Preparation and properties of peroxide dynamically vulcanized polypropylene/ethylene‐propylene‐diene monomer/zinc dimethacrylate thermoplastic olefin

Attempts were made to prepare the polypropylene (PP) /ethylene‐propylene‐diene monomer (EPDM) blends with zinc dimethacrylate (ZDMA) via peroxide dynamic vulcanization. PP was melt‐mixed with EPDM and ZDMA at different compositions (PP/EPDM/ZDMA, i.e., 70/30/0, 70/30/3, 70/30/6, and 70/30/9, w/w/w) using an internal mixer at 50 rpm rotor speed. The addition of ZDMA improved the rheological properties of the resulting materials in the melt state. The morphological studies revealed that the addition of ZDMA led to an improvement of size reduction and distribution uniformity for crosslinked EPDM phase. ZDMA showed a positive effect on the mechanical properties of the PP/EPDM/ZDMA composites, particularly on the toughness and extensibility. With the incorporation of ZDMA, the izod impact strength and the elongation of PP/EPDM/ZDMA composites increased from 41 kJ/m² to 72 kJ/m² and 110% to 495%, respectively. The crystallization behaviors analysis indicated that the addition of ZDMA promoted the nucleation process of PP but the crystallinity of the PP phase was decreased at the meantime. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Structure and properties of peroxide dynamically vulcanized polypropylene/ethylene–propylene–diene/zinc dimethacrylate composites

Peroxide dynamically vulcanized thermoplastic olefin (TPO) based on polypropylene (PP)/ethylene–propylene–diene (EPDM) loaded with zinc dimethacrylate (ZDMA) was prepared. The addition of ZDMA improved the complex viscosity of the resulting materials in the melt state significantly, as determined from oscillatory rheology analyses. Dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM) examinations were performed to evaluate the structure of the PP/EPDM/ZDMA composite. Atomic force microscope (AFM) and scanning electron microscopy (SEM) were used to study the morphology. The degree of crystallinity was evaluated using X‐ray diffraction method (XRD). The results revealed that incorporation of ZDMA resulted in a size reduction of the rubber droplets and improved the compatibility between rubber and PP phases. The nanoparticles of the polymerized ZDMA (PZDMA) served as an effective nucleating agent for the crystallization of PP. The rheological properties and mechanical properties were improved by ZDMA. Particularly, the izod impact strength of the PP/EPDM/ZDMA (80/20/6, w/w) composite is nearly 2 times higher than the PP/EPDM (80/20, w/w) and 12 times higher than the PP; besides, the elongation at break of the PP/EPDM/ZDMA (80/20/6, w/w) is 3 times higher than that of the PP/EPDM (80/20, w/w) and 6 times higher than the PP. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

In situ reactive compatibilized polypropylene/nitrile butadiene rubber blends by zinc dimethacrylate: Preparation,structure, and properties

This study demonstrated an approach of compatibilization between polypropylene (PP) and nitrile butadiene rubber (NBR) by using zinc dimethacrylate (ZDMA) as a reactive compatibilizer in the presence of peroxides. The PP/NBR/ZDMA ternary blends with improved mechanical properties were successfully prepared via peroxide dynamic vulcanization. The resultant blends exhibited a significant increase in mixing torque and complex viscosity after incorporation of ZDMA. Morphology studies showed that the addition of ZDMA reduced the size of the crosslinked NBR phase. Transmission electron microscopy (TEM) combined with scanning electron microscopy (SEM) verified that the possible reactions between ZDMA, NBR, and PP increased the interfacial thickness and improved the compatibility between NBR and PP phase. Crystallization behavior analysis indicated that incorporation of ZDMA promoted the nucleation process of PP. Thermal gravimetric analysis (TGA) showed that the maximum degradation temperature was increased by ZDMA. POLYM. ENG. SCI., 54:2321–2331, 2014. © 2013 Society of Plastics Engineers     

