Styrene-butyl Acrylate Research Articles

Self film‐forming and opaque hollow latexes fabricated via seeded emulsion polymerization followed by alkali post‐treatment

ABSTRACTIn order to obtain novel hollow latexes with both opaque and self film‐forming properties, the four‐layer core/shell latex particles—sequentially consisting of a high carboxyl‐containing soft core, a transition layer, a rigid supporting layer, and an outermost film‐forming layer—are first designed and prepared by emulsion polymerization, and then treated with alkali to fabricate self film‐forming hollow latexes. On the basis of the previous research on the three‐layer core/shell latex, influences of the composition and thickness of the film‐forming layer on the properties and morphologies of the four‐layer core/shell and the final hollow latexes are investigated. Results show that under optimized conditions with butyl acrylate/styrene (BA/St) mass ratio of 2/1, divinyl benzene (DVB) content of 1 wt %, and core/film‐forming layer mass ratio of 1/6 in the film‐forming layer preparation, the final hollow latex particles exhibit best morphology considering both light scattering efficiency and film‐forming capability at room temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42541.

Allylcyclohexylamine functionalized siloxane polymer and its phase separated blend as pervaporation membranes for 1,3-propanediol enrichment from binary aqueous mixtures

This work reports the synthesis of a novel allylcyclohexylamine functionalized siloxane and its phase separated blend with styrene-butyl acrylate copolymer and their application for pervaporative enrichment of 1,3-propanediol from dilute aqueous solutions. The phase separated blend allowed for the recovery of mechanical strength lost due to functionalization without loss in separation performance. Separation factors of 9–15 were achieved with functionalization levels of 50–90%, while 1,3-propanediol flux was 1.5×10−3–1.6×10−3 g/m2-s (5.5–5.8 g/m2-h). Separation efficiency increased with functionalization and decreased with increasing temperature and feed concentration. Solution diffusion model was used to compute the overall mass transfer coefficients, concentration polarization and intrinsic material mass transport properties. The overall mass transfer coefficient for 1,3-propanediol was between 1.0×10−7–1.4×10−7m/s while the boundary layer mass transfer coefficient ranged from 5×10−7m/s to 18×10−7m/s indicating the dominance of the membrane on the transport resistance. A computation of Hansens solubility parameters by a group contribution method was carried out to underscore the results. The membrane, with its good cost/performance tradeoff and excellent mechanical integrity, offers the possibility of fabrication into modules and scale up.

UV-curable electromagnetic shielding composite films produced through waterborne polyurethane-acrylate bonded graphene oxide: preparation and effect of different diluents on the properties

AbstractUV-curable electromagnetic shielding composite films (UV-EMSF) were prepared with graphene oxide/polyurethane-acrylate (GO-PUA) oligomers, different diluents (styrene-butyl acrylate or tripropyleneglycol diacrylate-butyl acrylate or trimethylol propane triacrylate-butyl acrylate) and photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone). The chemical structures, morphology, crystallinity and thermal behavior of UV-EMSF were investigated by Fourier transform-infrared spectroscopy, scanning electron microscope, X-ray diffraction and thermogravimetric analysis. The stability, optical transparency and electrical conductivity of emulsions were measured. The effects of different diluents on the properties such as gel content, solvent resistance, hardness, tensile strength, contact angle and adhesion force were systemically studied. It was found that the emulsions had a good stability and the electrical conductivity of the emulsions indicated that the addition of GO had an effect on the electric conductivity. The prepared UV-EMSF composites with low-cost, low pollution and easy-to-prepare low resistivity have a great potential application in different areas such as electronic, electrical, communications, plastic coatings and wood finishes.

Styrene-butyl acrylate copolymers latexes prepared with different functional monomers and their application as anti-icing coatings

