Polypropylene-elastomer (TPO) nanocomposites: 2. Room temperature Izod impact strength and tensile properties

Room temperature Izod impact strength was determined for polypropylene (PP)/ethylene-co-octene elastomer (EOR) blends and nanocomposites, containing organoclays based on montmorillonite (MMT), at fixed elastomer content of 30 wt% and 0-7 wt% MMT. A ratio of maleated polypropylene, PP-g-MA to organoclay of unity was used as a compatibilizer in the nanocomposites. The organoclay serves to reduce the size of the EOR dispersed phase particles and facilitates toughening. The Izod impact strength is also influenced by the molecular weight of PP, elastomer octene content, elastomer MFI in addition to MMT content. Nanocomposites based on a low molecular weight polypropylene (L-PP) containing a higher octene content elastomer showed higher impact strength at lower MMT contents compared to those based on a low octene content elastomer. The effect of elastomer octene content on impact strength of high molecular weight polypropylene (H-PP) nanocomposites is not so significant. Elastomers having a melt flow index (MFI) in the range of 0.5-1.0 showed significant improvement in the impact strength of L-PP based nanocomposites. Most H-PP/EOR blends gave ‘super-tough’ materials without MMT and maintain this toughness in the presence of MMT. The critical elastomer particle size below which the toughness is observed is reduced by decreasing the octene content of the elastomer. For the similar elastomer particle sizes in nanocomposites, the impact strength varies as H-PP > M-PP > L-PP. The tensile modulus and yield strength improved with increasing MMT content; however, elongation at break was reduced. The extruder-made TPO showed a good-balance of properties in the presence of MMT compared to reactor-made TPO having similar modulus and elastomer content.     

Polypropylene-elastomer (TPO) nanocomposites: 1. Morphology

PP/PP-g-MA/MMT/elastomer nanocomposites were prepared in a twin-screw extruder at fixed 30 wt% elastomer and 0-7 wt% MMT content. The ratio of maleated polypropylene, PP-g-MA and organoclay was maintained at 1. Elastomer particle size and shape in the presence of MMT were evaluated for three different molecular weight grades of polypropylene (PP) and five different ethylene-co-octene elastomers (EOR) with different melt flow index (MFI) and octene contents. The MMT particles are located exclusively in the PP phase in the PP/PP-g-MA/MMT/EOR nanocomposites as seen from TEM images. Injection molded nanocomposite samples show significant decreases in elastomer particle size and increases in elastomer aspect ratio and particle density compared to as-extruded or pelletized samples. The elastomer particle size decreased significantly with increased MMT content and the molecular weight of PP. Low molecular weight PP based nanocomposite showed a greater reduction in elastomer particle size compared to medium and high molecular weight PP based nanocomposites. Elastomers having MFI in the range of 0.5-1.0 gave minimum elastomer particle sizes in the PP/PP-g-MA/MMT/EOR nanocomposite. The elastomer particles were deformed during injection molding leading to an increase in their aspect ratio. The nanocomposites containing high octene content elastomer gave smaller elastomer particle size and higher elastomer aspect ratios compared to nanocomposites containing low octene content elastomer.     

Effect of added ionomer on morphology and properties of PP/organoclay nanocomposites

Ethylene-methacrylic acid ionomer (Surlyn) with concentration up to 20 wt% based on total weight of polymer resin was added into polypropylene (PP)/organoclay hybrids. The microstructure, rheological properties, crystallization properties and mechanical properties of the obtained nanocomposites have been investigated. The addition of ionomer markedly enlarged interlayer spacing of the platelets and led to an improved degree of exfoliation. Moreover, clay silicates were found to selectively disperse either inside the ionomer phase or at the phase boundary. Compared to the binary immiscible blends, an improved interfacial adhesion was achieved for PP/Surlyn/OMMT hybrids. Unlike PP/Surlyn binary blends, the viscoelastic properties of the hybrids significantly increased with increasing Surlyn concentration, which could be attributed to the improved clay dispersion and the contribution of silicate layers at the interface between PP and Surlyn. A synergistic role between Surlyn and clay was also found to suppress the crystallization of PP matrix. In addition, PP/Surlyn/OMMT hybrids exhibited superior tensile strain compared to the corresponding PP/PP-g-MA/OMMT. Both tensile strength and elongation at break showed maximum at Surlyn concentration of 5 wt%. By comparing the experimental tensile yield strength with model prediction, it was suggested that the clay platelets localized at the interface could play a role of interfacial activation to some extent.     