Silica‐reinforced dynamically vulcanized ethylene–propylene–diene monomer/polypropylene thermoplastic elastomers: Morphology,rheology, and dynamic mechanical properties

Attempts were made to prepare dynamically crosslinked ethylene–propylene–diene monomer/polypropylene (EPDM/PP, 60/40 w/w) blends loaded with various amounts of silica as a particulate reinforcing agent. The dispersion of silica between the two phases under mixing conditions, and also extent of interaction, as the two main factors that influence the blend morphology were studied by scanning electron microscopy. Increasing the silica concentration led to the formation of large‐size EPDM aggregates shelled by a layer of PP. Dynamic mechanical thermal analysis performed on the dynamically cured silica‐loaded blend samples showed reduction in damping behavior with increasing silica content. Higher rubbery‐like characteristics under tensile load were exhibited by the silica‐filled EPDM/PP‐cured blends. However, increasing the silica level to 50 phr led to the enhancement of interface, evidenced by increases in the tensile modulus and extensibility of the blend compared with those of the unloaded sample. Addition of a silane coupling agent (Si69) into the mix improved the mechanical properties of the blend, attributed to the strengthening of interfacial adhesion between the PP matrix and silica‐filled EPDM phase. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2000–2007, 2004     

Selective particle distribution and mechanical properties of nano‐CaCO3/ethylene‐propylene‐diene terpolymer/polypropylene composites with high content of nano‐CaCO3

T ernary composite of nano‐CaCO₃/ethylene‐propylene‐diene terpolymer (EPDM)/polypropylene (PP) with high content of nano‐CaCO₃ was prepared by two step compounding route, in which EPDM and nano‐CaCO₃ were mixed first, and then melt compounding with PP matrix. The influence of mixing time during the second compounding on distribution of nano‐CaCO₃ particles and the impact strength of the ternary composite have been investigated. It was found that the Izod impact strength of composite decreased with increasing mixing time. The observation of transmission electron microscopy obviously showed that nano‐CaCO₃ particles transported from EPDM to PP matrix firstly and then from PP to the vicinity of EPDM dispersed phase with the increase of mixing time. This phenomenon can be well explained by the minimization of the dissipative energy and the Young's equation. The scanning electron microscope images show that lots of nano fibrils exist at the interface between nano‐CaCO₃ agglomerates and matrix, which can dissipate lots of energy. The toughening mechanism has been interpreted in terms of three‐stage‐mechanism: stress concentration, void and shear band formation, and induced shear yielding. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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

The properties and structure of silane crosslinked polypropylene (PP)/ethylene propylene diene monomer (EPDM) elastomer blends had been carried out. Fourier transform infrared spectroscopy and gel content tests were employed to evaluate the crosslinking reaction of PP/EPDM blends. Crosslinking efficiency of PP/EPDM blends was investigated using thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, dynamic rheology, and tensile testing. Tanδ curves of silane crosslinked PP/EPDM blends exhibited an obvious “gel point” originated from the formation of dynamic crosslinking network. The blend corresponding to the “gel point” presented comprehensively improved mechanical properties. These results demonstrated that characteristic rheological parameters showed close correlations with key mechanical properties of silane crosslinked PP/EPDM blends. Scanning electron microscopy images illustrated that crosslinking had remarkably changed the morphologies of PP/EPDM blends. The large deformation mechanism of these blends had been suggested.     

Preparation of nano‐zinc oxide/EPDM composites with both good thermal conductivity and mechanical properties

