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Abstract: Large deformation response of alumina trihydrate (ATH) filled poly(methyl metacrylate) PMMA over a wide temperature range was investigated. A multi-particle unit cell model of PMMA/ATH composite with different volume fractions was employed to study the influence of interphase properties and interparticle distance. The model constitutes of amorphous polymer matrix, rigid fillers and interphase between filler and matrix. Polymer matrix was modeled using a thermodynamically consistent dual-mechanism viscoplastic model, whereas fillers were assumed as linear elastic. In numerical simulations, the interphase between filler and matrix was modeled through a user defined interphase model and matrix material was modeled through a user defined material model. Damage evolution in PMMA/ATH at large deformations due to particle debonding was studied based on a critical stress criterion. Composite elastic modulus results from finite element analysis of unit cell model were compared with analytical model predictions (Mori–Tanaka, Eshelby, Lielens models) at different temperatures for various volume fractions of fillers. The influence of interphase characteristics, interparticle distance and temperature on large deformation response of PMMA/ATH was examined through multi-particle unit cell model. [Copyright &y& Elsevier]

Abstract: Electronic structures and absorption spectra of mono-branched and di-branched di-anchoring triphenylamine cyanoacrylic dyes were calculated by density functional theory. Our result suggested that one can develop organic dyes focusing on the preferred higher absorptivity or the wider absorption range, based on the symmetric or asymmetric di-branched architectures, respectively. The calculated absorption spectra for mono-branched dyes are in good agreement with the experiment. Different types of aromatic rings in the π-conjugated backbone of mono-branched dyes have varying effect on the absorption wavelength in the order of pyrrole

The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers. [ABSTRACT FROM AUTHOR]

Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA–DVB polymer was up to 248°C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles. [Copyright &y& Elsevier]

Abstract: Films from multi-crosslinked polyurethane with different contents of guar gum (1–10wt%) were prepared through a solution-casting method, followed by a thermal treatment or natural light exposure crosslinking procedure. Acrylic terminated prepolymers were prepared by capping the NCO groups of polyurethane prepolymers with pentaerythritol triacrylate. The effect of the guar gum content on the miscibility, morphology and physical properties of the blend films was investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, surface properties and tensile tests. The results reveal that small guar gum content is well embedded in the crosslinked polyurethane network and forms films with good mechanical properties, thermal behavior and hydrophilic properties. These results prove guar gum to be eco-friendly filler for multi-crosslinked polyurethane network. In the case of polyether urethanes, incorporating up to 3wt% guar gum leads to a slight enhancement of the elongation at break, while for polyester urethanes incorporation up to 3wt% guar gum slight increases stress at break values. Incorporating guar gum into the polyurethane networks leads to an increase in the hydrophilic nature of the polymer blends and improved surface structure. The properties of guar gum – which can be abundantly found in nature – make it desirable for polymer blends for biomedical applications. [Copyright &y& Elsevier]

The effects of the type and content of comonomers on the rheological properties of acrylic copolymers in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) were explored. According to the de Gennes scaling law for solution, comparison of intrinsic viscosity and scaling analysis of the exponent in the specific viscosity- and relaxation time-concentration power law indicated that solution of both polyacrylonitrile (PAN) homo-polymer and copolymer poly(acrylonitrile-co-methyl acrylate) (poly(AN-co-MA)) in [BMIM]Cl behave in the same manner as neutral polymer in a θ-solvent. However, [BMIM]Cl acts as a more good solvent for poly(acrylonitrile-co-acrylamide) (poly(AN-co-AM)). The dissolution and unique rheological behavior of such solutions have been attributed to the interactions between copolymer chains and [BMIM]Cl. The interactions between nitrile group (−C≡N) and 1-butyl-3-methylimidazolium cation ([BMIM]+) should interrupt and break the dipolar-dipolar interactions of PAN resulting in the subsequent dissolution of the polymer in [BMIM]Cl. Such interactions between −C≡N and [BMIM]+ ion are still dominated by the solvating ability of poly(AN-co-MA) in [BMIM]Cl, even though carbonyl group (C=O) in MA repeating unit could coordinate to cation of the ionic liquid. The salvation capacity of [BMIM]Cl for poly(AN-co-AM) can be evidently improved due to the extra hydrogen bond interactions between −NH2 group of AM and anion of [BMIM]Cl. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: β-Galactosidase from Bacillus circulans was immobilized onto Eupergit C, C 250L, and Sepabeads EP, at low (3mg/g of gel), medium (30mg/g of gel) and high applied loads (120mg/g of gel). Comparison of the best conditions for the immobilization process at 25°C showed that Eupergit C and C 250L require milder conditions than Sepabeads EP (e.g. lower ionic strength and pH, shorter incubation time) to achieve immobilized activity yields over 90%. Seeking to increase the thermostability of the derivatives, the effects of two post-immobilization treatments were studied: alkaline incubation to favor the formation of additional covalent linkages, and blocking of excess oxirane groups by reacting with β-mercaptoethanol or glycine. The blocking process improved the thermal stability of all derivatives, with glycine having a greater effect than β-mercaptoethanol. Thermal stability further improved when an alkaline incubation was performed before blocking. The stabilization achieved by this combined strategy was more effective for Eupergit-based than for Sepabeads EP derivatives, and was higher at medium applied load (30mg/g of gel). Thus, stabilized biocatalysts obtained at medium load on Eupergit C and C 250L showed half-lives 10-fold higher than similar Sepabeads derivatives (387, 385 and 37h, respectively). These improved biocatalysts were used batchwise and in continuous processes for lactose hydrolysis in cheese wheys. Similar degrees of lactose hydrolysis were achieved with both Eupergit derivatives, but they varied depending on the substrate, being highest for Mozzarella cheese whey. The degree of lactolysis achieved at 50°C was between 80 and 90% after 2h, and derivatives could be reused batchwise for at least 6 cycles. [Copyright &y& Elsevier]

