Blends of EPDM rubber/Thermoplastics

Abstract: Blends containing recycled EPDM rubber and thermoplastics, EMA and LDPE
were studied. Two compatibilization methods, reactive and non-reactive,
were evaluated. Ethylene octene copolymer (EXACT 0210) was used as non-
reactive compatibilizer. Phenolic resins (SP1045 & HRJ10518) were reactive
agents. There existed an optimal composition of compatibilizers which were
25wt% in the case of reactive and non-reactive agents added to 15wt%EMA and
55-60wt% EPDM rubber. EXACT-compatibilized blends gave high elongation at
break while phenolic resin-compatibilized mixtures gave high stiffness in
comparison with the chosen reference material. Comparison in
compatibilizing capabilities HRJ-10518 and SP-1045 was carried out. The
former one had better capabilities than the latter at high compatibilizer
content. Talcum was used as anti-agglomeration agent but failed to work
properly. Pressing pressure could be minimized without any adverse effect.
Non-vulcanized rubber was used to enhance tear strength but its effect was
small by assuming that there exists degradation of the interfacial surface
at high temperature. SEM analysis revealed homogeneous microstructure in
both kinds of compatibilization. EXACT 0210-compatibilized blends showed
more plastic deformation of the matrix than reactive blends. Stable
connection between phases was also observed. Tensile strength of the LDPE
based blends were a little lower than that of EMA based blends and the
hardness was a little higher. Compared to EMA based blends, the elongation
at break was much lower while the young’s modulus was much higher with
LDPE based blends. Compression set of both LDPE and EMA based blends was
high compared to the reference materials.