Methacrylate Ester Monomers.

The Expert Panel for Cosmetic Ingredient Safety reviewed newly available studies since their original assessment in 2005, along with updated information regarding product types and concentrations of use, and confirmed that these 22 methacrylate ester monomers are safe as used in nail enhancement products in the practices of use and concentration as described in this report, when skin contact is avoided.

Injectable On-Demand Pulsatile Drug Delivery Hydrogels Using Alternating Magnetic Field-Triggered Polymer Glass Transitions.

Remote-controlled pulsatile or staged release has significant potential in a wide range of therapeutic treatments. However, most current approaches are hindered by the low resolution between the on- and off-states of drug release and the need for surgical implantation of larger controlled-release devices. Herein, we describe a method that addresses these limitations by combining injectable hydrogels, superparamagnetic iron oxide nanoparticles (SPIONs) that heat when exposed to an alternating magnetic field (AMF), and polymeric nanoparticles with a glass transition temperature (Tg) just above physiological temperature. Miniemulsion polymerization was used to fabricate poly(methyl methacrylate-co-butyl methacrylate) (p(MMA-co-BMA)) nanoparticles loaded with a model hydrophobic drug and tuned to have a Tg value just above physiological temperature (∼43 °C). Co-encapsulation of these drug-loaded nanoparticles with SPIONs inside a carbohydrate-based injectable hydrogel matrix (formed by rapid hydrazone cross-linking chemistry) enables injection and immobilization of the nanoparticles at the target site. Temperature cycling facilitated a 2.5:1 to 6:1 on/off rhodamine release ratio when the nanocomposites were switched between 37 and 45 °C; release was similarly enhanced by exposing the nanocomposite hydrogel to an AMF to drive heating, with enhanced release upon pulsing observed even 1 week after injection. Coupled with the apparent cytocompatibility of all of the nanocomposite components, these injectable nanocomposite hydrogels are promising as minimally invasive but remotely actuated release delivery vehicles capable of complex release kinetics with high on-off resolution.

Facile Photoresponsive Actuators Based on Ferrocene-Doped Poly(butyl methacrylate).

This paper presents facile photoresponsive actuators comprising ferrocene as a guest chromophore and poly(butyl methacrylate) (PBMA) as a host matrix. The ferrocene-doped PBMA film exhibits mechanical expansion and contraction when a 445 nm laser is turned on and off, respectively. The photoresponsive film is attached by a commercially available acetylcellulose adhesive tape, which exhibits a bending motion that is controlled by turning the laser on and off. Thereafter, the double-layer film is employed to fabricate a table-shaped lifting machine (0.7 mg) that lifts a 10.5 mg object up and down by turning the laser on and off, respectively, and the mechanical force offered by the double-layer film is recorded. Additionally, the film is coated with gold and applied to an electric circuit that serves as a reversible photoresponsive switch. This film preparation technique is applied to other chromophores (e.g., Coumarin 343, Rhodamine 6G, Sudan Blue II, and Solvent Green 3) to independently control the motions of the films with 445, 520, and 655 nm lasers. The ferrocene-containing films also exhibit photoinduced healing from mechanical damage. Finally, the photoirradiation-accompanied morphological changes in the film are observed via small-angle X-ray scattering.

Carcinogenicity and chronic toxicity of butyl methacrylate in rats and mice by a two-year inhalation study.

We conducted a two-year inhalation study of butyl methacrylate using F344/DuCrlCrlj rats and B6D2F1/Crl mice. Rats were exposed to 0, 30, 125 and 500 ppm (v/v) and mice were exposed to 0, 8, 30 and 125 ppm (v/v) using whole-body inhalation chambers. Non-neoplastic lesions developed in the nasal cavities of both rats and mice, but neoplastic lesions were not found. There was also a positive trend in the incidence of large granular lymphocytic (LGL) leukemia in the spleen of male rats. No changes were observed in female rats. Overall, there is some evidence of carcinogenicity in male rats, but there is no evidence of carcinogenicity in female rats. In male mice, there was a positive trend by Peto's test in the incidence of hepatocellular adenomas, and the incidence of hepatocellular adenomas and hepatocellular carcinomas combined was significantly increased compared to the controls by Fisher's exact test in the 30 ppm exposed male group. In female mice, the incidence of hemangiosarcoma in all organs combined showed a positive trend by Peto's test. Therefore, there is some evidence of carcinogenicity in male mice, and there is equivocal evidence of carcinogenicity in female mice.

