Effects of low contents of A₂M₃O₁₂ submicronic thermomiotic‐like fillers on thermal expansion and mechanical properties of HDPE‐based composites

In this work, pristine Al₂W₃O₁₂ and Y₂W₃O₁₂ submicronic fillers, belonging to A₂M₃O₁₂ family of thermomiotic materials, were incorporated into a high density polyethylene matrix (HDPE) in low contents (from 0.1 to 1.1 vol.%) to study the influence thereof on the coefficient of thermal expansion (CTE) and mechanical properties of the as‐prepared composites. The CTE of HDPE and HDPE/A₂M₃O₁₂ composites is affected by the first heating cycle, but it remained unchanged after the second heating run. Both Y₂W₃O₁₂ and Al₂W₃O₁₂ fillers decrease the CTE of composites. However, Y₂W₃O₁₂ acts more efficiently than Al₂W₃O₁₂ to decrease this property and caused a CTE reduction in the range of 20–25% for the temperature interval between 25 and 70°C during the second heating cycle. The filler content does not have a strong influence on CTE for both types of composites, considering the standard deviations. The thermal stability of HDPE is not affected by the addition of fillers. However, the fillers significantly increase the degree of crystallinity, especially in the case of Y₂W₃O₁₂. For the highest filler content (1.1 vol.%), the Young's modulus of composites increased up to 21 and 32% in the case of Al₂W₃O₁₂ and Y₂W₃O₁₂, respectively. POLYM. COMPOS., 39:E1821–E1833, 2018. © 2018 Society of Plastics Engineers