Aluminum amine-(bis)phenolate complexes for ring-opening polymerization of rac-lactide and ε-caprolactone. Issue 2 (June 2013)

• Record Type: Journal Article
• Authors: Cross, Edward D.; Tennekone, Gayan K.; Decken, Andreas; Shaver, Michael P.
• Is Part Of: Green materials. Volume 1:Issue 2(2013)
• Page Start: 79
• Page End: 86
• Publication Date: 2013-06
• Subjects: aluminum -- amine-(bis)phenolate -- biodegradable polymers -- catalysis -- poly(lactic acid)/ε-caprolactone -- poly(ε-caprolactone) -- rac-lactide -- ring-opening polymerization; Biodegradable plastics -- Periodicals; Building materials -- Environmental aspects -- Periodicals; Polymers -- Environmental aspects -- Periodicals; 620.192
• DOI: 10.1680/gmat.12.00006
• Languages: English
• ISSNs: 2049-1220

Abstract

Abstract : Five aluminum-based amine- bis (phenolate) complexes, three of them novel, with variation of the pendant donor arm were synthesized in excellent yields, and characterized by NMR spectroscopy and X-ray crystallogra-phy. The quantitative conversion of the aluminum alkyl species to the corresponding benzyl alkoxide was achieved by the addition of 1 mol eq. of benzyl alcohol, and was confirmed by 1 H NMR spectroscopy. The aluminum alkox-ides were excellent mediators for the ring-opening polymerization (ROP) of rac -lactide, yielding atactic poly(lactic acid), having excellent correlation between theoretical and calculated molecular weights accompanied by nar-row molecular weight distributions. ROP of ε-caprolactone by the aluminum alkoxides showed modest con-trol at 50°C in toluene, but much greater control was achieved when polymerizations were conducted at 25°C, with nar-rower molecular weight distributions observed in some cases. A relationship between the complex pendant donor arm and the resulting activity in the ROP of both rac-lactide and ε-caprolactone is discussed.