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Alternating Copolymerization of Propylene Oxide and Cyclohexene Oxide with Tricyclic Anhydrides: Access to Partially Renewable Aliphatic Polyesters with High Glass Transition Temperatures
journal contribution
posted on 2016-08-30, 16:20 authored by Maria
J. Sanford, Leticia Peña Carrodeguas, Nathan J. Van Zee, Arjan W. Kleij, Geoffrey W. CoatesRenewable,
biodegradable polymers, such as aliphatic polyesters,
based on sustainable sources have attracted considerable interest
as alternatives to petroleum-based polymers. One limiting factor in
the development of aliphatic polyesters as replacements for these
materials has been their relatively low glass transition temperatures
(Tg). For example, commercially available
poly(lactic acid) has a Tg of approximately
60 °C. Epoxide/anhydride copolymerizations offer an alternative
to the ring-opening polymerization of lactones for the synthesis of
aliphatic polyesters and allow for tuning of polymer properties through
two distinct monomer sets. We synthesized six partially or fully renewable
tricyclic anhydrides and copolymerized them with propylene oxide (PO)
and cyclohexene oxide (CHO). By varying both the epoxide and the anhydride,
we were able to tune the Tg of the resulting
polymers over a nearly 120 °C range from 66 °C to an exceptionally
high 184 °C. Polymers produced with PO had a lower range of Tg values (66–108 °C) and higher
molecular weights up to 32.2 kDa, while those produced with CHO had
higher Tg values (124–184 °C)
and lower molecular weights, showing the profound influence of both
monomer sets. To the best of our knowledge, these are the highest Tg values reported for entirely aliphatic polyesters.