Synthesis and characterization of poly(butyl acrylate–methyl methacrylate)/polyaniline core–shell latexes

Poly(butyl acrylate–methyl methacrylate) [P(BA–MMA]/polyaniline (PANI) core–shell complex particles were synthesized with a two‐step emulsion polymerization method with P(BA–MMA) as the core and PANI as the shell. The first step was to prepare P(BA–MMA) latex particles as the core via soapless emulsion polymerization. The second step was to prepare P(BA–MMA)/PANI core–shell particles. Sodium dodecyl sulfate was fed into the P(BA–MMA) emulsion as a surfactant, and this was followed by the addition of the aniline monomer. A bilayer structure of the surfactant over the surfaces of the core particles was desired so that the aniline monomer could be attracted near the outer surface of the core particles. In some cases, dodecyl benzene sulfonic acid was added after 2 h when the polymerization of aniline was started. The final product was the desired core–shell particles. The morphology of P(BA–MMA) and P(BA–MMA)/PANI particles was observed with transmission electron microscopy. The thermal properties were studied with thermogravimetric analysis and differential scanning calorimetry. Furthermore, conductive films made from the core–shell latexes were prepared, and the electrical conductivities of the films were studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 823–830, 2007     

Preparation and properties of core–shell nanosilica/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) latex

A core–shell nanosilica (nano‐SiO₂)/fluorinated acrylic copolymer latex, where nano‐SiO₂ served as the core and a copolymer of butyl acrylate, methyl methacrylate, and 2,2,2‐trifluoroethyl methacrylate (TFEMA) served as the shell, was synthesized in this study by seed emulsion polymerization. The compatibility between the core and shell was enhanced by the introduction of vinyl trimethoxysilane on the surface of nano‐SiO₂. The morphology and particle size of the nano‐SiO₂/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) [P(MMA–BA–TFEMA)] core–shell latex were characterized by transmission electron microscopy. The properties and surface energy of films formed by the nano‐SiO₂/P(MMA–BA–TFEMA) latex were analyzed by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, and static contact angle measurement. The analyzed results indicate that the nano‐SiO₂/P(MMA–BA–TFEMA) latex presented uniform spherical core–shell particles about 45 nm in diameter. Favorable characteristics in the latex film and the lowest surface energy were obtained with 30 wt % TFEMA; this was due to the optimal migration of fluorine to the surface during film formation. The mechanical properties of the films were significantly improved by 1.0–1.5 wt % modified nano‐SiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of core–shell nanoparticle‐based hindered amine stabilizer and its application in polyoxymethylene

Core–shell nanoparticles chemically functionalized by hindered amine stabilizer (HAS), poly(BA‐MMA‐co‐PMPA) (PBMP), were prepared by two‐stage emulsion polymerization from butyl acrylate, methyl methacrylate, and 1,2,2,6,6‐pentamethylpiperidin‐4‐yl acrylate. The incorporation of HAS into the particles was confirmed by nuclear magnetic resonance (¹H‐NMR) and the core–shell microstructure of PBMP particles was revealed by transmission electron microscopy. Furthermore, PBMP capable of one‐step toughening and photostabilizing, was melt‐blended with polyoxymethylene (POM), and its dispersion in POM was investigated by scanning electron microscope. The results showed that the core–shell nanoparticles could be well dispersed in POM matrix, indicating its good compatibility with POM. The UV resistance and impact resistance of POM were obviously improved by the HAS‐functional core–shell nanoparticles simultaneously. In addition, the core–shell nanoparticles could confer excellent protection to the surface of POM from UV‐light damage, regardless of the adverse effects on the thermal‐oxidative stability of POM, as investigated by thermogravimetry analysis under aerobic condition. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of poly(butyl acrylate)—laponite nanocomposite nanoparticles for improving the impact strength of poly(lactic acid)

