Styrene-acrylic Acid Research Articles

A novel γ-Al2O3 nanofiltration membrane via introducing hollow microspheres into interlayers for improving water permeability

Ceramic nanofiltration (NF) membranes with high resistance to harsh environments have been widely studied and applied in various fields, involving food, bioengineering and water purification. In this work, γ-Al2O3 hollow microspheres with mesoporous shell structures served as an interlayer on a high-flux α-Al2O3 hollow fiber microfiltration (MF) membrane to increase porosity and permeability. Here, the boehmite sol was made from the pseudo-boehmite precursor with a mild and environment friendly feature, instead of the conventional methods using aluminum alkoxides. The self-assembled microspheres (SAMs) mixture and boehmite sol were applied to make an interlayer and toplayer successively on α-Al2O3 substrates by dip-coating. Where, the SAMs constructed by poly-(styrene-acrylic acid) (PSA) microspheres and boehmite colloidal particles could stop the boehmite sol from permeating into inner pores of the support. Next, the composite membranes were calcined to remove organic components and finish the decomposition of the Al hydroxides at 600 °C for 2 h. The results show that the γ-Al2O3 composite NF membrane has a high pure water permeability of 26.4 L m−2 h−1 bar−1, with high retention rate for multivalent cations and low retention rate for monovalent cations, respectively, and the molecular weight cut-off (MWCO) of approximately 1500 Da.

Radiata pine wood treatment with a dispersion of aqueous styrene/acrylic acid copolymer

AbstractWood of radiata pine (Pinus radiataDon) was treated with an aqueous styrene/acrylic acid (St/AA) copolymer dispersion leading to weight percent gains (WPGs) of 10–42%. The reactivity of St/AA in wood and the modifying effects on wood properties were investigated. The St/AA precipitated in the cell lumens and condensed under catalysis at elevated temperatures was shown via scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Treatment did not cause positive bulking efficiency and anti-swelling efficiency, because St/AA cannot diffuse into the cell walls due to its high molecular mass. The modulus of elasticity and rupture (MOE and MOR, respectively), and the surface hardness of the wood were improved by 24.4, 22.2, and 40.6%, respectively. Compression strength increased by 81.6 and 48.2% in radial and longitudinal directions, but the impact strength was hardly influenced by the treatment. In addition, the treated wood was slightly more hydrophobic than untreated controls as shown by reduced moisture content and water uptake. Accordingly, treatment with St/AA leads to mechanical reinforcement of wood and enhances its water resistance, and as a consequence, it has an application potential to improve the wood quality.

Electronically Stabilized Copoly(Styrene-Acrylic Acid) Submicrocapsules Prepared by Miniemulsion Copolymerization.

This work reports the preparation and characterization of poly(styrene-acrylic acid) (St/AA) submicrocapsules by using the miniemulsion copolymerization method. AA was introduced to miniemulsion polymerization of St to increase the zeta potential and the resulting electrostatic stability of St/AA submicrocapsules. Phytoncide oil was adopted as the core model material. Miniemulsion copolymerization of St and AA was conducted at a fixed monomer concentration (0.172 mol) with a varying monomer feed ratio [AA]/[St] (0.2, 0.25, 0.33, 0.5, and 1.0). Concentrations of initiator (azobisisobutyronitrile; 1.0 × 10−3, 2.0 × 10−3, 3.0 × 10−3, and 4.0 × 10−3 mol/mol of monomer) and surfactant (sodium dodecyl sulfate; 0.6 × 10−3, 1.0 × 10−3, and 1.4 × 10−3 mol) were also controlled to optimize the miniemulsion copolymerization of St and AA. Dynamic light scattering and microscopic analyses confirmed the optimum condition of miniemulsion copolymerization of St and AA. Long-term colloidal stability of aqueous St/AA submicrocapsule suspension was evaluated by using TurbiscanTM Lab. In this work, the optimum condition for miniemulsion copolymerization of St and AA was determined ([AA]/[St] = 0.33; [SDS] = 1.0 × 10−3 mol; [AIBN] = 2.0 × 10−3 mol/mol of monomer). St/AA submicrocapsules prepared at the optimum condition (392.6 nm and −55.2 mV of mean particle size and zeta potential, respectively) showed almost no variations in backscattering intensity (stable colloids without aggregation).

