Mechanical properties and thermal stability of poly(L‐lactide)/calcium carbonate composites

Poly(L ‐lactide) (PLA) was melt‐mixed with micrometer‐sized and nanosized calcium carbonate (CaCO₃) particles before and after modification with calcium stearate. Adhesion between the CaCO₃ particles and the PLA matrix was assessed qualitatively by scanning electron microscopy observation of the fractured surface morphology of the composites. The effect of the incorporation of the CaCO₃ particles on the thermal stability of the PLA‐based composites was quantified by the temperatures corresponding to 5 and 50% of weight loss and the activation energy determined through thermogravimetric analyses of the composites. The tensile strength and modulus values of the composite were improved greatly without a significant loss in the elongation at break when the nanosized CaCO₃ was incorporated up to 30 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Toughening of polypropylene combined with nanosized CaCO3 and styrene–butadiene–styrene

Nanocomposites of nanosized CaCO₃/SBS/PP were prepared by using twin‐screw and single‐screw extruder. By adding nanosized CaCO₃ particles into SBS/PP blend, the notched impact strength, flexural modulus, and tensile strength of the composites can be improved, whereas, by adding microsized CaCO₃ particles into SBS/PP blend, the notched impact strength of the composite is decreased markedly. At nanosized CaCO₃ content of 16 phr (parts per hundred PP resin by weight), the impact strength of nanosized CaCO₃/SBS/PP composite reaches 56.55 KJ/m², which is 1.27 times that of SBS/PP blend. At nanosized CaCO₃ content of 4 phr, the tensile strength of the composites reaches 31.3 MPa, which is 1.23 times that of SBS/PP blend. The maximum and balanced torque of the composites improves significantly by the addition of CaCO₃ nanoparticles. The increased shear force during compounding continuously breaks down SBS particles, resulting in the reduction of the SBS particles size, and improving the dispersion of SBS particles in PP matrix. Thus the toughening effect of SBS on matrix was improved. Simultaneously, the existence of SBS provides the matrix with a good intrinsic toughness, satisfying the condition that nanosized inorganic particle of CaCO₃ efficiently toughens polymer matrix. The synergistic toughening function of nanosized CaCO₃ and SBS on PP matrix was exhibited. POLYM. ENG. SCI. 47:201–206, 2007. © 2007 Society of Plastics Engineers     

Thermomechanical properties of virgin and recycled polypropylene impact copolymer/CaCO3 nanocomposites

The effect of successive injection moldings on the thermal, rheological, and mechanical properties of a polypropylene impact copolymer (PP) was investigated. The crystal content decreased as the molecular weight decreased due to chain scission with repeated injection molding. The Young modulus and the yield stress remained constant, despite a drop in the strain to break. Virgin and recycled PP matrix were filled with nanosized calcium carbonate (CaCO₃) particles. The effect of morphology on the thermal and mechanical properties of nanocomposites of virgin and recycled PP filled with nanosized CaCO₃ particles was also studied. The mechanical properties of the nanocomposites were strongly influenced by the intrinsic toughness of the matrix and the concentration and dispersion of the filler. The yield strength and strain of virgin PP decreased gradually, while its Young's modulus increased slightly with increasing CaCO₃ loading. These phenomena were less pronounced for the recycled matrix. Incorporation of nanoparticles to virgin matrix produced an increase in tensile stiffness and ductility, when good dispersion of the filler was achieved. However, the impact strength dropped dramatically for high filler contents. A significant increase in impact strength was observed for the recycled PP. POLYM. ENG. SCI., 50:1904–1913, 2010. © 2010 Society of Plastics Engineers     

Preparation and properties of nano‐CaCO3/acrylonitrile‐butadiene‐styrene composites

CaCO₃/acrylonitrile‐butadiene‐styrene (ABS) and CaCO₃/ethylene‐vinyl acetate copolymer (EVA)/ABS nanocomposites were prepared by melting‐blend with a single‐screw extruder. Mechanical properties of the nanocomposites and the dispersion state of CaCO₃ particles in ABS matrix were investigated. The results showed that in CaCO₃/EVA/ABS nanocomposites, CaCO₃ nanoparticles could increase flexural modulus of the composites and maintain or increase their impact strength for a certain nano‐CaCO₃ loading range. The tensile strength of the nanocomposites, however, was appreciably decreased by adding CaCO₃ nanoparticles. The microstructure of neat ABS, CaCO₃/ABS nanocomposites, and CaCO₃/EVA/ABS nanocomposites was observed by scanning electron microscopy. It can be found that CaCO₃ nanoparticles were well‐dispersed in ABS matrix at nanoscale. The morphology of the fracture surfaces of the nanocomposites revealed that when CaCO₃/EVA/ABS nanocomposites were exposed to external force, nano‐CaCO₃ particles initiated and terminated crazing (silver streak), which can absorb more impact energy than neat ABS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Toughening of unmodified polyvinylchloride through the addition of nanoparticulate calcium carbonate and titanate coupling agent