Hybrid Copolymerization of Ethylene Oxide and tert-Butyl Methacrylate with Organocatalyst.

Hybrid copolymerization of structurally different, reactivity and mechanism distinct monomers (e.g., cyclic and vinyl type monomers) is of great interest and challenge for both academic research and practical application. Herein, ethylene oxide-co-tert-butyl methacrylate-co-poly(ethylene glycol) benzyl methacrylate (EO-co-BMA-co-bPEO), a statistical copolymer was synthesized via hybrid copolymerization of EO and BMA using an uncharged, non-nucleophilic organobase t-BuP4 as the catalyst. Detailed characterizations indicate that hybrid copolymerization of ethylene oxide and vinyl monomer forms a statistical copolymer concurrently with the transesterification of tert-butyl group and oligomer PEO anions. The application of the copolymer as all solid lithium-ion battery polymer electrolyte was investigated by detecting the ionic conductivity (σ) with electrical impedance spectrum measurement.

In Situ Synthesis of Poly(butyl methacrylate) in Anodic Aluminum Oxide Nanoreactors by Radical Polymerization: A Comparative Kinetics Analysis by Differential Scanning Calorimetry and 1H-NMR.

In this work, we explore the ability to generate well-defined poly(butyl methacrylate) (PBMA) nanostructures by "in situ" polymerization of butyl methacrylate monomer (BMA). PBMA nanostructures of high and low aspect ratios have been successfully obtained through the free radical polymerization (FRP) of a BMA monomer in anodic aluminum oxide (AAO) nanoreactors of suitable size. A polymerization kinetics process has been followed by differential scanning calorimetry (DSC) and proton Nuclear Magnetic Resonance spectroscopy (1H-NMR).The determination of the kinetics of polymerization through DSC is based on a quick and direct analysis of the exothermic polymerization process, whereas the analysis through 1H-NMR also allows the unambiguous chemical analysis of the resulting polymer. When compared to bulk polymerization, both techniques demonstrate confinement effects. Moreover, DSC and 1H-NMR analysis give the same kinetics results and show a gel-effect in all the cases. The number average molecular weight (Mn) of the PBMA obtained in AAO of 60-300 nm are between 30·103-175·103 g/mol. Even if the Mn value is lower with respect to that obtained in bulk polymerization, it is high enough to maintain the polymer properties. As determined by SEM morphological characterization, once extracted from the AAO nanoreactor, the polymer nanostructures show controlled homogeneous aspect/size all throughout the length of nanopillar over a surface area of few cm2. The Young's modulus of low aspect ratio PBMA nanopillars determined by AFM gives a value of 3.1 ± 1.1 MPa. In this work, a 100% of PBMA polymer nanostructures are obtained from a BMA monomer in AAO templates through a quick double process: 30 min of monomer immersion at room temperature and 90 min of polymerization reaction at 60 °C. While the same nanostructures are obtained by polymer infiltration of PBMA at 200 °C in about 6 h, polymerization conditions are much softer than those corresponding to the polymer infiltration process. Furthermore, the 1H-NMR technique has been consolidated as a tool for studying the kinetics of the copolymerization reactions in confinement and the determination of monomer reactivity ratios.

A miniaturized radial Langmuir trough for simultaneous dilatational deformation and interfacial microscopy.