In this article, nano‐zinc oxide (ZnO) filled ethylene propylene diene monomer (EPDM) composites are prepared, and the mechanical (static and dynamic) properties and thermal conductivity are investigated respectively, which are further compared with the traditional reinforcing fillers, such as carbon black and nano‐silica. Furthermore, influence of in‐situ modification (mixing operation assisted by silane at high temperature for a certain time) with the silane‐coupling agent Bis‐(3‐thiethoxy silylpropyl)‐tetrasufide (Si69) on the nano‐ZnO filled composites is as well investigated. The results indicate that this novel reinforcing filler nano‐ZnO can not only perform well in reinforcing EPDM but can also improve the thermal conductivity significantly. In‐situ modification with Si69 can enhance the interfacial interaction between nano‐ZnO particles and rubber matrix remarkably, and therefore contribute to the better dispersion of filler. As a result, the mechanical properties and the dynamic heat build‐up of the nano‐ZnO filled composites are improved obviously by in‐situ modification, without influencing the thermal conductivity. In comparison with traditioanl reinforcing fillers, in‐situ modified nano‐ZnO filled composites exhibit the excellent performance in both mechanical (static and dynamic) properties and better thermal conductivity. In general, our work indicates that nano‐ZnO, as the novel thermal conductive reinforcing filler, is suitable to prepare elastomer products serving in dynamic conditions, with the longer expected service life. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synchronous toughening and reinforcing of polypropylene with ultrahigh‐molecular‐weight polyethylene via melt blending: Mechanical properties,morphology, and rheology

Blending systems based on polypropylene (PP) and ultrahigh‐molecular‐weight polyethylene (UHMWPE) were prepared via a melt extrusion by the four‐screw and the twin‐screw extruders, respectively. The mechanical evaluation demonstrated that the synchronous toughening and reinforcing effects could be achieved from the combination of the PP and the UHMWPE, in which the toughness and the tensile properties could be improved with increasing the UHMWPE content, and achieved optimal values at a weight ratio of PP/UHMWPE (85/15). EPDM can be used as a compatibilizer to improve the compatibility and the interfacial adhesion between the PP and the UHMWPE. This resulted in more effective toughening and reinforcing effects. In contrast, for the PP/UHMWPE blends prepared by the normal twin‐screw extruder, the poor dispersion capacity for the UHMWPE resulted in a deterioration of all mechanical parameters. Morphological observation revealed that the UHMWPE domain was well distributed as tiny particles in the PP matrix, which was confirmed by the differential scanning calorimetry analysis. The toughening effect was attributed to the energy dissipation caused by these rigid tiny particles that detached from the matrix to initiate the local matrix shear yield and formed the void. Rheological investigation demonstrated that there was an interesting composition dependence of viscosity, for which the melt viscosities of the PP/UHMWPE blends decreased when 5 wt % UHMWPE was added, and then began to increase as the UHMWPE content continued to increase. However, this dependence on composition became weaker because of the compatibilization of the EPDM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3498–3509, 2006     

Morphology and properties of PP/EPDM binary blends and PP/EPDM/nano‐CaCO3 ternary blends

In this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO₃) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO₃ blend. The influence of EPDM and nano‐CaCO₃ respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO₃ blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO₃ was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO₃ in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structure,morphology, and properties of HNBR filled with N550, SiO2, ZDMA,and two of three kinds of fillers

The vulcanization properties, mechanical properties of hydrogenated nitrile rubber (HNBR) filled with carbon black (N550), zinc dimethacrylate (ZDMA), SiO₂ independently and two of three kinds of fillers together were investigated, respectively. The filler‐dispersion was characterized by the transmission electron microscopy (TEM) and dynamic mechanical properties. The results showed that HNBR composite filled with SiO₂ or ZDMA displayed high tensile strength, elongation at break and compression set. The HNBR composite filled with N550 displayed low compression set, tensile strength and elongation at break. The dispersion of SiO₂ in HNBR compound was better than that in HNBR vulcanizates because of SiO₂ particles self‐aggregation in vulcanizing processing. ZDMA particles with micron rod‐like and silky shape in HNBR compounds changed into near‐spherical poly‐ZDMA particles with nano size in HNBR vulcanizates by in situ polymerization reaction. The N550 particles morphology exhibited no much change between HNBR compounds and vulcanizates. N550/ZDMA have the most effective reinforcement to HNBR and the appropriate amount of ZDMA is about 25% of total filler amount by weights. The theory prediction for Payne effect (dispersion of the filler) shown by the dynamic properties is identical with actual state observed by TEM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of injection‐homo‐polypropylene filled with nano‐CaCO3