The aim of the study was to investigate and compare the effect of different joint surface contours and repair materials on transverse strength of repair acrylic resin with or without chemical treatment with ethyl acetate. A total of 60 rectangular heat cure acrylic specimens were fabricated and cut in the centre. The cut specimens were repaired by using heart cure acrylic resin, heart cure acrylic resin with chemical treatment self cure resin, self cure acrylic resin with chemical treatment, self cure acrylic resin with rounded joint surface contour, self cure acrylic with 45 degree bevel joint surface contour. The repaired specimens were tested for transverse strength in an Instron Universal Testing Machine and data thus collected was subjected to statistical analysis. One way ANOVA TEST (p?0.05) was used to determine the differences between the individual groups. The results showed that specimens repaired with heat cure acrylic resin with chemical treatment exhibited the highest transverse strength. Also rounded and 45 degree beveled joint surface enhanced the bond strength of repair material. Thus choice of material and method of repair have significant effect on strength of repaired denture. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the stability and capsular bag opacification with a modified disk-shaped 1-piece hydrophilic acrylic intraocular lens (IOL) suspended between 2 complete haptic rings connected by a pillar of the haptic material and with a commercially available 1-piece hydrophilic acrylic IOL. Setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design: Experimental study. Methods: Study and control IOLs were implanted into the left eyes and right eyes of 5 New Zealand rabbits. Eyes were examined at the slitlamp from 1 through 4 weeks. At 4 weeks, the globes were enucleated and evaluated under a very-high-frequency ultrasound. Photographs were taken and capsular bag opacification scored from the posterior aspect (Miyake-Apple view), and the eyes were processed for complete histopathology. Results: At 4 weeks, the posterior capsule opacification score was 0.0 in the study group and 1.75 ± 0.5 (SD) in the control group (P=.005, paired t test). Ultrasound examination showed that 2 of the study IOLs had no contact between the posterior optic surface and the posterior capsule. Minimal proliferative cortical material was confined to the peripheral space between anterior and posterior rings of the study IOL haptics in localized areas at the equatorial region of the capsular bag. Anterior capsule opacification was absent in all eyes. Conclusions: The study IOL is a modification of a previous design, incorporating haptic perforations between the peripheral rings. By maintaining an open capsular bag and enhancing endocapsular inflow of aqueous, this modified design appears to prevent capsular bag opacification. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to investigate how specificities of thin films prepared from aqueous polymer colloids (latexes) influence their friction properties, tested with a sliding stainless steel spherical tip. Two acrylic latexes containing either 1wt% or 4wt% of acrylic acid (AA) were used at pH 2 or 10. Bulk mechanical properties were also studied in order to improve the interpretation of friction results. Increasing AA concentration and pH increases the overall film rigidity, pH being more effective than AA concentration. Contact pressures are directly correlated to bulk mechanical properties whereas surface shear stresses are also strongly influenced by molecular interactions with the sliding tip. Friction coefficients are rather high, peaking at 5, because of important viscoelastic dissipation in the films as well as strong polar interactions introduced by AA, especially at high pH. The paper also addresses the question of the relevant characteristic length in this kind of friction study. [Copyright &y& Elsevier]

