Resin modification on interlaminar shear property of carbon fiber/epoxy/nano‐CaCO3 hybrid composites

Epoxy resin was modified by adding a silane coupling agent/nano‐calcium carbonate master batch. Then, samples of binary carbon fiber/epoxy composites and ternary fiber/nano‐CaCO₃/epoxy were prepared by hot press process. The interlaminar shear strength (ILSS) of the carbon fiber/epoxy composites was investigated and the results indicate that introduction of the treated nano‐CaCO₃ enhances ILSS obviously. In particular, the addition of 4 wt% nano‐CaCO₃ leads to 36.6% increase in the ILSS for the composite. The fracture surfaces of the carbon fiber/epoxy composites and the mechanical properties of epoxy resin cast are examined and both of them are employed to explain the change of ILSS. The results show that the change of ILSS is primarily due to an increase of the epoxy matrix strength and an increase of the fiber/epoxy interface. The bifurcation of propagating cracks, stress transfer, and cavitation are deduced for the reasons of strengthening and toughening effect of nano‐CaCO₃ particles. POLYM. COMPOS., 38:2035–2042, 2017. © 2015 Society of Plastics Engineers     

Effect of the mixing sequence on the morphology and properties of a polypropylene/polydimethylsiloxane/nano‐SiO2 ternary composite

Ternary composites of polypropylene (PP), polydimethylsiloxane (PDMS) elastomer, and nano‐SiO₂, prepared with three different mixing sequences, were studied for dispersion morphology and its effect on the crystallization of PP and the mechanical properties. The mixing sequence produced a significant effect on the dispersion morphology and, thereby, on the mechanical properties of the composites. A two‐step mixing sequence, in which nano‐SiO₂ was added in the second step to the PP/PDMS binary system, produced a significant encapsulation of nano‐SiO₂ by PDMS, and this, in turn, resulted in the poor modulus and impact strength of the composite. A one‐step mixing sequence of all three components produced a separated dispersion of PDMS and nano‐SiO₂ phases in the PP matrix with the occurrence of a fine band of nano‐SiO₂ particles at the boundaries of the PDMS domains and the presence of some nano‐SiO₂ filler particles inside the PDMS domains. This one‐step mixing sequence produced an improvement in the tensile modulus but a decrease in the impact strength with increasing nano‐SiO₂ content. In the third sequence of mixing, which involved a two‐step mixing sequence through the addition of PDMS in the second step to the previously prepared PP/nano‐SiO₂ binary system, the morphology of the dispersion showed separately dispersed PDMS and nano‐SiO₂ phases with a loose network of nano‐SiO₂ particles surrounding the PDMS domains. This latter series of ternary composites had the highest impact strength and exhibited high shear deformation under tensile and impact conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

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     

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     

Preparation and properties of nano‐Al2O3 particles/polyester/epoxy resin ternary composites

This article presents the results of an experimental study on the preparation and properties of new ternary composites composed of nano‐Al₂O₃ particles, polyester, and epoxy resin. The ternary composites were prepared by the addition of the nano‐Al₂O₃ particles in a binary matrix, with elevated viscosity, of the epoxy resin modified by the polyester. The nano‐Al₂O₃ particles were previously located and dispersed in the polyester phase. The study showed that the ternary system was a type of nanoscale dispersed composite with high strength and toughness as well as modulus, combined with excellent dielectric and heat‐resistance properties. All related properties of the composites were remarkably superior to those of both the binary matrix and the unmodified epoxy resin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 70–77, 2002     

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     

Effect of exfoliated organophilic montmorillonite on the structure and conductivity of polypropylene/polyaniline composites

This study concentrates on the effect of organophilic montmorillonite (OMMT) nanolayers on conductivity, structure, morphology, and mechanical properties of the polypropylene/polyaniline (PP/PANI) composites. The composite was prepared by in situ polymerization of aniline at different composition ratios in the presence of PP powder. The structure and conductivity of ternary PP/PANI/OMMT nanocomposites were compared with those of PP/PANI composites. DC electrical conductivity measurements indicated that electrical conductivity decreased in the presence of OMMT layers. Scanning electron microscopy showed that the surface of ternary nanocomposites have more rough regions. The interaction between PANI and OMMT was confirmed by Fourier transform infrared spectroscopy. The distribution of OMMT layers in the polymer matrix, as an effective parameter on the properties of nanocomposite, was investigated and confirmed using X‐ray diffraction and transmission electron microscopy. The results showed an exfoliated array for OMMT layers in the nanocomposite structure. The shear storage modulus for PP/PANI composites was lower than that for pure PP; however, it was increased for PP/PANI/OMMT nanocomposites. The data from the tensile and izod impact strength showed that the Young's modulus and izod impact strength were increased slightly by the addition of OMMT, whereas the elongation at break was decreased. POLYM. COMPOS., 38:699–707, 2017. © 2015 Society of Plastics Engineers     

