'Ductile' mixed biopolymer gel composites

The deformation and failure behaviour of novel 'pseudo-ductile' gelatin/mal todextrin mixed biopolymer gels have been assessed using dynamic mechanical tests, conducted on the stage of a confocal laser scanning microscope. The se materials exhibit a phase-separated structure, with spherical maltodextr in-rich inclusions within a continuous gelatin-rich matrix. Using both conv entional tension and notched compact tension tests, it was observed that th e apparent ductility was due to inclusion/matrix interfacial debonding, res ulting in reduced elastic modulus. Based upon a simple debonding model, an interfacial fracture energy of similar to 0.25 J m(-2) was determined. (C) 1999 Elsevier Science Ltd. All rights reserved.