Influence of Filler Size on Impact Properties of PP/Elastomer/Filler Ternary Composites

Influence of filler size on impact properties for polypropylene (PP)/elastomer/filler ternary composites was investigated. Calcium carbonate (CaCO₃) particles with a diameter in the range from 120 to 1200 nm were used as a filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) was used as an elastomer. In the PP/SEBS/CaCO₃ ternary composite, CaCO₃ particles and SEBS particles were dispersed in the PP matrix separately. In the case that SEBS elastomer volume fraction was below 0.12, the impact strength improved gradually with a decrease of CaCO₃ mean diameter from 1200 to 160 nm. In the case that SEBS volume fraction was above 0.17, the impact strength improved significantly by the incorporation of CaCO₃ particles with a mean diameter in the range from 120 to 900 nm. However, the impact strength hardly improved by the incorporation of CaCO₃ particles with a mean diameter of 1200 nm.     

Influence of the incorporation of fine calcium carbonate particles on the impact strength of polypropylene/polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene blends

The Izod impact strength of two kinds of ternary composites was investigated. One consisted of polypropylene (PP), the triblock copolymer polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene (SEBS), and calcium carbonate (CaCO₃) particles, and the other consisted of PP, carboxylated SEBS (C‐SEBS), and CaCO₃ particles. The mean size of the CaCO₃ particles was about 160 nm. According to scanning electron microscopy observations, the composite with SEBS showed a morphology in which SEBS domains and CaCO₃ particles were independently dispersed in the PP matrix. On the other hand, the composite with C‐SEBS showed a morphology in which CaCO₃ particles were encapsulated by C‐SEBS; that is, a core–shell structure was formed. The Izod impact strength of the composite with SEBS was higher than that of the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. According to observations of the fractured surface, the stress‐whitened area was larger in the composite with SEBS than in the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. The toughening mechanism of the composite, using nanometer‐sized CaCO₃ particles in combination with SEBS, was examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Microstructural characteristics of glass bead‐ and wollastonite‐filled isotactic‐polypropylene composites modified with thermoplastic elastomers

Microstructural characteristics of isotactic‐polypropylene/glass bead (iPP/GB) and iPP/wollastonite (iPP/W) composites modified with thermoplastic elastomers, poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were investigated. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical analyses (DMA) showed that the iPP/SEBS and iPP/SEBS‐g‐MA blends were partially compatible two‐phase systems. Well‐dispersed spherical GB and acicular W particles without evidence of interfacial adhesion were observed in the iPP/GB and iPP/W binary composites respectively. Contrary to the blends, melt flow rates of the iPP/GB and PP/W composites decreased more with SEBS‐g‐MA than with SEBS because of enhanced interfacial adhesion with SEBS‐g‐MA elastomer. The SEM analyses showed that the ternary composites containing SEBS exhibited separate dispersion of the rigid filler and elastomer particles (i.e., separate microstructure). However, SEBS‐g‐MA elastomer not only encapsulated the spherical GB and acicular W particles completely with strong interfacial adhesion (i.e., core‐shell microstructure) but also dispersed separately throughout iPP matrix. In accordance with the SEM observations, the DSC and DMA revealed quantitatively that the rigid filler and SEBS particles in iPP matrix acted individually, whereas the rigid filler particles in the ternary composites containing SEBS‐g‐MA acted like elastomer particles because of the thick elastomer interlayer around the filler particles. The Fourier transform infrared analyses revealed an esterification reaction inducing the strong interfacial adhesion between the SEBS‐g‐MA phase and the filler particles. POLYM. COMPOS., 31:1265–1284, 2010. © 2009 Society of Plastics Engineers     

Rheological behaviors of glass bead‐ and wollastonite‐filled polypropylene composites modified with thermoplastic elastomers