Influence of the compounding route on the properties of polypropylene/nano‐CaCO3/ethylene–propylene–diene terpolymer tercomponent composites

The influence of the compounding route of polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM)/nano‐CaCO₃ composites on their properties, including their mechanical properties, the dispersion degree of nano‐CaCO₃, and the morphology of EPDM, was studied. The results showed that the toughness of the composites and the morphology of the EPDM particles were markedly influenced by the compounding route, whereas the dispersion degree of nano‐CaCO₃ in the matrix was little influenced by the compounding route. The impact strength of composites prepared by one route was about 60 kJ/m² with 20 wt % nano‐CaCO₃. The results indicated that a sandbag of nano‐CaCO₃ embedded in EPDM could effectively improve the toughness of the composites. A sandbag composed of EPDM and nano‐CaCO₃ eliminated the deterioration effect of the nano‐CaCO₃ agglomerate on the toughness of the composites, whereas the nano‐CaCO₃ agglomerate separately dispersed in PP decreased the toughness of the tercomponent composite © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

High strength polyethylene fibers from high density polyethylene/organoclay composites

High strength fibers were prepared from high density polyethylene (HDPE)/organically modified montmorillonite (OMMT) composites. X‐ray diffraction study revealed that the composites were of conventional or phase‐separated type. As‐spun composite fibers were found to have higher drawability than as‐spun HDPE fiber. As a result of an increased drawability, fibers with much higher mechanical properties were obtained. The highest modulus and tensile strength obtained in the present study were 38 GPa and 1.7 GPa, respectively. Study of internal morphology suggests that the role of OMMT is to suppress a defect formation and allows the fiber to be drawn to higher draw ratio. Analysis of the mechanical properties of the fibers using a Griffith type relationship suggested that the fibers have much smaller defects and the predicted attainable strength for the fiber is much higher than that previously predicted for melt‐spun and hot drawn fiber. POLYM. ENG. SCI., 47:943–950, 2007. © 2007 Society of Plastics Engineers     

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     

Binary and ternary particulated composites: UHMWPE/CACO3/HDPE

A study of the influence of employing ultrahigh molecular weight polyethylene (UHMWPE) on the toughness of CaCO₃/high‐density polyethylene (HDPE) composites was carried out. Binary and ternary HDPE‐based composites with calcium carbonate in the range of 0–40% and UHMWPE in the range of 0–50% were produced by twin‐screw extrusion followed by compression molding. From tensile and impact tests, it was found that increasing calcium carbonate content increased tensile modulus, but decreased tensile strength, strain at break, and impact resistance. The addition of UHMWPE helped to increase the strain at break and impact resistance of composites moderately without decreasing modulus or strength. The degree of toughening was found to increase with increasing UHMWPE content, but to decrease as the filler volume fraction was increased. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1503–1513, 2000     

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     

Multiscale organic montmorillonite‐carbon fiber reinforcement for high impact polystyrene

An approach to the development of high impact polystyrene (HIPS) based on organic montmorillonite (OMMT) and carbon fiber (CF) reinforcement was reported in this article. OMMT were used to improve the interface compatibility and toughness of CF/HIPS composites. HIPS/OMMT/CF composites were prepared by melt compounding, followed by injection molding. The composites were characterized by some techniques including X‐ray diffraction (XRD), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and mechanical testing. In comparison to unmodified system, the incorporation of OMMT can significantly enhance the mechanical properties of the HIPS/CF composites. The optimum weight ratio of OMMT : CF : HIPS in the composite is 1/5/100. Compare with HIPS, the tensile modulus, tensile strength, bending modulus and bending strength of OMMT/CF/HIPS composite increased by 81%, 138%, 26%, and 46%, respectively. Moreover, the impact strength of OMMT/CF/HIPS composites increased by 31%, compared with CF/HIPS composite. POLYM. COMPOS., 36:811–816, 2015. © 2014 Society of Plastics Engineers     