Rheology,morphology, and mechanical properties of reactive compatibilized polypropylene/polystyrene blends via Friedel–Crafts alkylation reaction in the presence of clay

Attempts were made to study the effect of reactive compatibilization via Friedel–Crafts alkylation reaction, using AlCl₃ as a catalyst, on rheology, morphology, and mechanical properties of polypropylene/polystyrene ( PP/PS) blends in the presence of an organoclay (Cloisite 15A). During the reactive compatibilization process, PS showed much more degradation than that of PP in the presence of AlCl₃. It was found that the effect of generation of PP‐g‐PS copolymer at the interface of the PP/PS blend dominates the effects of degradation of PS and PP phases, which manifested itself by increased toughness as well as uniform dispersion of the dispersed PS particles in the PP matrix. Generation of PP‐g‐PS copolymer was confirmed by using Fourier‐transform infrared analysis. By using rheological and X‐ray diffraction analyses, it was shown that the clay had higher affinity to PS than that of PP. It was also shown that the clay located at the interface of PP and PS phases, leading to increased relaxation time of the deformed PS dispersed particles, exhibited higher dispersion in PP/PS blend, which resulted in higher ductility of the blend. By using the results of rheological studies, it was concluded that during reactive compatibilization of the blend nanocomposite, the clay migrated into the dispersed PS phase, which was confirmed by scanning electron microscopy analysis. It was demonstrated that the rheological studies have a reliable sensitivity to the clay partitioning and phase morphology of the studied blends and blend nanocomposites . J. VINYL ADDIT. TECHNOL., 24:18–26, 2018. © 2015 Society of Plastics Engineers     

Evaluation of amine functionalized polypropylenes as compatibilizers for polypropylene nanocomposites

The compatibilization effects provided by amine functionalized polypropylenes versus those of a maleated polypropylene, PP-g-MA, for forming polypropylene-based nanocomposites were compared. Amine functionalized polypropylenes were prepared by reaction of maleated polypropylene, PP-g-MA, with 1,12-diaminododecane in the melt to form PP-g-NH₂ which was subsequently protonated to form PP-g-NH₃⁺. Nanocomposites were prepared by melt processing using a DSM microcompounder (residence time of 10 min) by blending polypropylene and these functionalized materials with sodium montmorillonite, Na-MMT, and with an organoclay. X-ray and transmission electron microscopy plus tensile modulus tests were used to characterize those nanocomposites. Composites based on Na-MMT as the filler showed almost no improvement of tensile modulus compared to the polymer matrix using any of these functionalized polypropylenes, which indicated that almost no exfoliation was achieved. All the compatibilized nanocomposites using an organoclay, based on quaternary ammonium surfactant modified MMT, as the filler had better clay exfoliation compared to the uncompatibilized PP nanocomposites. Binary and ternary nanocomposites using amine functionalized polypropylenes had good clay exfoliation, but no advantage over those using PP-g-MA. The PP-g-MA/organoclay and PP/PP-g-MA/organoclay nanocomposites showed the most substantial improvements in terms of both mechanical properties and clay exfoliation.     

Phase morphology,thermomechanical, and crystallization behavior of uncompatibilized and PP‐g‐MAH compatibilized polypropylene/polystyrene blends

In this article, we discuss the phase morphology, thermal, mechanical, and crystallization properties of uncompatibilized and compatibilized polypropylene/polystyrene (PP/PS) blends. It is observed that the Young's modulus increases, but other mechanical properties such as tensile strength, flexural strength, elongation at break, and impact strength decrease by blending PS to PP. The tensile strength and Young's modulus of PP/PS blends were compared with various theoretical models. The thermal stability, melting, and crystallization temperatures and percentage crystallinity of semicrystalline PP in the blends were marginally decreased by the addition of amorphous PS. The presence of maleic anhydride‐grafted polypropylene (compatibilizer) increases the phase stability of 90/10 and 80/20 blends by preventing the coalescence. Hence, finer and more uniform droplets of PS dispersed phases are observed. The compatibilizer induced some improvement in impact strength for the blends with PP matrix phase, however fluctuations in modulus, strength and ductility were observed with respect to the uncompatibilized blend. The thermal stability was not much affected by the addition of the compatibilizer for the PP rich blends but shows some decrease in the thermal stability of the blends, where PS forms the matrix. On the other hand, the % crystallinity was increased by the addition of compatibilizer, irrespective of the blend concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42100.     