Copolymerization of Partly Incompatible Monomers: An Insight from Computer Simulations

In this work we used dissipative particle dynamics simulations to study the copolymerization process in the presence of spatial heterogeneities caused by incompatibility between polymerizing monomers. The polymer sequence details as well as the resulting system spatial structure in the case if phase segregation occurs during the chain growth can be predicted using the method. We performed the model verification with the available literature data on styrene-acrylic acid copolymerization in the bulk and a very good agreement between experimental and simulated data for both chain average composition and triad fractions was observed. Next, we studied the system properties for a model symmetric reaction process with the reactivity ratios r1 = r2 = 0.5 at different compositions and Flory-Huggins parameters \c{hi}. We found that the system average copolymer "composition-feed" curve does not depend on the \c{hi}-value, but there are significant changes in the copolymer sequences caused by the density fluctuations. Finally, we investigated the formation of gradient copolymers during living styrene-acrylic acid copolymerization at a highly asymmetrical feed composition.

Synthesis of cationic styrene-acrylic acid ester copolymer emulsion for paper sizing

Surface sizing is an effective way to increase paper’s water-resistance and printability. The purpose of this study was to study synthesis process to develop an efficient cationic styrene-acrylic acid ester emulsion (SAE) for the surface sizing of paper. Dimethylaminoethyl methacrylate methyl chloride (DMC) was used as the cationic monomer, and cationic starch or native starch was used as the emulsion stabilizer to copolymerize with styrene and butyl acrylate. The results indicated that the SAE synthesized with cationic starch and DMC had a high cationic charge density and a high DMC conversion rate. Paper sized with the cationic SAE had higher surface strength and lower Cobb value than the paper sized with other surface sizing agents such as, anionic SAE, and cationic or oxidized starch. Scanning electron micrographs revealed that the paper sized with a combination of oxidized starch and cationic SAE had smoother surface morphology when compared to the paper sized with oxidized starch alone, or with oxidized starch and anionic SAE.

Fabrication of polyacrylamide inverse opal photonic crystal Films based on co-deposition

Polyacrylamide (PAM) inverse opal films were successfully fabricated through a co-deposition method for the first time, based on poly(styrene-acrylic acid) (PSA) template. During solvent evaporation, PSA/PAM composite film was prepared by self-assembly deposition of PSA microspheres and polymerization of acrylamide (AM) precursor in one-step. By the removal of PSA template, the PAM inverse opal film was finally obtained. The results from scanning electron microscope (SEM) and fiber optic spectrometer revealed that the film had a three-dimensional ordered structure and uniform pores without over-layers and defects. Furthermore, effects of the template species and AM concentration on the film structures were also investigated. The results showed that the uniform film could be achieved at low AM concentration and in the presence of PSA as template. This uniform PAM inverse opal film had the potential applications to photonic crystals, photo-catalysts, and optical switches.

Synthesis and Properties of the Poly(styrene-acrylic acid)

Due to the smalle hole of the shale formantion, particles with smaller size, such as nanoparticles was developed to be used as plugging materials during the drilling of shale formation. In this article, poly (styrene-acrylic acid) particles were synthesized by soap-free emulsion polymerization of styrene (St) and acrylic acid (AA). The as-prepared polymer particles were characterized by Fourier transform infrared spectroscope (FT-IR), dynamic light scattering (DLS). In addition, salt tolerance, temperature resistance and compatible properties with additives in drilling fluid of the polymer particles were also investigated.

Tunable wettability of hierarchical structured coatings derived from one-step synthesized raspberry-like poly(styrene-acrylic acid) particles

Hierarchical structured coatings were fabricated by the assembly of raspberry-like P(S-AA) particles and their wettability could be tuned from hydrophilic to superhydrophobic.