Steady‐ and oscillatory‐shear rheological behaviors of polypropylene/glass bead (PP/GB) and PP/wollastonite (PP/W) melts modified with thermoplastic elastomers, poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and the corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were examined by means of a parallel‐plate rheometer. With adding the elastomers (SEBS and SEBS‐g‐MA) and fillers (spherical GB and acicular W) to PP, viscosity especially at low shear rates and shear‐thinning flow behavior at high shear rates were pronounced as evidenced quantitatively by Carreau–Yasuda (CY) parameters, but Cox–Merz analogy became weakened. Besides, melt‐elasticity in terminal region and relaxation time (t_c) in crossing point increased, indicating an enhancement in quasi‐solid behavior of molten PP. Comparing with the elastomers, rheological behaviors of molten PP were more influenced with adding the rigid fillers, especially with W due to distinct acicular shape of W particles. SEBS‐g‐MA elastomer more affected rheological behaviors of the ternary composites than SEBS elastomer, implying that SEBS elastomer and the filler particles behaved individually (i.e., development of separate microstructure) in (PP/GB)/SEBS and (PP/W)/SEBS ternary composites, but core‐shell microstructure developed with strong interfacial adhesion by adding SEBS‐g‐MA elastomer, and the filler particles encapsulated with the thick SEBS‐g‐MA elastomer interlayer (i.e., core‐shell particles) acted like neither big elastomer particles nor like individual rigid particles in melt‐state. Moreover, effects of SEBS‐g‐MA elastomer reached a maximum on rheological behaviors of (PP/W)/SEBS‐g‐MA ternary composite, indicating a synergy between core‐shell microstructure and acicular W particles. Correlations between oscillatory‐shear flow properties and microstructures of the blends and composites were evaluated using Cole–Cole (CC), Han–Chuang (HC), and van Gurp–Palmen (vGP) plots. COMPOS., 2012. © 2012 Society of Plastics     

Mechanical and rheological properties of multicomponent polypropylene blends

Polypropylene (PP) compositions containing CaCO₃ filler, EPDM (ethylene-propylene-ethylidenenorbornene) elastomer, and a non-reactive surfactant were investigated in the mixing chamber of a plastograph. Rheological properties were determined from the registered torque (M) vs. time and temperature (T) vs. time curves, while tensile characteristics of the blends were measured on compression molded plates. The homogenization process can be followed with the aid of 1 n M vs. 1/T diagrams. In the first few minutes of the mixing, beside homogenization, a significant breaking down of the elastomer takes place, and the size of the particles attains an equilibrium value. Dispersion time increases with increasing amount of EPDM and surface active-agent. Morphological investigations indicate the presence of a continuous PP phase containing dispersed CaCO₃ and elastomer particles. The rheological and tensile characteristics are seemingly determined by the total amount of additives, which imply that the elastomer and the filler has the same effect on the properties of the composite. Separation of the effects proved, however, that the effect of the two components are dissimilar, the filler exerts a larger influence on the investigated properties.     

Influence of stearic acid treatment of filler particles on the structure and properties of ternary‐phase polypropylene composites

In this study, ternary‐phase polypropylene (PP) composites containing an ethylene–octene copolymer (EOR) and calcium carbonate (CaCO₃) were investigated. Particular consideration was given to the influence of stearic acid treatment of the filler on the phase morphology and mechanical properties of the composites. In composites containing an uncoated filler, a separate dispersion of the elastomer and filler particles in the PP matrix was observed. The use of filler treated with stearic acid had no effect either on the dispersion or the interaction of the filler and the polymer components. However, the surface‐treated filler was found to promote the β‐hexagonal crystallization of PP and gave a composite with lower T_{c onset} and T_c values. As a consequence, differences in mechanical properties, in particular, impact strength, were exhibited in which calcium carbonate with stearic acid treatment was apparently more effective in increasing the impact strength of the composites in comparison with the composites containing the uncoated filler. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3445–3454, 1999     

Improvement of the mechanical properties of an HDPE/PS blend by compatibilization and incorporation of CaCO3

Generally, recycled polymer blends exhibit solid dispersion‐like morphology with poor mechanical properties. The aim of this work was to enhance the mechanical properties of a HDPE/PS (75/25) blend, in particular the stiffness and the impact strength. In order to improve the stiffness, CaCO₃ filler was incorporated. It was shown that PS and CaCO₃ were separately dispersed with poor adhesion to the HDPE matrix. The incorporation of CaCO₃ significantly enhanced the stiffness but lowers the impact resistance. Elastomer copolymers were incorporated in order to compensate for the embrittlement caused by the CaCO₃ filler. Depending on their chemical structure, either grafted with a reactive function or ungrafted, the elastomers acted differently at the interfaces of the HDPE/PS/CaCO₃ system. SEBS acts exclusively at the HDPE‐PS interface whereas SEBSgMA acts at both the HDPE‐PS and the HDPE‐CaCO₃ interface. The SEBSgMA elastomer lowered the stiffening effect caused by CaCO₃ and provided an insufficient increase in impact properties. One the other hand, SEBS, which concentrates its action at the HDPE‐PS interface, retained much of the stiffening effect of CaCO₃ and provided a greater improvement in impact properties than SEBSgMA. In the recycled HDPE/PS (75/25) blend, the incorporation of 20 vol% CaCO₃ and 4 vol% SEBS led to an increase in both impact strength (from 39 to 70 kJ/m²) and in stiffness (from 1335 to 1560 MPa). So, encouraging results were obtained, enabling us to predict a promising future for this approach to the recycling of commingled plastics.     