Effect of ethylene-propylene copolymer with residual PE crystallinity on mechanical properties and morphology of PP/HDPE blends

Morphology and mechanical properties of polypropylene (PP)/high density polyethylene (HDPE) blends modified by ethylene-propylene copolymers (EPC) with residual PE crystallinity were investigated. The EPC showed different interfacial behavior in PP/HDPE blends of different compositions. A 25/75 blend of PP/HDPE (weight ratio) showed improved tensile strength and elongation at break at low EPC content (5 wt %). For the PP/HDPE = 50/50 blend, the presence of the EPC component tended to make the PP dispresed phase structure transform into a cocontinuous one, probably caused by improved viscosity matching of the two components. Both tensile strength and elongation at break were improved at EPC content of 5 wt %. For PP/HDPE 75/25 blends, the much smaller dispersed HDPE phase and significantly improved elongation at break resulted from compatibilization by EPC copolymers. © 1995 John Wiley & Sons, Inc.     

Tuning the functionalization chemistry of polypropylene for polypropylene/clay nanocomposites

New polypropylene (PP)-graft-maleic anhydride (PP-g-MA) samples have been successfully synthesized by adding N-bromosuccinimide (NBS) during the reactive extrusion process. These NBS-mediated PP-g-MAs possess higher graft content than classic PP-g-MAs (i.e. without NBS) while they keep acceptable molar masses. NBS-mediated PP-g-MAs were used as matrices in model PP-g-MA/organoclay nanocomposites and compared with commercial and home-made classic PP-g-MAs in order to evaluate their ability to disperse the clay. Significantly better degrees of clay delamination and dispersion were reached using NBS-mediated PP-g-MAs than with classic PP-g-MAs. As expected, PP-g-MAs having high graft content showed the best clay dispersion. Within the examined range of molar masses, the PP-g-MA molar mass had no influence on the clay dispersion. However PP-g-MAs exhibiting important reduction of crystallinity lead to poor clay dispersion whatever the graft content. The PP-g-MA/organoclay nanocomposite prepared using the selected “optimized” NBS-mediated PP-g-MA exhibited the best improvement of thermal properties and one of the best clay dispersions. PP/PP-g-MA blends were prepared to evaluate the miscibility between PP and selected PP-g-MAs. No problem of miscibility between the selected NBS-mediated PP-g-MA and PP was noticed. Finally the PP/organoclay prepared using the selected NBS-mediated PP-g-MA as compatibilizer showed much better clay dispersion and thermal stability than the one prepared with the corresponding classic PP-g-MA, thus establishing the interest to use such new NBS-mediated PP-g-MAs as compatibilizers.     

The Effect of Multiple Compatibilizers on the Impact Properties of Polypropylene/Polystyrene (PP/PS) Blend

Effects of compatibilizers on impact properties of polypropylene/ polystyrene (PP/PS) blends were studied and carried out through melt blending using co- rotating twin-screw extruder. A combination of two compatibilizers, maleic anhydride grafted polypropylene (PP-g-MA) and styrene maleic anhydride (SMA) was applied into PP/PS blends. Results from the Izod impact strengths, SEM observations and contact angle measurements in PP(50)/PS(50) blends indicated a better compatibilization effect with the use of dual compatibilizers. This was most probably due to improved adhesion between phases in PP/PS blend systems. The use of dual compatibilizers in the blend compositions produced higher impact properties in the PP/PS blend systems compared to single compatibilizer system.     

Novel approach for the preparation of a compatibilized blend of nylon 11 and polypropylene with polyhydroxybutyrate: Mechanical,thermal, and barrier properties

