Depolymerizable polymers
Depolymerizable polymers or Low-Ceiling Temperature Polymers refer to polymeric materials that can undergo depolymerization to revert the materials to their monomers at relatively low temperatures, such as room temperature. For example, the ceiling temperature Tc for formaldehyde is 119 °C, and that for acetaldehyde is -39 °C.[1]
Introduction
Unlike stable polymers such as PVCs that have high thermal stability, depolymerizable polymers and closely related self-immolative polymers can be triggered by stimuli to break fast under moderate to low temperatures. The first type of polymers, poly (olefin sulfone), was reported by Snow and Frey in 1943.[2] It was further confirmed and explained in terms of the thermodynamics of a reversible propagation step by Dainton and Ivin.[3]
Applications
The first application of depolymerizable polymers is in transient electronics. Over the past several decades in the electronics industry, the research focus has been on durable and high-strength polymeric materials. Today, however, fast growing consumer electronic products and environmental concerns on electronic wastes, has increased the need for sustainable, recyclable materials. For example, a group of researchers employed light-sensitive poly(phthalaldehyde) as substrate materials for circuits. The destruction of the polymer substrate was triggered by UV irradiation (~379 nm).[1]
References
- Kaitz, Joshua A.; Lee, Olivia P.; Moore, Jeffrey S. (2015-01-01). "Depolymerizable polymers: preparation, applications, and future outlook". MRS Communications. 5 (2): 191–204. doi:10.1557/mrc.2015.28. ISSN 2159-6867.
- Snow, R. D.; Frey, F. E. (1943-12-01). "The Reaction of Sulfur Dioxide with Olefins: the Ceiling Temperature Phenomenon". Journal of the American Chemical Society. 65 (12): 2417–2418. doi:10.1021/ja01252a052. ISSN 0002-7863.
- Dainton, F. S.; Ivin, K. J. (1948-10-30). "Reversibility of the Propagation Reaction in Polymerization Processes and its Manifestation in the Phenomenon of a 'Ceiling Temperature'". Nature. 162 (4122): 705–707. doi:10.1038/162705a0. ISSN 1476-4687.