This work aims at preparing and characterizing poly(butyl acrylate) (PBA)—laponite (LRD) nanocomposite nanoparticles and nanocomposite core (PBA‐LRD)‐shell poly(methyl methacrylate) (PMMA) nanoparticles, on the one hand, and the morphology and properties of poly(lactic acid) (PLA)‐based blends containing PBA‐LRD nanocomposite nanoparticles or (PBA‐LRD)/PMMA core–shell nanoparticles as the dispersed phase, on the other hand. The PBA and (PBA‐LRD)/PMMA nanoparticles were synthesized by miniemulsion or emulsion polymerization using LRD platelets modified by 3‐methacryloxypropyltrimethoxysilane (MPTMS). The grafting of MPTMS onto the LRD surfaces was characterized qualitatively using FTIR and quantitatively using thermogravimetric analysis (TGA). The amounts of LRD in the PBA‐LRD nanocomposites were characterized by TGA. The PBA/PMMA core–shell particles were analyzed by ¹H‐NMR. Their morphology was confirmed by SEM and TEM. Mechanical properties of (PBA‐LRD)/PLA blends and (PBA‐LRD)/PMMA/PLA ones were tested and compared with those of the pure PLA, showing that core–shell particles allowed increasing impact strength of the PLA while minimizing loss in Young modulus and tensile strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Morphologies and dynamic mechanical properties of core‐shell emulsifier‐free latexes and their copolymers for P(BA/MMA)/P(MMA/BA) and P(BA/MMA)/PSt systems in the presence of AHPS

Different poly(methyl methacrylate/n‐butyl acrylate)/poly(n‐butyl acrylate/methyl methacrylate) [P(BA/MMA)/P(MMA/BA)] and poly(n‐butyl acrylate/methyl methacrylate)/polystyrene [P(BA/MMA)/PSt] core‐shell structured latexes were prepared by emulsifier‐free emulsion polymerization in the presence of hydrophilic monomer 3‐allyloxy‐2‐hydroxyl‐propanesulfonic salt (AHPS). The particle morphologies of the final latexes and dynamic mechanical properties of the copolymers from final latexes were investigated in detail. With the addition of AHPS, a latex of stable and high‐solid content (60 wt %) was prepared. The diameters of the latex particles are ～0.26 μm for the P(BA/MMA)/P(MMA/BA) system and 0.22–0.24 μm for the P(BA/MMA)/PSt system. All copolymers from the final latexes are two‐phase structure polymers, shown as two glass transition temperatures (T_gs) on dynamic mechanical analysis spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3078–3084, 2002     

Toughening modification of PS with n‐BA/MMA/styrene core–shell structured copolymer from emulsifier‐free emulsion polymerization

Core–shell structured particles, which comprise the rubbery core and glassy layers, were prepared by emulsifier‐free emulsion polymerization of poly(n‐butyl acrylate/methyl methacrylate)/polystyrene [P(n‐BA/MMA)/PS]. The particle diameter was about 0.22 μm, and the rubbery core was uncrosslinked and lightly crosslinked, respectively. The smaller core–shell structured particle–toughened PS blends were investigated in detail. The dynamic mechanical behavior and observation by scanning electron microscopy of the modified blend system with core–shell structured particles indicated good compatibility between PS and the particles, which is the necessary qualification for an effective toughening modifier. Notched‐impact strength and related mechanical properties were measured for further evaluation of the toughening efficiency. The notched‐impact strength of the toughened PS blends with uncrosslinked particles reached almost sixfold higher than that of the untoughened PS when 15 phr of the core–shell structured particles was added. For the crosslinked particles the toughening effect for PS was not obvious. The toughening mechanism for these smaller particles also is discussed in this article. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1290–1297, 2003     

Preparation of polyaniline coated polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) microparticles and the further fabrication of hollow polyaniline microspheres

In this article, the microparticles of polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) (PS‐PSS) coated by polyaniline (PANI) were prepared and hollow PANI microspheres were further obtained by dissolving the core. First, surface‐sulfonated monodispersed PS was prepared by copolymerization of sodium 4‐styrenesulfonate (SSS) and styrene with dispersion polymerization method. Then aniline was polymerized on the surface of the surface‐sulfonated PS (PS‐PSS) by chemical oxidative polymerization. After purification, we prepared core‐shell (PS‐PSS)/PANI particles. Hollow PANI microspheres were prepared by dissolving the plastic PS core of the (PS‐PSS)/PANI particles in chloroform. The growth process of PANI on the surface of PS‐PSS particles was investigated and the hollow PANI microspheres were characterized. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface modification of temperature‐responsive polymer particles by an electrically conducting polyaniline shell layer