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     

Phase structure and property relationships in ternary polypropylene/elastomer/filler composites: Effect of elastomer polarity

Ternary composites of polypropylene (PP), elastomer, and calcium carbonate (CaCO₃) filler were prepared to study their structure/property relationships. Two kinds of phase structure were formed, depending on the elastomer present in the composites. Separation of elastomer and filler particles was found when a nonpolar ethylene–octene copolymer was used. Encapsulation of filler by the elastomer was achieved by using a polar ethylene–vinyl acetate elastomer. The mechanical properties of ternary composites were strongly dependent on material composition and their phase structures. In the present study, composites with separate dispersion structure showed higher modulus and impact strength than those of encapsulation type. The deformation mechanisms of both composites were studied using scanning electron microscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1929–1939, 2000     

The morphology and mechanical properties of PP/EPDM/nano-CaCO3 composites: effect of initial mixing state

Polypropylene (PP) was blended with ethylene–propylene–diene terpolymer (EPDM) and calcium carbonate nanoparticles (nano-CaCO₃), where all the components were in different initial mixing states, i.e., all in solid (solid blending composite), nano-CaCO₃ and EPDM first forming solid master batch, then being mixed with solid PP (master batch blend composite) and all in melt (melt blending composite). The phase morphology, especially the distribution of nano-CaCO₃, and mechanical properties of the resultant composites and their dependence on the initial mixing states of the components were studied systematically. Morphological observation revealed that essentially different from the respectively dispersed morphology of nano-CaCO₃ particles and EPDM phase in the PP matrix in the solid blending composite, abundant well-dispersed nano-CaCO₃ particles concentrating around EPDM phase in the melt blending composite. Due to the cavitation initiated by the debonding and the fibrillation present at interface as a result of well-dispersed nano-CaCO₃ particles, its impact strength was pronouncedly enhanced, increasing 280 % compared to PP/EPDM composite. Our work paves the way to obtain high-performance PP composites.     

Characteristics of impact modified polystyrene/organoclay nanocomposites

The poor impact resistance of Polystyrene (PS) was enhanced by the addition of elastomeric material, SEBS‐g‐MA. To prevent the reduction in strength and stiffness, organoclay Cloisite® 25A was used as filler and introduced into the matrix by a corotating twin screw extruder. Throughout the study, the clay content was kept at 2 wt%, whereas the content of SEBS‐g‐MA was varied between 5 and 40 wt%. It was found that Cloisite® 25A displays well dispersion in the ternary nanocomposites and the degree of dispersion increases with the elastomer content. The elastomeric phase has a greater viscosity than pure PS. Thus, as expected, at low elastomer contents, it forms the dispersed phase in the matrix as droplets. Transmission electron microscopy results show that the clay layers reside at the interphase between PS and elastomer and also inside the elastomeric phase. Owing to the location of the clay particles, the average elastomer domain size in ternary nanocomposites are found to be greater than that in the relative binary blends of PS‐(SEBS‐g‐MA). Moreover, with the organoclay addition, phase inversion point shifts to lower elastomer contents. The mechanical test results showed that the nanocomposites containing 15 and 20 wt% SEBS‐g‐MA have the optimum average domain size that results in high‐impact strength values without deteriorating the tensile properties. POLYM. COMPOS., 31:1853–1861, 2010. © 2010 Society of Plastics Engineers.     

Largely improved toughness of PP/EPDM blends by adding nano-SiO2 particles

As a part of long-term project aimed at super polyolefin blends, in this work, we report the toughness and phase morphology of polypropylene (PP)/EPDM/SiO₂ ternary composites. Two processing methods were employed to prepare PP/elastomer/filler ternary composites. One was called one-step processing method, in which the elastomer and the filler directly melt blended with PP matrix. Another one was called two-step processing method, in which the elastomer and the filler were mixed first, and then melt blended with pure PP. Two kinds of PP (grafted without or with maleic anhydride (PP-g-MA)) and SiO₂ (treated with or without coupling agent) were used to control the interfacial interaction among the components. The dependence of the phase morphology on interfacial interaction and processing method was investigated. It was found that the formation of filler-network structure could be a key for a simultaneous enhancement of toughness and modulus of PP and its formation seemed to be dependent on the work of adhesion (W_AB) and processing method. As the W_AB of PP/EPDM interface was much lower than that of PP/SiO₂ and EPDM/SiO₂, and the two-step processing method was used, the formation of filler-network structure was favorable. In this case, a super toughened PP ternary composite with the Izod impact strength 2-3 times higher than PP/EPDM binary blend and 15-20 times higher than pure PP could be achieved.     