This article comprises of the interaction in the immiscible polymer system of nylon 11 (PA 11), polypropylene (PP), and polyhydroxybutyrate (PHB). Reactive compatibilization extrusion method with maleic anhydride-grafted polypropylene (PP-g-MA) is used to achieve compatibility within the polymer. To further improve the interaction of the blend at interphase, PHB was added as a dispersive phase in a concentration varying from 10 to 40% of the total batch. Addition of PHB motives the excellent dispersion of PP chain in PA 11 and assures the compatibility between the phases of PA 11 and PP-g-MA. The entire system of tertiary and binary phases was blended in a twin-screw extruder at different composition. The macro-optimal tensile strength, Young's modulus, bending strength, and notched impact strength of PA11/PP systems were found to be superior as compared to their noncompatibilized systems. The degradation temperature of the blends of PA11/PP and PA11/PHB/PP with and without compatibilizer was evaluated by thermogravimetric analysis (TGA). It was found that the high temperature of degradation was required for compatibilized ternary blend than that of the compatibilized binary blend. The distortion temperature of the systems was studied with the help of heat deflection temperature (HDT) and found to be advanced for blend having a higher concentration of the dispersed phase. Differential scanning calorimetry (DSC) was used to determine the % crystallinity, melting, and crystallization temperature of this system. Chemical resistance and barrier properties of the different compatibilized and noncompatibilized blends were studied. PHB dispersed phase with a reactive compatibilizer cause enhancement in chemical resistance and barrier properties of the blend. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48152.     

The effect of organoclay on the mechanical properties and morphology of injection‐molded polyamide 6/polypropylene nanocomposites

Nanocomposites containing a thermoplastic blend and organophilic layered clay (organoclay) were produced by melt compounding. The blend composition was kept constant [polyamide 6 (PA6) 70 wt % + polypropylene (PP) 30 wt %], whereas the organoclay content was varied between 0 and 10 wt %. The mechanical properties of the nanocomposites were determined on injection‐molded specimens in both tensile and flexural loading. Highest strength values were observed at an organoclay content of 4 wt % for the blends. The flexural strength was superior to the tensile one, which was traced to the effect of the molding‐induced skin‐core structure. Increasing organoclay amount resulted in severe material embrittlement reflected in a drop of both strength and strain values. The morphology of the nanocomposites was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersion X‐ray analysis (EDX), and X‐ray diffraction (XRD). It was established that the organoclay is well dispersed (exfoliated) and preferentially embedded in the PA6 phase. Further, the exfoliation degree of the organoclay decreased with increasing organoclay content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 175–189, 2004     

Cocontinuous phase morphology of asymmetric compositions of polypropylene/high‐density polyethylene blend by the addition of clay

A novel method of developing cocontinuous morphology in 75/25 and 80/20 w/w polypropylene/high density polyethylene (PP/HDPE) blends in the presence of small amount (0.5 phr) of organoclay has been reported. SEM study indicated a reduction in average domain sizes (D) of disperse HDPE when PP, HDPE, and the organoclay were melt‐blended simultaneously at 200°C. However, when the two‐sequential heating protocol was employed, (that is, the organoclay was first intercalated by HDPE chains at 150°C, followed by melt blending of PP at 200°C), very interestingly a cocontinuous morphology was found even for very asymmetric blend compositions. WAXD study revealed the intercalation of both PP and HDPE chains inside the clay galleries, when PP/HDPE and clay were melt‐mixed together at 200°C. However, when the two‐sequential heating protocol was used the organoclay platelets were selectively intercalated by the HDPE chains. Addition of SEPS in the blend decreased the D of HDPE domains in both the blending methods. Thus, the observed cocontinuous morphology in asymmetric composition of PP/HDPE blend in presence of clay is because of the barrier effect of the clay platelets in the HDPE phase that restrict the phase inversion into the domain/matrix morphology. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanocomposites formed from polypropylene/EVA blends

Rubber toughened polypropylene nanocomposites using two types of modified montmorillonite (organoclay) were explored with the objective of achieving an improved balance between stiffness and toughness. The effect of three blending sequences on microstructure and properties of the ternary nanocomposites was also investigated. A commercial grade of ethylene/vinyl acetate copolymer (EVA) containing 18 wt% of vinyl acetate was used as the impact modifier for polypropylene and an acrylic acid grafted polypropylene was used to compatibilize the systems studied. The toughened nanocomposites samples were prepared by melt compounding in a twin-screw extruder; the morphology and mechanical properties of the resulting materials were characterized by X-ray scattering, electron microscopy and tensile and impact testing. The results show that incorporation of EVA increases the toughness of the polypropylene but its stiffness decreased markedly due to the incorporation of the low modulus component. The addition of organoclay increased the modulus slightly for all the ternary nanocomposites with respect to the blend, but it remains lower than that of neat PP. Surprisingly, addition of organoclay to the blends promoted a drastic increase in the notched Izod impact strength and a considerable alteration of the shape of the dispersed EVA phase when the organoclay is located in this phase. Moreover, it was found that the blending sequence effects on the morphology and properties of the mixtures are dependent on the organoclay used.     

