Effects of titanate coupling agents on the rheological and mechanical properties of filled polyolefins

An experimental study was carried out to investigate the effects of titanate coupling agents on the rheological properties of p articulate‐filled polyolefin melts. Inorganic fillers used were CaCO3, talc, and fiberglass, and polyolefins used were high‐density polyethylene (HOPE) and polypropylene (PP). It was found that the addition of the coupling agent TTS to the PP‐CaCO3 and PP‐fiberglass systems reduced the melt viscosity considerably, whereas the addition of the coupling agent ETDS‐201 to the PP‐talc and HDPE‐talc systems affected the melt viscosity very little. Also carried out was an injection molding study to investigate the effects of different inorganic fillers and the titanate coupling agents used on the mechanical properties of the injection molded specimens. It was found that addition of titanate coupling agents generally resulted in reduced modulus and tensile strength, and increased elongation and impact strength of the filled systems. The PP‐CaCO3‐TTS and HDPE‐talc‐ETDS 201 systems were found to have impact strength improved by approximately 100 percent with the addition of a titanate coupling agent. The PP‐CaCO3‐TTS samples have ultimate tensile elongation approaching that of virgin PP.