Dynamic mechanical behavior of binary blends polyethylene/EPDM rubber and polypropylene/EPDM rubber

Abstract

The dynamic mechanical behavior of the binary blends high‐density polyethylene/EPDM rubber (ethylene‐propylene‐diene terpolymer) and isotactic polypropylene/EPDM rubber was investigated by means of a free‐oscillating torsional pendulum. Comparison of the moduli of the systems studied and predictions drawn from several models show that phase inversion in the polyethylene/EPDM blends takes place at the volume fraction vPE = 0.5, while polypropylene preserves a certain phase continuity also as the minor component (0.5 > vPP > 0.2) in blends with EPDM. Because of faster shrinkage in the course of cooling, inclusions are exposed to negative hydrostatic pressure, which accounts for a drop in the glass‐transition temperature of the rubber. The strength of the relaxation associated with the glass transition of inclusions and tensile impact strength increase proportionately to the rubber content in polypropylene (0 < vEPDM < 0.4). Dynamic mechanical response spectra of commercial EPDM/polyethylene impact modifiers are compared with the results for model systems.

Influence of curative, filler, compatibilizer, domain size, and blend ratio on the dynamic mechanical properties of silicone–EPDM blends

“…temperatures beyond the second tan 6 peak temperature, storage modulus is found to be higher as the ageing period is increased from 6 to 36 h. The unaged sample shows highest modulus immediately after the second tan 6 peak temperature but its value falls rapidly, and after 10°C the storage modulus of 36-h aged sample becomes higher and at 35°C it reaches the storage modulus value of the sample aged for 18 h. For the 50/50 blend of silicone/EPDM (mix I ) , the tan 6 peak temperature corresponding to the glass transition of silicone does not change with ageing time [ Fig. 5 ( a ) and Table IV] .…”

“…6 ( b ) 1. At 25"C, storage modulus is found to decrease with heat ageing up to 18 h and then it increases with further heat ageing.…”

Mechanical Properties of Impact i-PP/CSM Rubber Blends

“…The application range of the i-PP has been further widened by blending in it other polymers such as styrene-butadiene rubber [4], ethylene-propylene rubber [5][6][7][8][9][10], strene-ethylene-butylene-styrene rubber [11,12], and so on. Currently, impact modified isotactic polypropylenes are manufactured by sequential copolymerization methods [3,[13][14][15].…”

Polymer Blends

“…Physical properties of blends consisting of a continuous matrix and one or more dispersed (discrete) components can be predicted by using adapted models proposed for particulate composite systems (216)(217)(218)(219)(220). Most of these models do not consider effects of the particle size, but only of volume fractions of components in the system.…”

“…The remaining v 1s and v 2s are evaluated using equation 13. The theoretical critical volume fraction (percolation threshold) v cr ¼ 0.156 was calculated (78,219,226,227) for random spatial array of discrete spherical domains. Most reported values of q are located in the interval 1.6-2.0, which complies well with the theoretical prediction q ¼ 1.8 (224,227).…”