Nano‐CaCO₃/homo‐PP composites were prepared by melt‐blending using twin‐screw extruder. The results show that not only the impact property but also the bending modulus of the system have been evidently increased by adding nano‐CaCO₃. The nano‐CaCO₃ particles have been dispersed in the matrix in the nanometer scale which was investigated by means of transmission electron microscopy (TEM). The toughening mechanism of nano‐CaCO₃, investigated by means of dynamical mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM), lies on that the nano‐CaCO₃ particles take an action of initiating and terminating crazing (silver streak), which can absorb more impact energy than the neat PP. At the same time, the nano‐CaCO₃ particles, as the nuclear, decrease the crystal size of PP, the results of which were investigated by means of polarized optical microscope (POM). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Polypropylene (PP) is the second most widespread commodity polyolefin. Even a small quantity of inorganic component is sufficient to achieve significant improvement of stiffness, strength, thermal stability, biodegradability, etc. The major drawback of inorgano‐organic composite materials is insufficient compatibility of the PP matrix with inorganic filler. A suitable choice of the layered double hydroxide‐modifying anion opens a possibility to obtain PP‐inorganic nanocomposites without a need to use compatibilizers like maleic anhydride grafted PP. The nanocomposites were prepared by melt blending in a twin‐screw mini‐extruder and characterized by dynamic mechanical thermal analysis, and electron microscopy. Nonpolar PP matrix mix uniformly with clay organophilized with functionalized surfactant acids, giving rise to composites with improved thermo‐mechanical properties. Influences of the anionic modifier and the filler content (2 or 5% w/w) on mechanical properties and nanoscale structure of the composites are discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2429–2438, 2013     

Effect of styrene‐butadiene triblock copolymer structure on its compatibilization efficiency in PS/PB and PS/PP blends

Two styrene‐butadiene triblock copolymers differing in the length of their styrene blocks (40S‐60B‐40S and 10S‐60B‐10S) were used as compatibilizers for PS/PB (4/1) and PS/PP (4/1) blends. The supramolecular structure of the copolymers determined by small‐angle X‐ray scattering (SAXS), morphology of the blends using transmission electron microscopy (TEM), and their tensile impact strength were chosen as criteria of the compatibilization efficiency of the copolymers used. Different mechanisms of compatibilization for “symmetrical” system (PS/PB/SBS) and “asymmetrical” system (PS/PP/SBS) were proved. While for the PS/PB blend, the 40S‐60B‐40S copolymer proved to be a good compatibilizer, for the PS/PP blend, surprisingly, the 10S‐60B‐10S copolymer is more efficient.     

The Relationship between Microstructure and Properties in PP/Rubber Powder/nano‐CaCO3 Ternary Blends

Summary: A new kind of rubber powder with “salami” structure (RPS) was prepared by spray drying the mixture of styrene‐butadiene rubber latex and nano‐CaCO₃ slurry. It was found that RPS is an effective toughener with synergistic toughening effect on poly(propylene) (PP). The Izod impact strength of PP/RPS blend is not only higher than that of PP/rubber powder or PP/nano‐CaCO₃ blends, but also higher than that of a PP/rubber powder/CaCO₃ blend. TEM images show that the microstructure of the PP/RPS blend is an “island‐sea” structure with “salami” structure in RPS, in which nano‐CaCO₃ particles are embedded in styrene‐butadiene rubber particles. The relationship between properties and microstructure has been studied by using TEM, SEM, DSC, etc.

