Rheological properties and crystalline structure of the dynamically cured EPDM and PP/HDPE ternary blends

✍ Scribed by Chang Sik Ha; Sung Chul Kim

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 499 KB
• Volume: 35
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1988.070350821

✦ Synopsis

The rheological properties and crystalline structure of the polyolefin ternary blends of EPDM/polypropylene/gh density polyethylene were studied. Blends were prepared in a laboratory internal mixer by two different methods. In blend-cure process, blending and curing were performed simultaneously and EPDM was cured by dicumyl peroxide (DCP) in the presence of PP/HDPE under shear. The cure-blend was to cure EPDM alone first under shear (dynamic curing) and then mix the cured EPDM with PP and HDPE. The effect of DCP concentration, intensity of the shear mixing, and the rubber/plastic composition were studied using capillary rheometer and X-ray difiadometer. The PP-rich ternary blends showed the effect of the mechanooxidative degradation of PP by shear and peroxide. The melt viscosity increased with increasing DCP concentration in blends of EPDM-rich compositions. X-ray diffraction studies revealed that the inclusion of 25 w t 'R, of linear EPDM in the PP/HDPE mixture for the PP-rich ternary blends changed the crystal structure of polypropylene component in the ternary blends.

However, the dynamic curing did not alter the crystal structure of PP or HDPE in the blends.