Four polymer latexes, including Base latex synthesized using styrene and butyl acrylate as the main monomers, Latex Si prepared with 4.0 wt% of vinyl triethoxysilane, Latex F with 4.0 wt% of dodecafluoroheptyl methacrylate and Latex D4 with 8.5 wt% of octamethyl cyclotetrasiloxane (D4), were prepared through a semi-continuous emulsion polymerization. Characterization of the latex films revealed that water absorption of the films of Latex D4 and the Base latex were lower than those of Latexes F and Si; whereas their contact angle with water were also smaller than those of the other two latex films. The latexes were applied as coating onto steel and Al metals of different forms to evaluate their performance in corrosion and anti-icing tests. Coated on steel plates for water resistance test, it was found that Latex D4 and Base latex showed poorer performance; whereas the films made from Latex F and Latex Si showed better performance. In anti-icing tests, with the coating applied either on Al circular helix coils followed by refrigeration after water spray, or on Al stranded power line followed by anti-icing test in an IWT (ice wind tunnel), Latex D4 showed the best anti-icing performance, Base latex with the lowest performance, and the other two, Latex F and Latex Si, located in between. The test in IWT was also conducted with the latexes coated on stainless steel rods used in Al stranded power line with reinforced steel core. The anti-icing effectiveness was quite similar to those observed on Al coils or stranded power transmission lines: Latex D4 showed the highest performance and Base latex the lowest, although the differences of the magnitude in their performance were obviously different in different tests.

Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization

Abstract Oxidized starch-graft-poly(styrene-butyl acrylate) [OS-g-P(St-BA)] latex was synthesized by the graft copolymerization of OS with St and n-butyl acrylate (BA) via emulsion polymerization. The graft copolymers were characterized by Fourier transform infrared (FT-IR), transmission electronic microscopy (TEM), dynamic light scattering, thermogravimetry (TG), and differential scanning calorimetry (DSC). The effects of the amount of OS, monomers, and initiator on graft copolymerization were investigated. Under the optimal conditions, the percentage of graft (PG), grafting efficiency (GE), and ζ potential could reach 256.5%, 41.7%, and -30.1 mV, respectively. The results indicated that the OS grafted onto particles greatly enhanced the colloidal stability of latex. The thermal stability properties of OS-g-P(St-BA) were also improved by the addition of OS. The OS-g-P(St-BA) latex may be used to partly replace the conventional synthetic latex for paper coating.

Influence of main ingredients on properties of latex and latex film in polysiloxane modification of styrene-butyl acrylate copolymers

Water borne latexes of styrene (St) and butyl acrylate (BA) copolymer, modified with octamethylcyclotetrasiloxane (D4) were prepared through a semi-continuous emulsion polymerization with dodecylbenzene sulfonic acid (DBSA) as the catalyst for D4 ring-opening and ammonium persulfate (APS) as the initiator for St-BA polymerization. To enhance the compatibility of the silicone with St-BA copolymer by establishing chemical bonds between the two components, 3-(methacryloxy) propyl trimethoxysilane (MPTS) or hydroxyethyl acrylate (HEA) was employed as the coupling agents. The effect of DBSA location at start of emulsion polymerization was studied. It was found that more stable latex was obtained when DBSA was initially added in the reactor in comparison with its addition to the preemulsion followed by slow feeding to the reactor. HEA was also an effective coupling agent to improve the properties of the latex and the latex film. In addition, the influences of the amounts of APS, the catalyst DBSA, and D4 on the latex properties were studied. The process was optimized with regard to the ingredients used in the polymerization. To achieve stable latex with good latex film properties, APS amount should be kept between 0.18 and 0.28 wt.%, D4 monomer no more than 8 wt.% relative to the mass of all vinyl monomers, and the molar ratio of MPTS/D4 is recommended to be 1/4. With HEA as the coupling agent, its amount should be 6.6 wt.% relative to the mass of D4. The mechanical property of the latex film and its water absorption were also characterized.

In Situ synthesis of poly(styrene-butylacrylate-acrylic acid) latex/barium sulfate nanocomposite and evaluation of their film properties

Barium sulfate nanocrystals of average 40 nm sizes were prepared by the micellar solution spray process. The influences of atomized impingement flow on nanoparticle formation and stabilization were inspected on the basis of Fourier transform infrared (FTIR), X-ray diffraction, and transmission electron microscopy analysis. Poly(styrene–butylacrylate–acrylic acid) (PSBA) nanocomposites were synthesized by in situ copolymerization in the presence of 0.5–2.5% BaSO4 nanoparticles. FTIR and atomic force microscopy analysis confirmed the uniform dispersion of 2% or less nano-BaSO4 within the PSBA matrix. The strength of interfacial adhesion between the nanoparticle and copolymer was examined on the basis of hydroscopicity, differential scanning calorimetry, thermogravimetric analysis, and universal testing machine analysis of nanocomposite film. The glass transition and thermal decomposition temperatures of PSBA latex were shifted toward higher temperatures by the restriction of nano-BaSO4 on its segmental and long-range chain mobility. The well-dispersed nano-BaSO4, with a larger fraction of immobilized copolymer on the pigment surface, improves the scratch and abrasion resistance, decreases the water uptake, and increases the tensile strength and elongation at break of the latex film within the specific loading. Thus, fabricating the PSBA/BaSO4 nanocomposite presents an effective approach for development of latex coatings with enhanced performance. POLYM. COMPOS., 34:1670–1681, 2013. © 2013 Society of Plastics Engineers