Dispersion of nano-clay at higher levels into polypropylene with carbon dioxide in the presence of maleated polypropylene

The use of supercritical carbon dioxide (scCO₂) has proven to be beneficial for surface modified montmorillonite (MMT) nano-clay dispersion up to 6.6 wt% in a polypropylene (PP) matrix and lead to improved material mechanical properties in our earlier research. Our further modifications of the processing procedure including a sequential mixing technique successfully extended the technique to PP composites with as much as 10 wt% of clays and continuously increasing mechanical properties. In order to obtain additional enhancements of the composite properties at this clay level, polypropylene grafted with maleic anhydride (PP-g-MA) is included in this work. The results from the studies of the mechanical properties, rheological properties, and transmission electron microscopy (TEM) show that PP-g-MA is greatly beneficial in generating an exfoliated nano-clay morphology. Greater enhancements in the mechanical properties and nano-clay dispersion in the polymer matrix are observed when PP-g-MA is combined with the scCO₂ and sequential mixing techniques. The PP-g-MA based nano-clay composites have a high degree of exfoliated structure even with the addition of up to approximately 10 wt% nano-clay when using this technique, with mechanical properties such as yield strength and Young's modulus being increased by as much as 12 and 88%, respectively, relative to the polymer matrix. It is believed that the modulus reported here is the highest reported in the literature for conventional PP's.     

Morphology,Thermal and Mechanical Properties of Biodegradable Poly(butylene succinate)/Poly(butylene adipate-co-terephthalate)/Clay Nanocomposites

Sodium montmorillonite (Na-MMT) was successfully modified by octadecylamine (ODA) through a cation exchange technique that showed by the increased of basal spacing of clay by XRD. The addition of the organoclay into the PBS/PBAT blends produced intercalated-type nanocomposites with improvements in tensile modulus and strength. The highest tensile strength of nanocomposite was observed at 1 wt% of organoclay incorporated. A TGA study showed that the thermal stability of the blend increased after the addition of the organoclay by 1 wt%. SEM micrographs of the fracture surfaces show that the morphology of the blend becomes smoother with presence of organoclay.     

The Nucleating Effect of Montmorillonite on Crystallization of PET/Montmorillonite Nanocomposite

Poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites were prepared by solution intercalation method. The clay was organo-modified with intercalation agent of cetyltrimetylammonium chloride (CMC). XRD showed that the layers of MMT were intercalated by CMC. Four nanocomposites with organoclay contents of 1, 5, 10, and 15 wt% were prepared by solution blending. XRD showed that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay. The nucleating effect of organoclay is investigated using differential scanning calorimetry (DSC) analysis. Clay behaves as a nucleating agent and enhances the crystallization rate of PET. Maximum enhancement in crystallization rate for the nanocomposites was observed in blends containing ca. 10 wt% of clay in the range of 1–15 wt%. According to transmission electron microscopy (TEM), the organoclay particle was highly dispersed in the PET matrix without a large agglomeration of particles for low organoclay content (5 wt%). Agglomerated structure did form in the PET matrix at 15 wt% organoclay content.     

Study of compatibilizers for glass fibre reinforced nylon 6/polypropylene blends

The efficiency of a synthesized interfacial modifier agent, acrylic acid grafted polypropylene (AAgPP) in glass fibre reinforced nylon 6/polypropylene (GFRN6/PP) blends has been studied. Scanning electron microscopy clearly shows that the dispersed phase particle size decreases when AAgPP content increases (12‐fold decrease in diameter) resulting in a more stable morphology. The established emulsification curve for this system emphasizes the efficiency of the synthesised AAgPP as a potential interfacial modifier for GFRN6/PP blends. AAgPP at 7.5 wt% is to be considered as the critical concentration for our blend; such a concentration corresponds to maximum interaction between the matrix and the dispersed phase. Strong interactions between the blend components have been observed. The effect of increasing the compatibility agent content on Izod impact, tensile strength, tensile modulus and elongation at yield has also been investigated, and a bell‐shaped trend observed with a maximum at 7.5 wt% AAgPP content. A 25 % increase in impact strength for the unnotched specimen, a twofold increase in tensile strength and a fourfold increase in tensile modulus are obtained. At 7.5 wt% AAgPP, a tough–brittle fracture transition is observed with a 2.5 µm particle size diameter. © 2000 Society of Chemical Industry.     