INNOVATION: Interfacial rheological properties of complex fluid-fluid interfaces are strongly influenced by the film microstructure. Experimental investigations for correlating interfacial morphology and rheology are notoriously challenging. A miniaturized radial Langmuir trough was developed to study complex fluid-fluid interfaces under purely dilatational deformations that operates in tandem with a conventional inverted microscope for simultaneous interfacial visualization. EXPERIMENTS: Two materials were investigated at an air-water interface: poly(tert-butyl methacrylate) (PtBMA) and dipalmitoylphosphatidylcholine (DPPC). Surface pressure measurements made in the radial Langmuir trough were compared with a commercial rectangular Langmuir trough. Interfacial in situ visualization for each material was performed during the compression cycle in the radial trough. Challenges associated with the small size of the radial Langmuir trough, such as the influence of capillary deformation on the measured surface pressure, are also quantified. FINDINGS: Measured surface pressures between the newly developed radial trough and the rectangular Langmuir trough compare well. Micrographs obtained in the radial Langmuir trough were used to obtain film properties such as Young's modulus. The new advance in colloid and interface science is the ability to capture structure-property relationships of planar interfaces using microscopy and purely dilatational deformation. This will advance the development of constitutive modeling of complex fluid-fluid interfaces.

Small interfering RNA for cancer treatment: overcoming hurdles in delivery.

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

Amphiphilic block copolymer-grafted magnetic multi-walled carbon nanotubes as QuEChERS adsorbent for simultaneous determination of mycotoxins and pesticides in grains via liquid chromatography tandem mass spectrometry.

An amphiphilic block copolymer consisting of poly(N-acryloyl-glucosamine) (PAGA) and poly(tert-butyl methacrylate) (PtBMA) was designed and grafted on magnetic multi-walled carbon nanotubes (Fe3O4MWCNTs). The resultant Fe3O4MWCNTs@copolymer was proposed as QuEChERS adsorbent for determination of 15 mycotoxins and 25 pesticides in grains via liquid chromatography tandem mass spectrometry. The adsorbent was characterized by a transmission electron microscope, scanning electron microscope, elemental analysis, and other techniques. The common matrix interferences were efficiently removed by the proposed adsorbent, such as pigment, fatty acids, and the saccharide. PAGA segment played an important role in removing the hydrophilic interferences through hydrogen bonding due to the high density of hydroxyl groups. PtBMA segment removed the fatty residues through its strong hydrophobic carbon moiety. In comparison with the commercially available QuEChERS adsorbents, the proposed adsorbent had higher adsorption capacities towards the typical matrix interferences. To achieve satisfactory recoveries of analytes, various parameters in the QuEChERS procedure were comprehensively investigated. Under the optimal conditions, 95.0% of the analytes showed satisfactory recoveries in the range 70.0-120% as well as negligible matrix effects. The limits of detection (LOD) were in the range 0.00015-1.3 µg kg-1. Compared with previously reported QuEChERS methods, the proposed method had improved sensitivity and benefited from low matrix effects. The recoveries of analytes in various grains were in the range 60.8-108% with relative standard deviations (RSD) less than 13%. Moreover, the Fe3O4MWCNTs@copolymer exhibited good synthetic reproducibility and rapid magnetic separation (less than 10 s). The research provides a versatile platform to develop multi-functional QuEChERS adsorbents based on the amphiphilic block copolymer.

Effect of Graphene oxide or Functionalized Graphene Oxide on the Copolymerization Kinetics of Styrene/n-butyl Methacrylate.

Nanocomposite materials based on copolymers of styrene and n-butyl methacrylate with either graphene oxide (GO) or functionalized graphene oxide (F-GO) were synthesized using the in-situ bulk radical copolymerization technique. Reaction kinetics was studied both experimentally and theoretically using a detailed kinetic model also taking into account the effect of diffusion-controlled phenomena on the reaction kinetic rate constants. It was found that the presence of GO results in lower polymerization rates accompanied by the synthesis of copolymers having higher average molecular weights. In contrast, the presence of F-GO did not seem to significantly alter the conversion vs time curves, whereas it results in slightly lower average molecular weights. The first observation was attributed to side reactions of the initiator primary radicals with the hydroxyl groups on the surface of GO, resulting in lower initiator efficiency, whereas the second to grafted structures formed from copolymer macromolecules on the F-GO surface. The copolymerization model predictions including MWD data were found to be in satisfactory agreement with the experimental data. At least four adjustable parameters were employed and their best-fit values were provided.

