Synthesis of an acrylate elastomer with UV stabilization and its application in polyoxymethylene

In this study, an acrylate elastomer with light‐stable functional groups was synthesized by methyl methacrylate (MMA), butyl acrylate (BA), and a polymerizable UV stabilizer 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylproroxy) benzophenone (BPMA) via emulsion polymerization, and the product was poly[methyl methacrylate‐co‐butyl acrylate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylproroxy) benzophenone] [poly(MMA‐co‐BA‐co‐BPMA)]. The composition and characteristics of poly (MMA‐co‐BA‐co‐BPMA) were determined by using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H‐NMR), and ultraviolet–visible absorption spectroscopy (UV–vis). Further, the obtained poly(MMA‐co‐BA‐co‐BPMA) was blended with polyoxymethylene (POM) to modify its photostabilization, as well as the mechanical properties of POM composite were tested before and after UV irradiation. The result showed that poly(MMA‐co‐BA‐co‐BPMA) can be dispersed well in the POM matrix, which could play a role of improving compatibility with and toughening for POM, and its light‐stable functional groups could increase the UV resistance of POM composite. Mechanical properties of modified POM were kept well with higher impact strength and elongation at break than pure POM after UV irradiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical properties and surface morphology of photodegraded polyoxymethylene modified by a core–shell acrylate elastomer with UV stabilization

In order to improve the photostability of polyoxymethylene (POM), a core‐shell acrylate elastomer with UV stabilization, i.e. poly[(methyl methacrylate)‐(butyl acrylate)‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxypropoxy)benzophenone] (core‐shell poly(MMA‐BA‐BPMA)), was added into the POM matrix using a melt‐mixing method. The effect of the modification with core‐shell poly(MMA‐BA‐BPMA) on POM was compared with that of poly(MMA‐ co ‐BA‐ co ‐BPMA) copolymer. Scanning electron microscopy, metallographic microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X‐ray diffraction and X‐ray photoelectron spectroscopy were employed to characterize POM blends before and after UV irradiation, and the mechanical properties of the POM blends were investigated. The results showed that core‐shell poly(MMA‐BA‐BPMA) improved well the compatibility with and toughness of the POM matrix, and its light‐stable functional groups could increase the UV resistance of POM blends. During UV aging, the impact strength and elongation at break of POM/core‐shell poly(MMA‐BA‐BPMA) blends were retained, the growth rate of surface cracks of POM was inhibited effectively by core‐shell poly(MMA‐BA‐BPMA) and the degree of photo‐oxidation of POM blend surfaces was improved to a certain extent. Compared with poly(MMA‐ co ‐BA‐ co ‐BPMA), core‐shell poly(MMA‐BA‐BPMA) had a better UV stabilization effect on the POM matrix. Our results indicate that the core‐shell acrylate elastomer with toughening and UV stabilization functions can significantly improve the long‐term UV stability of POM. Copyright © 2012 Society of Chemical Industry     

Preparation of titanium dioxide/poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) hybrid composite particles via emulsion polymerization

Titanium dioxide core and polymer shell composite poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) [P(MMA‐BA‐MAA)] particles were prepared by emulsion copolymerization. The stability of dispersions of TiO₂ particles in aqueous solution was investigated. The addition of an ionic surfactant, sodium lauryl sulfate, which can be absorbed strongly at the TiO₂/aqueous interface, increases the stability of the TiO₂ dispersion effectively by increasing the absolute value of the ζ potential of the TiO₂ particles. The adsorption of the nonionic surfactant, Triton X‐100, on the surface of TiO₂ particles is less than that of the ionic surfactant. Fourier transform IR spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering characterized the composite particle size and size distribution. The field‐emission scanning electron microscopy results for the composite particles showed a regular spherical shape, and no bare TiO₂ was detected on the entire surface of the samples. The composite particles that were produced showed good spectral reflectance compared to bare TiO₂. Thermogravimetric analysis results indicated the encapsulated TiO₂ and estimated density of composite particles. There was up to 78.9% encapsulated TiO₂ and the density ranged from 1.76 to 1.94 g/cm³. The estimated density of the composite particles is suitable at 1.73 g/cm³, which is due to density matching with the suspending fluid. The sedimentation experiment indicates that reducing the density mismatch between the composite particles and suspending fluid may enhance the stability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 72–79, 2005     

