The effects of polymer‐nanofiller interactions on the dynamical mechanical properties of PMMA/CaCO3 composites prepared by microemulsion template

We prepared novel poly(methyl methacrylate) (PMMA)/CaCO₃ nanocomposites by using reverse micelle as a template. The nanoparticles of CaCO₃ were prepared by the reverse microemulsion with functional monomer, methyl methacrylate (MMA) as oily phase, and the PMMA/CaCO₃ nanocomposite was obtained via polymerization of MMA monomer. The SEM image showed that the nanoparticles of CaCO₃ were dispersed in the polymer matrix. Dynamic mechanical analysis (DMTA) was performed to investigate the interaction between the nanoparticles and the polymer chains. In the low‐temperature ripening process, two tan δ peaks were observed in the nanocomposite, corresponding to the glass transitions of the matrix and the interface layer. In the high‐temperature ripening process, only one tan δ peak was observed, suggesting that the interface layer forms a continuous phase. The nanoparticles behave as a physical crosslinker in the interface layer. Modification of the surface of nanoparticles with polyacrylamide and poly(N,N′‐methylenedisacrylamide) in the nanocomposite did not show an appreciable effect on the interaction of nanoparticles with the matrix. Upon removal of the aqueous phase around the nanoparticles, we obtained surface‐capped nanoparticles by using an improved reverse microemulsion technique. Another PMMA/CaCO₃ nanocomposite was also obtained with these modified nanoparticles. DMTA analysis of this nanocomposite demonstrated that the aqueous phase layer around the nanoparticles does not significantly affect the interaction between the nanoparticles and the polymer chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2739–2749, 2004     

Synthesis of CaCO3–P(MMA–BA) nanocomposite and its application in water based alkyd emulsion coating

As part of broader effort to synthesize a new class of water-based composite, hybrid emulsion polymerization was carried out with acrylic monomers [methyl methacrylate (MMA), n-butyl acrylate (BA)]. Nanocomposite of P(MMA–BA)/nano CaCO₃ was synthesized by in situ emulsion polymerization. Water-based alkyd coating with various proportions nano CaCO₃, P(MMA–BA) and its nanocomposite was formulated. Extent of polymerization with and without nano CaCO₃ was measured using gravimetric method. Thermal properties of neat polymer, nanocomposite and coating films were evaluated by TGA and DSC, DTA analysis. Uniform dispersion of nano CaCO₃ in polymer matrix was ensured from SEM/TEM images. Incorporation of nanoparticles to hybrid polymer and nanocomposite to alkyd emulsion showed significant enhancement in mechanical and thermal properties. Dual role of nanocomposite in coating; as a partial binder and a filler to improve property profile of neat coating has been reported.     

The influence of the different modifying agents on the synthesis of poly(methylmethacrylate)‐calcium carbonate nanocomposites via soapless emulsion polymerization

The synthesis of poly(methylmethacrylate)‐calcium carbonate nanocomposites via the soapless emulsion polymerization was investigated after the CaCO₃ nanoparticles were modified with different modifying agents. Such three kinds of modifying agents as sodium stearate (SS), oleic acid (OA), and PMMA were used to improve the surface property of CaCO₃ nanoparticles. What was the most important factor to improve the amount of nanoparticles in the composites is one of the general goals. As determined by Field‐emission scanning electron microscopy (FESEM), the nanocomposites size of the diluted polymer emulsion was over 250 nm, while the sample without CaCO₃ had a diameter of about 150 nm. It was worth pointing out that the surface morphology of polymer changed from slick to scraggy, when the nano‐CaCO₃ particles participated in the polymerization process. The increase of the droplet size and the change of the polymer morphology indicated that the CaCO₃ nanoparticles were present in the emulsion droplets. The X‐ray diffraction results of the nanocomposites showed the existence of typical calcite peaks. The results of the TGA, FTIR, and the contact angles indicated that the hydrophobic surface of CaCO₃ nanoparticles was crucial to improve the compatibility between the CaCO₃ and MMA monomer in emulsion system. The results of the TGA, FTIR, and the contact angles indicated that the hydrophobic surface of CaCO₃ nanoparticles was crucial to improve the compatibility between the CaCO₃ and MMA monomer in emulsion system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Synthesis of CaCO3–P(MMA–BA) nanocomposite and its application in water based alkyd emulsion coating