Mechanically adaptive nanocomposites with cellulose nanocrystals: Strain-field mapping with digital image correlation.

Strain-transfer plays a key role in overall modulus of mechanically adaptive nanomaterials. Herein, mechanically adaptive nanocomposites were prepared via introducing cellulose nanocrystal (CNC) percolating network into poly butyl methacrylate (PBMA) with polyethylene glycol (PEG) as a stabilizer. The prepared PBMA/CNC nanocomposites were soaked in deionized water at 23 °C and 37 °C for one week to investigate their mechanically adaption. The interactions between PEG, CNC, and PBMA were assessed by Fourier Transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. Incorporation of PEG to CNC and PBMA/CNC nanocomposites on the morphological and thermal properties was also investigated. The mechanical adaption of PBMA/CNC nanocomposites after switching dry-to-wet state and surrounding temperature (soaked in deionized water at 23 °C and 37 °C for one week, respectively) was evaluated by mechanical testing. Meantime, digital image correlation (DIC) was firstly used to study strain transfer mechanism in mechanical adaption which was carried out in real-time synchronized with mechanical measurement. It indicated that PEG improved the dispersion of CNC in PBMA/CNC nanocomposite and its thermal properties. Furthermore, CNC with PEG modification bridged PBMA during crack propagation and promoted the stress and stain transfer in PBMA/CNC nanocomposites according to DIC analysis.

Simultaneous detection of four kinds of methyl acrylate compounds in workplace air by a portable GC-MS technique / 中国职业医学

OBJECTIVE: To establish a method for simultaneously detecting methyl methacrylate, ethyl methacrylate, n-propyl methacrylate and butyl methacrylate in workplace air by a portable gas chromatography-mass spectrometer(GC-MS) technique. METHODS: The portable GC-MS hand-held probe was used for sampling and detection. Samples were separated with DB-5 rapid chromatographic column in order to maintain retention time and characteristics of the ions, and quantified by standard curve method. RESULTS: The linear correlation of this method was higher than 0.999 0. The minimum detection concentration was 0.03-0.06 mg/m~3, and the minimum quantitation concentration was 0.10-0.20 mg/m~3. The standard recovery rate was 82.22%-91.24%. The within-run and the between-run relative standard deviation were 7.67%-14.63% and 10.40%-13.79% respectively. CONCLUSION: The portable GC-MS technique could be used for qualitative and quantitative detection of above-mentioned four methylacrylate compounds in workplace air.

Damping Analysis of Some Inorganic Particles on Poly(butyl-methacrylate).

Viscoelastic polymers can be used as damping materials to control unexpected vibration and noise through energy dissipation. To investigate the effect of an inorganic filler on damping property, a series of inorganic particles, Ferriferous oxide(Fe3O4), Graphene/Fe3O4(GF), and Fe3O4 of demagnetization(α-Fe2O3) were incorporated into poly(butyl-methacrylate) (PBMA). The effects of the dispersion of particles, as well as the interaction between particles and the PBMA matrix on the damping property of composites, were systematically studied. Results revealed that the addition of three types of particles can effectively improve the damping properties and broaden the effective damping temperature range. Dispersion of α-Fe2O3 in the PBMA matrix is better than that of Fe3O4. As a result, the damping peak can be increased more. The interaction between GF and the PBMA matrix is stronger than that between Fe3O4 and the PBMA. The damping peak of the composites can be suppressed by GF, which is opposite to Fe3O4 and α-Fe2O3. In addition, glass transition temperature (Tg) of all composites in the study shifted to low temperatures.