PVC/CaCO₃ polymer nanocomposites of differing compositions were produced using a two‐roll mill and compression molding. In all formulations, 0.6 phr of titanate was incorporated to assist dispersion during processing. The morphology was observed using transmission electron microscopy, and the static and dynamic mechanical and fracture properties were determined. Fracture toughness examination was performed according to strain energy release test method. The presence of nanometer‐sized CaCO₃ particles led to a slight decrease in the tensile strength but improved the impact energy absorption, storage modulus, and fracture toughness. The use of titanate coupling agent softened the polymer matrix and reduced the matrix's modulus. Fracture surface examinations by scanning electron microscopy showed that the coupling agent improved particle–matrix bonding and inhibited void formation around the particles. Finite element analysis suggested that the improved particle–matrix bonding reduced the matrix's plasticity around the particles, which decreased the toughening efficiency of the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Investigation Into Poly(propylene)/Montmorillonite/Calcium Carbonate Nanocomposites

Summary: A novel method was used to prepare poly(propylene)/montmorillonite/calcium carbonate nanocomposites by melt‐mixing, using pristine montmorillonite (MMT), hexadecyltrimethylammonium bromide (C16), calcium carbonate (CaCO₃) and a matrix in a twin‐screw extruder. Two different sizes of calcium carbonate were used (nanosized CaCO₃ and micron‐sized CaCO₃, the average sizes being 60 nm and 12 μm respectively). The nanocomposite structure was evidenced using X‐ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution electronic microscopy (HREM). Tensile tests and Izod notch impact tests suggested that the incorporation of nanosized CaCO₃ into PP/montmorillonite nanocomposites increased the mechanical properties of the composites, but the improvement in the micro‐sized CaCO₃‐filled PP/montmorillonite nanocomposites was found to be minimal. The thermal stability and flammability properties were characterized by thermogravimetric analysis (TGA) and a cone calorimeter respectively.

     

Mechanical and thermal properties of bio‐based CaCO3/soybean‐based hybrid unsaturated polyester nanocomposites

Bio‐based calcium carbonate nanoparticles (CaCO₃) were synthesized via size reduction of eggshell powder using mechanical attrition followed by high intensity ultrasonic irradiation. The transmission electron microscopic (TEM) and BET surface area measurements show that these particles are less than 10 nm in size and a surface area of ～44 m²/g. Bio‐based nanocomposites were fabricated by infusion of different weight fractions of as‐prepared CaCO₃ nanoparticles into Polylite® 31325‐00 resin system using a non‐contact Thinky® mixing method. As‐prepared bio‐nanocomposites were characterized for their thermal and mechanical properties. TEM studies showed that the particles were well dispersed over the entire volume of the matrix. Thermal analyses indicated that the bio‐nanocomposites are thermally more stable than the corresponding neat systems. Nanocomposite with 2% by weight loading of bio‐CaCO₃ nanoparticles exhibited an 18°C increase in the glass transition temperature over the neat Polylite 31325 system. Mechanical tests have been carried out for both bio‐nanocomposites and neat resin systems. The compression test results of the 2% Bio‐CaCO₃/Polylite 31325 nanocomposite showed an improvement of 14% and 27% in compressive strength and modulus respectively compared with the neat system. Details of the fabrication procedure and thermal and mechanical characterizations are presented in this article. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1442–1452, 2013     

