Insights into the polymerization kinetics of thermoresponsive polytrimethylene carbonate bearing a methoxyethoxy side group. Issue 19 (21st August 2020)

• Record Type: Journal Article
• Authors: Brissenden, Amanda J.; Amsden, Brian G.
• Is Part Of: Journal of polymer science. Volume 58:Issue 19(2020)
• Page Start: 2697
• Page End: 2707
• Publication Date: 2020-08-21
• Subjects: biomaterial -- function polycarbonates -- monomer purification -- polymerization kinetics -- ring opening polymerization; Polymers -- Periodicals; Polymerization -- Periodicals; Polymerization; Polymers; Periodicals; 547.7
• DOI: 10.1002/pol.20200371
• Languages: English
• ISSNs: 2642-4150

Abstract

Abstract: The ring‐opening polymerization kinetics of 5‐[2‐(2‐methoxyethoxy)‐ethoxymethyl]‐5‐methyl‐1, 3‐dioxa‐2‐one (TMOE‐2) and 5‐[2‐{2‐(2‐methoxyethoxy)ethyoxy}‐ethoxymethyl]‐5‐methyl‐1, 3‐dioxa‐2‐one (TMOE‐3) was investigated using different catalysts with the aim to improve control over molecular weight. The possibility of monomer impurities driving the variability in molecular weight that has been seen in different reports, was assessed and evidence of catalysis via an imidazole impurity was found. The catalysts 1, 5, 7‐triazobicyclo(4.4.0)dec‐5‐ene (TBD), hydrogen chloride in diethyl ether (HCl·Et2 O), stannous 2‐ethylhexanoate (SnOct2 ), and catalyst free thermal polymerizations were conducted to understand the mechanisms influencing the molecular weight. TBD and HCl·Et2 O consistently achieved high conversion of the monomer; however, molecular weights greater than 7, 000 Da could not be achieved due to competing side reactions. SnOct2 catalyzed and catalyst free thermal polymerizations were highly influenced by monomer purity and achieved lower conversion than TBD and HCl·Et2 O. Understanding these mechanisms will guide future synthesis of poly(TMOE‐2) and poly(TMOE‐3) for biomedical applications. Abstract : The polymerization of 5‐[2‐(2‐methoxyethoxy)‐ethoxymethyl]‐5‐methyl‐1, 3‐dioxa‐2‐one) (TMOE‐2) and (5‐[2‐{2‐(2‐methoxyethoxy)ethyoxy}‐ethoxymethyl]‐5‐methyl‐1, 3‐dioxa‐2‐one) (TMOE‐3) was investigated using different catalysts to produce high molecular weight polymers. While 1, 5, 7‐triazobicyclo(4.4.0)dec‐5‐ene (TBD), hydrogen chloride in diethyl ether (HCl·Et2 O) yielded high monomer conversion, molecular weights greater than 7 kDa could not be achieved. Stannous 2‐ethylhexanoate (SnOct2 ), and catalyst free thermal polymerizations were highly influenced by monomer purity and achieved lower conversion than TBD and HCl·Et2 O.