Seawater Degradable Thermoplastic Polyurethanes

Document Type

Article

Publication Date

2-5-2010

Department

Polymers and High Performance Materials

Abstract

Degradable thermoplastic polyurethane (TPU) elastomers incorporating poly(D,L-lactide-co-glycolide) (PLGA) were synthesized and characterized. The soft segments consisted of a mixture of poly(butylene adipate) (PBA) and PLGA with PBA/PLGA ratios of 100/0, 75/25, and 50/50 wt %. Two PLGA polyesters were used. BD-PLGA was initiated from butanediol; whereas BHMBA-PLGA was initiated from 2,2-bis-(hydroxymethyl)butanoic acid. The hard segments consisted of dicyclohexylmethane4,4'-diisocyanate (H(12)MDI) and 1,4-butanediol (BD). The hard segment content, expressed as the weight ratio of BD to polyol used in the TPU formulation, was set either at 8 or 12% (31.2 or 38.1% hard segment by weight, respectively). In all cases initial [NCO]/[OH] ratio was 1.03. The tensile modulus of the TPUs ranged from 9 to 131 MPa and ultimate strains ranged from 100 to 750%. DMA was used to probe the thermomechanical transitions of the TPUs and indicated useful application temperatures from well below zero up to 60-80 degrees C depending on the formulation. Hydrolytic degradation of the TPUs was tested in sea-water at 37 degrees C. All of the PLGA-containing TPUs showed enhanced degradation compared to those with only PBA as the soft segment. The latter compositions remained essentially unchanged throughout the test while the PLGA-containing TPUs lost as much as 45% of their initial mass in 153 days. Molecular weights of TPUs containing degradable polyols were lower than those derived from 100% PBA polyol. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1873-1880, 2010

Publication Title

Journal of Applied Polymer Science

Volume

115

Issue

3

First Page

1873

Last Page

1880

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