This paper studied the adsorption of cations, anions, nanometric metal-organocomplexes from the individual and binary solutions by acrylic hydrogels. We establish that the efficiency of sorption and strength of retention of metal compounds as cations is higher than of anions. Thus the number of bioelements adsorbed by acrylic hydrogels decreases in the row: Fe3+ > Cu2+ > Mn2+ > MnO4- > (Cu-Humate)- > (Fe-Humate)- > H2PO4-, while their desorption obeys an inverse relationship. Adsorption of bioelements is synchronous with swelling of hydrogels, desorption (in acidic medium at pH 4) -- with their collapse. By efficiency criiteria of bioelements sorption and slow desorption into the environment the hydrogel based on acrylamide-acrylonitrile has optimal parameters and can be used as an active component of the artificial soil or in mixture with a neutral filler (sand). Hydrogel matrix is brought into equilibrium with solutions of bioelements with final treatment by sulphate- and phosphate-containing solutions to form soluble nanocomposites of bioelements in the hydrogel pores which can diffuse into the external solution under the action of organic acids of plant origin. Such system of artificial soil provides accelerated growth and increased plants' productivity. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of new urethane dimethacrylate oligomers based on polytetrahydrofuran (PTHF)/poly(butylene adipate) (PBA): trimethyl-1,6-diisocyanatohexane (TMDI): 2-hydroxyethyl methacrylate (HEMA) (molar ratio 1:2:2) is presented. Organic–inorganic hybrid composites comprising urethane methacrylic macromers and 3-(trimethoxysilyl)propyl methacrylate (MPTS) taken in various gravimetric ratios were prepared by one-pot process through the UV-curing of photopolymerizable mixtures in the presence of 1wt.% Irgacure 819 photoinitiator, followed by the sol–gel reactions (hydrolysis and condensation) at ambient temperature. Additionally, in some formulations prior obtained silver nanoparticles (AgNPs) were incorporated before photopolymerization. Infrared spectroscopy monitored the microstructural evolution of the silica phase as well as the progress of double bond conversion during photopolymerization, while photo-differential scanning calorimetry (photo-DSC) gave us information on polymerization rate and conversion. The photopolymerization results show that the photopolymerization rates of the hybrid formulations are in the range of 0.084–0.158s−1, whereas the conversion degree after 5min of UV irradiation is over 70%. The thermal stability, Young’s modulus and tensile strength of the hybrid films are enhanced with the increase in alkoxysilane content, indicating significant reinforcement of the matrix in the presence of Sih name="sbnd" />Si linkages. The existence and homogeneous dispersion of nanosilver into the polymer matrix has been supported by EDX and TEM analysis, the last allowing a visualization of the formation of silver nanoparticles with size between 2 and 13nm (mean diameter 6.3nm). The four diffraction peaks appeared in the wide angle X-ray scattering spectrum can be assigned to the face-centered cubic silver phase, indicating the formation of metallic silver. The water/ethanol resistance for the hybrid coatings is augmented by the increase of inorganic content. [Copyright &y& Elsevier]

Abstract: Polymethyl-methacrylate (PMMA) is thermosetting plastic and called acrylic glass. PMMA sheet used in the industry to make aircraft and aquariums windows, and flat cut out letters. This research was to investigate tool wear, which was vertical milling of Polymethyl- methacrylate (PMMA). The experiment was done with HSS four flute end-milling cutter. The experiment was applied on two factors were consisted of three levels of cutting speed and feed rate. The tool wear was measured by the nose wear of end milling cutter. The results revealed that main factor affected on tool wear was feed rate. On the other hand, cutting speed was not main affected factor. Higher feed would cause of high tool wear than lower feed rate. High cutting speed that applied with high feed rate can be rapidly increase tool wear. Lower feed is better parameter for tool life of HSS end milling cutter. To keep long tool life, the low feed rate together with high cutting speed was recommended to milling PMMA sheets. [Copyright &y& Elsevier]