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     

熔融挤出法制备PA6-66/蒙脱土纳米复合材料的研究

采用聚合物熔融挤出的方法，用自制的有机蒙脱土与PA6—66熔融复合，制备出剥离型PA6—66／蒙脱土纳米复合材料；并对材料的结构与性能进行了测试。TEM结果表明，蒙脱土晶层均匀地分散于基体中，平均厚度约10nm，形成结构均匀的纳米复合材料。DSC、MFR测试结果表明，纳米复合材料的热性能和加工性能优于基体；同时对复合材料的力学性能进行测试，结果表明，纳米级蒙脱土起到了显著增强作用，复合材料拉伸强度升高了17．1％；拉伸模量提高了将近30％；屈服强度是纯PA6／66的1．22倍。     

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     

Novel Comb-Like Copolymer Dispersant for Polypropylene/CaCO3 Composites and Its Influence on Dispersion,Crystallization, Mechanical,and Thermal Properties

A novel comb-like copolymer with carboxyl group as an anchoring group and polycaprolactone as a solvent chain was first used as the dispersant of CaCO₃ particles in polypropylene (PP). The dispersion of CaCO₃ particles in PP matrix was significantly improved in the presence of comb-like copolymer dispersant because of the strong repulsive force caused by steric hindrance effect. The influences of the coating amount of comb-like copolymer dispersant on crystallization behaviors, mechanical properties, and thermal stabilities were systematically investigated. The crystallization temperature, crystallinity, and crystallization rate of PP/CaCO₃ composites prepared with monolayer-coated CaCO₃ were all improved, where the monolayer comb-like copolymer coating remained as a rigid layer and provided a noticeable nucleating effect. The PP/CaCO₃ composites coated with monolayer SP comb-like copolymer also had the best mechanical properties, including tensile strength, Young’s modulus, flexural modulus, and impact strength because of the good dispersion of CaCO₃ particles in PP matrix. The thermal stability of PP/CaCO₃ composites were measured by thermogravimetric analysis. The results showed that SP comb-like copolymer dispersant treated CaCO₃ filled composites had excellent thermal stability than untreated and neat PP, especially for the composite prepared with monolayer-coated CaCO₃.     

Optimization of mechanical properties of PP/Nanoclay/CaCO3 ternary nanocomposite using response surface methodology

Response surface method of experimental design was applied to optimize the mechanical properties of polypropylene (PP)/nanoclay/CaCO₃ hybrid ternary nanocomposite using three different levels of melt flow index (MFI) of PP, nanoclay, and CaCO₃ contents. The samples were prepared by melt mixing in a lab scale corotating twin screw extruder. The main effect of each parameter on the tensile modulus, tensile strength, and impact strength was extensively discussed. The structure of obtained nanocomposite was studied using X‐ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) techniques. Tensile modulus and impact resistance of prepared ternary nanocomposite were correlated to considered parameters using a second‐order polynomial model. Also, the optimum values of studied variables were determined using contour plots. The obtained results show that increasing the nanoclay and CaCO₃ contents improve the tensile modulus up to 45%, whereas the optimum value of impact strength, about 54%, is achieved at low concentrations of nanoclay (2 wt %) and CaCO₃ (8 wt %). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical properties of modified biofiller‐polypropylene composites

This article reports the mechanical, thermal, and morphological properties of polypropylene (PP)‐chicken eggshell (ES) composites. Mechanical properties like tensile strength, tensile modulus, izod impact strength, flexural modulus of PP composites with normal (unmodified) eggshell and chemically treated ES [modified ES (MES) with isophthalic acid] have been investigated. PP–calcium carbonate (CaCO₃) composites, at the same filler loadings, were also prepared and used as reference. The results showed that PP composites with chemically MES had better mechanical properties compared to the unmodified ES and CaCO₃ composites. An increase of about 3–18% in tensile modulus, 4–44% in izod impact strength and 1.5–26% in flexural modulus at different filler loading was observed in MES composites as compared to unmodified ES composites. Scanning electron microscopy (SEM) micrographs of fractured tensile specimens confirmed better interfacial adhesion of MES with polymer matrix resulting into lower voids and plastic deformation resulting in improved mechanicals of the composites. TEM micrographs showed acicular needle shaped morphology for modified ES and have contributed to better dispersion which is the prime reason for enhancement of all the mechanical properties. At higher filler loading, the modulus of MES composite was found to be higher by 5% as compared to commercial CaCO₃ composites. POLYM. COMPOS., 35:708–714, 2014. © 2013 Society of Plastics Engineers