     

Morphologies of polyethylene–ethylene/propylene/diene monomer particles in polypropylene‐rich polyolefin blends: Flake structure

Morphologies of polyethylene–ethylene/propylene/diene monomer (PE/EPDM) particles in 93/7 polypropylene (PP)/PE blends were investigated. SEM micrographs of KMnO₄‐etched cut surfaces and fracture surfaces of the blends revealed the existence of the “flake” structure. In the particles, crystalline PE formations with flake shape, which remain after etching, are called flakes. In addition to the PE‐crystalline flakes, amorphous PE, located between PE crystalline lamellae and EPDM rubber, complement the flake structure. The flakes are usually linked with the PP matrix, as seen in the heptane‐treated cut surfaces. These links, although observed with compatibilized samples, originate from the crystalline nature of PE particles, if no compatibilizer is added. Separately, the morphology of Royalene (consisting of high‐density PE and EPDM rubber, used as a PP/PE compatibilizer) was investigated by low‐voltage scanning TEM. The interaction of the components in the PE/EPDM blends can explain the formation of the flakes and toughening of the PP/PE blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3087–3092, 2003     

Viscoelasticity behaviors of lightly cured natural rubber/zinc dimethacrylate composites

Zinc dimethacrylate (ZDMA) can be polymerized during peroxide curing to form the polymerized ZDMA (PZDMA) at nanoscales. At the same time, the covalent crosslink of the rubber matrix and ionic crosslink introduced by the graft‐PZDMA also are formed. The structure evolution of this type of composites is complex. In this article, the dynamic viscoelasticity characteristics of lightly cured ZDMA/natural rubber (NR) composites were investigated using a Rubber Process Analyzer 2000 (RPA2000). Our goal was to study the internal structures of this type of composites in an early curing stage. The dynamical viscoelasticity of the composites cured for 1 min was focused. The results of RPA2000 indicated that the PZDMA could act as particles to form a strong filler–filler structure which resulted in apparent Payne effect. A “primary network” structure might be formed which contained covalent crosslink points, ionic crosslinks, physical adsorption, and PZDMA. The stress‐softening behavior was also investigated. At last, the scanning electron microscope analysis verified that most of the ZDMA had been polymerized to form PZDMA “nanoparticle” when the composites were cured for 1 min. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Effects of crosslinked elastomer particles on heterogeneous nucleation of isotactic PP in dynamically vulcanized EPDM/PP and EOC/PP blends

The isothermal and non-isothermal crystallizations of PP in neat form and in the TPVs EPDM/PP and EOC/PP were investigated using differential scanning calorimetry (DSC). The crystallization of PP was systematically studied by fitting mathematical models, and was later confirmed by X-ray diffraction (XRD) and by scanning electron microscopy (SEM). The experiments revealed that crosslinked elastomer particles first accelerated the primary nucleation of the PP matrix, acting effectively as a nucleating agent that reduces the induction time while increasing the nucleation efficiency. In the secondary nucleation regime (growth of spherulites), the crosslinked elastomer particles enhanced crystal growth rate, reducing the nucleation energy contribution from PP chain folding. Moreover, the crosslinked elastomer particles increased the final thickness of PP lamellae from that of neat PP, and this was corroborated by the XRD results. On comparing the two types of elastomer, it was found that the EOC particles were more effective in heterogeneous cell nucleation than the EPDM particles. The morphological study by SEM revealed completely altered PP spherulite size and shape, as well as their altered distribution, affected by heterogeneous nucleation effects of the crosslinked elastomer particles.     

Preparation of nano poly(phenylsilsesquioxane) spheres(nano‐PPSQ) and study of the thermal stability and crystallization behavior of PP/nano‐PPSQ composites

