Emulsion Polymerization Of Acrylate Research Articles

Mesoporous Fe3O4/SiO2/poly(2-carboxyethyl acrylate) composite polymer particles for pH-responsive loading and targeted release of bioactive molecules.

pH-responsive polymer microspheres undergoing reversible changes in their surface properties have been proved useful for drug delivery to targeted sites. This paper is aimed at preparing pH-responsive polymer-modified magnetic mesoporous SiO2 particles. First, mesoporous magnetic (Fe3O4) core-particles are prepared using a one-pot solvothermal method. Then, magnetic Fe3O4 particles are covered with a C[double bond, length as m-dash]C functional mesoporous SiO2 layer before seeded emulsion polymerization of 2-carboxyethyl acrylate (2-CEA). The composite polymer particles are named Fe3O4/SiO2/P(2-CEA). The average diameters of the Fe3O4 core and Fe3O4/SiO2/P(2-CEA) composite polymer particles are 414 and 595 nm, respectively. The mesoporous (pore diameter = 3.41 nm) structure of Fe3O4/SiO2/P(2-CEA) composite polymer particles is confirmed from Brunauer-Emmett-Teller (BET) surface analysis. The synthesized Fe3O4/SiO2/P(2-CEA) composite polymer exhibited pH-dependent changes in volume and surface charge density due to deprotonation of the carboxyl group under alkaline pH conditions. The change in the surface properties of Fe3O4/SiO2/P(2-CEA) composite polymer particles following pH change is confirmed from the pH-dependent sorption of cationic methylene blue (MB) and anionic methyl orange (MO) dye molecules. The opening of the pH-responsive P(2-CEA) gate valve at pH 10.0 allowed the release of loaded vancomycin up to 99% after 165 min and p-acetamido phenol (p-AP) up to 46% after 225 min. Comparatively, the amount of release is lower at pH 8.0 but still suitable for drug delivery applications. These results suggested that the mesoporous Fe3O4/SiO2 composite seed acted as a microcapsule, while P(2-CEA) functioned as a gate valve across the porous channel. The prepared composite polymer can therefore be useful for treating intestine/colon cancer, where the pH is comparatively alkaline.

Preparation of high‐barrier performance paper‐based materials from biomass‐based silicone‐modified acrylic polymer emulsion

AbstractHigh‐barrier performance, especially under extreme working conditions, is the key to replacing other types of packaging materials with paper‐based materials. In this paper, two biomass‐based polymers, sodium alginate (SA), and chitosan, were used to form a barrier coating with silicone emulsions to prepare a high‐performance paper‐based barrier material. By double coating, the water and oilproof functions were superimposed. The two prepared coated papers were characterized by infrared spectroscopy analysis, contact angle test, and scanning electron microscopy analysis, while their water resistance, oil resistance, thermal oil resistance, and thermal stability were tested. The water and oil repellency were achieved by double coating. The Cobb value of the chitosan‐silicone emulsion‐coated paper reached 5.3 g/m2, with a Kit grade of Level 12, and could block the penetration of castor oil at 80°C within 24 h. The Cobb value of the sodium alginate‐silicone emulsion‐coated paper was 41.6 g/m2, much higher than that of the uncoated paper, with a Kit grade of up to Level 10, which could slow down the rate of castor oil penetration at 80°C within 24 h. The test results showed that there was no chemical reaction between the paper‐based coatings, and the coated paper surface had good film formation, while the double coating method increased the thermal decomposition temperature of the overall barrier coating, effectively improving the thermal stability of the coating and achieving high‐barrier performance at lower cost and under extreme working conditions.Highlights Water and oil resistance under extreme operating conditions. High‐performance paper‐based barrier materials. Dual‐layer coating method for water and oil repellency. High‐barrier performance at lower cost. Excellent hot oil resistance and thermal stability.

Flexible Embedded Metal Meshes by Sputter-Free Crack Lithography for Transparent Electrodes and Electromagnetic Interference Shielding.