As part of broader effort to synthesize a new class of water-based composite, hybrid emulsion polymerization was carried out with acrylic monomers [methyl methacrylate (MMA), n-butyl acrylate (BA)]. Nanocomposite of P(MMA–BA)/nano CaCO₃ was synthesized by in situ emulsion polymerization. Water-based alkyd coating with various proportions nano CaCO₃, P(MMA–BA) and its nanocomposite was formulated. Extent of polymerization with and without nano CaCO₃ was measured using gravimetric method. Thermal properties of neat polymer, nanocomposite and coating films were evaluated by TGA and DSC, DTA analysis. Uniform dispersion of nano CaCO₃ in polymer matrix was ensured from SEM/TEM images. Incorporation of nanoparticles to hybrid polymer and nanocomposite to alkyd emulsion showed significant enhancement in mechanical and thermal properties. Dual role of nanocomposite in coating; as a partial binder and a filler to improve property profile of neat coating has been reported.     

Rheological and mechanical properties of PVC/CaCO3 nanocomposites prepared by in situ polymerization

Poly(vinyl chloride) (PVC)/calcium carbonate (CaCO₃) nanocomposites were synthesized by in situ polymerization of vinyl chloride (VC) in the presence of CaCO₃ nanoparticles. Their thermal, rheological and mechanical properties were evaluated by dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), capillary rheometry, tensile and impact fracture tests. The results showed that CaCO₃ nanoparticles were uniformly distributed in the PVC matrix during in situ polymerization of VC with 5.0 wt% or less nanoparticles. The glass transition and thermal decomposition temperatures of PVC phase in PVC/CaCO₃ nanocomposites are shifted toward higher temperatures by the restriction of CaCO₃ nanoparticles on the segmental and long-range chain mobility of the PVC phase. The nanocomposites showed shear thinning and power law behaviors. The ‘ball bearing’ effect of the spherical nanoparticles decreased the apparent viscosity of the PVC/CaCO₃ nanocomposite melts, and the viscosity sensitivity on shear rate of the PVC/CaCO₃ nanocomposite is higher than that of pristine PVC. Moreover, CaCO₃ nanoparticles stiffen and toughen PVC simultaneously, and optimal properties were achieved at 5 wt% of CaCO₃ nanoparticles in Young's modulus, tensile yield strength, elongation at break and Charpy notched impact energy. Detailed examinations of micro-failure micromechanisms of impact and tensile specimens showed that the CaCO₃ nanoparticles acted as stress raisers leading to debonding/voiding and deformation of the matrix material around the nanoparticles. These mechanisms also lead to impact toughening of the nanocomposites.     

Water-Based PMMA-Nano-CaCO3 Nanocomposites by In Situ Polymerization Technique: Synthesis,Characterization and Mechanical Properties

Water-based nanocomposite was synthesized using in-situ polymerization of Methyl Methacrylate. Nano-CaCO₃ was added during polymerization along with aqueous solution of surfactant. Quantity of nano-CaCO₃ was varied as 0, 2 and 4% of monomer quantity. XRD gram shows the presence of nano-CaCO₃, which causes the crystalline nature to nanocomposites. TEM images of nano-CaCO₃ show cubic structure. Synthesis of nanocomposite follows pseudo–first-order kinetics polymerization. PMMA-4% CaCO₃ nanocomposite showed significant improvement in UV absorbance and in mechanical properties like adhesion, scratch resistance as compared to neat PMMA and 2% CaCO₃ nanocomposite.     