Low-Power All-Organic Electrophoretic Display Using Self-Assembled Charged Poly( t-butyl methacrylate) Microspheres in Isoparaffinic Fluid.

The increasing demands for display devices with low power consumption and outdoor readability have stimulated comprehensive research into full-color reflective displays that employ color-tunable photonic crystal technologies. Although the recently developed crystalline colloidal arrays (CCAs) of the charged microspheres have shown the outstanding color tunability, the practical application is limited because the use of highly polar liquid medium such as water is required to maintain the charges on the surface of microsphere, whereas it is not suitable for long-term use in an electric field. Herein, a self-assembled CCA from charged poly( t-butyl methacrylate) microspheres was successfully fabricated, which was stabilized by the charged inverse micelles of sodium di-2-ethylhexyl-sulfosuccinate in a nonpolar isoparaffinic fluid. A charged all-organic CCA was found to exhibit full-color tunability with a 1000-fold reduction in the power consumption (∼6 µW cm-2) under a direct current voltage bias of 4 V in comparison to that in an aqueous system, which is a promising feature for a low-power-consumption display device.

Preparation and oil absorbency of kapok-g-butyl methacrylate.

Butyl methacrylate (BMA) was grafted onto kapok fiber using benzoyl peroxide (BPO) as initiator. The structure of the grafted kapok was investigated using Fourier transform infrared spectroscopy and scanning electron microscopy. The results illustrated that BMA was successfully grafted onto the kapok fiber surface. The effects of monomer concentration, temperature and time on the oil absorbency of grafted kapok fiber were investigated. The oil absorbencies of raw kapok, NaClO2-treated kapok fiber and kapok-g-butyl methacrylate were evaluated and compared. Compared with raw kapok fiber, grafted kapok fiber showed the highest oil absorbency, with the increase percentage of 63.4%, 42.5% and 56.4% for chloroform, toluene and n-hexane, respectively. Furthermore, the as-developed grafted kapok fiber exhibited excellent reusability, and can be utilized as an eco-friendly material for recovering oil released into the surroundings.

Determining the Chemical-Heterogeneity-Corrected Molar Mass Averages and Distribution of Poly(styrene-co-t-butyl methacrylate) Using SEC/MALS/UV/DRI.

Chemical heterogeneity, defined as the change (or lack thereof) across the molar mass distribution (MMD) in the monomeric ratio of a copolymer, can influence processing and end-use properties such as solubility, gas permeation, conductivity, and the energy of interfacial fracture. Given that each parent homopolymer of the copolymer monomeric components has a different specific refractive index increment (∂n/∂c) from the other component, chemical heterogeneity translates into ∂n/∂c heterogeneity. The latter, in turn, affects the accuracy of the molar mass (M) averages and distributions of the copolymers in question. Here, employing size-exclusion chromatography coupled on-line to multi-angle static light scattering, ultraviolet absorption spectroscopy, and differential refractometry detection, the chemical heterogeneity (given as mass percent styrene) was determined for a poly(styrene-co-t-butyl methacrylate) copolymer. Also determined were the chemical-heterogeneity-corrected M averages and MMD of the copolymer. In the present case, the error in molar mass incurred by ignoring the effects of chemical heterogeneity in the M calculations is seen to reach as high as 53,000 g mol-1 at the high end of the MMD. This error could be much higher, however, in copolymers with higher M or with larger difference among component ∂n/∂c values, as compared to the current analyte.

Nanostructured Thermal Responsive Materials Synthesized by Soft Templating.