Preparation of proton exchange membranes by radiation-induced grafting of alpha methyl styrene–butyl acrylate mixture onto polyetheretherketone (PEEK) films

Radiation-induced graft copolymerization of alpha methyl styrene (AMS)–butyl acrylate (BA) mixture onto poly(etheretherketone) (PEEK) was carried out to produce copolymer films which were subsequently sulfonated to develop proton exchange membranes. The characterization of membranes was carried out with infrared spectroscopy (FTIR), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis (XRD), contact angle and electron probe microanalysis (EPMA). The presence of sulfonic acid groups within the polymer matrix was confirmed by FTIR. The crystallinity of membranes decreased significantly upon sulfonation process. The melting temperature of the membranes also decreased as compared to the virgin and the grafted films. At the same time, glass transition temperature (Tg) of membranes increased as the grafting increased. Virgin film showed stable thermogram up to ~500 °C while the grafted film had two-step degradation pattern. Sulfonation introduced one additional decomposition range in the membrane. Contact angle images showed the hydrophilic nature of the membrane surface. The EPMA showed the presence of the sulphur across the membrane matrix in a homogenous manner. The membranes showed low resistivity of 62 Ω cm for the graft level of 27 %.

Preparation and characterization of emulsifier-free polyphenylsilsesquioxane-poly (styrene–butyl acrylate) hybrid particles

The core–shell polyphenylsilsesquioxane-poly (styrene–butyl acrylate) hybrid latex paticles with polyphenylsilsesquioxane as core and poly (styrene–butyl acrylate) as shell were successfully synthesized by seeded emulsion polymerization using polyphenylsisesquioxane (PPSQ) latex particles as seeds. X-ray diffraction (XRD) indicated that the polyphenylsilsesquioxane (PPSQ) had ladder structure, and PPSQ had incorporated into the hybrid latex particles. Transmission electron microscopy (TEM) confirmed that the resultant hybrid latex particles had the core–shell structure. TEM and dynamic light scattering (DLS) analysis indicated that the polyphenylsisesquioxane latex particles and obtained core–shell hybrid latex particles were uniform and possessed narrow size distributions. X-ray photoelectron spectroscopy (XPS) analysis also indicated that the PPSQ core particles were enwrapped by the polymer shell. In addition, compared with pure poly (styrene–butyl acrylate) latex film, the polyphenylsilsesquioxane-poly (styrene–butyl acrylate) hybrid latex film exhibited lower water uptake, higher pencil hardness and better thermal stability.

Thermal properties of a novel nanoencapsulated phase change material for thermal energy storage

A novel nanoencapsulation of a paraffine type phase change material, RT80, in a styrene–butyl acrylate copolymer shell using the miniemulsion polymerization process was carried out. General characteristics of the RT80 nanoparticles in terms of thermal properties, morphology, chemical composition and particle size distribution were characterized by Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Dynamic Light Scattering (DLS). The influence of different monomers (styrene, butyl acrylate) and the surfactant/paraffin mass ratios on nanoparticles properties such as thermal capacity, particle size and morphology were systematically investigated. In all cases studied, encapsulation efficiency was close to 80wt% with a particle size distribution between 52 and 112nm and regular spherical shape and uniform structure. The amount of encapsulated paraffin achieved was comprised between 8 and 20%. Melting and crystallization heats were found to be approximately 5–25Jg−1, mainly depending on surfactant/paraffin mass ratio. Melting temperature of RT80 nanoparticles slightly decreased (1–7°C) respect to the raw RT80. In addition, the encapsulated RT80 nanoparticles show thermal stability even after 200 thermal (heat-cooling) cycles.

