In this work, polyolefin-blend/clay nanocomposites based on low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and organically modified clay (OC) were prepared by melt extrusion. Various grades of maleic anhydride (MA) grafted polyethylene (PE-g-MA) were used and examined as compatibilizers in these nanocomposites. Differential scanning calorimetry analysis showed that OC and compatibilizer affect the crystallization behavior of LDPE/LLDPE with different mechanisms. Thermodynamic calculations of wetting coefficient based on interfacial energy between OC, LD, and LL, Morphological characterization based on field emission scanning electron microscopy, X-ray diffraction, small angles X-ray scattering, and dynamic rheology measurements revealed that the compatibilizer and OC were localized at the interface of LDPE and LLDPE phases with a preferred tendency toward one phase. Results demonstrated that at a specific amount of OC, there is an optimum compatibilizer concentration to achieve nanodispersed OC and beyond that the compatibilizer causes a structural change in the polymer crystalline morphology. It was also found that the tensile property enhancement of LDPE/LLDPE/OC nanocomposites is closely related to the crystalline structure development made by incorporation of both OC and compatibilizer.compatibilizer, crystalline morphology, immiscible polyolefin blend, organically modified nanoclay, polymer-clay nanocomposite
| INTRODUCTIONPolymer/clay nanocomposite is created when the clay galleries containing silicate layers develop interfacial interactions with hosting polymers and are well dispersed in the polymer matrix. [1,2] As the pristine silicate layers are not able to provide such interactions in many polymer matrices, organically modified clays (OC) are necessarily employed in such nanocomposites. However, achieving nanostructured morphology is still problematic for nonpolar polymers like polyolefins even with OCs. [3][4][5] To promote the interfacial interaction between polyolefins and OC, suitable compatibilizers must be used. Effect of OC on the nucleation and crystal growth rate of