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     

Toughened nylon66/nylon6 ternary nanocomposites by elastomers

The elastomer toughening of PA66/PA6 nanocomposites prepared from the organic modified montmorillonite (OMMT) was examined as a means of balancing stiffness/strength versus toughness/ductility. Several different formulations varying in OMMT content were made by mixing of PA6 and OMMT as a master‐batch and then blending it with PA66 and different elastomers in a twin screw extruder. In this sequence, the OMMT layers were well exfoliated in the nylon alloy matrix. The introduction of silicate layers with PA6 induced the appearance of the γ crystal phase in the nanocomposites, which is unstable and seldom appears in PA66 at room temperature and it further affected the morphology and dispersion of rubber phase resulting in much smaller rubber particles. The incorporation of POE‐g‐MA particles toughened the nanocomposites markedly, but the tensile modulus and strength were both reduced. Conversely, the use of OMMT increased the modulus but decreased the fracture toughness. The nanocomposites exhibited balanced stiffness and toughness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Morphology,thermal, and mechanical properties of polyamide 66/clay nanocomposites with epoxy‐modified organoclay

A new kind of organophilic clay, cotreated by methyl tallow bis‐2‐hydroxyethyl quaternary ammonium and epoxy resin into sodium montmorillonite (to form a strong interaction with polyamide 66 matrix), was prepared and used in preparing PA66/clay nanocomposites (PA66CN) via melt‐compounding method. Three different types of organic clays, CL30B–E00, CL30B–E12, and CL30B–E23, were used to study the effect of epoxy resin in PA66CN. The morphological, mechanical, and thermal properties have been studied using X‐ray diffraction, transmission electron microscopy (TEM), mechanical, and thermal analysis, respectively. TEM analysis of the nanocomposites shows that most of the silicate layers were exfoliated to individual layers and to some thin stacks containing a few layers. PA66CX–E00 and PA66CX–E12 had nearly exfoliated structures in agreement with the SAXS results, while PA66CX–E23 shows a coexistence of intercalated and exfoliated structures. The storage modulus of PA66 nanocomposites was higher than that of the neat PA66 in the whole range of tested temperature. On the other hand, the magnitude of the loss tangent peak in α‐ or β‐transition region decreased gradually with the increase in the clay loading. Multiple melting behavior in PA66 was also observed. Thermal stability more or less decreased with an increasing inorganic content. Young's modulus and tensile strength were enhanced by introducing organoclay. Among the three types of nanocomposites prepared, PA66CX–E12 showed the highest improvement in properties, while PA66CX–E23 showed properties inferior to that of PA66CX–E00 without epoxy resin. In conclusion, an optimum amount of epoxy resin is required to form the strong interaction with the amide group of PA66. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1711–1722, 2006     

Rheology and processability of polyamide66 filled with different‐sized and size‐distributed calcium carbonate

Two‐sized calcium carbonates (CaCO₃) were blended and filled into polyamide66 (PA66). The shear viscosity of PA66/CaCO₃ composites was measured with a capillary extrusion rheometer. The results showed that the shear viscosity of the efficient size distribution samples (PA66 was filled with 600/2500 mesh CaCO₃ blending) obviously decreased compared with that of the single‐size distribution samples (PA66 was filled with 600 or 2500 mesh CaCO₃). The shear viscosity of PA66/CaCO₃ composites at different temperatures was also studied. The results showed that the flow activation energy and flow activation entropy of the efficient size distribution samples obviously increased compared with those of the single‐size distribution samples. The change in flow activation entropy was used to explain the experimental results of shear viscosity. The processability of PA66/CaCO₃ composites was evaluated with a HAAKE torque rheometer. The results showed that the processability of the efficient size distribution samples was obviously improved and the best efficiency of processability improvement appeared in the 30 wt% CaCO₃ content. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Mechanical Properties of PMMA‐Sepiolite Nanocellular Materials with a Bimodal Cellular Structure

Bimodal cellular poly(methyl methacrylate) with micro‐ and nano‐sized (300–500 nm) cells with up to 5 wt% of sepiolite nanoparticles and porosity from 50% to 75% are produced by solid‐state foaming. Uniaxial compression tests are performed to measure the effect of sepiolite concentration on the elastic modulus and the yield strength of the solid and cellular nanocomposites. Single edge notch bend tests are conducted to relate the fracture toughness of the solid and cellular nanocomposites to sepiolite concentration. The relative modulus is independent of sepiolite content to within material scatter when considering the complete porosity range. In contrast, a mild enhancement of the relative modulus is observed by the addition of sepiolite particles for the foamed nanocomposites with a porosity close to 50%. The relative compressive strength of the cellular nanocomposites mildly decreases as a function of sepiolite concentration. A strong enhancement of the relative fracture toughness by the addition of sepiolites is observed. The enhancement of the relative fracture toughness and the relative modulus (at 50% porosity) can be attributed to an improved dispersion of the particles due to foaming and the migration of micro‐sized aggregates from the solid phase to the microcellular pores during foaming.     