Influence of Adhesive System on Performance of SiO/C Lithium-ion Battery

Silicon based anode material is turning into the research hot point of lithium-ion battery material field due to Si inside supporting higher capacity. Furthermore binder applied as major accessory material of anode system could bring anode material & current collector together, thus the influence given by binder system to battery performance becomes the key point. The paper describes the procedure of adopting commercial LiCoO 2 SiO/C as composite material & electrolyte, with using styrene butadiene rubber and acrylic acid copolymer as binder to figure out lithium-ion battery with 2.5Ah, which is testified to present better performance on cold temperature & cycle life plus having a little bit swelling compared with the lithium-ion battery using only styrene butadiene rubber as binder.

A new approach of fabricating monodisperse micrometer hollow zirconia spheres

The monodisperse micrometer hollow zirconia sphere was prepared in mixed solvents. It was fabricated by using the preformed poly(styrene-acrylic acid) (PSA) as template spheres which was mixed with zirconyl chloride octahydrate in ethanol solvent under steam treatment. The hollow zirconia spheres obtained by the calcination of PSA/ZrO2 composite spheres had a narrow particle size distribution and commendable surface topography characterized by SEM. The calcined hollow zirconia spheres displayed monoclinic crystalline reflection peaks characterized by XRD. Besides, the micro-morphology, composition and molecular composition of sample were analyzed by FESEM, TG–DSC and FTIR, respectively.

Synthesis and Characterization of Sulfonated Poly‐(styrene‐co‐acrylic acid) for Applications as Pronton Exchange Membranes

SummaryPolymeric membranes were prepared using the mass copolymerization of styrene/acrylic acid (St/AA) at 90/10, 92/8 and 94/6 ratios. Divinyl benzene (DVB) was also added at concentrations of 0.1 and 0.001% weight for each St/AA ratio. The obtained copolymers were sulfonated by treating the materials with concentrated sulfuric acid for 0, 30 and 85 minutes to enhance their ion exchange capacities. The materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), cross‐linking level by gel percentage and acidity through sodium hydroxide titration. The FTIR spectra of the membranes before sulfonation showed the existence of traditional bands that corresponded to the polymer components; some homopolymer main bands were lost, whereas two new bands appeared during the copolymerization reaction. The TGA analyses showed a higher decomposition temperature for the DVB cross‐linked membranes, while DSC did not provide much information due to the hygroscopic nature of the membranes. The gel percentage was effectively related to the DVB level. The membranes acidity increased with increasing acrylic acid content, sulfonation time and DVB percentage; however, the acidic values are highly dependent on the solubility of the materials.

Lipase immobilization on magnetic microspheres via spacer arms: Effect of steric hindrance on the activity

Poly(styrene-acrylic acid) magnetic microspheres with an average diameter of 2 μm were successfully prepared and used as carriers to immobilize lipase. Lipase immobilized on microspheres with no spacer arm exhibited low activities, which were attributed to steric hindrance on the lipase conformation. To avoid steric effects, ethylenediamine and poly(ethylene glycol) (PEG) 400/800/4000 were utilized as spacer arms to bind the lipase to the microspheres. The immobilized lipase activities were improved using PEG 800/4000 as a spacer arm. Furthermore, the influence of enzyme loading on lipase activity was investigated, and the results indicated that enzyme overloading could exert steric effect on lipase activity. The degree of PEG modification was demonstrated to affect lipase activity because excess PEG on the surface of microspheres could interact with lipase due to its mobility, consequently reducing lipase activity.

