Processability,morphology, thermal,and mechanical properties of rigid PVC composites with liquid macromolecular modifier‐coated CaCO3

Rigid poly(vinyl chloride) (PVC)/CaCO₃ and PVC/liquid macromolecular modifier (LMM) coated CaCO₃ (PVC/LCC) composites were both fabricated by melt mixing. The processability, micro‐structure, dynamic mechanical behavior and mechanical properties of PVC/CaCO₃ and PVC/LCC composites were studied by using torque rheometer, scanning electron microscope (SEM), dynamic mechanical analysis (DMA), and universal mechanical testing machine. The results showed that the synergistic effect of LMM and CaCO₃ particles accelerated the plasticization of PVC resins. The processability of PVC/LCC composites was improved. The dispersion of LCC in PVC matrix was improved by the modification of CaCO₃ particles with LMM. The T_gs of PVC/LCC composites were enhanced by filling with LCC. Because of the synergistic toughening of LMM and CaCO₃ particles, the PVC/LCC composites exhibited excellent notched impact properties at the optimum value of LCC particles content. POLYM. COMPOS., 36:1286–1292, 2015. © 2014 Society of Plastics Engineers     

Effect of particle size and surface modification on mechanical properties of poly(para‐dioxanone)/inorganic particles

Poly(para‐dioxanone) (PPDO)‐based composites have been prepared by blending PPDO with three different types of CaCO₃ particles, CC1 (nano‐CaCO₃), CC2 (CaCO₃ whisker), and CC3 (silane‐coated CaCO₃ whisker). The effects of particles size, interface adhesion, and crystallinity of composites on mechanical properties were discovered through analysis of the morphology of fracture surfaces, thermal characteristics, and crystalline structure. DSC revealed that the CaCO₃ particles acted as a nucleating agent and promoted crystallinity of PPDO. The effect of CaCO₃ particles on crystallization of PPDO was clearly revealed by using the nucleating efficiency. Smaller size particles exhibit greater nucleating efficiency. Adhesion between PPDO and the CaCO₃ particles plays major roles on the mechanical properties of composites. The tensile strength of PPDO was improved over 54%. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Preparation,characterization, and properties of polyethylene composites highly filled with calcium carbonate through co‐rotating conical twin‐screw extrusion

A series of highly filled polyethylene (PE) composites in which the calcium carbonate content was as high as 50–75 wt% was prepared by co‐rotating conical twin‐screw extrusion (Co‐RCE). The effects of Co‐RCE processing and CaCO₃ content on the morphology, structure, and properties were investigated in detail. The results indicated that the Co‐RCE processing improved the filler dispersion and thereby enhanced the melt processability of the blends. Observation by polarized light microscopy and analysis by differential scanning calorimetry and wide‐angle X‐ray diffraction showed that the crystallinity of PE decreased with the increase of CaCO₃ content. In comparison with neat PE, an increase of up to 20^oC in onset weight loss temperature was observed in the CaCO₃‐filled PE composites, as confirmed by thermogravimetric analysis. Tensile tests indicated that the elongation at break of the highly CaCO₃‐filled PE composites was much higher than that of the neat PE. Meanwhile, the highly filled composites still exhibited superior tensile strength. J. VINYL ADDIT. TECHNOL., 20:108–115, 2014. © 2014 Society of Plastics Engineers     

Thermal properties of calcium carbonate powder reinforced vinyl ester composites: Pilot study

The viscoelastic properties of vinyl ester (VE) composites filled with calcium carbonate (CC) (CaCO₃) powder have been evaluated using the dynamic mechanical analysis (DMA) technique. It was found that irrespective of the percentage by weight of CaCO₃ powder, the VE composites postcured in an oven up to 60°C have higher glass transition temperatures (T_g) and storage modulus than their counterparts cured at ambient conditions. However, the loss moduli were lower for composites postcured in an oven than their ambient cured counterparts. It was also found that the crosslinking density of the composites slightly increased with particulate (CaCO₃) loading and composites postcured in an oven have higher crosslinking density than their counterparts cured at ambient conditions. These results confirmed an increase in stiffness for composites with postcuring treatment. Micrographs by SEM were obtained and confirmed a close inter phase adhesion of the CC filler with the VE resin matrix in the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and properties of HDPE/CaCO3/OMMT ternary nanocomposite