In this research an attempt was made to prepare biocompatible electrically conductive composite polymer particles in view of their wide applications in biotechnology. Temperature‐sensitive polymer particles have applications as drug carriers, bioseparators, bioreactor cell activators and diagnostic reagents. So a combination of diverse properties in a single polymer composite is expected to increase its application potential. Here temperature‐responsive poly(N‐isopropyl acrylamide‐methyl methacrylate‐N,N′‐methylene‐bis‐acrylamide) (P(NIPAM‐MMA‐MBAAm)) core particles were prepared by emulsion copolymerization without using any stabilizer. In a second step seeded chemical oxidative polymerization of different amounts of aniline was carried out in the presence of submicron‐sized core particles to obtain P(NIPAM‐MMA‐MBAAm)/polyaniline composite particles. For a comparative study, reference polyaniline particles were prepared by chemical oxidative polymerization. Fourier transform IR spectroscopy, UV?visible spectroscopy, thermal and X‐ray diffraction analyses showed that composite particles prepared with higher aniline content (0.8 g) per unit mass (g) of core particles had high surface coverage compared with lower aniline content (0.1 g). © 2013 Society of Chemical Industry     

Nanocomposite particles with core–shell morphology III: preparation and characterization of nano Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–poly(styrene–methyl methacrylate) particles via miniemulsion polymerization

Encapsulation of inorganic nanoparticles (as a core) by polymers (as a shell) is one of the interesting research subjects that lead to the synthesis of nanocomposite. These materials include properties of not only the organic polymer (e.g. optical properties, toughness, processability, flexibility, etc.) but also the inorganic nanoparticles (e.g. mechanical strength, thermal stability, etc.). Some of the applied preparative methods are dry-spray, dispersion, suspension, emulsion and miniemulsion polymerization techniques. Here, miniemulsion polymerization technique was used in order to obtain white-color nanocomposite latex particles containing nano-alumina (40–47 nm) encapsulated by copoly [styrene (St)–methyl methacrylate (MMA)] under high-shear ultrasonic irradiation. At first, bare nano-alumina was encapsulated with the copolymer to obtain latex particles. In another attempt and in order to investigate the effect of compatiblizing system, alumina nanoparticles were coated with oleic acid in order to form modified alumina core. Then miniemulsion polymerization was performed in the minidroplets including modified alumina, St and MMA for obtaining core/shell nanocomposite particles. The progress of encapsulation polymerization was followed by different instrumental techniques such as FT-IR spectra, thermal gravimetric analysis, dynamic light scattering, induced-coupled plasma, TEM and SEM.     

Synthesis and characteristics of poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles

In this work, the poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles was synthesized by three processes. The first process was to synthesize the poly(methyl methacrylate-co- methacrylic acid) (poly(MMA–MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second process was to polymerize MAA, N-isopropylacrylamide (NIPAAm) and N,N′-Methylenebisacrylamide (MBA) in the presence of poly(MMA–MAA) latex particles to form the linear poly(MMA–MAA)/crosslinking poly(MAA-NIPAAm) core–shell latex particles, and then the core–shell latex particles were heated in the presence of ammonia solution to form the poly(MAA-NIPAAm) thermosensitive hollow latex particles. In the third process, the poly(MAA-NIPAAm) hollow latex particles reacted with ZnO nanoparticles to form the poly(MAA-NIPAAm)/ZnO thermosensitive composite hollow latex particles on which the ZnO nanoparticles were adsorbed. Besides, a novel process was used to synthesize the poly(MAA-NIPAAm)/ZnO composite latex particles in which the ZnO nanoparticles were encapsulated. The effects of various variables on the morphology of poly(MAA-NIPAAm)/ZnO composite hollow latex particle were studied.     

