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][2]

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.[3] The first type of polymers, poly (olefin sulfone), was reported by Snow and Frey in 1943.[4] It was further confirmed and explained in terms of the thermodynamics of a reversible propagation step by Dainton and Ivin.[5] Closely related to depolymerizable polymers, self-immolative polymers can also irreversibly disassemble into their constituent parts in response to stimuli such as temperature, biological inputs or pH.[6]

Aspirational applications

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Demand for recycling has also prompted search for polymers that are transient. For example, poly(phthalaldehyde) is a possible photodegradable substrate material for circuits.[1] Other applications include controlled release of small molecules, and as stimuli-responsive photoresists for lithography.[7] Some polymers are contemplated for controlled release of drugs.[2]

References

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  1. ^ a b 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.
  2. ^ a b Yardley, Rebecca E.; Kenaree, Amir Rabiee; Gillies, Elizabeth R. (2019). "Triggering Depolymerization: Progress and Opportunities for Self-Immolative Polymers". Macromolecules. 52 (17): 6342–6360. Bibcode:2019MaMol..52.6342Y. doi:10.1021/acs.macromol.9b00965. S2CID 202067871.
  3. ^ Peterson, Gregory I.; Larsen, Michael B.; Boydston, Andrew J. (2012-09-25). "Controlled Depolymerization: Stimuli-Responsive Self-Immolative Polymers". Macromolecules. 45 (18): 7317–7328. doi:10.1021/ma300817v. ISSN 0024-9297.
  4. ^ 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.
  5. ^ 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. S2CID 4105548.
  6. ^ Roberts, Derrick A.; Pilgrim, Ben S.; Dell, Tristan N.; Stevens, Molly M. (2020-04-08). "Dynamic pH responsivity of triazole-based self-immolative linkers". Chemical Science. 11 (14): 3713–3718. doi:10.1039/D0SC00532K. ISSN 2041-6539. PMC 8152797. PMID 34094059.
  7. ^ Kaitz, Joshua A.; Lee, Olivia P.; Moore, Jeffrey S. (2015-06-01). "Depolymerizable polymers: preparation, applications, and future outlook". MRS Communications. 5 (2): 191–204. doi:10.1557/mrc.2015.28. ISSN 2159-6867. S2CID 138265011.


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