The experimental results and simulation of temperature dependence of brittle‐ductile transition in PVC/CPE blends and PVC/CPE/nano‐CaCO3 composites

The effect of chlorinated polyethylene (CPE) content and test temperature on the notched Izod impact strength and brittle‐ductile transition behaviors for polyvinylchloride (PVC)/CPE blends and PVC/CPE/nano‐CaCO₃ ternary composites is studied. The CPE content and the test temperature regions are from 0–50 phr and 243–363 K, respectively. It is found that the optimum nano‐CaCO₃ content is 15 phr for PVC/CPE/nano‐CaCO₃ ternary composites. For both PVC/CPE blends and PVC/CPE/nano‐CaCO₃ ternary composites, the impact strength is improved remarkably when the CPE content or test temperature is higher than the critical value, that is, brittle‐ductile transition content (C_BD) or brittle‐ductile transition temperature (T_BD). The T_BD is closely related to the CPE content, the higher the CPE content, the lower the T_BD. The temperature dependence of impact strength for PVC/CPE blends and PVC/CPE/nano‐CaCO₃ ternary composites can be well simulated with a logistic fitting model, and the simulation results can be illustrated with the percolation model proposed by Wu and Jiang. DMA results reveal that both PVC and CPE can affect the T_BD of PVC/CPE blends and PVC/CPE/nano‐CaCO₃ composites. When the CPE content is enough (20 phr), the CPE is more important than PVC for determining the T_BD of PVC/CPE blends and PVC/CPE/nano‐CaCO₃ composites. Scanning electron microscopy (SEM) observations reveal that the impact fractured mechanism can change from brittle to ductile with increasing test temperature for these PVC systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Production of nano‐calcium carbonate from shells of the freshwater channeled applesnail,Pomacea canaliculata,by hydrothermal treatment and its application with polyvinyl chloride

The use of naturally renewable shells of the freshwater channeled applesnail, Pomacea canaliculata, as a filler to replace commercial calcium carbonate (CaCO₃) was investigated in this study. Ground P. canaliculata shell particles were converted to nano‐CaCO₃ particles by the displacement reaction of calcium chloride in sodium carbonate solution followed by hydrothermal treatment at 100°C for 1 h to synthesize nano‐CaCO₃ with particle sizes of 30–100 nm in diameter. The mechanical properties, in terms of the tensile strength, elongation at brake and impact strength, of polyvinyl chloride (PVC) were greatly improved by mixing with nano‐CaCO₃ at 5–10 parts per hundred of resin. Additionally, the presence of nano‐CaCO₃ at the same levels increased the flame resistance and thermal stability of the PVC composite materials. POLYM. COMPOS., 36:1620–1628, 2015. © 2014 Society of Plastics Engineers     

Effects of poly(1,2‐propylene glycol adipate) and nano‐CaCO3 on DOP migration and mechanical properties of flexible PVC

Nano‐CaCO₃ was used as nano‐scale filler and poly(1,2‐propylene glycol adipate) (PPA) was used as polymeric plasticizer in flexible poly(vinyl chloride) (PVC) sheets for the partial replacement of di(2‐ethyl hexyl) phthalate (DOP) in this paper. The effect of PPA and nano‐CaCO₃ on restraining DOP migration was evaluated via extraction tests. The results showed that the introduction of nano‐CaCO₃ can decrease the extraction rate of DOP in the PVC matrix. The tensile strength and elongation at break of CaCO₃‐1/PPA‐20/DOP‐30/PVC were similar to those of DOP‐50/PVC, and CaCO₃‐1/PPA‐20/DOP‐30/PVC exhibited the superior suppression of DOP migration compared with DOP‐50/PVC. Thermogravimetry analysis (TGA) indicated that the addition of nano‐CaCO₃ effectively improved the thermal stability of the nanocomposites. Therefore, the combination of PPA and nano‐CaCO₃ is an effective approach to suppress the migration of DOP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Interfacial structures and mechanical properties of PVC composites reinforced by CaCO3 with different particle sizes and surface treatments