Effects of the reinforcement and toughening of acrylate resin/CaCO3 nanoparticles on rigid poly(vinyl chloride)

Novel composite particles based on nanoscale calcium carbonate (nano‐CaCO₃) as the core and polyacrylates as the shell were first synthesized by in situ encapsulating emulsion polymerization in the presence of the fresh slush pulp of calcium carbonate (CaCO₃) nanoparticles. Subsequently, these modified nanoparticles were compounded with rigid poly(vinyl chloride) (RPVC) to prepare RPVC/CaCO₃ nanocomposites. At the same time, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were investigated, and the synergistic effect of modified nanoparticles with chlorinated polyethylene (CPE) was also studied. The results showed that in the presence of nano‐CaCO₃ particles, the in situ emulsion polymerization of acrylates was carried out smoothly, and polyacrylates successfully encapsulated on the surface of nano‐CaCO₃ to prepare the modified nanoparticles, breaking down nano‐CaCO₃ particle agglomerates, improving their dispersion in the matrix, and also increasing the particle–matrix interfacial adhesion. Thus, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were very significant, and the cooperative effect of the nanoparticles with CPE occurred in the united modification system. Scanning electron microscopy analyses indicated that large‐fiber drawing and network morphologies coexisted in the system of joint modification of nanoparticles with CPE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3940–3949, 2007     

Poly(vinyl alcohol)/CaCO3‐diacid nanocomposite: Investigation of physical and wetting properties and application in heavy metal adsorption

Poly(vinyl alcohol) (PVA) nanocomposite and modified CaCO₃ nanoparticles (NPs) were fabricated by ultrasound agitation method with particle content altering from 3, 5, and 8 wt %. The CaCO₃ surface was successfully treated by 10 wt % of bioactive dicarboxylic acid (DA). The influences of loading modified NPs on the thermal, mechanical, adsorption, contact angle, and physical properties of the poly(vinyl alcohol) nanocomposite films were thoroughly studied. The results showed that incorporation of modified CaCO₃ into the PVA matrix had better performance than the pure PVA. Meanwhile, tensile strength, Young's modulus, and thermal stability are enhanced from 33.36 MPa, 1.26 GPs, and 242.918C (neat PVA) to 81.7 MPa, 4.81 GPa, and 312.95 °C (PVA/CaCO₃‐DA NC 5 wt %), respectively. Also, the adsorption capacity of the PVA/CaCO₃‐DA NCs 5 and 8 wt % revealed that the NC films could act as an appropriate absorbent for the removal of Cd(II) ions with maximum adsorption capacity of about 20.70 and 25.19 mg g^?1 for Cd(II), respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45414.     

Effect of Processing Method on Morphological and Rheological Properties of PC/CaCO3 Nanocomposites

The focus of this work is to investigate the effect of different manufacturing methods on nanoparticles dispersion and rheological properties of polycarbonate (PC) filled nano-calcium carbonate (CaCO₃) nanocomposites. Two methods were used to prepare the PC/CaCO₃ nanocomposites through twin-screw extruder: one was compounding PC with CaCO₃ nano-powder, named PC-CP; another was compounding PC with CaCO₃ aqueous suspension, named PC-CAS. The relationship between the processing method and the particle dispersion, matrix molecular weight and rheological properties of the nanocomposite was discussed. Morphological observation showed that nanoparticles were dispersed more homogeneously in PC-CAS. Gel permeation chromatography (GPC) test showed that molecular weight drop of PC-CAS was smaller than PC-CP when CaCO₃ content under 2.2 wt%. Melt flow rate (MFR) and capillary rheological behavior indicated the change of rheological property of PC-CP was larger than PC-CAS while CaCO₃ content under 2.6 wt%. In general, both the dispersion and rheological property of PC-CAS were better than PC-CP under a reasonable CaCO₃ content.     