A series of binary composites based on HDPE (high density polyethylene) and nanoinorganic particles such as nano‐CaCO₃ and OMMT (organic montmorillonite) were prepared. Their properties including tensile, impact strength, and some thermal properties were tested. The results showed that binary composite has partial improvement in mechanical properties compared with pure HDPE. A ternary composite nano‐CaCO₃/OMMT/HDPE was prepared and characterized. It was found that the mechanical and thermodynamic properties of this ternary composite have been enhanced greatly compared with both pure HDPE and binary composites. The tensile strength, Young's modulus, flexural strength, elastic modulus, and impact strength of nano‐CaCO₃/OMMT/HDPE were increased 124.6%, 302.7%, 73.86%, 58.97%, and 27.25%, respectively. The DMA test results showed that the mechanical properties of ternary composite were increased because of the limitation on the movement of HDPE due to inorganic particles. The synergistic effect introduced by nanoparticles may play an important role in all these processes. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

High density polyethylene/micro calcium carbonate composites: A study of the morphological,thermal, and viscoelastic properties

High density polyethylene (HDPE) with micro calcium carbonate (CaCO₃) masterbatch was pelletized by using a twin screw extruder and different ASTM specimens were molded by an injection molding machine. The morphology of the composites was characterized by scanning electron microscopy (SEM) and Image Analysis software. The dispersion and interfacial interaction between CaCO₃ and the polymer matrix were also investigated by SEM. The thermal properties of HDPE and its composites were investigated by differential scanning calorimetry (DSC). The crystallization process of the composites samples was found to be slightly different than that of the neat HDPE. Otherwise, the presence of CaCO₃ did not have a considerable effect on the melting behavior of the composites. Thermogravimetric analysis (TGA) revealed that the composites had better thermal stability than the neat HDPE resin as indicated by a higher temperature of 50% weight loss (T_50%) for the composites as compared to that of the neat resin. The viscoelastic properties of the composites and HDPE were also investigated via torsional and rotational techniques. The presence of CaCO₃ increased the shear modulus at low frequency of the composites at 80°C over that of the neat resin. However, at higher frequencies, the difference between the neat resin and the composites' shear modulus was less than that at low frequencies. The complex viscosity of the composite increased upon the addition of CaCO₃. However, the shear sensitivities of the neat resin and the microcomposite were similar. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

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     

In situ production of fatty acid ethyl ester from low quality rice bran

Low quality rice bran with high free fatty acid content was utilized to produce fatty acid ethyl ester (FAEE) via in situ method. The effects of extraction solvent, acid and alkaline catalysts on the yield rate, esterification rate and transesterification rate were studied. About 12% (w_FAEE/w_rice-bran) of FAEE was obtained when absolute ethanol was used as solvent to extract rice bran oil. The esterification rate and transesterification rate reached 98% and 83%, respectively. With the aid of petroleum ether, the yield rate of FAEE could be improved to 16% (w_FAEE/w_rice-bran), and the esterification rate and transesterification rate reached 99% and 86%. Hydrophobic CaCO₃ nanorods were also synthesized as value-added byproduct. Based on the proposed method, the production process of FAEE could be simplified and the production cost could be reduced.     

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     

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.     

