The Montmorillonite-Erucamide nanocomposite (MMT-EU) can be used to reduce and to control the values of coefficient of friction of low-density polyethylene films (LDPE), widely used by the food industry. In this work, the effect of the addition of 5 wt% and 10 wt% of MMT-EU on the mechanical properties of LLDPE films involving the weld region was investigated. The MMT-EU concentration range was defined considering its possible technological application as an additive to stabilize the friction coefficient of polymeric films. The result shows a significant improvement in the values of stiffness, strength and ductility of polymeric films. In addition, it did not change the coefficient of friction, but the brightness of the LLDPE films decreased and the opacity increased, due to the increase in the crystallinity degree of the LLDPE polymer promoted by MMT-EU, not being a problem for the application of these films.

ABSTRACT The present manuscript approaches the mechanical interpretation about the volume changes of auxetic metamaterials within a multiscale perspective. The kinematic fields resulting from the mechanical tests were assessed via digital image correlation (DIC). The multiscale mechanical characterization is grounded within sound homogenization principles based on representative volume elements (RVE) at large deformations. The main achieved results concern in highlight that even though the Poisson’s ratio still widely used to characterize the mechanical behavior of auxetic metamaterials, it does not represent a suitable variable to quantify the multiscale volume changes, mainly when finite deformations take place. In this regard, a proper homogenized kinematical quantity is used in this work. Moreover, statistical tools are employed aiming at a better understanding to what extent the multiscale kinematics influence the volume changes and the overall auxetic behavior of the material.

Abstract Aiming at multiscale numerical investigations of fibrous connective tissues, the present work proposes a finite strain viscoelastic model suitable to represent the local mechanical response of living cells in conjunction with finite element simulations of nanoindentation tests. The material model is formulated in a thermodynamically consistent framework based on a variational constitutive approach. As a case of study, a numerical investigation of the local compressible response of fibroblast cells is addressed. Moreover, a set of cyclic, stress relaxation and creep experiments are simulated in order to investigate the capability of the model to predict rate dependence of cells, showing sound agreement with experimental data. The proposed model may be used as a suitable tool for a better understanding of stiffness and energetic dissipation of cells.