The preparation of nano poly(phenylsilsesquioxane) particles (nano‐PPSQ) and the influence of nano‐PPSQ on the thermal stability and crystallization of polypropylene (PP) were studied. The morphology and thermal stability of PP/nano‐PPSQ composites were characterized by scanning electron microscopy (SEM) and the thermogravimetric analysis (TGA). The SEM result showed that the particles were well dispersed in the PP matrix. The TGA results of the PP/nano‐PPSQ composites indicated that the incorporation of nano‐PPSQ can improve the thermal stability of PP. The crystallization behavior and kinetics of PP/nano‐PPSQ composite were studied by X‐ray diffraction (XRD) and differential scanning calorimetry (DSC). The XRD revealed that the addition of nano‐PPSQ influences the crystallinity and crystal size of PP. The Avrami, Ozawa, and combined Avrami/Ozawa (Mo method) equations were applied to describe the crystallization kinetics and estimate the kinetic parameters of mathematical models under the nonisothermal crystallization of PP and PP/nano‐PPSQ composites. The results show that nano‐PPSQ influences the crystallization temperature and rate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The effect of interface characteristics on the static and dynamic mechanical properties of three‐component polymer alloys

The effect of interfacial characteristics on the structure‐property relationships of ternary polymer alloys and blends comprising polypropylene (PP), ethylene‐vinyl alcohol copolymer (EVOH) and glass beads (GB) or fibers (GF) was investigated. The systems studied were based on a binary PP/EVOH immiscible blend, representing a blend of a semi‐crystalline apolar polymer with a semi‐crystalline highly polar copolymer. The ternary systems studied consisted of filler particles encapsulated by EVOH, with some of the minor EVOH component separately dispersed within the PP matrix. Modification of the interfacial properties was done using silane coupling agents for the EVOH/glass interface and compatibilization using a maleic anhydride grafted PP (MA‐g‐PP) for the PP/EVOH interface. Both glass fillers increased the dynamic modulus and decreased the damping of the neat polymers and of their binary blends, especially in the rubbery region. GF has a more profound effect on both the modulus and the damping. Glass surface treatments and compatibilization have only a marginal effect on the dynamic mechanical behavior of the ternary blends. Yet, compatibilization shifted the polymers' T_gS to higher temperatures. Both glass fillers increased the elastic modulus of the binary blends, where GF performed better than GB as a reinforcing agent. GF slightly increased the strength of the binary blends while, GB reduced it. Both fillers reduced the ductility of the binary blends. The blends' mechanical properties were related to the morphology and their components' crystallinity. The compatibilizer increases both stiffness and strength and reduces deformability.     

Influence of Copolymer Composition and Curing on Toughness of Isotactic Polypropene Blended Together with Metallocene‐EPDM and Ethene/Propene/Vinylcyclohexane Terpolymers

Ethene/propene terpolymers containing either 1‐vinylcylohexene‐4 (VCHen) or vinylcyclohexane (VCHan) as termonomer component were prepared using MAO‐activated rac‐Me₂Si(2‐MeBenz[e]Ind)₂ZrCl₂ (MBI). Propene content was varied between 26 and 72 wt.‐% with less than 1 mol‐% termonomer incorporation. Blends containing 85 vol.‐% isotactic polypropene (i‐PP) and 15 vol.‐% of the two EP terpolymer families were prepared by melt‐compounding in a twin‐screw kneader at 200°C to examine the role of sulfur‐mediated crosslinking of the unsaturated EPDM terpolymer phase in comparison to the corresponding blends containing non‐crosslinked saturated EP/VCHan terpolymers. The observed glass temperature (T_g) depression of the T_g of EP(D)M phases with respect to the T_g of the corresponding bulk EP(D)M was attributed to the presence of thermally induced stresses in both blend systems. Blends of i‐PP with crosslinked EPDM showed smaller T_g depression with respect to those of iPP/EPM blends containing non‐crosslinked EP and EPM dispersed phases. Morphology differences were detected for i‐PP/EPM and dynamically vulcanized i‐PP/EPDM blends by means of atomic force microscopy (AFM). The crosslinked i‐PP/EPDM blends exhibited significantly improved low temperature toughness as compared to the corresponding non‐crosslinked i‐PP/EPM blends. Curing of the EPDM elastomer phase in i‐PP/EPDM (85 vol.‐%/15 vol.‐%) blends afforded significantly improved toughness/stiffness balance and a wider toughness window with respect to the corresponding i‐PP/EPM and i‐PP/EP blends without sulfur‐cured rubber phases.