A facile and novel fabrication method is demonstrated for creating flexible poly(ethylene terephthalate) (PET)-embedded silver meshes using crack lithography, reactive ion etching (RIE), and reactive silver ink. The crack width and spacing in a waterborne acrylic emulsion polymer are controlled by the thickness of the polymer and the applied stress due to heating and evaporation. Our innovative fabrication technique eliminates the need for sputtering and ensures stronger adhesion of the metal meshes to the PET substrate. Crack trench depths over 5 μm and line widths under 5 μm have been achieved. As a transparent electrode, our flexible embedded Ag meshes exhibit a visible transmission of 91.3% and sheet resistance of 0.54 Ω/sq as well as 93.7% and 1.4 Ω/sq. This performance corresponds to figures of merit (σDC/σOP) of 7500 and 4070, respectively. For transparent electromagnetic interference (EMI) shielding, the metal meshes achieve a shielding efficiency (SE) of 42 dB with 91.3% visible transmission and an EMI SE of 37.4 dB with 93.7% visible transmission. We demonstrate the highest transparent electrode performance of crack lithography approaches in the literature and the highest flexible transparent EMI shielding performance of all fabrication approaches in the literature. These metal meshes may have applications in transparent electrodes, EMI shielding, solar cells, and organic light-emitting diodes.

Soft intercalated slope stability optimization with a modified polymer curing agent

The demand for high-grade roads is significantly higher in developing countries. However, slopes containing coal gangue weak interlayer pose significant safety risks to highways, railways, and other infrastructures. To address this issue, this study aims to find the best polymer cement ratio scheme of traditional pure acrylic emulsion polymer curing agents. Based on this scheme, a reinforcement method was designed, which combined modified polyvinyl acetate with the coal gangue soft interlayer. The slope test results using a rigid model box showed that the shear strength of the root–soil composite in the PVAC group was higher than that in the pure acrylic emulsion group under different vertical consolidation pressures. Over time, the cumulative soil loss rate of the pure acrylic emulsion group gradually increased, and the soil pH decreased. Conversely, the PVAC group showed minimal changes in these two indicators with time. Under the same conditions, the slope shear strength of the PVAC group remained stronger than that of the pure acrylic emulsion group. The standard deviations of multiple tests for the PVAC group and pure acrylic emulsion group, under a vertical consolidation pressure of 100 kPa, were 7.2 kPa and 9.2 kPa, respectively, indicating greater stability in the PVAC group. With a stability coefficient of 3.39, which surpasses that of the pure acrylic emulsion group, the PVAC group exhibited enhanced slope stability. These results indicate that this method can effectively enhance the stability of coal gangue soft interlayer slopes without causing environmental pollution.

Emulsion polymerization of super-hydrophobic acrylate enabled by a novel “ferrying” strategy for developing waterborne coatings with reduced surface tension and glossiness

The emulsion polymerization of high-alcohol acrylates with extreme hydrophobicity while achieving high monomer conversion has been posed significant challenges. In this study, the emulsion copolymerization of super-hydrophobic stearyl acrylate (SA) with an 18-carbon alkyl group has been successfully conducted by a novel “ferrying” strategy. Specifically, an emulsifier with a 23-carbon alkyl group (hydrophobic) and a 20-oxethyl group (hydrophilic) simultaneously was designed to facilitate the efficient transfer of SA through hydrophobic interaction from monomer drops to micelles, leading to a remarkable improvement in monomer conversion. The self-migration of the 18-carbon alkyl groups grafted onto the copolymer chains, which moved from the inner matrix to the coating surface, resulted in the creation of the waterborne coating with low surface tension during the film formation process. Moreover, it was confirmed that the self-crystallization of the 18-carbon alkyl groups caused the coating to exhibit a self-matting effect with low glossiness. Using an industrial formula, the effects of different types and dosages of emulsifiers, as well as the dosage of SA, on the total monomer conversion, SA conversion, and coating properties were extensively investigated. This work not only broadens the monomer range for emulsion polymerization to highly hydrophobic species, but also provides a variety of industrial waterborne products with low surface tension and low glossiness derived from high-alcohol acrylates, contributing to the development of environmentally friendly chemical industries.