Nanoindentation and morphological studies on nylon 66/organoclay nanocomposites. II. Effect of strain rate

Strain rate effects on surface deformation behavior of exfoliated nylon 66 (PA66)/organoclay nanocomposites have been explored by nanoindentation in present study. Sharp indenter (Berkovich) has been used to indent on the surfaces of polymer/clay nanocomposite with different strain rates. Significant strain-rate hardening has been found consistently existing in both neat PA66 and its nanocomposite systems from surface to subsurface (a few micron deep into the bulk). However, strain rate shows almost no effect on the elastic moduli of the neat system and the nanocomposites. The elastic modulus and hardness increase with the indentation depth due to inhomogeneous distributions of the crystalline morphology as well as clay concentration for the case of the nanocomposites along the indentation direction. The mechanical properties observed are correlated with the inhomogeneous microstructures of the studied systems. The plastic index of PA66 and the nanocomposites have been evaluated as a function of strain rate.     

Microstructure and mechanical behavior of polyamide 66‐precipitated calcium carbonate composites: Influence of the particle surface treatment

The effects of interfacial adhesion strength on the mechanical behavior of composites of polyamide 66 and precipitated calcium carbonate (CaCO₃) particles have been investigated. The 50 nm average diameter particles have been surface‐treated using two kinds of coupling agent having various affinities with respect to the matrix. The surface‐modified particles have been incorporated into the polyamide matrix via melt processing. Tensile and impact tests, associated with dynamical mechanical analysis, have been performed on injection‐molded samples. The structural characterization of the specimens has been carried out using differential scanning calorimetry and wide‐angle X‐ray scattering. It is observed that the matrix structure is roughly insensitive to the surface treatment, despite a weak nucleating effect of the filler particles. In contrast, the particle surface treatment strongly influences the particle dispersion in the polymer matrix. Although dispersion was not optimized, the elastic properties of the reinforced polyamide increase with the CaCO₃ content, below as well as above the glass transition temperature. Impact toughness decreases for CaCO₃ weight fraction greater than 5%. Scanning electron microscopy investigation reveals that the interfacial adhesion affects local deformation processes, such as debonding and fibrillation of the polymer matrix around the particles, during the macroscopic deformation of the composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 989–999, 2006     

Effect of particle size on microstructural and mechanical properties of UHMWPE–TiO2 composites produced by gelation and crystallization method

In this study, Ultra-high-molecular-weight polyethylene (UHMWPE) in 0.5 wt % concentration—0.5, 1, and 2 wt % nanosized and micron-sized TiO₂ composites were produced via gelation/crystallization method in decalin + antioxidant solution at 150 °C for 45 min by using magnetic stirrer. The gel composites were cooled in an aluminum tray embedded in iced water under ambient conditions and dried in an oven at 130 °C for 90 min to remove any residual trace of decalin and to strengthen the UHWMPE matrix. Scanning electron microscopy–EDS images indicate that TiO₂ particles were integrated well with the polymer matrix. differential scanning calorimetry studies revealed that the crystallinity of pure UHMWPE was calculated as 56% and an increase of 13.32% for micron sized and 19.25% for nano sized TiO₂. Crystalline and amorphous phases of UHMWPE–TiO₂ composites confirmed by Raman are in good agreement with the literature. The elastic modulus of test materials ranged from 610 to 791 MPa for micron sized and raised from 675 to 1085 for nano sized reinforcing agents. Ultimate tensile stress increased about 35% for micron sized and 60% for nano sized weight 1% TiO₂ reinforced composites. Biomineralization tests (performed in stimulated body fluid, at 37 °C and 6.5 pH during 1 month) have shown that produced composites are compatible as acetabular liner replacement for hipjoints due to no accumulation (Ca, P, Na, etc.) on UHMWPE–TiO₂ composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47402.     