유화제 및 단량체비에 따른 스티렌-부틸 아크릴레이트계 폴리머 시멘트 모르타르의 특성

본 연구는 시멘트 혼화용 폴리머를 스티렌과 부틸 아크릴레이트를 단량체로 이용하여 유화제의 첨가량을 달리하여 합성제조하고 제조된 폴리머를 시멘트 모르타르에 혼입하여 그 특성을 파악함으로써 시멘트 혼화용으로써의 사용가능성을 확인하고자 하는 기초적 실험이다. 유화제 첨가량과 단량체비를 달리하여 스티렌-부틸 아크릴레이트(styrene/butyl acrylate)계 폴리머 시멘트 모르타르의 특성은 물-시멘트 비, 공기량, 강도, 방수성 및 염화물 이온 침투저항성을 측정하여 그 특성을 파악하고자 하였다. 연구 결과 보통 시멘트 모르타르에 비해 유화제의 첨가량이 6%일 때, S/BA의 단량체비가 60:40일 때 우수한 강도특성을 나타냈으며, 방수성과 염화물 이온 침투 저항성에서는 유화제의 첨가량과 단량체비보다는 폴리머-시멘트 비에 의해 크게 개선되는 것을 알 수 있었다. 따라서 S/BA를 시멘트 혼화용으로 혼입한 폴리머 시멘트 모르타르의 현장적용이 가능할 것으로 판단되었다. The purpose of this study is to clarify the effect of the emulsifier ratio on the properties of the polymer cement mortars based on styrene-butyl acrylate (S/BA) latexes, and to obtain necessary basic data to develop appropriate latexes for cement modifiers. The polymer dispersions for cement modifiers was synthesized using styrene and butyl acrylate. Polymer cement mortars based on S/BA latexes were prepared with various monomer and emulsifier ratios, and their water-cement ratio, air content, flexural and compressive strengths, water absorption and chloride ion penetration were tested. From the test results, the maximum flexural and compressive strengths of polymer cement mortars based on S/BA latexes were obtained at a bound styrene content of 60% and an emulsifier ratio of 6%. Also, the water absorption and chloride ion penetration depth are greatly affected by the polymer-cement ratio rather than the bound styrene and emulsifier content. Accordingly, it is judged that S/BA latexes can be used place of the conventional polymer dispersions of cement modifier.

Effect of silica nanoparticles surface treatment on in situ polymerization of styrene–butyl acrylate latex

In this study, silica nanoparticles were treated by γ-methacryloxypropyltrimethoxy silane (MPS), via a two-step sol–gel route. The effects of treatment conditions; such as: pH, time, silane and water amounts on the surface modification of silica nanoparticles were evaluated. MPS grafting on the surface of nanoparticles was characterized using FTIR, TGA and TEM techniques. The un-treated and MPS-treated silica nanoparticles were used for in situ preparation of silica/styrene:butyl acrylate latex nanocomposites. The synthesized latex samples were characterized using; FTIR, dynamic light scattering (DLS) and field emission-SEM (FESEM) techniques. Mechanical properties of nanocomposite latex samples were evaluated using DMTA and Taber abrasion test method.The results showed the chemical interactions between MPS and silica nanoparticles. The treatment conditions such as; silane and water contents, reaction time and pH, have significant effect on the MPS grafting of nanoparticles as a result of increase in the rate of silane hydrolysis. FTIR and DLS studies indicated successfully performing of in situ polymerization of silica/acrylate nanocomposites. The latex particles size was affected by inclusion of either un-treated or MPS-treated nanoparticles. The average diameter of latex containing MPS-treated nanoparticles (129nm) was larger than that of neat latex (98nm). The FESEM study revealed a better distribution of the treated nanoparticles compared with their untreated counterparts. Eventually, the results revealed that addition of either un-treated or MPS treated nanoparticles significantly enhanced mechanical properties of acrylate latex samples.

Facile preparation of α-Fe2O3/carbon and polyhydroxy iron cation/polyaniline hollow particles

By virtue of a smartly designed strategy, we successfully prepared the α-Fe2O3/carbon and electromagnetic polyhydroxy iron cation/polyaniline (PIC/PANi) hollow particles. First, poly(styrene-butyl acrylate)/polyhydroxy iron cation (P(S-BA)/PIC) composite particles were prepared based on electrostatic attraction between the P(S-BA) and PIC. Second, the coating of P(S-BA)/PIC composite particles with PANi was achieved by the “Swelling–Diffusion–Interfacial-Polymerization Method”. Finally, α-Fe2O3/carbon and PIC/PANi hollow particles were obtained by calcination or solvent extraction of the P(S-BA)/PIC/PANi composite particles, respectively. The whole preparation process was monitored by transmission electron microscope, scanning electron microscope, Fourier transform infrared, and X-ray diffraction. The synthesized α-Fe2O3/carbon and PIC/PANi hollow particles possessed of a narrow size distribution and well-defined morphology.