Effect of Magnesium Hydroxide and Aluminum Hydroxide as Thermal Barriers on the Flame-Retardant Behavior of Acrylic-Based Coating

In the effort to improve fire safety in residential, industrial, or naval structures, the study of flame-retardant coatings has become increasingly interesting. Flame-retardant additives are definitely the most traveled route; however, often these additives are halogenated compounds that increase the amount of smoke and toxic decomposition of the products during polymer combustion. It is necessary to develop new fire retardant (FR) agents that respect the environment and are safe for human health. This work aims to study two completely harmless hydroxides, Mg(OH)2 and Al(OH)3, added in low percentages (2 wt.%) to an already marketed acrylic polymer emulsion (79.2 wt.% of solid content, 37.3 wt.% and 41.8 wt.%, respectively, for polymer and fillers contents) in order to decrease the dangerous effects of these additives on the physical integrity and durability of the coatings. The hydroxides content was added in 6.2 wt.% and 5.6 wt.%, respectively, to polymer and total solids present in the emulsion. Flame exposure tests are conducted at different times (15 s and 30 s) to verify the flame stability and thermal insulation exerted by the investigated coatings. Furthermore, through a precise analysis of the areas damaged by the combustion process, it is possible to link the flame-retardant properties to the FR choice and its particle size, finding a promising solution in the sample based on small Mg(OH)2 particles for fire protection in naval applications.

Effect of organically modified titania and zirconia nanoparticles on characteristics, properties of coating based on acrylic emulsion polymer for outdoor applications

AbstractEffect of titania nanoparticles modified with 3 wt% [3‐(methacrylloxy)propyl]trimethoxysilane (m‐TiO2 NPs) and zirconia nanoparticles modified with 3 wt% (3‐glycidyloxypropyl)triethoxysilane (m‐ZrO2 NPs) on properties and morphology of acrylic emulsion polymer coating was investigated. With suitable weight ratio of m‐TiO2/m‐ZrO2 NPs, the acrylic coating could be improved abrasion resistance, weather durability, reflectance index (400–1400 nm) as well as thermal‐oxidation stability in comparison with the coatings having the same content of single modified nanoparticles. The starting thermal degradation temperature of acrylic coating filled by mixture of m‐TiO2 NPs and m‐ZrO2 NPs was approximately 10°C higher than that of the acrylic coating contained separately modified nanoparticles. The mixture of m‐TiO2 NPs and m‐ZrO2 NPs were used in solar reflective paint. Replacement of rutile TiO2 microparticles by 1 wt% mixture of modified nanoparticles, the solar reflective paint (SRP) could be improved water resistance and cooling performance. The water permeability of the SRP coating with mixture of modified nanoparticles was reduced by nearly 50%. The results of cooling performance test indicated that SRP loaded 1 wt% (m‐TiO2 NPs and m‐ZrO2 NPs) (weight ratio of 1/1) replaced 1 wt% TiO2 microparticles could reduce outside temperature of chamber test by nearly 11°C and ambient inside temperature of chamber test by 7.5°C. This novel solar reflective paint is considered as promising material for outdoor applications.

Sustained oxygen release of hydrogen peroxide-acrylic resin inclusion complex for aquaculture

Abstract To overcome the lack of dissolved oxygen in high-density aquaculture water, a hydrogen peroxide-acrylic resin inclusion complex with sustained oxygen releasing effect was designed and prepared. The resin was synthesized by emulsion polymerization of acrylic acid, methyl methacrylate and butyl acrylate in a mass ratio of 2: 3: 5, and neutralized with sodium hydroxide solution by 50%. The resin solution was mixed in a mixture of urea and 30% hydrogen peroxide solution (CO(NH2)2: H2O2, 1: 1, mol: mol), and dried at 40 °C for 4 h to obtain the hydrogen peroxide-acrylic resin inclusion complex. The product with 4.0% resin by mass of hydrogen oxygen solution, could release oxygen for 92 h in pond water. After optimization by adding a small amount of NaCl, Na2SO4, and EDTA, it was mixed with calcium carbonate and magnesium stearate in a mass ratio of 5: 4: 0.9, and pressed into tablets (1.2 × 0.6 cm, 0.99 g). One tablet in 50 L simulated micro ecosystem aquaculture water with 20 of Carassius auratus fish could release oxygen for 116 h and brought fish with 83.3% of survival rate higher than 51.7 and 70.0% of blank and sodium percarbonate groups.