Formation and mechanical characterization of ionically crosslinked membranes at oil–water interfaces

Here we report on the preparation and mechanical characterization of a 2-D self-assembled membrane formed by ionically crosslinking the polyelectrolyte parts of a gradient amphiphilic copolymer at oil and water interfaces. To fabricate these membranes, chloroform solutions of styrene-acrylic acid copolymers were suspended as pendant drops in an aqueous embedding phase. Due to the amphiphilic nature of these molecules, the copolymer chains migrate to the oil-water interface creating an interfacial layer. Upon the addition of zinc acetate to the embedding phase, crosslinks between copolymer molecules are formed via zinc-carboxylate complexes. While ionically crosslinked block copolymer membranes were critically damaged after one expansion cycle, ionically crosslinked gradient copolymers formed durable membranes that maintained their physical integrity through multiple expansion-compression-expansion cycles. This difference in mechanical behavior is attributed to the fact that gradient copolymers are more effective interfacial modifiers and have a significantly different molecular alignment at the oil-water interface. Additionally by changing the incubation time from 20 to 30 minutes, the low-strain dilatational modulus of these membranes was significantly increased due to higher interfacial coverage and crosslinking density. Longer incubation times also led to a distinct yield point and plastic deformation behavior at larger strains. Further mechanical characterization of the membranes showed that they can be quite robust and that by replacing the internal oil phase with an aqueous solution, future testing of membrane filtration and permeation may be possible.

Study of the particles’ structure dependent rheological behavior for polymer nanospheres based shear thickening fluid

A novel kind of shear thickening fluid (STF) was developed via dispersing poly(styrene–acrylic acid) (PS–AA) nanospheres into ethylene glycol (EG). By varying the structure characteristics of the PS–AA particles, STFs with different rheological properties can be obtained. Firstly, the influence of the styrene/acrylic acid ratio on the PS–AA nanospheres was investigated. It was found that the higher ratio often led to the better shear thickening (ST) effects and under the optimum condition the maximum viscosity of the STF could reach to 152Pa s, while the ST effects decreased under further increasing the monomer ratio. Then, the divinyl benzene (DVB) was introduced to increase the cross-link density of the PS–AA. In comparison with the non-cross-link PS–AA nanospheres, the poly(styrene–acrylic acid–divinyl benzene) (PS–AA–DVB) based STFs exhibited much higher ST effects and the maximum viscosity was up to 385Pas when the DVB was only increased to 0.3%. In combination of the rheological properties and the structure characterization, a possible mechanism for the ST behavior was proposed and the influence of the particles’ characteristics on the mechanical performance of the PS–AA based STF was carefully analyzed.

Improvement of Ink Jet Printing Paper Quality with Oxidized Starch Ester and Additives

The effect of esterified starch as surface sizing agent for inkjet printing paper has been evaluated and compared with oxidized starch. Also the influence of various additives including cationic poly-DADMAC, stearic acrylic copolymer, calcium chloride, and GCC was examined. Results showed that starch ester gave higher ink density than oxidized starch. Addition of poly-DADMAC improved water fastness. In general, low molecular weight poly-DADMAC performed better than high molecular weight one, and it was attributed to the fact that it gave more uniform film forming characteristics in surface sizing. Use of styrene acrylic acid copolymer increased hydrophobicity of the paper surface, but it did not increase the ink density. Use of GCC and calcium chloride had only marginal effect on printing quality.

Gradient copolymers of styrene–methyl acrylate and styrene–acrylic acid by organostibine-mediated controlled/living radical polymerization and their glass transition behaviors

Gradient copolymers of styrene–methyl acrylate (poly(St-grad-MA)) were synthesized by semi-batch organostibine-mediated controlled/living radical polymerization (SBRP) in bulk at 60 °C. The number-average molecular weights of the copolymers increase linearly with the total conversion, and the polydispersity indices of all the final copolymers are less than 1.20. The relationships of the cumulative composition (Fcum) and instantaneous composition (Finst) with the degree of polymerization demonstrate the formation of different gradient chain structure and composition of copolymers. Furthermore, amphiphilic gradient copolymers of styrene–acrylic acid (poly(St-grad-AA)) with a small amount of residual MA units were achieved through the hydrolysis of poly(St-grad-MA) under basic conditions. The glass transition temperature (Tg) behaviours of poly(St-grad-MA) and poly(St-grad-AA) were compared in detail. Tg values of poly(St-grad-MA) increase with increasing Fcum,St, while poly(St-grad-AA) has the maximum Tg value and both the two kinds of copolymers have the maximum Tg breadth values with Fcum,St range of 0.4–0.5. The Tg breadth values of poly(St-grad-AA) copolymers are larger than that of the corresponding poly(St-grad-MA) due to the more strongly segregating components of St–AA than St–MA. The typical wide Tg breadths of all the copolymers further prove their gradient structures.