The effects of particle size and surface treatment of CaCO₃ particles on the microstructure and mechanical properties of poly(vinyl chloride) (PVC) composites filled with CaCO₃ particles via a melt blending method were studied by SEM, an AG‐2000 universal material testing machine and an XJU‐2.75 Izod impact strength machine. The tensile and impact strengths of CaCO₃/PVC greatly increased with decreasing CaCO₃ particle size, which was attributed to increased interfacial contact area and enhanced interfacial adhesion between CaCO₃ particles and PVC matrix. Titanate‐treated nano‐CaCO₃/PVC composites had superior tensile and impact strengths to untreated or sodium‐stearate‐treated CaCO₃/PVC composites. The impact strength of titanate‐treated nano‐CaCO₃/PVC composites was 26.3 ± 1.1 kJ m⁻², more than three times that of pure PVC materials. The interfacial adhesion between CaCO₃ particles and PVC matrix was characterized by the interfacial interaction parameter B and the debonding angle θ, both of which were calculated from the tensile strength of CaCO₃/PVC composites. Copyright © 2005 Society of Chemical Industry     

Investigation of the addition of nano‐CaCo3 at dry mixing or onset of fusion on the dispersion,torque, and mechanical properties of compounded PVC

A Brabender torque rheometer equipped with an internal mixer was used to study the influence of compounding method on the properties of (rigid PVC)/(treated and untreated nano‐CaCO₃) nanocomposites. Two different methods were studied for the addition of surface treated and untreated nano‐CaCO₃ during the melt mixing of rigid PVC. Direct dry mixing of rigid PVC and nano‐CaCO₃, and addition of nano‐CaCO₃ at the onset of PVC fusion were investigated. Dispersion of treated and untreated nano‐CaCO₃ was studied by X‐ray diffraction and scanning electron microscopy. Results showed that using direct dry mixing improved the dispersion of nano‐CaCO₃ in the PVC matrix by lowering the fusion time. The mechanical properties of the nanocomposite samples such as impact strength, tensile strength, and elongation at break were improved by using this method. The addition of treated nano‐CaCO₃ at the onset of fusion caused a simultaneous decrease in torque. Also, rigid PVC nanocomposites prepared with treated nano‐CaCO₃ showed better mechanical properties than those of nanocomposites prepared with the untreated nano‐CaCO₃. J. VINYL ADDIT. TECHNOL., 18:153–160, 2012. © 2012 Society of Plastics Engineers     

Ultraviolet light aging properties of PVC/CaCO3 composites

The ultraviolet radiation aging behaviors of PVC/CaCO₃ and PVC/CaCO₃/macromolecular modifier composites were studied through whiteness measurement, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy, and mechanical properties test. It was found that nano‐CaCO₃ particles used as ultraviolet light screening agents could significantly enhance the antiaging properties of PVC materials. Due to the macromolecular modifier coated on nano‐CaCO₃ particles, the compatibility of nano‐CaCO₃ and PVC matrix was improved, resulting in uniform dispersion of nano‐CaCO₃ in PVC matrix. Therefore, the PVC/CaCO₃/MP composite exhibited better antiaging properties than PVC/CaCO₃ composite. After 12 h of ultraviolet irradiation, the tensile strength retention, elongation at break retention, and impact strength retention of PVC/CaCO₃/MP composite were 79.5%, 74.5%, and 75.3%, which were much higher than that of neat PVC and PVC/CaCO₃ composite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 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     