Zwitterionic monomers as stabilizers for high solids content polymer colloids for high-performance coatings applications

Despite the huge and increasing application of high solids content polymer colloids for coating application, there are few challenges that still limit their full potential. The most emerging one is the use of surfactants for colloidal stabilization that affects negatively the coating performance. Moreover, due to their particulate nature, the waterborne dispersions presents lower mechanical performance with respect to the solvent-based counterparts. In this work, the possibility of use of zwitterionic monomers that contain multiple ionic functional groups, to provide colloidal stability of industrially relevant high solids content waterborne dispersions (50 %) was investigated. For that aim, small amount of 2-(methacryloyloxy) ethyl dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) zwitterionic monomer was employed to form in-situ stabilizing units during methyl methacrylate/n-butyl acrylate (MMA/BA) emulsion polymerization. The main challenge was to avoid DMAPS aqueous phase polymerization, hence, to achieve its high incorporation onto hydrophobic MMA/BA polymer particles, a key requirement for colloidal stabilization. Certainly, high DMAPS incorporations were achieved (>50 %) providing excellent colloidal stability, and due to the stiff nature of the multiple ionic group, impressive improvement of mechanical properties of the resulting coating films. Additionally, DMAPS presence in the polymer chains conveys to the coatings enhanced water resistance and high humidity permeation, paving a way towards powerful barrier coatings application.

Preparation and evaluation of a coated smectite clay-based material modified with epichlorohydrin-dimethylamine for the diclofenac removal.

This study reports the analysis of diclofenac removal from aqueous solution using a novel adsorbent coating with amphoteric surface. This adsorbent coating was improved using a new amphoteric ratio to increase its performance for the removal of pharmaceuticals such as diclofenac. The adsorbent coating was formulated using acrylic polymer emulsion, smectite-based clay powder and epichlorohydrin-dimethylamine to obtain a layer form via the implementation of a facile synthesis method. In a previous study, this adsorbent coating was successful to remove cationic and anionic dyes. Therefore, this research aimed to further investigate and test its application in the removal of other emerging water pollutants like pharmaceuticals. SEM, EDX, and FTIR analyses were carried out for the characterization of this novel adsorbent. The effects of adsorbent composition, diclofenac concentration, temperature, and solution pH were studied and modeled. The best conditions to improve the diclofenac adsorption was 303 K and pH 3 where the adsorption capacity was 25.59 mg/g. Adsorption isotherms and kinetics were quantified and modeled, and the corresponding adsorption mechanism was also analyzed. Diclofenac adsorption with this novel material was exothermic and spontaneous. This alternative adsorbent is promising for diclofenac removal from industrial wastewater systems.

Construction of insulating layers on conductive nickel-plated core particles by thermal fusion of heterocoagulated polymer shell particles

In this study, we developed a method for fabricating conductive particles with an insulating layer on the surface, which can be applied to anisotropic conductive films. Core-shell particles were prepared from conductive nickel-plated core particles and positively charged polystyrene (PSt) shell particles carrying phosphonium groups on their surface by the heterocoagulation technique. The effect of alkyl chain lengths (ethyl, n-butyl, and n-octyl) of (4-vinylbenzyl)trialkylphosphonium chloride on the interfacial properties was investigated by surface tension measurement. Monodisperse PSt shell particles with a controlled particle size were successfully synthesized by emulsifier-free emulsion polymerization of styrene, (4-vinylbenzyl)triethylphosphonium chloride, and n-butyl acrylate. The effects of stirring time, temperature, NaCl concentration, and PSt shell particle concentration on heterocoagulation between the nickel-plated core particles and PSt shell particles were investigated. Uniform core-shell particles with a coverage of 60% could be prepared even though the heterocoagulation temperature was below the glass transition temperature and the NaCl concentration was below the critical coagulation concentration of the PSt shell particles. When the core-shell particles obtained through the heterocoagulation process were heated above the glass transition temperature of the shell particles for 6 h, a smooth polymeric insulating layer with melted shell particles was successfully formed on the surface of the nickel-plated core particles.