Abstract: Electrical conductive pressure-sensitive adhesives (PSAs) are not commercially available on the market. The development of these PSAs requires special suitable self-adhesive polymers and their modification through adding of electrical conductive fillers. From the evaluated PSAs the best performances were achieved using acrylic PSAs. Common fillers for electrical conductivity are carbon nano-fillers, metallic powders like copper, aluminum, nickel, silver or gold. Acrylic PSA containing electrical conductivity fillers are applied for the manufacturing of diverse technical self-adhesive products, such as broadest line of electrically conductive sensitive double-sided, one-sided and carrier-free tapes. After addition of electrical conductive fillers the main typical properties for pressure-sensitive adhesives like tack and peel adhesion are deteriorated. In the last time the research and development on the area of nano carbon black or nanotubes as electrical conductive fillers is observed. [Copyright &y& Elsevier]

Abstract: VHB 4910 is an important polymeric material that has potential use as electro-active polymer in producing actuators. Such polymer, a member of the acrylic polymer group, is a very soft viscoelastic material. In this contribution, a comprehensive mechanical characterization of this important viscoelastic material has been carried out using different standard experiments such as single-step relaxation tests, multi-step relaxation tests and loading–unloading cyclic tests. In modelling the mechanical behaviour, a modified version of the micro-mechanically motivated Bergström–Boyce viscoelastic model has been used along with a finite linear evolution law. The model validation shows its excellent capability to predict the experimental results. [Copyright &y& Elsevier]

The focus of the development of UV-crosslinkable self-adhesive medical products is on one hand directed toward customer-oriented requirements such as tack, adhesion, cohesion, biocompatibility, and permeability for water vapor or air. The customer wants highly tolerable, breathable products, which are also characterized by very good skin and optimal release. On the other hand, the economic targets of medical products manufactures must be considered. Development in the area of UV-crosslinkable acrylic pressure-sensitive adhesives (PSA) for medical application describes the variety of acrylic composition, residue monomers content, quality control of peel adhesion level and repeating during the time, biocompatibility of the acrylic self-adhesive layers and their practical medical application. The new class of unsaturable copolymerizable photoinitiator, such as 4-acryloyloxy benzophenone was used for the synthesis of photoreactive UV-crosslinkable solvent-borne acrylic PSA. The properties of acrylic PSA were determined as well. [ABSTRACT FROM AUTHOR]

In this paper, acryl resin based on ADS process parameters, and its benefit on TFT LCD product is introduced. By analysis of adhesion, exposure energy, developing time, bleach energy and cure parameters, acryl resin optimized process parameters are confirmed. With JSR PC548 positive acryl resin, our ADS product achieves good surface planarization and the product logic power has a nearly 30% decrease. [ABSTRACT FROM AUTHOR]

The influence of different superplasticisers and mixing procedures of latex on the properties of styrene-acrylic ester latex-modified mortars (LMM) was studied. The results indicate that the water-reducing effect of latex in LMM with naphthalene formaldehyde condensate superplasticiser (NF) is 27% higher than that in LMM with polycarboxylic superplasticiser, which demonstrates that more polymer particles are free in pores (not adsorbed by cement grains) and act as ball bearing in LMM with NF. The mixing procedure of latex influences the microstructure and mechanical properties of LMM. LMM added latex and water simultaneously (LMM-S) show higher compressive, flexural and adhesive strength at later stage than LMM added latex later than water (LMM-L). The scanning electronic microscopy observation results also illustrate that more polymer particles are adsorbed by cement grains in LMM-S than in LMM-L. [ABSTRACT FROM AUTHOR]

Wood connections made with high-performance pressure sensitive adhesive (PSA) tapes have significant promise for mitigating damage in buildings under high wind or seismic conditions. Benefits may include improved joint ductility and sealing protection from water-intrusion damage from hurricanes. In this work a series of connection tests were performed primarily on acrylic PSA tapes in accordance with ASTM D 1761-88 (2000). Performance results for PSA tape/wood joints are presented and trends examined for comparisons of commercial PSA tapes from three manufacturers. The results also provided implementation data on required application pressure levels and time duration, and comparisons with adhesive connection types. Specific parameters were discussed and examined using statistical methods to quantitatively determine performance gains or losses. The variables investigated included the use of oriented strand board (OSB) versus plywood sheathing, the effect of priming and surface sanding on adhesion, and a comparison of connections involving mechanical fasteners with those that utilized only adhesive tape or a combination of the two. Properly bonded OSB and plywood connections provided fairly ductile failure modes. The overall results of the study suggest that the International Building Code (IBC) ban on construction adhesives for shear walls in high seismic zones could be lifted for high-performance acrylic PSA tapes. [ABSTRACT FROM AUTHOR]

