Biodegradable films containing halloysites: mechanical, dynamic-mechanical properties and morphological aspects

The contribution reports on mechanical and dynamic-mechanical properties of environmental-friendly blown films based on a commercial PHBV/PBAT blend and containing up to 10 % by weight of neat or silanized halloysite nanotubes. Results were integrated and partly interpreted in terms of morphological issues obtained by SEM analysis of criofractured sections of all considered films. Static and dynamic tensile tests, performed in both machine (MD) and transverse (TD) directions, highlighted effects related to filler content and silanization. In presence of chemically modified fillers, film samples showed more marked increases of some typical mechanical parameters as stiffness and tensile strength with respect to samples containing the same amount of untreated clay nanotubes. This behavior is usually explainable by a better dispersion of filler and a good adhesion at the matrix interface: features clearly confirmed by morphological observations of composite films including chemically treated halloysites.