Tough, Self-Recoverable, Spiropyran (SP3) Bearing Polymer Beads Incorporated PAM Hydrogels with Sole Mechanochromic Behavior.

Spiropyran-containing hydrogels that can respond to external stimuli such as temperature, light, and stress have attracted extensive attention in recent years. However, most of them are generally dual or multiple stimuli-responsive to external stimuli, and the interplay of different stimulus responses is harmful to their sensitivity. Herein, spiropyran bearing polymer beads incorporated PAM (poly(AM–co–MA/DMSP3)) hydrogels with sole mechanochromic properties were synthesized by emulsion polymerization of acrylamide (AM) and methyl acrylate (MA) in the presence of spiropyran dimethacrylate mechanophore (DMSP3) crosslinker. Due to the hydrophobic nature of MA and DMSP3, the resultant hydrogel afforded a rosary structure with DMSP3 bearing polymer beads incorporated in the PAM network. It is found that the chemical component (e.g., AM, MA, and DMSP3 concentrations) significantly affect the mechanical and mechanoresponsive properties of the as-obtained poly(AM–co–MA/DMSP3) hydrogel. Under optimal conditions, poly(AM–co–MA/DMSP3) hydrogel displayed high mechanical properties (tensile stress of 1.91 MPa, a tensile strain of 815%, an elastic modulus of 0.67 MPa, and tearing energy of 3920 J/m2), and a good self-recovery feature. Owing to the mechanoresponsive of SP3, the hydrogels exhibited reversible color changes under force-induced deformation and relaxed recovery states. More impressive, the poly(AM–co–MA/DMSP3) hydrogel showed a linear correlation between tensile strain and chromaticity (x, y) as well as a stain and resting time-dependent color recovery rate. This kind of hydrogel is believed to have great potential in the application of outdoor strain sensors.

The Influence of CaCl2-Blended Acrylic Polymer on Steel Rebar Corrosion and Acid Attack Resistance of Mortar

A realistic forecast of the impact of CaCl2-blended acrylic polymer (CP) emulsions on steel reinforcement corrosion is difficult without a detailed study. This is traceable to the conflicting effects of cement additives on the chloride threshold value, pore solution chemistry, and matrix resistivity. Hence, in the study reported herein, the actual influence of 0.5–1.5 wt% CP on rebar corrosion was assessed via an accelerated corrosion test. The macrocell current, half-cell potential measurements (HCP), reinforcement cover crack propagation, and rebar deterioration were monitored. The resistance of mortar specimens to acid-induced degradation was also evaluated over time. The corrosion test results indicate that steel rebar corrosion initiation in the mortar expedited as the CP dosage in mixtures increased. Consequently, the time required for the CP-modified specimens to crack shortened. Moreover, non-uniform rebar section loss and surface crack width widening were also observed in CP-modified mortar specimens. However, X-ray diffraction (XRD) analyses of the plain Ref and 1.5% CP corrosion byproduct residues indicated that key phases such as akaganeite, goethite, lepidocrocite, hematite, and magnetite were quantitatively similar. Interestingly, the addition of 1.0–1.5% CP to mixtures enhanced the acid attack resistance of mortars. For now, these results indicate that CP should only be used as a chemical admixture in unreinforced cement composites.

Polypropylene fiber reinforced concrete improved by using silica fume and acrylic emulsion polymer

The current study aims at exploring the beneficial effect of silica fume (SF) and acrylic emulsion polymer (PR) on the enhanced properties of polypropylene fiber reinforced concrete (FRC) with the supplementary cementitious binder comprised of the Portland cement, slag, silica fume and fly ash. The compressive strength and impact-abrasion resistance were used for the estimation of engineering properties while the water absorption performance, surface electricity resistance, and rapid chloride penetration resistance were used for estimation of durability. Experimental results showed that a sole addition of SF increased the compressive strengths but decreased the abrasion-impact resistances of modified FRCs, which was just opposite to the influence of a sole addition of PR. A sole addition of either the SF or PR could moderately improve the durability of modified FRCs, respectively. However, due to the beneficial effect of the complementary interaction between SF and the optimal amount of PR, the mechanical properties and durability of modified FRCs seemed to become significantly improved.