An investigation on the mechanical and dynamic rheological properties of single and hybrid filler/polypropylene composites based on talc and calcium carbonate

Some results of experiments on the mechanical and rheological properties of mineral filled polypropylene were presented. Single filler and hybrid filler composites of talc and calcium carbonate (CaCO₃) were prepared in a co‐rotating twin‐screw extruder. The effect of filler type, filler content, and coupling agent on the mechanical and rheological properties of the polypropylene were studied. The coupling agent was maleic anhydride‐grafted polypropylene (PP‐g‐MA). It was found that the mechanical properties are affected by filler type, filler concentration, and the interaction between filler and matrix. The tensile strength of the composite is more affected by the talc while the impact strength is influenced mostly by CaCO₃ content. The elongation at break of PP/CaCO₃ composites was higher than that of PP/talc composites. The incorporation of coupling agent into PP/mineral filler composites increased the mechanical properties. Rheological properties indicated that the complex viscosity and storage modulus of talc filled samples were higher than those of calcium carbonate filled samples while the tan δ was lower. The rheological properties of hybrid‐filler filled sample were more affected by the talc than calcium carbonate. The PP‐g‐MA increased the complex viscosity and storage modulus of both single and hybrid composites. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

Toughness of HDPE/CaCO3 microcomposites prepared from masterbatch by melt blend method

In this study, a series of high‐density polyethylene and micro/nanocalcium carbonate polymer composites (HDPE/CaCO₃ nanocomposites) were prepared via melt blend technique using a twin screw extruder. Nanocomposite samples were prepared via injection molding for further testing. The effect of % loading of CaCO₃ on mechanical and fracture toughness of these composites has been investigated in details. The effect of precrack length variation on the fracture toughness of the composite samples was evaluated, and the morphology of the fractured samples was also observed using scanning electron microscopy (SEM). It was found that increasing the % of CaCO₃ and precrack length decreased the fracture toughness. Fracture surface examination by SEM indicated that the diminished fracture properties in the composites were caused by the aglomerization of CaCO₃ particles which acted as stress concentrators. A finite element analysis using ANSYS was also carried out to understand the effect of agglomeration size, interaction between the particles and crack tip length on the fracture properties of these composites. Finally, a schematic presentation of the envisioned fracture processes was proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Mechanical properties of styrene–butadiene–styrene block copolymer composites filled with calcium carbonate treated by liquid polybutadienes

The factors influencing the mechanical properties of styrene–butadiene–styrene block copolymer (SBS) composites filled with liquid polybutadiene (LB)‐surface‐treated calcium carbonate (CaCO₃) were investigated with respect to the molecular structure of the LB, the amount of the LB adsorbed on the CaCO₃ surface, the heat treatment conditions, and the surface treatment method. The mechanical properties, such as the modulus, tensile strength at break, tear strength, storage modulus, and tension set, of the SBS composites were improved remarkably through the filling of CaCO₃ surface‐treated with a carboxylated LB with a high content of 1,2‐double bonds. The heat treatment of LB–CaCO₃ in air was also effective in enhancing such properties. When SBS, CaCO₃, and LB were directly blended (with the integral blend method), secondary aggregation of CaCO₃ took place, and the mechanical properties of the composite were significantly lower. In the integral blend method, LB functioned as a plasticizer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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     

Mechanical properties and morphologies of polypropylene/single‐filler or hybrid‐filler calcium carbonate composites

Three types of polypropylene (PP) with different intrinsic toughness were used to study the mechanical properties and morphologies of the PP composites filled with single‐filler and hybrid‐filler of calcium carbonate particles. The calcium carbonate particles used were with average particle sizes of 25 μm (CC25), and 0.07 μm (CC0.07), respectively. A hybrid‐filler CaCO₃ named CC25/CC0.07 was used as a mixture of CC25 and CC0.07 (CC25/CC0.07 weight ratio = 1:1). It was found that the type of PP and the particle size of inorganic filler were the two important factors for the determination of mechanical properties of the composites. And the general mechanical properties of the composites filled with hybrid‐filler CaCO₃ were better than those of the composites filled with single‐filler CaCO₃, but the synergistic hybridization effect of the hybrid‐filler CaCO₃ did not exist. The major toughening mechanism of the PP/CC25 composites was the cavitation of the matrix caused by CC25, and the major toughening mechanism of the PP/CC0.07 composites was the pinning effect introduced by CC0.07. For the PP/CC25/CC0.07 composites, the cavitation of the matrix caused by CC25 and the pinning effect introduced by CC0.07 existed simultaneously. And when the intrinsic toughness of the matrix was large enough, the major factor to toughen PP was the pinning effect introduced by CC0.07, otherwise the major factor to toughen PP was the cavitation of the matrix caused by CC25. POLYM. ENG. SCI., 47:95–102, 2007. © 2007 Society of Plastics Engineers     