Synthesis,physical properties,and characterization of starch‐based blend films by adding nano‐sized TiO2/poly(methyl metacrylate‐co‐acrylamide)

The purpose of this study was to improve the physical properties and to expand the application range of starch‐based blend films added nano‐sized TiO₂/poly(methyl methacrylate‐co‐acrylamide) (PMMA‐co‐AM). Starch‐based blend films were prepared by using corn starch, polyvinyl alcohol (PVA), nano‐sized PMMA‐co‐AM, nano‐sized TiO₂/PMMA‐co‐AM particles, and additives, i.e., glycerol (GL) and citric acid (CA). Nano‐sized PMMA‐co‐AM was synthesized by emulsion polymerization and TiO₂ nanoparticles were also prepared by using sol–gel method. Nano‐sized TiO₂/PMMA‐co‐AM particles were synthesized by wet milling for 48 h. The morphology and crystallinity of TiO₂, nano‐sized PMMA‐co‐AM and TiO₂/PMMA‐co‐AM particles were investigated by using the scanning electron microscope (SEM) and X‐ray diffractometer (XRD). In addition, the functional groups of the TiO₂/PMMA‐co‐AM particles were characterized by IR spectrophotometry (FTIR). The physical properties such as tensile strength (TS), elongation at break (%E), degree of swelling (DS), and solubility (S) of starch‐based films were evaluated. It was found that the adding of nano‐sized particles can greatly improve the physical properties of the prepared films. The photocatalytic degradability of starch/PVA/nano‐sized TiO₂/PMMA‐co‐AM composite films was evaluated using methylene blue (MB) and acetaldehyde (ATA) as photodegradation target under UV and visible light. The degree of decomposition (C/C₀) of MB and ATA for the films containing TiO₂ and CA was 0.506 and 0.088 under UV light irradiation and 0.586 (MB) and 0.631 (ATA) under visible light irradiation, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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 titanium dioxide core/polymer shell hybrid composite particles prepared by emulsion polymerization

Titanium dioxide inorganic core and polymer shell composite poly(methyl methacrylate‐co‐butylacrylate‐co‐methacrylic acid) [P(MMA‐co‐BA)‐MAA] particles were prepared by emulsion copolymerization. Fourier transform IR (FTIR) spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering (DLS) characterized the composite particle size and size distribution. The field emission SEM (FE‐SEM) results of the composite particles showed regular spherical shape and no bare TiO₂ was detected on the whole surface of the samples. The composite particles were produced, showing good spectral reflectance compared with bare TiO₂. TGA results indicated the encapsulation efficiency and estimated density of composite particles. Encapsulation efficiency was up to 78.9% and the density ranged from 1.76 to 1.94 g/cm³. Estimated density of the composite particles is suitable to 1.73 g/cm³, due to density matching with suspending media. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2970–2975, 2004     

The effects of acrylate monomers and polystyrene addition on the morphology of DOP‐plasticized styrene–acrylate polymer particles prepared by SPG emulsification and suspension polymerization

Fairly uniform copolymer particles of methyl acrylate (MA), butyl acrylate (BA), or butyl methacrylate (BMA) were synthesized via Shirasu porous glass (SPG) membrane and followed by suspension polymerization. After a single‐step SPG emulsification, the emulsion composed mainly of the monomers. Hydrophobic additives of dioctyl phthalate (DOP), polystyrene molecules, and an oil‐soluble initiator, suspended in an aqueous phase containing poly(vinyl alcohol) (PVA) stabilizer and sodium nitrite inhibitor (NaNO₂), were subsequently subjected to suspension polymerization. Two‐phase copolymers with a soft phase and a hard phase were obtained. The composite particles of poly(St‐co‐MA)/PSt were prepared by varying the St/PSt ratios or the DOP amount. The addition of PSt induced a high viscosity at the dispersion phase. The molecular weight slightly increased with increasing St/PSt concentration. The multiple‐phase separation of the St‐rich phase and PMA domains, observed by transmission electron microscopy, was caused by composition drift because the MA reactivity ratio is greater than that of St. The addition of DOP revealed the greater compatibility between the hard‐St and soft‐MA moieties than that without DOP. The phase morphologies of poly(St‐co‐MA), poly(St‐co‐BMA), and their composites with PSt were revealed under the influence of DOP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1195–1206, 2006     

Solid‐phase photocatalytic degradation of polystyrene with TiO2/Fe(St)3 as catalyst