Phase structure and mechanical properties of PP/EPR/CaCO3 nanocomposites: Effect of particle's size and treatment

Calcium carbonate (CaCO₃) reinforced polypropylene/ethylene propylene rubber (PP/EPR) copolymer composites for automotive use were developed by means of extrusion and injection molding process. Three kinds of CaCO₃ (stearic acid treated and untreated) nanoparticles and microparticles were used as fillers. The influence of stearic acid, particle size, and filler content on the state distribution and morphology were investigated by SEM and rheological measurements. Two different morphologies were observed: EPR and CaCO₃ dispersed in the PP matrix and a core shell structure, depending on the interactions between EPR and CaCO₃. Toughening mechanisms and mechanical properties of the different systems were investigated. Significant improvement in tensile modulus is observed in all composites, depending on filler content. Elongation and notched impact strength were drastically decreased, especially for composites with nano CaCO₃. Better impact properties were obtained with low content of treated particles, showing the importance of filler treatment. POLYM. ENG. SCI., 55:2859–2868, 2015. © 2015 Society of Plastics Engineers     

Morphology prediction of ternary polypropylene composites containing elastomer and calcium carbonate nanoparticles filler

In this work, the morphology was studied in ternary composites of polypropylene (PP) with nanosized calcium carbonate (nano‐CaCO₃) fillers and elastomer inclusions and the thermodynamic consideration was used to analyze the formation of phase structure of the composites. The wetting coefficient (ω_a), interfacial tension (γ_AB), and work of adhesion (W_AB) were calculated to predict dispersion state of nano‐CaCO₃ fillers. A comparison of the prediction and SEM analysis was given. The results show that three types of phase structures were formed: an encapsulation of the filler by elastomer, a separate dispersion of the filler and elastomer, and a particular structure of the filler at the PP/elastomer interface. The predictions by ω_a were all successfully supported‐up by SEM analysis and the predictions by W_AB were however trustless. Both γ_AB and W_AB can predict a separate dispersion or an encapsulation phase structure, but they were not available for the particular structure of the filler at the PP/elastomer interface. ω_a was competent and favored for the prediction of all three types of morphology among the three parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1578–1584, 2007     

Disappearance of the filler—An interesting interfacial evolution during the photooxidative aging of polypropylene composites

The interface between the matrix and filler in polyolefin composites plays an important role in their photooxidative aging processes. An interesting phenomenon, the gradual disappearance of filler particles was observed during the early natural aging of polypropylene (PP)/CaCO₃ composites. Similar phenomena were also observed in a PP/SiO₂ composite and PP/poly(methyl methacrylate) blend. The morphological observation and tensile and chemical analyses indicated that the photooxidized groups of the PP chain interacted strongly with the filler particles; this increased the tensile strength during the early aging stage. The PP matrix was entangled in the filler particles. Therefore, the filler particles were embedded in the matrix, and the fracture occurred in the PP matrix instead of at the interface between them. On the basis of these results, a “disappearing” filler mechanism for the PP composites was proposed. This work provides a possible way for improving the mechanical properties of PP composites with appropriate aging. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42546.     

Mechanical and rheological properties of PP/SEBS/OMMT ternary composites

The microstructure and mechanical properties of polypropylene (PP)/OMMT binary nanocomposites and PP/styrene‐6‐(ethylene‐co‐butylenes)‐6‐styrene triblock copolymer (SEBS)/OMMT ternary nanocomposites were investigated using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and rheology and electromechanical testing machine. The results show that the organoclay layers are mainly intercalated and partially exfoliated in the PP‐based nanocomposites. The additions of SEBS and OMMT have no significant effect on the crystallization behavior of PP. At the same time, it can be concluded that the polymer chains of PP and SEBS have intercalated into the organoclay layers and increase the gallery distance after blending process based on the analytical results from TEM, XRD, and rheology, which result in the form of a percolated nanostructure in the PP‐based nanocomposites. The results of mechanical properties show that SEBS filler greatly improve the notched impact strength of PP, but with the sacrifice of strength and stiffness. OMMT can improve the strength and stiffness of PP and slightly enhance the notched impact strength of PP/PP‐g‐MA. In comparison with neat PP, PP/OMMT, and PP/SEBS binary composites, notched impact toughness of the PP/SEBS/OMMT ternary composites significantly increase. Moreover, the stiffness and strength of PP/SEBS/OMMT ternary nanocomposites are slightly enhanced when compared with neat PP. It is believed that the synergistic effect of both SEBS elastomer and OMMT nanoparticles account for the balanced mechanical performance of the ternary nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Nanocomposites of poly(vinyl chloride) and nanometric calcium carbonate particles: Effects of chlorinated polyethylene on mechanical properties,morphology, and rheology