Effect of calcium carbonate whisker content on the morphology,crystallization, and mechanical properties of poly(para‐dioxanone)/Calcium carbonate whisker composites

In this work, poly(para‐dioxanone) (PPDO) was mixed with 0, 1, 5, 10, 20, and 30 weight percent (wt%) calcium carbonate (CaCO₃) whiskers by solution coprecipitation. Samples were compression molded into bars using a platen vulcanizing press. It has assessed the influence of the CaCO₃ whisker content on the morphology, thermal, mechanical, and crystalline properties of the PPDO/CaCO₃ whisker composites, using differential scanning calorimetry (DSC), polarized optical microscopy, scanning electron microscopy, and X‐ray diffraction. DSC showed that the glass transition temperature (T_g) and crystallization temperature (T_c) of the composites increased with increasing CaCO₃ whisker content. At low CaCO₃ whisker content (1 wt%), the degree of crystallinity (Dc) of PPDO increased sharply. The addition of higher content of CaCO₃ whisker would cause more agglomeration in PPDO matrix, so that the mechanical properties of PPDO/CaCO₃ whisker composites would gradually decrease. The mechanical properties of PPDO were changed by the presence of CaCO₃ whiskers; the optimal amount of CaCO₃ whisker was 1 wt%, which sharply improved the tensile strength of PPDO by 54%. POLYM. COMPOS., 37:3442–3448, 2016. © 2015 Society of Plastics Engineers     

Viscosity effect in polyolefin ternary blends and composites

Ternary blends of PP (80) /rubber (EPM, EPDM) (10) / PE (10) and PP (80) / rubber (10) / CaCO₃ (10) composites were prepared in a twin-screw extruder. With polyethylene (PE) viscosity comparable to, or higher than that of rubber, the dispersed phase formed a reticulate structure with reduced size. On the contrary, when the viscosity of PE was significantly lower than that of rubber, the dispersed phase formed almost homogeneous morphology. With reticulate morphology, PE crystallinity content, hardness, modulus, and elongation at break of the ternary blend increased. In polypropylene (PP) / rubber / CaCO₃ composites, better dispersion of CaCO₃ in the PP matrix was obtained when the viscosity of rubber was significantly higher than that of matrix. With better dispersion, hardness and tensile properties were improved, but the impact strength more or less decreased. © 1993 John Wiley & Sons, Inc.     

Mechanical and thermal properties of talc and calcium carbonate filled polypropylene hybrid composites

The main aim of this work was to study and compare the mechanical and thermal properties of hybrid polypropylene (PP) composites and single‐filler PP composites. With two main types of mineral fillers—calcium carbonate (CaCO₃) and talc—PP composites of different filler weight ratios (talc/CaCO₃) were compounded with a twin‐screw extruder and then injection‐molded into dumbbell specimens with an injection‐molding machine. Tensile, flexural, and impact tests were performed to determine and compare the mechanical properties of the hybrid and single‐filler PP composites. A synergistic hybridization effect was successfully achieved; the flexural strength and impact strength were highest among the hybrids when the PP/talc/CaCO₃ weight ratio was 70:15:15. The nucleating ability of the fillers and its effects on the mechanical properties were also studied with differential scanning calorimetry. Because of the influence of talc as the main nucleating agent, the hybrid fillers showed significant improvements in terms of the nucleating ability, and this contributed to the increase in or retention of the mechanical properties of the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3327–3336, 2004