The influence of amine (polar) and vinyl (nonpolar) functionalized organosilanes were investigated on the total performance of neat high-density polyethylene (HDPE) and wood-HDPE composites. Thus, micro-size silicate-based mineral fillers were treated with 3 mass% amine and vinyl silanes and then 15 and 30 mass% plus 1 and 5 mass% of treated mineral fillers were blended with neat HDPE and wood-HDPE composites, respectively. Based on the achieved mechanical, thermal, rheological, water absorption, and microstructural results, the affinity of amine functional group and HDPE matrix predominantly decreased the rigidity, improved the thermal stability, reduced the water uptake, and facilitated the dispersion of fillers within the polymeric composite. As demonstrated by FTIR test, due to the lack of chemical bonding between the polyethylene and amine/vinyl functional groups, the electrostatic forces can explain the affinity between the filler and matrix. The affinity of the non-polar vinyl group and non-polar HDPE matrix resulted in the agglomeration of mineral fillers that can represent the repulsive electrostatic forces between the vinyl treated filler and the polymeric matrix. (C) 2018 Elsevier Ltd. All rights reserved.