The components were then melt-mixed and dynamically vulcanised in a mini-extruder (DSM
Research, The Netherlands), which is a conical co-rotating fully intermeshing twin-screw extruder with
a capacity of about 4 cm3
. A recirculation channel allows varying of the blending time. All blends
were prepared under nitrogen atmosphere to prevent oxidative degradation. The blending conditions
were chosen carefully by variation of rotor speed, blending temperature and mixing time; the optimal
blending conditions result in a mixing time, temperature and rotor speed of 6 min, 260°C and 80 rpm,
respectively. The peroxide (0.25 wt%), used as crosslinking agent, was first dissolved in mineral oil (2
wt%) and subsequently premixed with the rubber in a Haake 69 cm3
batch kneader before the
nylon/rubber blend was compounded in the mini-extruder. The peroxide was dissolved in mineral oil
in order to achieve a better dispersion in the rubber