The influence of monomer types on the colloidal stability in the miniemulsion copolymerization involving alkoxysilane monomer

Unlike conventional emulsion polymerization, monomer droplet nucleation becomes dominant in miniemulsion polymerization, offering the miniemulsion polymerization a great advantage over conventional emulsion polymerization when incorporating alkoxysilane monomer, which can easily undergo premature hydrolysis and condensation reactions, into polymer latex. The extensive premature hydrolysis and condensation can lead to the issue of the colloidal instability. In this article, the influence of monomer types on the colloidal stability in the miniemulsion co-(or ter-)polymerization was investigated when incorporating alkoxysilane monomer into styrene or acrylate latex. In the cases of butyl acrylate (BA)/γ-methacryoxypropytrimethoxysilane (MPMS), BA/methyl methyacrlate (MMA)/MPMS, and BA/styrene (St)/MPMS miniemulsion polymerization, nearly no coagulum was observed. The obtained latex had a long shelf life. However, the coagulum was formed in the late stage of MMA/MPMS and St/MPMS miniemulsion copolymerization. The shelf life of the corresponding latex was short. The selection of the main monomer, which can fast consume alkoxysilane comonomer, was critical to obtain the stable latex. In this way, the alkoxysilane groups were completely buried in particles thus the coagulation caused by condensation reactions derived from the alkoxysilane hydrolysis among particles was suppressed.     

Vi‐PDMS incorporated with protein‐based coatings designed for permeability‐enhanced applications

Functional polydimethylsiloxanes containing vinyl groups (Vi‐PDMS) were used for silicone‐based organic polymers in composites and adhesive formulations. Poly(butyl acrylate/methyl methacrylate/vinyl silicone oil)/casein–caprolactam [P(BA‐MMA‐Vi‐PDMS)/CA‐CPL] nanoparticles were prepared via emulsifier‐free polymerization. The well‐defined core–shell structure of P(BA‐MMA‐Vi‐PDMS)/CA‐CPL nanoparticles was verified by transmission electron microscopy. The results of scanning electron microscopy and contact angle measurements proved that the as‐obtained coatings exhibited porous and hydrophobic properties, which were helpful for superior water vapor permeability. By comparing the appearance of the coatings before and after adhesion analysis, the excellent adhesion strength was proved to be dominated by Vi‐PDMS. The relationship between interface morphology and properties of the resultant coatings was investigated in detail. The nucleation mechanism for this soap‐free emulsion synthesis was also proposed accordingly. These results could help in designing coatings with better surface properties and wider application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46501.     

Dulse‐derived porous carbon–polyaniline nanocomposite electrode for high‐performance supercapacitors

Dulse‐derived porous carbon (DDPC)–polyaniline (PANI) nanocomposites were fabricated by a method based on the in situ chemical oxidation polymerization of aniline on DDPC. The characterization of the material showed that the nano‐PANI was grown on the surface of DDPC in the form of nanosticks or nanoparticles. The DDPC–PANI nanocomposites were further used as electrode materials for energy‐storage applications. Meanwhile, the effect of the amount of aniline on the electrochemical performance of DDPC–PANI was also investigated. The results show that a maximum specific capacitance of 458 F/g was achieved for the DDPC–PANI nanocomposites; this was higher than that of the DDPC electrode (218 F/g), and the PANI electrode (318 F/g). The specific capacitance of DDPC–PANI remained 66.0% of the initial value after 5000 cycles; this was higher than that of PANI (50.5%). Finally, a device of DDPC–PANI–activated carbon (AC) was assembled with DDPC–PANI as a positive electrode, which exhibited a high energy density of 9.02 W h/kg, which was higher than that of PANI–AC device. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45776.     

Preparation of monodispersed hollow polymer particles by seeded emulsion polymerization under low emulsifier conditions

In a low emulsifier system, the MMA‐BA‐MAA copolymer emulsions were prepared as seed latices and the seeded emulsion polymerization of MMA‐MAA‐DVB was consequently carried out to prepare carboxylated core particles. The hydrophobic shell was then synthesized onto the core using styrene, acrylonitrile, and divinylbenzene as comonomers. The hollow latex particles were obtained by alkalization treatment of the core‐shell latex particles. The effects of the feeding rate of monomer mixture, contents of emulsifier SDBS and crosslinking agent DVB, and ratio of the monomers during the core stage and shell stage on the morphology and volume expansion of the latex particles were investigated. The results show that the monodispersed hollow latex particles with large size can be obtained when the feeding rate is 0.1 g/min, SDBS content is 0.15 and 0.2 wt % during the core stage and shell stage, respectively, DVB contents are 1% during the preparation of shell copolymers, and the monomer ratio of the core particle to shell layer is 1 : 8. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1505–1510, 2005     

