Effect of carbon nanotube-silane addition on mechanical properties of chloroprene rubber-filled carbon black / Kok-Tee Lau...[et al.]

Chloroprene-filled CNT rubber has been investigated for the electromagnetic
shielding application. Nevertheless, there are continuous studies to overcome
CNTs agglomeration, materials loss and air contamination issues generated
during conventional melt compounding process. Thus, the current study
proposes the usage of polar and low molecular weight ethanol solvent as
dispersant for CNT fillers and silane-based Si-69 as coupling agent. Si-69 is a
widely used fillers’ coupling agent because of its reliable performance in the
industrial-scaled rubber compounding process. This study is to investigate the
effect of carbon nanotube (CNT)-Silane addition as secondary fillers on tensile
strength, elastic modulus and cure characteristics of hloroprene rubber (CR)-
filled carbon black (CB) compound. The CR-filled CB was prepared by
internal mixing, followed by roll-mill process in which CNT-Silane dispersion
was added. For comparison, the samples of CR-filled CB without CNTs
addition and with as-received CNTs addition were prepared and
characterized. The CR composite added with CNT-Silane dispersion displayed
tensile strength and elastic modulus (at 300% elongation) of 23 MPa and 18
MPa respectively, which are 4% higher than the CR composite added with asreceived
CNTs. The findings were supported by the FESEM micrograph of
tensile fracture samples that showed the CNT-Silane addition produced better
CNTs dispersion in the CR-filled CB compound. Furthermore, the usage of CNT-Silane improved the CR-filled CB compound processibility by reducing
the minimum (ML) and maximum torque (MH) values from 0.34 and 1.11 N.m
in as-received CNT samples to 0.32 and 1.04 N.m respectively in CNT-silane
samples.