To investigate the influence of the organosilicon-acrylic on wetting properties of porous media, contact angle tests were performed on two different sandstones. In addition, the effectiveness of the emulsion on wettability alteration of porous media was validated by capillary rise and spontaneous imbibition tests. The results of wettability tests showed that the wettability of two sandstones was altered from water-wet to gas-wet after treatment with the emulsion. The principle that the critical radius of pore throats and wettability of porous media affect liquids flow was derived analytically and verified experimentally. Coreflood results demonstrated that the latex resulted in increasing the water permeability through altering the rock wettability to gas-wetting, then decreasing the friction drag between liquids and rocks surface. Thereby, the emulsion treatment could increase the flowback rate of trapped liquids. Experimental results were in good agreement with the theoretical analysis. In conclusion, all results indicated that the emulsion could alter the wettability from water-wet to intermediate gas-wet and enhance water permeability in porous media. It was extrapolated that the emulsion had the tremendous potential to be applied in field conditions, enhancing gas productivity through the cleanup of trapped water in the vicinity of the wellbore. [ABSTRACT FROM AUTHOR]

Mechanical failure of monodisperse Ni/Au coated acrylic particles has been investigated by individual compression tests using nanoindentation-based technique equipped with a flat diamond punch. We have found that both fracture property and morphology of particles depend on the compression loading rate. The breaking strain of the metal coating decreases with increasing loading rate, while the breaking stress increases. Two obvious fracture patterns with cracking in meridian or latitude direction are identified according to the loading rate, and attributed respectively to tension- or bendingdominated deformation of the coating. The findings reported here give a significant guiding to the manufacture design of metal coated polymer particles for Anisotropic Conductive Adhesive (ACA) packaging. [ABSTRACT FROM AUTHOR]

The distributions of three sodium alkyl sulfate surfactants in dry adhesive films cast from water-based latexes were characterized using confocal Raman microscopy (CRM) and contact angle (CA) and tack measurements. Sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), and sodium octadecyl sulfate (SODS) were added to dialyzed commercial adhesive latex at various concentrations. Uneven distributions were found for all three surfactants along with a tendency to enrich film–air interfaces and, to a much lesser extent, film–glass interfaces. SDS demonstrated the greatest tendency to concentrate near film surfaces followed by STS and SODS. For all three surfactants, water CA values for dried films decreased sharply with increasing concentrations in the latex, but significant differences were observed, with SDS again having the greatest impact followed by STS and SODS. Tack of dried polymer films was also found to decrease with increasing latex surfactant levels, with SDS producing the sharpest drop as well as the lowest plateau values. Results indicate that interfacial enrichment by surfactants is detectable via both CRM and CA measurements, and this enrichment can significantly affect the performance of films. Finally, surface enrichment levels are qualitatively related to measures of the surfactants’ affinity for aqueous solutions, as characterized by the logarithm of their 1-octanol–water distribution coefficients (Kow). [ABSTRACT FROM AUTHOR]

An improvement in the rates of Morita-Baylis-Hillman reactions between isatin derivatives and acrylic esters or acrylonitrile under solvent-free conditions is presented. The reactions proceeded expediently at 0 °C under catalysis by 1,4-diazabicyclo[2,2,2]octane (DABCO) to afford the desired adducts. The optimized conditions are indicative of the presence of the more ordered transition states involved in these reactions, supporting the previously suggested mechanism for similar reactions. [ABSTRACT FROM AUTHOR]

Acrylic bone cements based on PMMA have been used for more than four decades in orthopaedics for the fixation of joint replacements to bone tissue. One of the most widely used ceramics as filling of these cements is hydroxyapatite (HA), which is the main inorganic component of bone tissue. The aim of this work is the preparation and characterization of different formulations of acrylic bone cements modified with micro and nanoparticles of HA. The study was carried out using two types of HA: Porous Coralina® HAP-200 and HA nanoparticles obtained by wet precipitation, both silanized. Several formulations were prepared with different content of HA an immersed in simulated body fluid (SBF) for 30 days. The characterization was conducted by scanning electron microscopy (SEM) coupled to an EDX device. Besides, were evaluated the mechanical properties of compressive strength and traction according to ISO 5833 and ASTM D638 respectively. The modified bone cements with micro and nanoparticles of HA in 30 and 55% present values of compressive and tensile strength higher than those set by the standard. In addition, is observed the formation of apatitic structures in the surface of the cements after 30 days of soaking in SBF. The formulations modified with HA nanoparticles shown higher bioactivity properties in comparison with the modified with Porous Coralina® HAP-200. The aggregation of synthetic HA nanoparticles caused a decrease in the mechanical properties evaluated. [ABSTRACT FROM AUTHOR]