A novel photodegradable TiO₂‐Fe(St)₃‐polystyrene (TiO₂‐Fe(St)₃‐PS) nanocomposite was prepared by embedding TiO₂ and Fe(St)₃ into the commercial polystyrene. Ferric stearate was added into polymer as cocatalyst in order to improve the dispersion in polystyrene and photocatalytic efficiency of TiO₂ nanoparticles. Solid‐phase photocatalytic degradation of the TiO₂‐Fe(St)₃‐PS nanocomposite was carried out in an ambient air at room temperature under ultraviolet lamp. The properties of TiO₂‐Fe(St)₃‐PS composite film were compared with that of the pure PS film and the TiO₂‐PS composite film, through weight loss monitoring, scanning electron microscope, gel permeation chromatogram, and FTIR spectroscopy. The photodegradation efficiency of TiO₂‐Fe(St)₃‐PS composite film was higher than that of the pure PS film and the TiO₂‐PS composite film under the UV light irradiation. The average molecular weight (M_w) of TiO₂‐Fe(St)₃‐PS composite film decreased 63.08%, and the number of average molecular weight (M_n) decreased 79.49% after UV light irradiation for 480 h. Photo‐oxidation leads to an increase in the low molecular weight fraction by chain scission, thereby facilitating biodegradation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Corrosion Protection of Stainless Steel by Poly(Carbazole-co-pyrrole) Films Deposited on TiO2 Sol–Gel Film

The poly(carbazole-co-pyrrole) copolymer was synthesized on TiO₂ sol–gel precoated 304 stainless steel (TiO₂) by cyclic voltammetry in tetrabutylammonium perchlorate containing acetonitrile solution. The synthesized coating was characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and solid-state conductivity measurements. Corrosion protection behavior of the TiO₂/poly(carbazole-co-pyrrole)-coated steel was evaluated by open circuit potential–time curves, potentiodynamic polarization, and electrochemical impedance spectroscopy methods. Corrosion test results showed that TiO₂/poly(carbazole-co-pyrrole) composite film enhanced corrosion resistance of stainless steel up to 50 days of immersion in 0.1M HCl corrosive medium.     

Solid‐state synthesis and characterization of polyaniline/nano‐TiO2 composite

Polyaniline/nano‐TiO₂ composites with the content of nano‐TiO₂ varying from 6.2 wt % to 24.1 wt % were prepared by using solid‐state synthesis method at room temperature. The structure and morphology of the composites were characterized by the Fourier transform infrared (FTIR) spectra, ultraviolet‐visible (UV–vis) absorption spectra, X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical performances of the composites were investigated by galvanostatic charge–discharge measurement, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results from FTIR and UV–vis spectra showed that the composites displayed higher oxidation and doping degree than pure PANI. The XRD and morphological studies revealed that the inclusion of nano‐TiO₂ particles hampered the crystallization of PANI chains in composites, and the composites exhibited mixed particles from free PANI particles and the nano‐TiO₂ entrapped PANI particles. The galvanostatic charge–discharge measurements indicated that the PANI/nano‐TiO₂ composites had higher specific capacitances than PANI. The composite with 6.2 wt % TiO₂ had the highest specific capacitance among the composites. The further electrochemical tests on the composite electrode with 6.2 wt % TiO₂ showed that the composite displayed an ideal capacitive behavior and good rate ability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,characterization, and antimicrobial activity of silver nanoparticles on poly(GMA‐co‐EGDMA) polymer support

Poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) (poly(GMA‐co‐EGDMA) macroporous copolymer decorated with silver nanoparticles was prepared by a modification of poly(GMA‐co‐EGDMA) in the reaction with arginine, and consequent reduction of silver ions with amino groups. The mercury intrusion porosimetry, transmission electron microscopy, X‐ray diffraction, UV–vis reflection spectroscopy, and inductively coupled plasma atomic emission measurements were used to characterize obtained composite. The coordination of silver nanoparticles to the poly(GMA‐co‐EGDMA) copolymer was studied using infrared spectroscopy. Time dependence and concentration dependence of the antimicrobial efficiency of composite were tested against Gram‐negative bacteria Escherichia coli , Gram‐positive bacteria Staphylococcus aureus , and fungus Candida albicans . The composite ensured maximum reduction of both bacteria, while the fungi reduction reached satisfactory 96.8%. Preliminary antimicrobial efficiency measurements using laboratory flow setup indicated potential applicability of composite for wastewater treatment. POLYM. COMPOS., 38:1206–1214, 2017. © 2015 Society of Plastics Engineers     

