This article describes two basic studies of the effect of PVC modification by NBR over a wide range of compositions. The first is a study based on a PVC compound modified with up to 120 phr of a pre-crosslinked NBR polymer in a powder form. The second study evaluates a range of different NBR polymers with varying features in a simple PVC compound. The objective of both studies is to explore the effect of the NBR modification on the PVC compound properties, with a focus on the performance benefits.