We capitalized herein the inherent tortuosity of bicontinuous microemulsion to conceive nanostructured drug-delivery devices. First, we show that it is possible to synthesize bicontinuous materials with continuous hydrophilic domains of the poly(N-isopropylacrylamide) (PNIPAM) network entangled with continuous hydrophobic polymer domains, with dual-phase continuity being imposed by the bicontinuous microemulsions used as a soft template. Particular attention is paid to the microemulsion formulations using a surfmer to preserve the one-to-one replication of the bicontinuous nanostructure after polymerization. These materials keep a volume phase transition with temperature that allows considering them as drug carriers for controlled release. PNIPAM, which plays the role of the active ingredient reservoir, is confined in the bicontinuous structure. As expected, the PNIPAM enclosure limits the surface area in contact with the releasing aqueous solution and thus slows down the desorption of aspirin, which is used as a model drug. The hydrophobic polymers play the role of in situ-created transport barriers without hindering it as all the loaded aspirin in this bicontinuous structure still remains available.

The application of self-assembled nanostructures in peptide-based subunit vaccine development.

Peptide based-vaccines are becoming one of the most widely investigated prophylactic and therapeutic health care interventions against a variety of diseases, including cancer. However, the lack of a safe and highly efficient adjuvant (immune stimulant) is regarded as the biggest obstacle to vaccine development. The incorporation of a peptide antigen in a nanostructure-based delivery system was recently shown to overcome this obstacle. Nanostructures are often formed from antigens conjugated to molecules such as polymers, lipids, and peptide, with the help of self-assembly phenomenon. This review describes the application of self-assembly process for the production of peptide-based vaccine candidates and the ability of these nanostructures to stimulate humoral and cellular immune responses.

Fabrication of a bioadhesive transdermal device from chitosan and hyaluronic acid for the controlled release of lidocaine.

A novel efficient transdermal (TD) lidocaine (LD) delivery device based on chitosan (CS) and hyaluronic acid (HA) was successfully developed in the present investigation. CS was grafted with glycidyl methacrylate (GMA) and butyl methacrylate (BMA) to fabricate a versatile material with improved adhesion and mechanical properties. HA was hydrophobically modified by covalently conjugating 3-(dimethylamino)-1-propylamine (DMPA) to encapsulate poorly water soluble LD and was uniformly dispersed in modified CS matrix. The prepared materials were characterized through FTIR, NMR, XRD, SEM, TEM and tensile assay. The dispersion of amine functionalized HA (AHA) on modified CS matrix offered strong matrix - filler interaction, which improved the mechanical properties and drug retention behavior of the device. In vitro skin permeation study of LD was performed with modified Franz diffusion cell using rat skin and exhibited controlled release. The influence of storage time on release profile was investigated and demonstrated that after the initial burst, LD release profile of the device after 30 and 60days storage was identical to that of a device which was not stored. In vivo skin adhesion test and skin irritation assay in human subjects, water vapor permeability and environmental fitness test was performed to judge its application in biomedical field. All results displayed that the fabricated device is a potential candidate for TD LD administration to the systemic circulation.

Fractionation of Poly(butyl methacrylate) by Molecular Topology Using Multidetector Thermal Field-Flow Fractionation.

Thermal field-flow fractionation (ThFFF) is an interesting alternative to column-based fractionation being able to address different molecular parameters including size and composition. Until today it has not been shown to be able to fractionate polymers of similar molar masses and chemical compositions by molecular topology. The present study demonstrates that poly(butyl methacrylates) with identical molar masses can be fractionated by ThFFF according to the topology of the butyl group. The influence of the solvent polarity on the thermal diffusion behavior of these polymers is presented and it is shown to have a significant influence on the fractionation of poly(n-butyl methacrylate) and poly(t-butyl methacrylate). Fractionation improves with increasing solvent polarity and solvent polarity may have a greater influence on fractionation than solvent viscosity. It is found that the thermal diffusion coefficient, D(T), as well as the hydrodynamic diameter, D(h), exhibit increasing trends with increasing solvent polarity. The solvent quality has a significant influence on the fractionation. It is found that cyclohexane, being a theta solvent for poly(t-butyl methacrylate) but not for poly(n-butyl methacrylate), significantly improves the fractionation of the samples by decreasing the diffusion rate of the former but not the latter.