Acyclic and cyclic structures and total energies of radicals HO4⋅ CH3O4⋅ and C2H5O4· were calculated by ab initio quantum chemical methods. Depending on the computational method and basis sets used, the cyclic conformer of the HO4· radical is 4.8 to 7.3 kJ mol-1 more stable than the acyclic one. For the first two representatives of the homologous series of alkyl tetraoxyl radicals, CH3O4· and C2H5O4, MP2/6-311++G** calculations predict insignificant energy differences (1.2 kJ mol-1) between six-membered cyclic and acyclic conformers. Apparently, these radicals can exist in both forms. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigates the effect of accrylated guar gum (GG) with GG in acrylic emulsions. The study The study uses a modified Schotten-Baumann reaction to form the modified and accrylated GG with different degrees of substitution (DS) which were then analyzed. It reveals the lower viscosity of accrylated GGs in emulsions as compared with GG in emulsion due to increase hydrophobic nature.

The article focuses on the use of radical polymerization of multifunctional acrylate monomers to fabricate large nanomembranes. It states that nanomembranes have unique features that are not attainable with other nanomaterials that possess different dimensionality such as nanotubes and nanocrystals. It mentions that only if high cross-linking density is introduced would robust nanomembranes be available, and that it is not possible to use only organic components alone to create a stable nanomembrane.It comments on the use of acrylic components to fabricate frees-standing nanomembranes.

Abstract: To improve the optical properties of acrylic pressure-sensitive adhesives (PSAs) for liquid crystal displays (LCDs), hafnium carboxyethyl acrylate (HCA) was introduced as high refractive index material. Also, UV-curing was used to realize rapid crosslinking so as to enhance the degree of thermal stability. A prism coupler, a UV–visible spectrometer and a thermogravimetric analyzer were employed to assess the optical properties and thermal stability. The results show that the refractive index of the acrylic PSAs with HCA increases suitably compared to that of binder acrylic PSAs in the visible wavelength. Also, a substantial effect is shown on the thermal stability in that hafnium carboxyethyl acrylates are crosslinked due to the presence of tetra-functional acrylic groups caused by the rapid UV-curing. [Copyright &y& Elsevier]

Failure of the bond between denture teeth and base acrylic resin has been shown to be a cause of denture failure leading to inconvenience and costly repair. The optimal combination of acrylic resin denture tooth, denture base material, laboratory protocol and processing method has not yet been established. Extensive research enables the following recommendations for best practice to be made. Adopt practices that maximise the strength of the bond: select appropriate denture teeth; select base acrylic resin from the same manufacturer as the denture teeth; remove the glaze from ridgelaps of the denture teeth; apply monomer to the ridgelaps of the denture teeth before packing the base acrylic resin dough; use the manufacturers' recommended liquid/powder ratio; follow the manufacturers' recommended curing cycle; allow the flask to cool slowly and rest before deflasking. Adopt practices that avoid factors detrimental to bond strength: remove all traces of wax from the ridge laps of the denture teeth; remove all traces of mould seal from the ridgelaps of the denture teeth. It is evident that a number of factors are involved which may assist or prevent formation of an adequate bond, suggesting that attention to detail by the dental technician may be the most critical factor. [ABSTRACT FROM AUTHOR]

In this work, a detailed experimental study on the influence of fluid properties on the droplet behavior subjected to a shear flow and harmonic surface vibration is conducted. The experiments were executed in a rectangular channel and an acrylic channel wall was utilized to analyze the droplet wetting behavior. Both the effect of shearing mechanism induced by airflow and harmonic vibration induced by an electromagnetic shaker for droplet volumes in the range of 5−40 µl are studied here. Furthermore, the effect of fluid viscosities on the motion of droplets is analyzed for a wide range of water and glycerine mixture ratios. Experiments show that the critical bulk velocity at which the droplet movement begins is a function of fluid properties and droplet sizes. Increasing the droplet volume results in a decrease of the critical bulk velocity, while the droplet deformation increases. On the contrary, increasing the glycerine content of the liquid droplets results in an increase in both the critical bulk velocity and droplet deformation. The droplet movement can be categorized into three motion patterns based on experimental observations: (i) the droplet shape is largely retained with a small tail formation at the rear end, (ii) small droplets detach from the tail at rear end of the main droplet, (iii) the droplet deforms over its entire length resulting in forming of a film. [ABSTRACT FROM AUTHOR]

