The present work aims to evaluate the interaction of calcium carbonate nanoparticles coated with myristic acid (nCaCO3-MA) in the low density polyethylene (LDPE) properties. The nanocomposites were produced from a factorial statistical design, which established the range of processing conditions analyzed (screw speed, feed speed, number of reverse elements on the screw profile and filler content). Mechanical, thermal and rheological behaviors were evaluated. The results showed that the interaction of all processing variables together was the most significant parameter in the planning. As filler content, screw and feed speeds and number of reverse elements increased, nanocomposites more toughnesss were produced. The crystallinity degree, maximum degradation temperature and the elastic behavior of the materials also increased. From these results, it was possible to conclude that the processing conditions led to better dispersion of the nanoparticles in the LDPE matrix. The myristic acid proved to be a good surface modifier to CaCO3 nanoparticles, maintaining nanoparticle stability and ensuring good interaction between filler and polymer phase.