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     

Effect of calcium carbonate on the mechanical and thermal properties of isotactic polypropylene/ethylene vinyl acetate blends

The effect of calcium carbonate (CaCO₃) on the mechanical properties (with heat treatment) and thermal properties of polypropylene and isotactic polypropylene (i‐PP)/ethylene vinyl acetate (EVA) blends was investigated. CaCO₃, in five different concentrations (3, 6, 9, 12l, and 15 wt %), was added to i‐PP/EVA (88/12) to produce ternary composites. The mechanical properties, including the yield and tensile strengths, elastic modulus, Izod impact strength for notch radii of 0.25 and 1 mm, and hardness with and without an annealing heat treatment, and the thermal properties, such as the melting point and melt‐flow index, of the composites were investigated. The annealing heat treatment was carried out at 100°C for three different holding times: 75, 100, and 150 h. On the basis of the results, attempts were made to establish a relationship between the CaCO₃ content, the annealing holding time, and the mechanical and thermal properties to obtain the best results. The tensile test results showed that the heat treatment was not effective for the ultimate tensile strength, and the yield strength and tensile strength decreased gradually as the CaCO₃ content increased. However, CaCO₃ was effective for higher elastic modulus, impact strength, and hardness values. A considerable increase in the elastic modulus was found with a 3% CaCO₃ concentration for a holding time of 100 h. The maximum impact strength for a notch radius of 1 mm was obtained with 3% CaCO₃ with annealing for a holding time of 100 h, whereas a 9% CaCO₃ concentration produced higher toughness values for a notch radius of 0.25 mm. The fracture surfaces also supported the results from the Izod impact tests. Similarly, hardness values increased with the annealing heat treatment and increasing CaCO₃ content. However, different holding times showed similar effects on the hardness values. The increased CaCO₃ content caused the melting point to increase 5°C, whereas the melt‐flow index showed a sharp decrease as the CaCO₃ content increased to 3%. Taking into consideration the mechanical and thermal properties and the annealing holding time, we recommend a CaCO₃ concentration of 3% with an annealing heat treatment for 100 h for optimum properties of such ternary composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1126–1137, 2005     

Photo polymerization of acrylamide onto calcium carbonate particle surfaces and filled nylon‐6

The polymerization of acrylamide (AAM) onto calcium carbonate (CaCO₃) particle surfaces induced by ultraviolet light and the properties of polyamide‐6 (PA6) filled with the surface‐treated CaCO₃ were studied. Electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), particle size distribution, impact strength and degree of polymerization measurements were determined. After AAM polymerization, a PAAM layer was formed on the CaCO₃ surface. This layer tightly banded the CaCO₃ particle and could not be washed away by acetone. A N_1s peak was observed in the ESCA spectra of the treated CaCO₃ particles. The average particle size of the treated CaCO₃ increased compared to that of the original CaCO₃. The interfacial interaction and impact strength of the treated CaCO₃–filled PA6 were enhanced compared to those of the untreated CaCO₃–filled PA6. Polym. Eng. Sci. 44:1277–1282, 2004. © 2004 Society of Plastics Engineers.     

EVA nanocomposites based on South African Koppies clay

South African Koppies bentonite was organomodified with single‐tail and double‐tail alkyl ammonium cationic surfactants with the latter intercalated both below and above the clay cationic exchange capacity. Corresponding poly(ethylene‐co‐vinylacetate) nanocomposites were prepared by twin‐screw melt compounding. Transmission electron microscopy indicated the presence of mixed nano‐sized and micron‐sized clay morphologies. X‐ray diffraction studies revealed that the crystallinity of the particles improved and that the d‐spacing values increased on incorporating the clays in the polymer matrix. It is postulated that, rather than indicating polymer co‐intercalation, this is caused by further intercalation of either excess surfactants or surfactant residues that were released by shear delamination of the clays during compounding. Improved mechanical properties were realized especially when using the clay containing the longer double‐tail surfactant intercalated at levels in excess of the cation exchange capacity of the clay. The nanocomposites showed improved tensile modulus and elongation‐at‐break values at the expense of a reduction in impact strength, whereas tensile strength was about the same as for the neat polymer. J. VINYL ADDIT. TECHNOL., 20:143–151, 2014. © 2014 Society of Plastics Engineers     

A study on HDPE/sulfonated EPDM‐treated CaCO3 blends

In this article, sulfonated ethylene‐propylene‐diene monomer terpolymer (H–SEPDM) was used to treat CaCO₃ particles. CaCO₃ particles are encapsulated by H–SEPDM through the reaction of sulfonic acid group (? SO₃H) in H–SEPDM with CaCO₃ to improve the interface adhesion of CaCO₃ with HDPE. In case the treated CaCO₃ is blended with HDPE, a brittle–ductile transition occurs. The impact strength of the blend rises sharply at 25–30 wt % CaCO₃, and amounts to more than 700 J/m, four times as high as that of HDPE at 30 wt % CaCO₃, without much loss of its yield strength and modulus. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2140–2144, 2001