Effects of inorganic nano‐particles on plasticizers migration of flexible PVC

The influences of nano‐particles (nano‐sized CaCO₃ and nano‐sized SiO₂) on plasticizers volatility, solvent extraction stability, and exudation stability of flexible PVC were studied. The results showed that nano‐particles could reduce migration of plasticizers, thus improved the ability of anti‐migration of flexible PVC. Further more, nano‐sized SiO₂ shows excellent property than nano‐sized CaCO₃ in resistance migration of plasticizers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study on mechanical and flow properties of acrylonitrile‐butadiene‐styrene/poly(methyl methacrylate)/nano‐calcium carbonate composites

Acrylonitrile‐butadiene‐styrene (ABS)/poly(methyl meth‐acrylate) (PMMA)/nano‐calcium carbonate (nano‐CaCO₃) composites were prepared in a corotating twin screw extruder. Four kinds of nano‐CaCO₃ particles with different diameters and surface treatment were used in this study. The properties of the composites were analyzed by tensile tests, Izod impact tests, melt flow index (MFI) tests, and field emission scanning electron microscopy (FESEM). This article is focused on the effect of nano‐CaCO₃ particles' size and surface treatment on various properties of ABS/PMMA/nano‐CaCO₃ composites. The results show that the MFI of all the composites reaches a maximum value when the content of nano‐CaCO₃ is 4 wt%. In comparison with untreated nano‐CaCO₃ composites, the MFI of stearic acid treated nano‐CaCO₃ composites is higher and more sensitive to temperature. The tensile yield strength decreases slightly with the increase of nano‐CaCO₃ content. However, the size and surface treatment of nano‐CaCO₃ particles have little influence on the tensile yield strength of composites. In contrast, all of nano‐CaCO₃ particles decrease Izod impact strength significantly. Stearic acid treated nano‐CaCO₃ composites have superior Izod impact strength to untreated nano‐CaCO₃ composites with the same nano‐CaCO₃ content. Furthermore, the Izod impact strength of 100 nm nano‐CaCO₃ composites is higher than that of 25 nm nano‐CaCO₃ composites. POLYM. COMPOS., 31:1593–1602, 2010. © 2009 Society of Plastics Engineers     

Mechanical properties of talc‐ and (calcium carbonate)‐filled poly(vinyl chloride) hybrid composites

The main objective of this study was to investigate and compare the mechanical properties of poly(vinyl chloride) (PVC) composites filled with calcium carbonate (CaCO₃), talc, and talc/CaCO₃. Talc and CaCO₃ with different grades were incorporated into the PVC matrix. To produce the composites, the PVC resin, fillers, and other additives were first dry‐blended by using a laboratory mixer before being milled into sheets in a two‐roll mill. Test specimens were prepared by compression molding, after which the mechanical properties of the composites were determined. Single and hybrid filler loadings used were fixed at 30 phr (parts per hundred parts of resin). Talc‐filled composite showed the highest flexural modulus and the lowest impact strength, whereas uncoated, ground, 1‐μm CaCO₃ (SM 90) showed optimum properties in terms of impact strength and flexural modulus among all grades of CaCO₃. It was selected to combine with talc at different ratios in the hybrid composites. The impact strength of the hybrid composites gradually increased with increasing SM 90 content, but the flexural and tensile properties showed an opposite behavior. Hybrid (10 phr talc):(20 phr SM 90)‐filled PVC composite reached a synergistic hybridization with balanced properties in impact strength, as well as flexural and tensile properties. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Effects of mold cavity temperature on surface quality and mechanical properties of nanoparticle‐filled polymer in rapid heat cycle molding

