Reinforcement of polyolefins-based nanocomposites: combination of compatibilizer with high shear extrusion process

Abstract

The structure and properties of polypropylene (PP) and ethylene propylene copolymer (EPR) blends filled with nanosilica have been investigated. The nanocomposites were prepared via direct melt mixing using high shear corotating twin screw extruder. The effects of the process as well as adding amaleated-Polyethylene MAPE compatibilizer were assessed by morphology studies, thermal analysis and mechanical testing. From SEM and TEM investigations, a separate dispersion of filler and rubber in the PP matrix prevails in the PP/EPR/SiO 2 systems. Encapsulation of the filler particles into the elastomer takes place when MAPE is used, promoting filler/polymer interactions and resulting in a simultaneous improvement in stiffness and toughness. Interestingly, the results indicated that high-shear processing is an effective method to improve the dispersion of the EPR phase and fillers through the matrix. The dispersed phase droplet size was reduced with the increase of the shear rate by varying the screw rotation speed from 300 to 800 rpm, which induces a high shear stress exerted onthe materials. To sum up, what is expected from an efficient compatibilization-process association is the reduction of the dispersed elastomer domains characteristic size, their stabilization by creation of an interphase and thus, enhanced mechanical properties. POLYM. ENG. SCI., 55:2328-2338, 2015

The effect of extrusion reprocessing cycles on the structure and properties of nano-silica reinforced polypropylene/ethylene-propylene-rubber composites

“…As mentioned in a previous study, 5 the incorporation of 5 wt% of MAPE into the (PP/EPR)/3%SiO 2 composite enhances the interface quality by improving the adhesion between the nano-filler and the polymer matrix.…”

“…This is attributed to the increase of the long chains fraction generated by the interactive reactions taking place at the interfaces of the constituents. 5 Accordingly, the proportion of the macromolecules having high molar masses and the density of the interchain entanglements obviously increase. These effects confer a greater flow resistance to the compatibilized composites, giving rise to a lower MFI as compared to the matrix component.…”

“…1–4 However, this toughening strategy sacrifices the rigidity of polymer matrices. In a previous study, 5 a low loading level of silica nanoparticles was added to the PP/EPR blends in order to provide the optimum balance of toughness and stiffness. Thus, the ternary PP-based composites present high stiffness and good ductility, obtained by relevant choices of mineral fillers (silica nanoparticles) and organic compatibilizers as well as processing conditions.…”

High shear dispersion of tracers in polyolefins for improving their detection

“…Nonetheless, all the traced blends processed at 1200 rpm reveal a noticeable reduction in mechanical properties owing to the degradation of the PP polymer chains resulting from all the thermal and mechanical history experienced by the polymer blends during the process [34,35] .…”

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

“…Polypropylene (PP) is one of the most promising thermoplastic polymer with many outstanding properties, but the relatively poor toughness at low temperature restricts its application fields . Thermoplastic elastomers are usually used to toughen PP .…”