Enhancement of Mechanical Properties of Emulsion Copolymers by Gradual Variation in Feed Composition. I: Effect of Particle Size in the Butyl Acrylate-Styrene System

Using a semicontinuous seeded emulsion polymerization process with a gradual variation in feed composition, butyl acrylate (BA)/styrene copolymers were obtained (variable composition copolymers, VCCs). BA seed particles of two different diameters were used to prepare copolymer materials with 50–85 wt.% styrene. In each reaction, cumulative copolymer composition was followed by 1H-NMR; with such data, a histogram showing the relative content of copolymer chains corresponding to each composition interval was built. The VCCs presented higher moduli and ultimate mechanostatical properties than their equivalent core-shell type polymers. The mechanical performance of VCC materials was explained considering the respective histograms.

Modification of polypropylene via the free‐radical grafting ternary monomer in water suspension systems

AbstractMaleic anhydride, styrene, and butyl acrylate were grafted onto polypropylene (PP) via free‐radical polymerization. The grafted product, polypropylene‐g‐(maleic anhydride–styrene–butyl acrylate) (PP‐g‐PMSB), was prepared in a water suspension system, and a nongrafted polymer, poly(maleic anhydride–styrene–butyl acrylate) (PMSB′), was produced at the same time. The optimal synthesis conditions were determined by orthogonal experiments. The crystallinity, thermal stability, melt flow rate, and hydrophilicity of the grafting samples were investigated in the presence or absence of PMSB′. The results indicate that the grafting percentage (Gp) of PP‐g‐PMSB and the content of PMSB′ (Cm) increased as the monomer content increased under the optimum reaction conditions. All of these ternary monomers were grafted onto the PP backbone as long‐chain branches. With increasing Gp, PP‐g‐PMSB's polarity and thermal stability increased, the crystallinity decreased, and the molecular distribution became narrower. The contact angle decreased to 72.12° when Gp was 6.87%. With increasing Cm, the crystallinity and thermal stability of the grafting products decreased compared to PP‐g‐PMSB and the molecular distribution grew wider. The contact angle decreased to 63.51° when Cm was 3.64%; this indicated that the presence of PMSB′ further improved the hydrophilicity of the grafted products. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Preparation and properties of soapless poly(styrene–butyl acrylate–acrylic acid)/SiO2 composite emulsion

Soapless emulsion polymerization of styrene-butyl acrylate-acrylic acid was carried out using single or combined polymerizable emulsifiers, such as hydroxypropyl methacrylate sodium sulfate (HPMAS), sodium vinyl sulfate, and vinyl alkylphenol polyether sulfates (NRS-10), in the presence of colloidal nano-SiO2 solution in order to obtain films with high degree of hardness and water-resistance. Monomer conversion, formation of coagulum, viscosity, particle size, size distribution, and surface tension of the emulsions, as well as the film properties, were determined and compared with those of an emulsion prepared with the conventional emulsifier sodium dodecyl sulfate and polyoxyethylene octylphenol ether. Emulsions prepared from a mixture of two polymerizable emulsifiers NRS-10 and HPMAS (1:1, weight ratio) have presented high monomer conversion, low coagulum, and small particle sizes. When the emulsifier level increased within a certain level, the monomer conversion increased but particles size decreased. Increased amounts of reactive emulsifiers led to low monomer conversion, large amount of coagulum and small particle sizes. With the increase of nano-SiO2 the particle sizes and the viscosity of the emulsion also increased. The introduction of reactive emulsifiers improved the water-resistance of the resulting films, and the addition of nano-SiO2 increased the hardness of the coatings. Under optimal conditions, the coatings made from emulsions produced from a combination of reactive emulsifiers such as NRS-10 and HPMAS (1:1, weight ratio) at 2 % level (based on monomer weight) exhibited remarkable hardness, adhesion force and water-resistance.

Dynamic mechanical study on multilayer core–shell latex for damping applications

Multilayer core–shell poly (styrene-butyl acrylate) latex particles were synthesized via semi-continuous emulsion polymerization, and the process was monitored by a dynamic laser scattering (DLS). The layers of the latex particles were designed to have progressively decreasing glass transition temperatures (Tg) from the core (layer 1) to the outmost shell (layer 4), which was achieved by varying the mass ratio of butyl acrylate (BA) to styrene (St) in the synthesis of each layer. Divinylbenzene (DVB) was added as the crosslinking agent in each layer except for the outmost layer in order to ensure that a continuous film can be formed at room temperature. The damping properties of the formed films as well as the influences of synthesis variables, including the content of DVB added in the internal layers (i.e., layers 1, 2, and 3), the total mass ratio and sequence between layers 3 and 4, and the Tg of each layer were studied by dynamic mechanical analysis (DMA). The results showed that four-layer core–shell latex particles with proper DVB content in each layer exhibited the best damping properties, with a broad effective damping range (tanδ>0.3) ranging from −12.0°C to 97.2°C. The widening of the damping peak can be explained by the formation of a gradient IPN structure in latex particles. Furthermore, the morphology of the formed films was studied by AFM in tapping mode.

