Atomic force microscopy investigation of phase morphology correlated with adhesive properties for modified telechelic natural rubber based-pressure sensitive adhesive

Atomic force microscopy (AFM) is a powerful technique to determine phase morphology and surface mechanical properties of materials. In this research natural rubber was degraded and grafted by malelic anhydride before modification with 3-amino-1,2,4-triazole to obtain modified telechelic natural rubber or modified TNR. It was then blended with cumarone-indene resin at 10, 30, and 50 phr, acting as tackifier. Phase morphology and surface topography were investigated by intermitted AFM. The results showed that tackifier enriched domains were clearly observed in modified TNR matrix after added 30 and 50 phr and the domain sizes were approximately to be the order of micrometer (5-10 mu m) which it increased with increasing tackifier content. The intermolecular hydrogen bonding interaction between tackifier and modified TNR was observed by attenuated total reflectance Fourier transform infrared spectroscopy. The adhesive properties (loop tack, peel, and shear strength) were governed by the size of tackifier enriched domains, surface mean roughness and compatibility or interaction between modified TNR rubber and cumarone-indene tackifier resin.