Preparation of poly(methyl methacrylate‐co‐maleic anhydride)/SiO2?TiO2 hybrid materials and their thermo‐ and photodegradation behaviors

The optically transparent poly(methyl methacrylate‐co‐maleic anhydride) P(MMA‐co‐MA)/SiO₂? TiO₂ hybrid materials were prepared using 3‐aminopropyl triethoxysilane as a coupling agent for organic and inorganic components. Real‐time FTIR was used to monitor the curing process of hybrid sol, indicating that imide group formation decreased with increasing titania content. scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry results confirmed their homogeneous inorganic/organic network structures. TGA analysis showed that incorporated titania greatly prohibits the thermodegradation of hybrid films, especially at the content of 5.3 wt %, showing an increase of about 32.6°C at 5% loss temperature in air. The UV degradation behavior of P(MMA‐co‐MA) studied by quasi‐real‐time FTIR showed that TiO₂ incorporated in the hybrid network provides a photocatalytic effect rather than a UV‐shielding effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1714–1724, 2005     

Synthesis and properties of poly(acrylonitrile‐co‐p‐trimethylsilylstyrene) and poly(acrylonitrile‐co‐p‐trimethylsilylstyrene‐co‐styrene)

Copolymerization of acrylonitrile (AN) with p‐trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M₁) and TMSS (M₂) were determined to be r₁ = 0.068 and r₂ = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl₄ on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl₄ in solution led to a decrease in MW. Poly(AN‐co‐TMSS‐co‐St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) with commercial poly(AN‐co‐St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X‐ray photoelectron spectroscopy. The data obtained indicate that the silicon‐containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000     

Structure and properties of composite films prepared from cellulose and nanocrystalline titanium dioxide particles

Composite films were successfully prepared from cellulose and two kinds of nanocrystalline TiO₂ particles in a NaOH/urea aqueous solution (7.5 : 11 in wt %) by coagulation with H₂SO₄ solution. The structure, morphology, and properties of the films were characterized by transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, TGA, tensile testing, UV–vis spectroscopy, and antibacterial test. The results indicated that TiO₂ particles in a cellulose matrix maintained the original nanocrystalline structure and properties. TiO₂(I) (anatase) and TiO₂(II) (the mixture of anatase and rutile) particles exhibited a certain miscibility with cellulose. The tensile strength of two kinds of composite films was higher than 70 and 75 MPa, when the content of TiO₂(I) and TiO₂(II) was 4 and 11 wt %, respectively. The cellulose composite films containing nanocrystalline TiO₂ particles displayed distinct antibacterial abilities and excellent UV absorption. This work provides a potential way for preparing functional composite materials from cellulose and inorganic nanoparticles in a NaOH/urea aqueous solution, without a destruction of the structure and properties of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3600–3608, 2006     

Preparation and characterization of titanium dioxide core and polymer shell hybrid composite particles prepared by two-step dispersion polymerization

Titanium dioxide core and polymer shell composite poly (styrene-co-divinylbenzene)-methacrylic acid [P (St-co-DVB)-MAA]] particles were prepared by two-step dispersion polymerization. Fourier transform IR spectroscopy and elemental analysis were used to measure the content of methacrylic acid in composites particles. X-ray measurement photoelectron spectroscopy (XPS) measurements indicated the presence of an MAA unit on the surface of the composite particles. The combined results of the elemental analysis and the XPS measurements showed that the copolymer on the surface of poly (St-co-DVB)-MAA composite particles was rich in MAA compared with that in the interior of the composite particles. Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology characterization. The composite particles produced showing good spectral reflectance compare with bare TiO₂. TGA results indicated that the encapsulation efficiency and estimated density of composite particles. Encapsulation of TiO₂ was up to 87.4% and the density was ranged from 1.78 to 2.06 g/cm³. Estimated density of the composite particles is suitable to 1.73 g/cm³, due to density matching with suspending fluid.     