Acrylonitrile‐butadiene‐styrene (ABS)/poly methyl methacrylate (PMMA) and ABS/PMMA/nano‐CaCO₃ composites were prepared in a corotating twin screw extruder. Single‐gate and double‐gate samples were molded based on a rapid heat cycle molding (RHCM) system. Effects of mold cavity temperature on surface quality and mechanical properties of single‐gate and double‐gate samples in RHCM process were conducted. The results showed that surface quality of plastic parts can be improved significantly by increasing mold cavity temperature. Nano‐CaCO₃ particles on the surface of plastic parts can be eliminated by using high mold cavity temperature. The roughness and gloss of two kinds of plastic parts (ABS/PMMA and ABS/PMMA/nano‐CaCO₃) stabilized at the same level when the mold cavity temperature is above glass transition temperature of resin material. Weld line can be eliminated in RHCM process during high mold cavity temperature. The tensile strength of both ABS/PMMA and ABS/PMMA/nano‐CaCO₃ exhibited decreasing trend with the increase of mold cavity temperature. Reduction of internal stress gave rise to the increase of Izod impact strength of ABS/PMMA for both sing‐gate and double‐gate samples. However, influence regularity of mold cavity temperature on Izod impact strength of ABS/PMMA/nano‐CaCO₃ is depended on the number of gates. For all the samples in this study, too high of mold cavity temperature (higher than 125°C) deprave Izod impact strength of plastic parts. Both ABS/PMMA and ABS/PMMA/nano‐CaCO₃ are not susceptible to weld line. When the mold surface temperature is approximately equal to glass transition temperature of resin material, all the samples are found to give the best combination of properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41420.     

Mechanical properties,thermal stability,and crystallization kinetics of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)/calcium carbonate composites

Bacterial polyester poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P3/4HB) containing 5 mol% 4HB was composited with different calcium carbonate (CaCO₃) fillers. The effect of CaCO₃ contents on thermal properties, mechanical property, and crystallization kinetics was evaluated. The thermal stability of P3/4HB was reduced by mixing with CaCO₃ particles. With increasing CaCO₃ content, the elongation at break, tensile strength, and impact strength decrease; however, elastic modulus increases. When P3/4HB with 20 mol% 4HB was added into the P3/4HB/CaCO₃ composite, the impact strength were enhanced significantly; however, the elongation at break and tensile strength were only slight to moderate improvements. However, when compared with nano‐ and light‐CaCO₃, heavy CaCO₃ had the best mechanical properties. The nonisothermal and isothermal crystallization results demonstrated that the crystallization rate of P3/4HB was reduced and the highest crystallinity was obtained for all kinds of CaCO₃ fillers at 40 phr content. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Fabrication and characterization of in situ synthesized nano‐CaCo3‐reinforced polypropylene composite materials

To improve the impact toughness of polypropylene (PP), nano‐CaCO₃ was prepared by an in situ synthesis. The surface of the nano‐CaCO₃ was modified by KH‐550 silane coupling agent and NDZ‐401 titanium acid ester coupling agent. Nano‐CaCO₃/PP composite materials were fabricated through a melt‐blending method and characterized, and their mechanical properties were analyzed. The impact toughness and the tensile strength of the PP were improved significantly by the incorporation of nano‐CaCO₃. When the weight fraction of nano‐CaCO₃ was 2%, the maximum impact toughness and tensile strength of the PP nanocomposites were 293% and 259%, respectively, of the values for neat PP. Observation of the impact fracture surface of the nanocomposites indicated that the dispersion of nano‐CaCO₃ modified by NDZ‐401 coupling agent was more homogeneous than that of nano‐CaCO₃ modified by the KH‐550 silane coupling agent. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Mechanical properties and morphology of polypropylene‐calcium carbonate nanocomposites prepared by dynamic packing injection molding

In this article, dynamic packing injection molding (DPIM) technology was used to prepare injection samples of Polypropylene‐Calcium Carbonate (PP/CaCO₃) nanocomposites. Through DPIM, the mechanical properties of PP/nano‐CaCO₃ samples were improved significantly. Compared with conventional injection molding (CIM), the enhancement of the tensile strength and impact strength of the samples molded by DPIM was 39 and 144%, respectively. In addition, the tensile strength and impact strength of the PP/nano‐CaCO₃ composites molded by DPIM increase by 21 and 514%, respectively compared with those of pure PP through CIM. According to the SEM, WAXD, DSC measurement, it could be found that a much better dispersion of nano‐CaCO₃ in samples was achieved by DPIM. Moreover, γcrystal is found in the shear layer of the DPIM samples. The crystallinity of PP matrix in DPIM sample increases by 22.76% compared with that of conventional sample. The improvement of mechanical properties of PP/nano‐CaCO₃ composites prepared by DPIM attributes to the even distribution of nano‐CaCO₃ particles and the morphology change of PP matrix under the influence of dynamic shear stress. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Precipitated calcium carbonates as weathering enhancers and impact modifiers for rigid PVC siding and profiles