Polyaniline/Ag nanocomposite synthesized by using aniline as dispersant and stabilizer of nanosilver sol

Polyaniline/silver (PANI/Ag) nanocomposite was successfully prepared by in‐situ polymerization from nanosilver sol using aniline (An) as both dispersant and stabilizer and characterized by FT‐IR, XRD SEM, TEM and electrochemical methods, respectively. The results showed that core‐shelled composite particles of less than 100 nm were synthesized with PANI as shell formed around a core of silver nanoparticles at higher aniline levels. Compared to pure PANI, PANI/Ag nanocomposites have higher electrical conductivity (65.98 S/cm) and current response and capacitance as well. Potentio dynamic polarization showed the anodic shifting of zero current potential and a lower exchange current density for the PANI/Ag composite. Compared with PANI, the PANI/Ag nanocomposite is a promising candidate for coatings with improved anti‐corrosion performance. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Core–shell particles to toughen epoxy resins. I. Preparation and characterization of core–shell particles

A two-stage, multistep soapless emulsion polymerization was employed to prepare various sizes of reactive core–shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerizing with various concentrations of glycidyl methacrylate (GMA) as the shell. Ethylene glycol dimethacrylate (EGDMA) was used to crosslink either the core or shell. The number of epoxy groups in a particle of the prepared CSP measured by chemical titration was close to the calculated value based on the assumption that the added GMA participated in the entire polymerization unless it was higher than 29 mol %. Similar results were also found for their solid-state ^13C-NMR spectroscopy. The MMA/GMA copolymerized and EGDMA-crosslinked shell of the CSP had a maximum glass transition temperature (T_g) of 140°C, which was decreased with the content of GMA at a rate of −1°C/mol %. However, the shell without crosslinking had a maximum T_g of 127°C, which decreased at a rate of −0.83°C/mol %. The T_g of the interphasial region between the core and shell was 65°C, which was invariant with the design variables. The T_g of the BA core was −43°C, but it could be increased to −35°C by crosslinking with EGDMA. The T_g values of the core and shell were also invariant with the size of the CSP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2069–2078, 1998     

Synthesis and characterization of poly(butyl acrylate)/silica and poly(butyl acrylate)/silica/poly(methyl methacrylate) composite particles

Poly(butyl acrylate)/poly(methyl methacrylate) (PBA/PMMA) core–shell particles embedded with nanometer‐sized silica particles were prepared by emulsion polymerization of butyl acrylate (BA) in the presence of silica particles preabsorbed with 2,2′‐azobis(2‐amidinopropane)dihydrochloride (AIBA) initiator and subsequent MMA emulsion polymerization in the presence of PBA/silica composite particles. The morphologies of the resulting PBA/silica and PBA/silica/PMMA composite particles were characterized, which showed that AIBA could be absorbed effectively onto silica particles when the pH of the dispersion medium was greater than the isoelectric potential point of silica. The critical amount of AIBA added to have stable dispersion of silica particles increased as the pH of the dispersion medium increased. PBA/silica composite particles prepared by in situ emulsion polymerization using silica preabsorbed with AIBA showed higher silica absorption efficiency than did the PBA/silica composite particles prepared by direct mixing of PBA latex and silica dispersion or by emulsion polymerization in which AIBA was added after the mixing of BA and silica. The PBA/silica composite particles exhibited a raspberrylike morphology, with silica particles “adhered” to the surfaces of the PBA particles, whereas the PBA/silica/PMMA composite latex particles exhibited a sandwich morphology, with silica particles mainly at the interface between the PBA core and the PMMA shell. Subsequently, the PBA/silica/PMMA composite latex obtained had a narrow particle size distribution and good dispersion stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3425–3432, 2006     

Synthesis of a core–shell polyacrylate elastomer containing ultraviolet stabilizer and its application in polyoxymethylene

