E. Sheng et al., INTERFACIAL EFFECTS OF A MULTIFUNCTIONAL ADDITIVE ON CARBON-BLACK FILLED RUBBER, Surface and interface analysis, 22(1-12), 1994, pp. 491-496
Interfacial effects of a multifunctional additive (MFA), i.e. n-tallow
-1,3-propanediamine salt of a carboxylic acid, on carbon black filled
rubber have been studied. Surfaces of several normal cure rate carbon
blacks were characterized by XPS and vapour-phase chemical derivatizat
ion, and the carbon blacks were found to have very few functional grou
ps on their surfaces. The MFA has been found to decompose at approxima
tely 120-degrees-C and the decomposition generates a diamine and a car
boxylic acid. Bound rubber, determined by omicron-xylene extraction, w
as found to decrease with the addition of MFA and a limiting bound rub
ber value was obtained at the MFA loading which corresponds to a monol
ayer coverage of the carbon black. The reduction of bound rubber with
the addition of MFA is attributed to the release of the occuluded rubb
er within carbon black agglomerates as a result of improved dispersion
induced by the MFA. Mechanical properties were found to improve with
the addition of MFA and the improvement was again attributed to the di
spersing effect of MFA. Optimum mechanical properties were again obser
ved to occur at an MFA loading which approximately corresponds to a mo
nolayer coverage of the carbon black surface.