The aim of this study was to investigate the influence of the processing conditions in single and co‐rotational twin screw extruders on the mechanical and morphological properties of elastomeric poly (methyl methacrylate)/polycarbonate (PMMAe/PC) blends until the phase inversion. The characterizations were performed by measuring the melt flow index, capillary rheometry, thermogravimetric analysis, tensile tests, Izod impact, and atomic force microscopy (AFM). The thermal and rheological properties showed that PC had a higher sensitivity to processing conditions than PMMAe. The increase in PC concentration altered the mechanical properties of the PMMAe/PC blends with variations according to processing conditions. The morphology of PMMAe/PC blends up to phase inversion was visualized by AFM, and the results showed that the material processed with a single screw extruder obtained similar morphologies to that material processed in twin screw extruder.

The aim of this study is to evaluate toughness mechanism of elastomeric poly(methyl methacrylate) (PMMAe) and polycarbonate (PC) blend through crack propagation at high speed tensile tests. Samples are processed using two types of extruders, single and twin screw, in order to eliminate the influence of processing in the final product's properties. Pure polymers and polymer blend samples are cryo‐ultramicrotomed and their morphology is characterized using atomic force microscopy (AFM). Fractured samples obtained from uniaxial tensile tests at high strain rate are inspected using optical microscopy (OM) and scanning electron microscopy (SEM). The results obtained for the PMMAe/PC blend in tests at high deformation rate showed that the shear rate during the mixing process influences the maximum strength of the polymer blend near its region of co‐continuous morphology. The visual evaluation of the fracture surface and the fractographic analysis corroborated the results of this study of polymer toughening.

Styrene–ethylene–butylene–styrene (SEBS) copolymer, grafted or not, with maleic anhydride and organophilic montmorillonite clay was melt mixed with polypropylene (PP) using different mixing sequences to understand its effect on properties and morphology. The addition of clay changed the blend morphology from large elongated domains to droplets. The nanocomposites without maleic anhydride presented clay in the intercalated form. In the formulation containing maleic anhydride, clay is exfoliated on the blend, indicating that the maleic anhydride group acted to increase the interaction between the clay lamellae and the polymer chains. The best balance of mechanical properties was achieved in the formulation in which the clay was first melt mixed in SEBS without maleic anhydride and afterward melt mixed with clay and PP. It is reported in the literature that nanocomposites with exfoliated structures have better mechanical properties than nanocomposites with intercalated structure. However, in this study, an opposite trend was found, which may be related to the higher amount of crystalline phase formed in the intercalated structure nanocomposites, since the clay intercalation phenomenon in the polymer chains favored the polymer crystallization process.

This work aims at evaluating the rheological and thermal properties and non‐isothermal crystallization kinetics of blends of linear homopolymer polypropylene (HPP) and branched polypropylene (BPP). Two linear polypropylene's of different melt flow index (MFI) are used: H301 (10 g per 10 min) and H604 (1.5 g per 10 min); and one BPP (2 g pr 10 min). The rheological result shows that the H301/BPP blends have an increase in complex viscosity proportional to the addition of BPP amount, while for the H604/BPP blends, it is observed a higher influence of H604 on rheological properties. With the addition of 25 wt% of BPP, the strain hardening behavior is observed in the extensional rheology tests of the polymer blend. The DSC results show that the melt temperature and the crystallinity content in blends with BPP are affected by the molecular weight (MW) of the linear polymer. Results suggest that Pseudo‐Avrami/Jeziorny and Mo models can be used to predict the experimental results of crystallization kinetics of the blends with sufficient precision for all systems studied, regardless of MW. Therefore, it is possible to use the blends of HPP/BPP in processes that demand a combination of rheological properties, such as high strain hardening, and fast crystallization.

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