Improving oxidation stability and mechanical properties of natural rubber vulcanizates filled with calcium carbonate modified by gallic acid

A novel technique to modify the surface of calcium carbonate (CaCO₃) nanoparticles, used as an antioxidant and reinforcing filler, by gallic acid is disclosed. The new properties of the modified CaCO₃ could make it more useful and practical for the rubber industry. Thermal gravimetric (TGA), Fourier transform infrared spectroscopy, and transmission electron microscopy analyses showed that the gallic acid was bound onto the surface of CaCO₃. The gallic acid modified CaCO₃ exhibited a significant antioxidation property, as revealed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) analysis. The mechanical properties of natural rubber vulcanizates filled with the gallic acid modified CaCO₃ showed an enhanced reinforcement with increasing loading levels, and increased resistance to ozonolysis over that seen with the unmodified CaCO₃ mixed with Irganox 1010 as the commercial antioxidant.     

Effect of Nano-CaCO3 on Mechanical and Thermal Properties of Polyamide Nanocomposites

Polyamide-CaCO₃ nanocomposites were prepared by melt intercalation on twin-screw extruder. Various particle sizes (23, 17 and 11 nm) of CaCO₃ were synthesized by in-situ deposition technique. The shape and sizes of nano-CaCO₃ particles were confirmed by transmission electron microscopy (TEM). Nano-CaCO₃ was added from 1 to 4 wt% in the polyamide. Properties such as Tensile strength, Elongation at break, Hardness, and Flame retardency were studied. These results were compared with commercial CaCO₃ filled composites. Nano-CaCO₃ filled in polyamide shows, 3 fold improvement in Young's modulus in comparison to commercial CaCO₃ and 4–7 folds to virgin polyamide. Besides that, a polyamide nanocomposite shows 2 times improvements in flame retarding and vicat softening properties compared to commercial CaCO₃. Moreover, thermal degradation was studied on TGA and found to be improved compared to commercial CaCO₃. This was due to uniform dispersion of nano-CaCO₃ with greater surface area in comparison to commercial CaCO₃ in the polyamide matrix. Extent of dispersion of nano-CaCO₃ was studied along with microcracks generated during tensile testing using scanning electron microscope (SEM).     

Synthesis of new electromagnetic nanocomposite based on modified Fe3O4 nanoparticles with enhanced magnetic,conductive, and catalytic properties

A new method for the fabrication of an electromagnetic nanocomposite based on Fe₃O₄ and polyaniline (PANI) is offered. The authors focused on improvement of the physical and electromagnetic properties of the nanocomposite using a new synthetic method. Supermagnetic Fe₃O₄ nanoparticles were synthesized through coprecipitation method. As a chemical modification, the third generation of poly (amidoamine) dendrimer was grafted on the surface of the nanoparticles. PANI was grafted from –NH₂ functional groups of dendrimer via in situ polymerization of aniline. Finally, Au nanoparticles were loaded on the nanocomposite and its catalytic activity for reduction reactions was studied.     

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.     

A Novel Epoxy Resin/CaCO3 Nanocomposite and its Mechanism of Toughness Improvement

Summary: In this work, epoxy resin/CaCO₃ nanocomposites were prepared by in situ and inclusion polymerization. Nanoparticles with a size of 30–40 nm were dispersed efficiently in bisphenol‐A alkaline solution before polymerization and the dispersion could be kept in the resultant composite by a reaction that took place at the nanoparticle surface and among the nanoparticles when epichlorohydrin was added. Furthermore, the slightly conglomerated nanoparticles could even be separated by epoxy resin growing among them. This method showed a better dispersion of nanoparticles compared with solution‐blending as observed with TEM. Owing to better combination of epoxy resin and nanoparticles, the resultant nanocomposite showed a 12 °C increase in T_g compared to the nanocomposite prepared by solution‐blending. Tensile test revealed that the tensile strain of nanocomposites rises as the nano‐CaCO₃ content increases.

