Fatty-acid derived polymers yield recyclable and highly versatile adhesives

Researchers have presented a new family of polymer adhesives that offer a sustainable and recyclable alternative to conventional polymer adhesives and can be used across a wide range of applications, from industrial adhesives to surgical superglues. The new chemical approach to aLA polymerization addresses the performance and environmental challenges of traditional polymers, providing environmentally friendly adhesive solutions. Polymer adhesives are ubiquitous in modern life and are widely used in many medical, consumer, and industrial products. Given this diversity, each adhesive material is often tailored for a specific use, and its performance in one application often does not easily translate to another. Moreover, many adhesives are nonrecyclable and contain chemicals or volatile organic substances that are harmful to health and the environment. Thus, there is a growing demand for multipurpose polymer adhesives that work well across various surfaces and environmental conditions while also being non-toxic, environmentally sustainable, and capable of closed-loop recycling. Polymers derived from aLA – a naturally occurring fatty acid – have the potential to address these needs. However, they suffer from spontaneous depolymerization under conditions relevant to most real-world applications.

To address this critical limitation, Subhajit Pal and colleagues developed a family of stabilized aLA polymer adhesives with a wide range of physical properties. Pal et al. found that minor modifications to monomer composition – namely, the incorporation of an electrophilic stabilizer – prevented aLA depolymerization and enabled the practical design of aLA polymer adhesives.  The authors synthesized several aLA adhesives and tested them across a range of uses. Pressure-sensitive adhesives demonstrated tenfold higher peel strength than conventional options and worked effectively in both dry and wet conditions; structural adhesives matched the strength of petroleum-derived epoxies and were self-healing and reprocessable; and aLA surgical superglue successfully sealed mouse amniotic sac punctures, improving fetal survival from 0% to 100%. Additionally, Pal et al. developed a closed-loop recycling process that regenerated aLA monomers using only aqueous media, demonstrating their sustainability. “Although aLA is naturally occurring, it is, ironically, manufactured primarily from petroleum-based starting materials,” writes Zhibin Guan in a related Perspective. “Looking ahead, developing commercially viable, high-performance polymeric materials from renewable resources is undoubtedly one of the most important directions in modern polymer science.”