Percutaneous vertebroplasty (PVP) with polymethylmethacrylate (PMMA) is a minimally invasive procedure that provides significant pain relief in a high percentage of patients with osteoporotic fractures. The complication rate of PVP is reported to be below 6%. This case illustrates, for the first time, an arterial PMMA embolus to the aorta and its branches as a complication of PVP. [Copyright &y& Elsevier]

Abstract: Objective: To describe a novel technique for constructing polymethylmethacrylate (acrylic) cranioplasty to repair large cranial defects. Methods: A rim of bone is cut from the edge of the skull defect using a craniotome. This bony rim provides a scaffold to fashion the acrylic cement away from the patient thus avoiding thermal injury to the brain. The inner edge of the bony rim is drilled circumferencially to form a groove. Acrylic is then used to fill the defect in the bony rim with continuous manipulation of the paste from both sides to form a dome in the shape of the skull. The groove allows the edge of the acrylic dome to fit snugly with the bony rim thus avoiding sinking. The final cranioplasty, comprised of the hardened acrylic dome with the surrounding bone rim, is firmly attached to the skull with bioplates. Results: We used the modified acrylic cranioplasty technique in three patients. Modified acrylic cranioplasty is cheaper and immediately available, compared with ten cases of titanium cranioplasty, with similar cosmetic outcome, intraoperative blood loss and operating theatre time. Conclusion: Our technique is quick and easy to perform, avoids thermal injury to the brain and produces a strong implant with excellent cosmesis even with large bony defects. [Copyright &y& Elsevier]

The grafting of the side chain flouroalkyl acrylate monomers onto HDPE gave rise to the remarkable improvements in the ultimate strengths, Modulus and impact strengths of the obtained graft copolymers. • The graft copolymerization of the three different fluoroalkyl acrylates onto HDPE was carried out successfully. • The role of percent grafting and chain lengths of the perfluorinated moieties on the properties of HDPE were investigated. • The remarkable expansions were recorded in unit cell parameters of HDPE crystallized in the orthorhombic symmetry. • Remarkable mechanical improvements were achieved thanks to the semi-fluorinated acrylates having different chain lengths. • The formation of efficient fibrillar structures was observed at the fractured surfaces belonging to the copolymer samples. This comprehensive study paves way to investigate the effects of not only the extent of grafting but also the chain length of the perfluorinated pendant tail presenting in the three different fluoroalkyl acrylate monomers on the significant characteristic properties; namely the thermal behavior, crystal structure quality, mechanical performance and morphological structure of high density polyethylene (HDPE). The individual graft copolymerizations of the monomer onto HDPE were conducted at the content level from 5 % to 30 % via bulk-melt polymerization. The characterizations of copolymers were performed with differential scanning calorimeter (DSC), powder X-ray diffractometer, universal testing machine and scanning electron microscope (SEM) techniques. As for the results deduced from DSC analysis, both the melting temperatures of HDPE and degree of crystallinity were found to increase systematically with the enhancement in the percent grafting level up to 10 % beyond which the parameters were noted to decrease drastically and reach towards globally minimum values. According to the XRD results, as the percentage of grafting enhanced, the remarkable expansions were observed in unit cell parameters of HDPE crystallized in the orthorhombic symmetry. Moreover, the presence of relatively higher amount of -CF 2 groups in the perfluorinated pendant tail caused the formation of three-dimensional lateral repulsions due to its helix structure. Furthermore, there seemed to remarkably improve in the mechanical performance features in case of percent grafting level of 70.6 % where the tensile strength, Modulus and impact strength parameters were measured to be about 42.51 MPa, 539.90 MPa and 41.11 kj/m2, respectively. These reinforcements were found to be explained by the improvement in the regulation, orientations, alignments of HDPE chains. Furthermore, the formation of thick, bulky and long-fibrils were observed at high percent grafting. [ABSTRACT FROM AUTHOR]