Development of mesoporous titanium dioxide hybrid poly(vinylidene fluoride) ultrafiltration membranes with photocatalytic properties

A photocatalytic activity ultrafiltration membrane (UFM) was prepared by the blending of a poly(vinylidene fluoride) (PVDF) polymer with mesoporous titanium dioxide (M‐TiO₂) particles via the phase‐inversion method. The microstructure of the membrane and Ti element distribution were characterized by scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. Their properties were also determined by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, tensile stress tests, contact angle tests, bovine serum albumin retention, water flux, and permeation flux. When the M‐TiO₂ concentration reached 1 wt %, the thermal stability, mechanical properties, hydrophilicity, flux, and antifouling performance of the M‐TiO₂/PVDF UFM were improved to an optimal value with the M‐TiO₂ particles successfully entrapped and evenly distributed throughout the PVDF polymer matrix. Compared with the P25‐modified PVDF UFM (1 wt %), the M‐TiO₂‐modified PVDF UFM (1 wt %) exhibited better photocatalytic activity and wonderful stability in the UV photocatalytic degradation of the organic dye Rhodamine B. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43427.     

Resins containing amino and carboxylic acid groups. Synthesis,characterization, and metal ion retention properties

The crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide], P(MAPDSA), and poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐acrylic acid], P(MAPDSA‐co‐AA), were synthesized by radical polymerization. The resins were completely insoluble in water. Due to the lower metal ion retention of P(MAPDSA), the metal ions investigated under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) ions by batch and column equilibrium procedures were carried out only for P(MAPDA‐co‐AA), particularly for Hg(II). The resin–Hg(II) ion equilibrium was achieved before 15 min. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.89 meq/g. The resin showed a high selectivity to Hg(II) ions. The recovery of the resin was investigated at 25°C with different concentrations of HNO₃ and HClO₄. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 525–530, 2005     

High PVC film‐forming composite latex particles via miniemulsification,part 1: Preparation

Miniemulsification technology was used to encapsulate TiO₂ particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO₂ particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO₂ particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO₂ loading increased from 11 to 43% PVC, the particle size of the TiO₂ dispersion decreased while the polymer‐encapsulated TiO₂ particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO₂ particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO₂ and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the T_g. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006     

Morphologies of polybutylacrylate/poly(styrene‐co‐methyl methacrylate) latex prepared by starved emulsion polymerization Part I. Thermodynamics equilibrium morphology

Heterogeneous latexes were prepared by a semicontinuous seeded emulsion polymerization process under monomer starved conditions at 80 °C using potassium persulfate as the initiator and sodium dodecyl sulfate as the emulsifier. Poly(butyl acrylate) latexes were used as seeds. The second‐stage polymer was poly(styrene‐co‐methyl methacrylate). By varying the amounts of methyl methacrylate (MMA) in the second‐stage copolymer, the polarity of the copolymer phase could be controlled. Phase separation towards the thermodynamic equilibrium morphology was accelerated either by ageing the composite latex at 80 °C or by adding a chain‐transfer agent during polymerization. The morphologies of the latex particles were examined by transmission electron microscopy (TEM). The morphology distributions of latex particles were described by a statistical method. It was found that the latex particles displayed different equilibrium morphologies depending on the composition of the second‐stage copolymers. This series of equilibrium morphologies of [poly(butyl acrylate)/poly(styrene‐co‐methyl methacrylate)] (PBA/P(St‐co‐MMA)) system provides experimental verification for quantitative simulation. Under limiting conditions, the equilibrium morphologies of PBA/P(St‐co‐MMA) were predicted according to the minimum surface free energy change principle. The particle morphology observed by TEM was in good agreement with the predictions of the thermodynamic model. Therefore, the morphology theory for homopolymer/homopolymer composite systems was extended to homopolymer/copolymer systems. © 2002 Society of Chemical Industry     

Self‐assembled poly(styrene‐co‐N‐isopropylacrylamide) film induced by capillary force

The monodisperse poly(styrene‐co‐N‐isopropylacrylamide) (poly(St‐co‐NIPAAm)) particles prepared by emulsifier‐free emulsion polymerization with microwave irradiation were induced by capillary forces to self‐assemble, and formed the two‐dimensional films on the clean glassware wafer substrates. The morphologies of the two‐dimensional films were characterized by scanning electron microscopy (SEM) and atom force microscopy (AFM). The results showed that monodisperse poly(St‐co‐NIPAAm) particles could form ordered two‐dimensional films by capillary forces. With NIPAAm concentration increasing, there gradually appeared surface undulations or surface defective region on the two‐dimensional films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3514–3519, 2006