A core–shell polyacrylate elastomer containing ultraviolet (UV) stabilizer was synthesized via semicontinuous seeded emulsion polymerization from butyl acrylate (BA), methyl methacrylate (MMA), and a polymerizable UV stabilizer 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylproroxy)benzophenone (BPMA). The core–shell poly(MMA‐BA‐BPMA) was investigated by Fourier transform infrared spectroscopy, gel permeation chromatography UV–visible (UV–vis) absorption spectroscopy, and transmission electron microscope. Furthermore, the obtained core–shell poly(MMA‐BA‐BPMA) elastomer was used as a modifier to enhance the UV resistance and impact resistance of polyoxymethylene (POM). As studied by scanning electron microscope, the core–shell poly(BA‐MMA‐BPMA) elastomer could be well dispersed in POM matrix, indicating that the elastomer had good compatibility with POM. In addition, the POM/poly(MMA‐BA‐BPMA) blend was examined by differential scanning calorimetry before and after UV irradiation. The results showed that the melting point decreased as the irradiation time increased; however, the crystallinity culminated at 500‐h UV irradiation slightly decreased and at last leveled off. The mechanical properties of POM/poly(BA‐MMA‐BPMA) before and after UV irradiation were also studied. It revealed that the photostabilizing fragments in the elastomer could provide long‐term UV resistance to POM. Besides, the impact strength was also improved when compared with pure POM. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Preparation and characterization of poly(butyl acrylate‐co‐2‐ethylhexyl acrylate) grafting of vinyl chloride resin with good impact resistance

Crosslinked poly(butyl acrylate‐co‐2‐ethylhexyl acrylate) [P(BA–EHA)] latex was synthesized by seeded emulsion polymerization. P(BA–EHA)/poly(vinyl chloride) (PVC) composite latex was prepared using P(BA–EHA) latex as the seed. The effects of the amount of P(BA–EHA) on the latex particle diameters and mechanical properties of the materials are discussed. The grafting efficiency (GE) of P(BA–EHA)‐grafted vinyl chloride (VC) in the synthesized resin was investigated, and the GE increased with an increasing P(BA–EHA)/VC ratio. The morphology of P(BA–EHA)/PVC was characterized using TEM, SEM, and DMA. TEM indicated that the particles of the P(BA–EHA)/PVC composite latex have a clear core–shell structure. DMA illustrated that the compatibility between P(BA–EHA) and PVC was well improved. With an increasing P(BA–EHA) content, the loss peak in the low‐temperature range became stronger than that of pure PVC, and the maximum values of the loss peaks gradually shifted to higher temperature. SEM showed that the fractured surface of the composite sample exhibited better toughness of the material. The notched impact strength of the material with 4.2 wt % P(BA–EHA) was 11 times that of PVC. TEM showed that P(BA–EHA) was uniformly dispersed in the PVC matrix and that the interface between the two phases was indistinct. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 643–649, 2003     

Enhanced properties of poly(vinylidene fluoride) with low filler content SiO<Subscript>2</Subscript>-g-(MMA-co-BA) core-shell nanoparticles

γ-methacryloxypropyl trimethoxysilane (γ-MPS) modified nano-silica particles (85 nm) were prepared and used to copolymerize with methyl methacrylate (MMA) and butylacrylate (BA) monomers by miniemulsion polymerization method. The obtained SiO₂-g-(MMA-co-BA) nanoparticles with different core/shell ratios were used to improve the properties of poly (vinylidene fluoride) (PVDF). SEM result showed SiO₂-g-(MMA-co-BA) nanoparticles dispersed in PVDF matrix uniformly due to the good miscibility between PVDF and MMA-co-BA shell. The prepared SiO₂-g-(MMA-co-BA) particles behaved a novel toughening ability and even 1 wt% modifier could induce the ductile fracture of PVDF and the PVDF blends showed an excellent toughness and stiffness balance. The toughening mechanism results indicated that debonding between the PVDF and SiO₂-g-(MMA-co-BA) particles promoted shear yielding of PVDF matrix. The novel toughening behavior of PVDF was also related with the crystal transformation. During the notched Izod impact test, the α→β phase transformation took place, which should play an important role in toughening of PVDF.