Fluorine and Siloxane Free Waterborne Near Superhydrophobic Organic Coating Based on Styrene Acrylic Polymer Emulsion through Surface Engineering

AbstractA superhydrophobic coating, free of fluorinated and siloxane materials, has been prepared via reactive compatibilization of all organic blends of hydrophilic and hydrophobic materials. In this case, styrene acrylic emulsion and a combination of hydrophobic waxes (functional rice bran wax and functional polypropylene wax) are blended together in the presence of polycarbodiimide as the reactive compatibilizer. The effect of blending and crosslinking on surface morphology is studied by Fourier transform infrared spectroscopy analysis, microscopy analyses (SEM and AFM), contact angle, and surface energy measurements. After heat treatment and crosslinking, synergistic improvements of surface properties with a gradual trend toward superhydrophobicity are observed (water contact angle ≈144° and roll‐off angle of <10°). The system is free of nanoparticles, and the desired surface morphology and microstructure is formed from the mixture of renewable (rice bran) wax and petrochemical (polypropylene) wax. These coatings are shown to have easy‐cleaning as well as self‐cleaning characteristics. Further, the coatings can withstand exposure to solvents as well as mechanical abrasion.

Application of an Acrylic Polymer and Epoxy Emulsion to Red Clay and Sand.

The use of nontraditional soil stabilizers increases. Various new soil binding agents are under study to augment renewability and sustainability of an earth structure. However, despite increasing interest involved in red clay, there is minimal research investigating the stabilizing red clay with polymer. This paper presents the findings obtained by applying the acrylic polymer and epoxy emulsion as binding agent for red clay and that for sand. The epoxy–hardener ratio, amount of epoxy emulsion, and amount of polymer aqueous solution were manipulated to quantify their effects on red clay and sand, respectively. After compacting a pair of cylindrical samples of which diameter and height are 5 cm and 10 cm, respectively, it is cured for 3 and 7 days in a controlled condition. Each pair is produced to represent the engineering performance at each data point in the solution space. An optimal composition of the binding agents for red clay and that for sand mixture are identified by experimenting every data point. In addition, given lime into each sample, the maximum unconfined compressive strength (UCS) endured by red clay sample and that by sand sample are 2243 and 1493 kPa, respectively. The UCS obtained by the sample mixed with clay and sand reaches 2671 kPa after seven days of curing. It confirms that the addition of lime remarkably improves the UCS. When the clay–sand mixture, of which the ratio is 70:30, includes 5% lime, the UCS of the mixture outperforms. Indeed, these findings, i.e., the optimal proportion of components, may contribute to the increase of initial and long-term strength of an earth structure, hence improving the renewability and sustainability of the earth construction method.

Kinetics, process design and implementation of zwitterionic adsorbent coating for dipolar dyes removal in wastewater treatment industry

Kinetic, thermodynamics and process design of the adsorption of dipolar dye molecules, namely Brilliant green (BG) and Naphthalene Blue 12B (NB12B), from aqueous solution using a zwitterionic adsorbent coating (ZwitAd) were investigated. This zwitterionic adsorbent coating was synthesized by a facile technique, which implied only 3 main chemicals: acrylic polymer emulsion (binder), bentonite (fillers) and EPIDMA (cationic polyelectrolyte). The scale-up of this formulation was proved showing that this coating adsorbent is viable to be adopted in a large-scale production. This novel adsorbent was synthesized in a coating form to obtain a feasible and practical application for the adsorption of both cationic and anionic dyes from wastewaters. Besides, this new adsorbent could be easily separated from the system without applying extra processing methods such as filtration or centrifugation. Adsorption studies showed that Freundlich model described satisfactorily the BG adsorption, whereas the NB12B adsorption was fitted with Langmuir isotherm. A single stage process was designed and the corresponding mathematical formulations was developed using the best adsorption models. Process design was performed to optimize the adsorbent amount for achieving a specific target of given initial effluent concentration and volume of treated wastewater. This optimization contributed to minimize the capital investment cost in order to satisfy a standard defined for the dye removal. Different alternatives for the application of this novel adsorbent in an industrial facility have been described and discussed. This study contributes with new findings to improve the implementation of novel adsorbents for water treatment and purification at industrial scale.