Morphology,thermal and mechanical behavior of polypropylene nanocomposites toughened with poly(ethylene‐co‐octene)

Rubber‐toughened polypropylene (PP) nanocomposites containing organophilic layered silicates were prepared by means of melt extrusion at 230 °C using a co‐rotating twin‐screw extruder in order to examine the influence of the organoclay and the addition of PP grafted with maleic anhydride (PPgMAH) as a compatibilizer on the morphological, mechanical and thermal properties. The mechanical properties of rubber‐toughened polypropylene nanocomposites (RTPPNCs) were studied through tensile, flexural and impact tests. Scanning electron microscopy (SEM) was used for investigation of the phase morphology and rubber particles size. X‐ray diffraction (XRD) was employed to characterize the formation of nanocomposites. The thermal properties were investigated by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The dynamic mechanical properties were examined by using dynamic mechanical analysis (DMA). From the tensile and flexural tests, the optimum loading of organoclay in RTPP was found to be 6 wt%. The optimum loading of PPgMAH, based on the tensile and flexural properties, was also 6 wt%. The increase in the organoclay and PPgMAH content resulted in a severe embrittlement, manifested by a drop in the impact strength and tensile elongation at break. XRD studies revealed that intercalated RTPPNCs had been successfully prepared where the macromolecular PP segments were intercalated into the interlayer space of the organoclay. In addition, the organoclay was dispersed more evenly in the RTPPNC as the PPgMAH content increased. TGA results revealed that the thermal stability of the RTPPNC improved significantly with the addition of a small amount of organoclay. Copyright © 2006 Society of Chemical Industry     

SBS nanocomposites as toughening agent for polypropylene

The toughening of polypropylene [PP] with styrene–butadiene–styrene rubber [SBS]/montmorillonite [MMT] nanocomposites was investigated with respect to morphological, thermal, and mechanical properties. The MMT/SBS nanocomposites were prepared in an internal mixer, using an epoxidized SBS [SBSe] to investigate its effect as a compatibilizer. The MMT/SBS nanocomposite was added to PP up to 10 wt%, aiming at material toughening. Transmission electron microscopy (TEM) revealed MMT induced dispersed-phase reductions when compared to typical PP/SBS blends. In addition, changes in the PP crystallization process were observed in the presence of the nanocomposite. Surprisingly, the use of nanofiller, combined with SBSe compatibilizer agent, increased the PP impact strength by about 60%, with no reduction in the tensile module.     

The Effect of Spray-Freeze Drying of Montmorillonite on the Morphology,Dispersion, and Crystallization in Polypropylene Nanocomposites

The spray-freeze drying (SFD) technique was applied to sonicated aqueous suspensions of spray-dried montmorillonite clay (MMT) to produce highly porous agglomerates (SFD-MMT). Both MMT (used as a reference) and SFD-MMT were subsequently incorporated in polypropylene (PP) via melt compounding to produce 2 wt % nanocomposites with and without maleic anhydride grafted polypropylene (PP-g-MA). Polypropylene nanocomposites containing SFD-MMT exhibited thinner silicate flake layers compared to large agglomerates in PP/MMT nanocomposites. SFD-MMT particles became even more finer in the presence of PP-g-MA (i.e., in PP/PP-g-MA /SFD-MMT) where it hindered PP crystallization instead of serving as nucleation sites for the PP crystallization during rapid cooling. SFD-MMT improved the thermal stability of PP/PP-g-MA by 30°C compared to only 5–8°C for MMT/nanocomposites. MMT acts as a heterogeneous nucleating agent in the nucleation-controlled PP nanocomposites, but the hindrance effect was observed for the PP/PP-g-MA with SFD-MMT. PP/PP-g-MA/SFD-MMT exhibited twice the edge surface energy as compared to PP/PP-g-MA/MMT. The incorporation of both types of MMT raised the tensile moduli of PP and PP/PP-g-MA, with no improvement in their tensile strength and a decrease in the elongation at break. The PP/PP-g-MA/SFD-MMT showed brittle failure. POLYM. ENG. SCI., 60:168–179, 2020. © 2019 Society of Plastics Engineers