ABSTRACT
The correlation between the mechanical strength and the crystallization behavior of natural rubber (NR)/halloysite nanotube (HNT) composites is discussed. This includes two separate series, i.e., effects of HNT loadings, e.g., 0–10 phr and use of modified palm stearin (MPS) as a compatibilizer for such composite. As for the HNT loadings, the tensile strength of NR is improved with the addition of HNT. This improvement is attributed to the unique structure of HNT, which facilitates good dispersion and strong interfacial interaction. HNT also plays an important role in assisting the strain-induced crystallization of NR. Crystallization under strain is observed using synchrotron wide-angle X-ray scattering (WAXS). The stress-strain curves and the corresponding degree of crystallinity after straining provides further evidence. Subsequently, MPS at 0–2 phr was introduced. It was found that the addition of MPS significantly enhanced the modulus, tensile strength and tear strength of the composites. This clearly corresponded to interaction between NR and HNT promoted by MPS. As for the crystallization of the composites, the results obtained from stress-strain curves are in very good agreement with the outputs observed by synchrotron WAXS.