A study conducted to determine the suitability of calcium carbonate (CaCO₃) fillers in exterior PVC applications revealed that the surface-treated precipitated CaCO₃s of average particle sizes 0.5 micron and 0.07 micron, in fact, minimized the initial yellowing of PVC seen on weathering. It is hypothesized that these particle-size CaCO₃s, being optimum for light scattering, provide greater UV protection. Further, the high surface areas of these CaCO₃s increase the capacity to neutralize the HCl responsible for yellowing of the PVC. The optimum filler level is 5 to 10 phr. At this loading level, long-term impact strength is also retained.     

Toughening and reinforcement of rigid PVC with silicone rubber/nano‐CACO3 shell‐core structured fillers

To improve the mechanical properties and structure of poly(vinyl chloride) (PVC)/nano‐CaCO₃ nano composite, a core (nano‐CaCO₃)/shell (SR) structured filler (40–60 nm) was successfully prepared by refluxing methyl vinyl silicone rubber (SR) and nano‐CaCO₃ particles (coupling agent KH550, KH560, or NDZ‐101 as interfacial modifier) in toluene with vigorous stirring, according to an encapsulation model. It is effective in rigid PVC composite's toughness and reinforcement. The interfacial modifier's structure and interaction of nanocomposites of PVC/SR/nano‐CaCO₃ were studied. The results indicate that KH560 has the optimal interfacial modificatory effect. The environmental scanning electron microscope (ESEM) study testified that PVC/SR/nano‐CaCO₃ nanocomposites had a typical rubber–plastics‐toughening mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2560–2567, 2006     

Effect of surface modifiers and surface modification methods on properties of acrylonitrile–butadiene–styrene/poly(methyl methacrylate)/nano‐calcium carbonate composites

Nano‐calcium carbonate (nano‐CaCO₃) was used in this article to fill acrylonitrile–butadiene–styrene (ABS)/poly(methyl methacrylate) (PMMA), which is often used in rapid heat cycle molding process (RHCM). To achieve better adhesion between nano‐CaCO₃ and ABS/PMMA, nano‐CaCO₃ particles were modified by using titanate coupling agent, aluminum–titanium compound coupling agent, and stearic acid. Dry and solution methods were both utilized in the surface modification process. ABS/PMMA/nano‐CaCO₃ composites were prepared in a corotating twin screw extruder. Influence of surface modifiers and surface modification methods on mechanical and flow properties of composites was analyzed. The results showed that collaborative use of aluminum–titanium compound coupling agent and stearic acid for nano‐CaCO₃ surface modification is optimal in ABS/PMMA/nano‐CaCO₃ composites. Coupling agent can increase the melt flow index (MFI) and tensile yield strength of ABS/PMMA/nano‐CaCO₃ composites. The Izod impact strength of composites increases with the addition of titanate coupling agent up to 1 wt %, thereafter the Izod impact strength shows a decrease. The interfacial adhesion between nano‐CaCO₃ and ABS/PMMA is stronger by using solution method. But the dispersion uniformity of nano‐CaCO₃ modified by solution method is worse. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of High‐Energy Vibromilling on Interfacial Interaction and Mechanical Properties of PVC/Nano‐CaCO3 Composites