Nanocomposites of poly(vinyl chloride) (PVC) and nano‐calcium carbonate (CaCO₃) particles were prepared via melt blending, and chlorinated polyethylene (CPE) as an interfacial modifier was also introduced into the nanocomposites through preparing CPE/nano‐CaCO₃ master batch. The mechanical properties, morphology, and rheology were studied. A moderate toughening effect was observed for PVC/nano‐CaCO₃ binary nanocomposites. The elongation at break and Young's modulus also increased with increasing the nano‐CaCO₃ concentration. Transmission electron microscopy (TEM) study demonstrated that the nano‐CaCO₃ particles were dispersed in a PVC matrix uniformly, and a few nanoparticles agglomeration was found. The toughening effect of the nano‐CaCO₃ particles on PVC could be attributed to the cavitation of the matrix, which consumed tremendous fracture energy. The notched Izod impact strength achieved a significant improvement by incorporating CPE into the nanocomposites, and obtained the high value of 745 J/m. Morphology investigation indicated that the nano‐CaCO₃ particles in the PVC matrix was encapsulated with a CPE layer through preparing the CPE/nano‐CaCO₃ master batch. The evaluation of rheological properties revealed that the introduction of nano‐CaCO₃ particles into PVC resulted in a remarkable increase in the melt viscosity. However, the viscosity decreased with addition of CPE, especially at high shear rates; thus, the processability of the ternary nanocomposites was improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2714–2723, 2004     

SEBS/PP热塑性弹性体的制备与性能研究

以苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)和聚丙烯(PP)为基体树脂,以碳酸钙(CaCO3)为填充材料,用氢化白油调节其硬度及加工流动性,在一定的工艺条件下添加助剂用开炼机混炼制备SEBS/PP热塑性弹性体;研究了氢化白油、CaCO3和热塑性弹性体等对SEBS/PP共混体系性能的影响。     

Nanoscale Cellular Foams from a Poly(propylene)‐Rubber Blend

Plastic foams with nano/micro‐scale cellular structures were prepared from poly(propylene)/thermoplastic polystyrene elastomer (PP/TPS) systems, specifically the copolymer blends PP/hydrogenated polystyrene‐block‐polybutadiene‐block‐polystyrene rubber and PP/hydrogenated polystyrene‐block‐polyisoprene‐block‐polystyrene. These PP/TPS systems have the unique characteristic that the elastomer domain can be highly dispersed and oriented in the machine direction by changing the draw‐down ratio in the extrusion process. A temperature‐quench batch physical foaming method was used to foam these two systems with CO₂. The cell size and location were highly controlled in the dispersed elastomer domains by exploiting the differences in CO₂ solubility, diffusivity, and viscoelasticity between the elastomer domains and the PP matrix. The average cell diameter of the PP/TPS blend foams was controlled to be 200–400 nm on the finest level by manipulating the PP/rubber ratio, the draw‐down ratio of extrusion and the foaming temperature. Furthermore, the cellular structure could be highly oriented in one direction by using the highly‐oriented elastomer domains in the polymer blend morphology as a template for foaming.

     

Dynamic mechanical properties and morphology of high‐density polyethylene/CaCO3 blends with and without an impact modifier

Dynamic mechanical analysis and differential scanning calorimetry were used to investigate the relaxations and crystallization of high‐density polyethylene (HDPE) reinforced with calcium carbonate (CaCO₃) particles and an elastomer. Five series of blends were designed and manufactured, including one series of binary blends composed of HDPE and amino acid treated CaCO₃ and four series of ternary blends composed of HDPE, treated or untreated CaCO₃, and a polyolefin elastomer [poly(ethylene‐co‐octene) (POE)] grafted with maleic anhydride. The analysis of the tan δ diagrams indicated that the ternary blends exhibited phase separation. The modulus increased significantly with the CaCO₃ content, and the glass‐transition temperature of POE was the leading parameter that controlled the mechanical properties of the ternary blends. The dynamic mechanical properties and crystallization of the blends were controlled by the synergistic effect of CaCO₃ and maleic anhydride grafted POE, which was favored by the core–shell structure of the inclusions. The treatment of the CaCO₃ filler had little influence on the mechanical properties and morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3907–3914, 2007