like Apple Music. (Photo ...

View more: Apple iOS 16.2 RC Update Brings iPhone 5G Connection to India

5 Free Websites You Can Take Short Online Courses From

If you are looking to expand your knowledge to bulk up your resume or simply looking for a productive way to pass the time, taking online courses might have already crossed your mind. With the increased demand for information accessibility in the Internet Age and the pandemic years, many ...

View more: 5 Free Websites You Can Take Short Online Courses From

Young scientist becomes first Vietnamese awarded by UK Royal Aeronautical Society

Dr. Nguyen Huyen Duc was granted the Young Persons’ Achievement Award 2022 by the UK’s Royal Aeronautical Society. (Source: VietnamPlus) London (VNA) – With the Young Persons’ Achievement Award, Dr. Nguyen Huyen Duc has become the first Vietnamese scientist to receive the prize from the UK’s Royal Aeronautical Society (RAeS).Duc is the ...

View more: Young scientist becomes first Vietnamese awarded by UK Royal Aeronautical Society

AIS joins e-waste blockchain initiative

Ms Saichon unveils the blockchain-based E-Waste+ platform. Advanced Info Service Plc (AIS), Thailand's biggest mobile operator by subscriber base, has joined hands with partners to launch an electronic waste blockchain system that allows users to track and trace e-waste through the recycling process and calculate carbon reduction scores. Blockchain-based ...

View more: AIS joins e-waste blockchain initiative

Huawei committed to cultivating digital talent

From left, David Li, chief executive of Huawei Technologies Thailand, Mr Supachai, acting Capt Montree Munkong, advisor to the Digital Economy and Society minister, and Mr Deng at the Thailand Talent Transformation Symposium. Global multinational Huawei Technologies has joined hands with partners in the public and private sectors to ...

View more: Huawei committed to cultivating digital talent

Fans are going nuts over this official Avengers concept art

Avengers: Infinity War is one of the highlights of the MCU, a movie worth revisiting time and again. The film delivers various iconic moments as the Avengers try to stop Thanos (Josh Brolin) from obtaining all six Infinity Stones. As a result, we witness several exciting team-ups as the Avengers ...

View more: Fans are going nuts over this official Avengers concept art

iCloud backups will now be end-to-end encrypted

Apple has just made a couple of significant security announcements. The most noteworthy is that iCloud backups will now be end-to-end encrypted. This is part of a larger security initiatives that Apple is calling Advanced Data Protection which will see the number of data categories being end-to-end encrypted rising ...

View more: iCloud backups will now be end-to-end encrypted

Hong Kong’s Pando Finance launches blockchain-themed ETF to give investors a taste of cryptocurrencies ‘with minimum risk’

How Silicon Valley looks at the Taiwan miracle (9): Ethnic Chinese associations and industry leaders

Elon Musk found a successor to act as Tesla Global CEO

Indian GCCs to add 3.64 million jobs over next 12 months

Scoop: HUL, other FMCG majors in sale talks with nutrition firm Oziva

Exclusive: Swiggy may fire 250 employees in December, more layoffs possible in coming months

Social platforms flag age-gating fears in MeitY’s IT rules meet

Spice Money to offer B2B transactions on ONDC next quarter

iPhone 14’s Emergency SOS via satellite feature may launch in the UK next week

New kilonova has astronomers rethinking what we know about gamma-ray bursts

Tecno MegaBook S1 brings 15.6″ 120Hz display and 12th Gen Core i7

Mars is hiding exciting mysteries beneath its surface 

OTHER TECH NEWS

Top Car News Car News