This graphical abstract shows the dependence of the ultimate strengths, Young's modulus and impact strength on the percentage of side chain flouroalkyl acrylate polymer content in graft coproducts. • Side chain graft copolymerization of the fluoroalky acrylate onto HDPE was performed with high yield. • Impressive mechanical reinforcement was obtained by using the flouroalkyl acrylate including perfluorinated pendant units. • The grafting onto HDPE caused the linearly increament in the free volumes in consistence with the percent poly(ABCF13). • Significant changes in a and b unit cell parameters as well as particle size of HDPE crystals with grafting were recorded. • The graft copolymerization brought about the significant increments in the melting temperature of HDPE crystalline domains. This study mainly aims to investigate the role of grafted semifluorinated acrylic compound in the crucial characteristic properties of high density polyethylene (HDPE). Graft copolymerization of the semifluorinated acrylic compound, 3,3,4,4,5,5,6,6,7,7,8,8,8-dodecafluoro-5-methyloctyl-4-(acryloyloxy) benzoate (ABCF13) onto HDPE within the different content levels of ABCF13 (5, 10, 15, 20, 30 and 40 %) was performed by bulk-melt polymerization method. The changes in the thermal, microstructural and free volume characteristics of graft coproducts with extent of grafting were investigated in detail by means of DSC, powder X-ray diffraction and PALS techniques, respectively. The experimental findings showed that the melting temperature of crystalline domains and crystallinity ofHDPE reached the maxima at the 15 % and 40 % ABCF13 contents, respectively. The grafting of ABCF13 onto HDPE also gave rise to significant expansion and contraction in lateral dimensions of orthorhombic unit cell parameters in the crystalline domains of HDPE. Moreover, PALS analyses depicted that the size of the free volumes increased almost linearly with the grafting percentage. As for mechanical behaviours of the graft products, remarkable improvements were achieved in especially tensile strength (from 18.75 MPa to 43.75 MPa) and impact strength (from 19.30 Mpa to 38.72 MPa). The morphological properties of the fractured surfaces obtained from tensile and impact tests of products were also examined by SEM analysis. The samples possessed completely homogeneous structure without any phase separation. A gradual transition from ductile behaviour to brittle nature was observed as the grafting level increased in the products. [ABSTRACT FROM AUTHOR]

• Chitosan-based with disulfide groups were employed in reversible thiol immobilization. • Benzothiazole disulfide exchange in functionalization of soft materials was realized. • Selective conjugation and cleavage of thiols demonstrated. In this study, we report on the fabrication of chitosan based hydrogel scaffolds incorporating reactive disulfide functionalities towards the reversible thiol immobilization and release endeavor. Native chitosan chemically modified with polyethylene glycol (PEG) groups was exploited in hydrogel synthesis together with an acryloyl group containing benzothiazole disulfide compound. The chemical crosslinking and incorporation of the reactive disulfide groups into the gel network was maintained by Michael addition of chitosan amino groups onto acrylic benzothiazole compound and bisacryloyl modified polyethylene glycol crosslinker. A series of hydrogels with different amounts of thiol reactive benzothiazole disulfide groups was obtained with moderately high gel conversions. The characterization of the hydrogels was performed by equilibrium swelling, structural morphology and rheology studies. The amount of reactive disulfide groups in the hydrogels were determined using UV–vis spectroscopy. Facile conjugation of a thiol-containing methyl red dye via thiol-disulfide exchange was demonstrated. The on demand cleavage of the attached thiol probe from the scaffold was achieved in the presence of a disulfide reducing agent, namely dithiothreitol (DTT). The efficient and simple fabrication of these hydrogels, as well as benign and reversible immobilization of thiol containing molecules onto the network could make these scaffolds as attractive platforms for biomedical applications such as bioconjugation/bioimmobilization, controlled drug/protein release and tissue engineering. [ABSTRACT FROM AUTHOR]

This study focuses on the characterization of acrylic reactive mixtures designed for liquid composite molding (LCM) and yielding thermoplastic matrices for composite applications. Conversion degree, complex viscosity, and cure exothermicity are tracked during the radical polymerization. Results show that these systems suffer from Trommsdorff's effect, that is, the polymerization is highly exothermic. The rheological study also highlights a limit of injectability for LCM processes around a conversion degree of 10%. The vitrification curve, which correlates conversion degree to glass‐transition temperature, has been established for methyl methacrylate/poly(methyl methacrylate) mixtures. It constitutes a useful tool to identify the thermal conditions required to reach a full monomer conversion and thus, to manage the residual monomer content. The use of such acrylic‐based reactive solutions for fast LCM processing appears appropriate as fully polymerized matrices were obtained in less than 5 min at 90 °C. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47391. [ABSTRACT FROM AUTHOR]