High-impact Composites of Polypropylene and Nitrile Butadiene Rubber with Improved Compatibility of the Polymer Components, Obtained by Melt Reactive Compounding. Part 2: The Influence of the Composition and Concentration of the Polymer Compatibiliser on the Impact Strength of the Composites

Abstract

We have studied the impact strength of composites of structural designation containing polypropylene (PP) and 23 wt% nitrile butadiene rubber BNKS-18AMN, obtained by peroxide modification in the presence of polar vinyl monomers: maleic anhydride, its polyester with monoethylene glycol (MEG), and a complex of MEG with aromatic amine antioxidant Diaphene FP (DFP). The composites also contained compatibilisers based on PP or its blends with 10 wt% BNKS-18AMN, modified with analogous peroxide modifying systems. Measurements of impact strength were conducted at temperatures of + 23°C and −30°C; the concentration range of all tested compatibilisers in the composites was 3–20 wt%. The dependence of the impact strength on the content of compatibilisers at both temperatures has a complex extremal nature. It was established that, of all the tested composites, the highest level of impact strength and a relatively slow fall in its values are ensured by a compatibiliser containing complex coagent MEG + DFP. The obtained results may be explained by the increased volume and more homogeneous structure of the transition interphase layer formed under these compounding conditions owing to the specific and effective nature of interaction of the MEG molecules with functional groups of the nitrile butadiene rubber in the interphase region of these composites, promoted by the presence of the secondary aromatic amine complexly bound with the MEG.