Synthesis and characterization of core–shell polysilsesquioxane-poly(styrene-butyl acrylate-fluorinated acrylate) hybrid latex particles

Core–shell polysilsesquioxane-poly(styrene-butyl acrylate-fluorinated acrylate) [PSQ–P(St-BA-FA)] hybrid latex particles were successfully prepared by seeded emulsion polymerization with polymethacryloxypropylsilsesquioxane (PSQ) synthesized by the hydrolysis and polycondensation of (3-methacryloxypropyl)trimethoxysilane (MAPTS) in the presence of emulsifiers as seeds. The chemical composition and core–shell morphology of the resultant hybrid particles were investigated by Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM), respectively. TEM and dynamic light scattering (DLS) analysis indicated that the core–shell hybrid particles were uniform and possessed narrow size distributions. The surface properties of the latex films produced from the core–shell hybrid particles were also investigated by contact angle (CA) analysis and X-ray photoelectron spectroscopy (XPS) analysis. The results proved the enrichment of fluorine on the film surface, and the latex films had high contact angles and low surface free energies. Optical measurements indicated that the incorporation of fluorinated acrylate onto PSQ particles can effectively reduce light reflectivity of the obtained transparent hybrid latex film. Atom force microscopy (AFM) characterization showed that the obtained hybrid latex film had a smooth surface. Additionally, thermogravimetric analysis (TGA) indicated that the PSQ–P(St-BA-FA) hybrid latex film had better thermal stability than the poly(styrene-butyl acrylate) [P(St-BA)] latex film.

Mechanical Spectroscopy, a Tool to Characterize Cement Latex Composites

Fair dispersion of polymer and control of component grain size are key properties to achieve high performances building material (i.e. ultra high strength concrete, self-levelling floor, or exterior insulation composite system). As microstructure analysis in an organic/inorganic hydrated co-matrix material is time consuming, mechanical spectroscopy temperature analysis could characterise both the polymer and the hydrates in the same run. The temperature dependence of the storage modulusG’and the loss modulus G’’ of some composite building material was therefore measured between 173 and 470 K by mechanical spectroscopy (Dynamic Mechanical Analysis). A model material was then defined to enable DMA latex/cement interaction study. The latex was reinforced by either a microfiller (OMYA limestone) or a microfiller and a nanofiller (hydrated Lafarge cement paste CEM I 52.5 R). The latex evaluated in this study was a 210nm styrene butyl acrylate (SBA). The measurements confirmed that polymer environment was not hindered by micro or nanofiller (i.e. cement). The hydrated cement paste transformation onset was measured at 373K, but occurred at higher temperature as latex content increased. ESEM micrographs performed during heating have proven that within the hydrated cement paste many parallel cracks propagated at once, while within SBA hydrated cement paste no cracks were observed. The hydrated cement microstructure was modified by SBA, and became less sensitive to temperature increase due to SBA latex ability to deform.

Preparation of Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride) by emulsifier-free emulsion polymerization and its interaction with DNA

Cationic magnetic polymer particles Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride), a type of potential gene carrier, were prepared by emulsifier-free emulsion polymerization with oleic acid modified magnetite Fe3O4, styrene, butyl acrylate and [2-(methacryloxy)ethyl]trimethylammonium chloride) (METAC). The morphology of the particles was characterized by transmission electron microscopy and the composites of particles were characterized by FT-IR spectroscopy, X-ray diffraction. These results showed that magnetic particles were well dispersed in polymers with the content of about 15%(wt/wt). The composites exhibited superparamagnetism and possessed a certain level of magnetic response. The interactions between the particles with calf-thymus DNA (ct DNA) were confirmed by zeta potential measurement, UV–vis spectroscopy and fluorescence spectroscopy. The DNA-binding capacity determined by the agarose gel electrophoresis showed good binding capacity of the emulsion to DNA. These results suggested the potential of the cationic magnetic polymer emulsion as gene target delivery carrier.