Effect of Polyolefin Elastomers’ Characteristics and Natural Magnesium Hydroxide Content on the Properties of Halogen-Free Flame-Retardant Polyolefin Composites

Abstract

This study examines the preparation of several composites that are based on natural magnesium hydroxide (n-MDH) and various poly(ethylene-co-octene) polyolefin elastomers (POEs). Design of experiment (DoE) principles have been applied in order to optimize the mechanical, rheological, and flame-retardant properties of the final composites. DoE allows one to evaluate the influence of each variable on an experiment’s final properties. By increasing the density and crystallinity of the POE, a higher elastic modulus was obtained, which resulted in greater tensile strength and lower elongation at break. Improved flame retardant properties (as measured by the limiting oxygen index (LOI) and vertical burning tests) were obtained by increasing the amount of filler within the composite up to 65% and using a polymer with high crystallinity. More specifically, the best balance between mechanical, rheological, and flame retardant properties was provided by DoE using 63.75% n-MDH filler. The agreement between the predicted performance and the final properties of the composites has enabled the innovative use of DoE to provide reliable predictions about the final mechanical and flame retardant properties of the compounds that are used for low voltage electrical cable applications.