Thermally Remendable Polyurethane Network Cross-Linked via Reversible Diels-Alder Reaction.

Elena Platonova,Egor Afanasyev,Islam Chechenov,Alexander Pavlov,Vitaliy Solodilov,Alexey Shapagin,Alexander Polezhaev

doi:10.3390/polym13121935

Abstract

We prepared a series of thermally remendable and recyclable polyurethanes crosslinked via reversible furan-maleimide Diels–Alder reaction based on TDI end-caped branched Voranol 3138 terminated with difurfurylamine and 4,4′-bis(maleimido)diphenylmethane (BMI). We showed that Young modulus strongly depends on BMI content (from 8 to 250 MPa) that allows us to obtain materials of different elasticity as simple as varying BMI content. The ability of DA and retro-DA reactions between furan and maleimide to reversibly bind material components was investigated by NMR spectroscopy, differential scanning calorimetry, and recycle testing. All polymers obtained demonstrated high strengths and could be recovering without significant loss in mechanical properties for at least five reprocessing cycles.

Highlights

IntroductionGlobal polyurethane production is more than 22 million tons (for PU foams), and most of this production will not be recycled [1,2]
Global polyurethane production is more than 22 million tons, and most of this production will not be recycled [1,2]
We showed that Young modulus strongly depends on BMI content that allows us to obtain materials of different elasticity as simple as varying BMI content

Summary

Introduction

Global polyurethane production is more than 22 million tons (for PU foams), and most of this production will not be recycled [1,2]. The synthetic design of recyclable materials is essential for sustainability, and there is a noticeable growth in the number of papers in the field in the last decade [1]. There are two ways to increase polyurethane sustainability: developing materials based on biorenewable sources such as lignin or sugars [3,4,5,6] and developing recycling technologies [7,8]. The polyurethane polymer family is not limited to thermoplastics, but there are many crosslinked formulations required for high solvent resistance [13,14], high strength [15,16], and abrasion resistance [17]. Crosslinked polymers cannot be reshaped or repaired and recycled when damaged once a crosslinked network is formed [10,18]. There are several approaches to commercial crosslinked PUs recycling: advanced chemical and thermochemical recycling, mechanical recycling, energy recovery, and product recycling, but all of them suffer from inefficiency and high cost [1,10]

Methods

Results

Conclusion