Summary: The effects of interfacial interaction between nano‐CaCO₃ and PVC on mechanical properties and morphology of PVC/nano‐CaCO₃ composites were studied. Nano‐CaCO₃ was treated with vibromilling in the presence of PVC and coupling agents. The mechanical properties of PVC/treated nano‐CaCO₃ are remarkably improved. Transmission electron microscopy results revealed that vibromilled nano‐CaCO₃ particles are well dispersed in PVC matrix with good homogeneity and well adhered to PVC matrix. Molau test indicated that chemical reaction between newly formed surface of nano‐CaCO₃ and PVC or coupling agent took place. Theoretical calculation results show that the interfacial interaction between PVC and nano‐CaCO₃ are substantially improved through vibromilling treatment of nano‐CaCO₃ in the presence of PVC and coupling agent.

Molau test results of the samples in THF.     

Effect of interfacial interaction on the crystallization and mechanical properties of PP/nano‐CaCO3 composites modified by compatibilizers

To investigate the effect of interfacial interaction on the crystallization and mechanical properties of polypropylene (PP)/nano‐CaCO₃ composites, three kinds of compatibilizers [PP grafted with maleic anhydride (PP‐g‐MA), ethylene–octene copolymer grafted with MA (POE‐g‐MA), and ethylene–vinyl acetate copolymer grafted with MA (EVA‐g‐MA)] with the same polar groups (MA) but different backbones were used as compatibilizers to obtain various interfacial interactions among nano‐CaCO₃, compatibilizer, and PP. The results indicated that compatibilizers encapsulated nano‐CaCO₃ particles, forming a core–shell structure, and two interfaces were obtained in the compatibilized composites: interface between PP and compatibilizer and interface between compatibilizer and nano‐CaCO₃ particles. The crystallization and mechanical properties of PP/nano‐CaCO₃ composites were dependent on the interfacial interactions of these two interfaces, especially the interfacial interaction between PP and compatibilizer. The good compatibility between PP chain in PP‐g‐MA and PP matrix improved the dispersion of nano‐CaCO₃ particles, favored the nucleation effect of nano‐CaCO₃, increased the tensile strength and modulus, but reduced the ductility and impact strength of composites. The partial compatibility between POE in POE‐g‐MA and PP matrix had little effect on crystallization and mechanical properties of PP/nano‐CaCO₃ composites. The poor compatibility between EVA in EVA‐g‐MA and PP matrix retarded the nucleation effect of nano‐CaCO₃, and reduced the tensile strength, modulus, and impact strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polystyrene/CaCO3 composites with different CaCO3 radius and different nano‐CaCO3 content—structure and properties

The Archimedes' principle and physical theory are attempted to analysis the densification and structure of the polystyrene (PS) composites by melt compounding with CaCO₃ having different particle size. The difference between the measured specific volume (ν) andthe theoretically calculated specific volume (ν_mix), Δν = ν−ν_mix, can reflect the densification of the composites. It is clearly demonstrated that the PS composites become more condensed with the reduction of the CaCO₃ particle size. Especially, when the content for nano‐CaCO₃ achieves 2 wt%, the Δν value of the composites reaches the least, which shows the best densification. Meanwhile, the glass transition temperature (T_g) reaches the maximum value of about 100°C by differential scanning calorimetry (DSC) and thermal mechanical analysis (TMA), which indirectly reveals the composites microstructure more condensed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that 2 wt% nano‐CaCO₃ uniformly disperses in PS composites. The CaCO₃ selected in this experiment has certain toughening effect on PS. The impact and tensile strength increase with addition of nano‐CaCO₃, but the elongation at break decreases. When nano‐CaCO₃ content achieved 2 wt%, the impact and tensile strength present the maximum value of 1.63 KJ/m² and 44.5 MPa, which is higher than the pure PS and the composites filled with the same content of micro‐CaCO₃. POLYM. COMPOS., 31:1258–1264, 2010. © 2009 Society of Plastics Engineers