The dispersion mechanism of nanoparticles through in situ and inclusion polymerization.     

Novel Uncured Epoxy Resin/CaCO3 Nanocomposites

In this paper, we synthesized epoxy resin/CaCO₃ nanocomposites through in-situ and inclusion polymerization, and the nanoparticles were well dispersed in the resin matrix observed by SEM. The effects of the nanoparticles on the properties of epoxy resin are discussed.     

Preparation and properties of nanocomposite of poly(phenylene sulfide)/calcium carbonate

Summary A way to prepare Poly (phenylene sulfide) (PPS) nanocomposite was introduced in the paper. The nanocomposite of PPS/CaCO₃ can be prepared by melt mixing process. The dispersion of the CaCO₃ nanoparticles in PPS was good when filler content below 5 wt %. Differential scanning calorimeter (DSC) and small-angle light scattering (SALS) results indicated that the CaCO₃ nanoparticles could induce the nucleation but retard the mobility of polymer chains. The results of mechanical tests showed that a small amount of nanoparticles has resulted in a slight improvement in the tensile strength and a significantly 300% increase in the fracture toughness. We believe that the CaCO₃ nanoparticles can act as stress concentration sites, which can promote cavitation at the particles boundaries during loading. The cavitation can trigger mass plastic deformation of the matrix, leading to much improve fracture toughness.     

Novel conductive magnetic nanocomposite based on poly (indole-co-thiophene) as a hemoglobin diagnostic biosensor: Synthesis,characterization and physical properties

The novel conductive nanocomposite has been successfully prepared by emulsion polymerization. First, magnetite nanoparticles were synthesized via coprecipitation reaction. Then, poly (indole-co-thiophene)@Fe₃O₄ nanocomposite was prepared via emulsion copolymerization of indole and thiophene monomers using sodium dodecyl sulfate as an emulsifier and ammonium persulfate as an oxidant in the presence of Fe₃O₄ nanoparticles. Characterization of the synthesized copolymer, Poly (In-co-T), and its magnetic nanocomposite were studied by Fourier transform infrared spectra, X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetric, UV-vis spectrophotometer, and vibrating sample magnetometer. Also, the electrical conductivity of copolymer and nanocomposite were determined by four-probe instrument. Results showed a synergic effect in thermal stability by good interaction between polymer chain and magnetic nanoparticles. The conductivity of the nanocomposite was higher than bare copolymer, and increase of nanoparticles content caused an increment in the conductivity of the nanocomposites. The applicable properties of proposed conductive nanocomposite as a base at electrochemical biosensing have been investigated.     

Preparation of epoxy resin/CaCO3 nanocomposites and performance of resultant powder coatings

Epoxy resin/CaCO₃ nanocomposites were prepared by the methods of extruding, solution blending, and in situ and inclusion polymerization, respectively. The contents of nanoparticles in the nanocomposites were varied from 5 wt % to 15 wt %. Powder coatings with different content of nanoparticles were made from the nanocomposites. The results showed that the cupping property and impact resistance decreased with the increase of coating film thickness. The dispersion of nanoparticles in epoxy matrix affected the impact resistance and cupping property of the obtained coating films greatly. The coating films made from the nanocomposite prepared by in situ and inclusion polymerization showed that the best impact resistance and the maximum cupping property was achieved when nano‐CaCO₃ content was 5 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2656–2660, 2006     

Double In Situ Approach for the Preparation of Polymer Nanocomposite with Multi-functionality

A novel one-step synthetic route, the double in situ approach, is used to produce both TiO₂ nanoparticles and polymer (PET), and simultaneously forming a nanocomposite with multi-functionality. The method uses the release of water during esterification to hydrolyze titanium (IV) butoxide (Ti(OBu)₄) forming nano-TiO₂ in the polymerization vessel. This new approach is of general significance in the preparation of polymer nanocomposites, and will lead to a new route in the synthesis of multi-functional polymer nanocomposites.