Plane stress essential work of fracture of ‘pseudo-ductile’ gelatin/maltodextrin biopolymer gel composites

Abstract

Mixed biopolymer gels, comprised of spherical ‘maltodextrin-rich’ inclusions within a ‘gelatin-rich’ continuous matrix phase, have been shown to exhibit a form of ‘pseudo-ductility’ during tensile deformation, due to debonding of the inclusion/matrix interface during straining. A plane stress work of fracture technique, using thin sheet double edge notched tension (DENT) specimens, has been applied to these composites to assess the elastic and plastic contributions to crack growth during fracture. A transition from plane stress to mixed mode failure was observed to occur when the intact ligament length decreased below ∼8 B to 9 B (where B is the sheet thickness). With the DENT technique, a specific essential work of fracture (elastic contribution) of ∼110 J m −2 was calculated for the current gelatin/maltodextrin composition, under plane stress conditions.