Photoenzymatic RAFT Emulsion Polymerization with Oxygen Tolerance

Photoenzymatic reversible addition-fragmenatation chain transfer (RAFT) emulsion polymerization, surfactant-free or ab initio, of various monomers is reported with oxygen tolerance. In surfactant-free emulsion polymerizatoin, poly(N, N-dimethylacrylamide)s were used as stabilizer blocks for emulsion polymerization of methyl acrylate, n-butyl acrylate and styrene, producing well-defined amphiphilic block copolymers, including those with an ultrahigh molecular weight, at quantitative conversions. The controlled character of surfactant-free emulsion polymerization was confirmed by kinetic studies, chain extension studies and GPC analyses. Temporal control was demonstrated by light ON/OFF experiments. In ab initio emulsion polymerization of methyl acrylate and methyl methacrylate, low-dispersity hydrophobic polymers were synthesized with predictable molecular weights. This study extends the monomer scope suitable for photoenzymatic RAFT polymerization from hydrophilic to hydrophobic monomers and demonstrates that oxygen-tolerance can be equally achieved for emulsion polymerization with excellent RAFT control.

Surface functionalization of poly(vinylidene fluoride) membrane by radiation‐induced emulsion polymerization of hydroxyethyl acrylates in an aqueous medium

AbstractDecades ago, surface modification of poly(vinylidene fluoride) (PVDF) membrane became an essential subject. The change is mainly to enhance the hydrophilicity properties of the membrane in order to increase the adsorption capacity, thus making as a novel adsorbent. This study aims to used radiation‐induced polymerization and compares the final properties of PVDF grafted hydroxyethyl acrylates (HEA) prepare by two different approaches. The PVDF‐grafted‐HEA has achieved either direct polymerization or emulsion polymerization. Tween‐20 has been used as a surfactant in emulsion polymerization. The final PVDF‐grafted poly‐HEA was analyzed using several different instruments to observe the changes in terms of morphological structure, topography properties, thermal stability, mechanical strength, and hydrophilicity. Significant differences were seen in morphology and contact angles properties. By emulsion polymerization, poly‐HEA grafted in the shape of micelles compare to by direct polymerization shown a thin homogenous layer. Thus, the surface roughness of PVDF by emulsion is higher lead to higher contact angles. Even though both approaches demonstrate significant changes in the physicochemical properties of the PVDF membrane, it is revealed that radiation‐induced direct polymerization approaches could achieve a hydrophilic PVDF‐grafted HEA.

Control of Vancomycin Activity through the Encapsulation and Controlled Release from a Propargyl Acrylate-Poloxamer Nanocomposite System.

Vancomycin is a potent antibacterial drug that suffers from poor bioavailability due to its poor water solubility and relatively high molecular weight. Consequently, the application of vancomycin to treat bacteria-induced disease is limited. In this study, the ability of a temperature-stimulated propargyl acrylate-poloxamer nanocomposite (PAPN) system to encapsulate and release vancomycin is investigated. A controllable encapsulation and release system can be used to not only increase and prolong the bioavailability of vancomycin but also activate vancomycin with a temperature change. The PAPN system was prepared using an emulsion polymerization of propargyl acrylate followed by a surface decoration with a poloxamer at a precisely controlled grafting density. The activity of the PAPN system loaded with vancomycin is compared to that of the free drug and unmodified propargyl acrylate nanoparticles. It is shown that the activity of the PAPN system loaded with vancomycin is comparable to that of a freshly prepared, free-floating vancomycin solution. Upon storage, the activity of the free vancomycin in solution decreases, while the PAPN system loaded with vancomycin retains its high activity. Additionally, the PAPN system is able to effectively encapsulate and deactivate vancomycin until heated above a lower critical solution temperature (LCST). At temperatures above the LCST, the PAPN system releases vancomycin restoring the activity of the drug.