A Convenient and Templated Method for the Fabrication of Monodisperse Micrometer Hollow Titania Spheres

A simple and widely applicable methodology was presented to synthesize monodisperse micrometer hollow titania spheres (HTS) based on the templating method. It was performed by using the preformed poly(styrene‐acrylic acid) (PSA) as template spheres which was mixed with tetrabutyltitanate (TBOT) in an ethanol solvent under steam treatment. The HTS which were obtained by the calcination of PSA/TiO2 composite core‐shell spheres had a narrow particle size distribution and commendable surface topography characterized by SEM. The calcined HTS at 500°C displayed crystalline reflection peaks that were characteristic to the anatase phase by XRD. Moreover, some key influencing factors including TBOT concentration and reaction time were analyzed. As expected, the diameter of HTS could be readily controlled by altering the size of PSA template spheres. In addition, the approach was also applied to fabricate hollow zirconia spheres and other inorganic spheres.

Synthesis and Evaluation of Starch Graft Copolymer Applied as Dispersant in Coal-Water Slurry

In this paper, a starch-based dispersant for Chinese Shenhua coal-water slurry (CWS) was synthesized by radical polymerization using styrene sulfonate and acrylic acid as graft monomers in oxidation-reduction initiator system. Chemical structure and thermal performance of the copolymer were investigated by Fourier Transform Infrared Spectrum (FT-IR) and Thermogravimetric Analyzer (TGA). The rheological characteristics of the slurry were studied by varying dispersant dosage and shear rate，and the results show, At coal concentration of 66 wt%, dispersant dosage of 0.4 wt% and shear rate of 100 s-1, the CWS gives the minimum viscosity of 848 mPa•s. Bleeding ratio tests indicate the dispersant can stabilize the slurry. Based on the above, the starch-based dispersant has due structure and a bright prospect for the application for CWS.

New membranes obtained by grafted irradiated PVDF foils

The present work describes a new method to produce membranes of poly(Acrylic-acid-Xmonomer) using the grafting procedure. PVDF foils irradiated with Ar+ beam with energies between 30 and 150keV were employed as substratum. Different combinations of monomers in water solutions were used: acrylic acid (AAc); acrylic acid–glycidyl methacrylate (AAc–GMA); acrylic acid–styrene (AAc–S), acrylic acid-N-isopropyl acrylamide (AAc–NIPAAm) and acrylic acid-N-isopropyl acrylamide–glycidyl methacrylate (AAc-NIPAAm–GMA). A large percentage of grafting results for specific values of: ion fluence and energy, AAc and sulfuric acid concentration, and different substrata PVDF polymorphous (alpha or beta). At a particular time of the grafting process, the poly(AAc-Xmonomer) membranes detach from the substratum and continue their grafting in the solution. This method is useful to produce increased replicated membranes of the irradiated original surface.

Cadmium ion-doped magnetic poly(styrene-acrylic acid) nanospheres for sensitive electrochemical immunoassay

A novel class of molecular tags, cadmium ion-doped magnetic poly(styrene-acrylic acid) nanospheres (Cd-MPSA), was first synthesized and functionalized with polyclonal rabbit anti-human luteinizing hormone antibodies (PAb2) for highly efficient electrochemical immunoassay of luteinizing hormone (LH). Transmission electron microscope (TEM) and Fourier transform infrared spectroscope (FTIR) were employed to characterize the prepared Cd-MPSA. By using Cd-MPSA-labeled PAb2 as molecular tags, a novel sandwich-type immunoassay protocol was built for determination of LH on monoclonal mouse anti-human luteinizing hormone antibody (MAb1)-functionalized gold electrode. The assay was carried out in pH 5.3 HAc-NaAc buffer solution by square wave voltammetry (SWV). The signal was obtained by the reduction of the doped cadmium ions in the Cd-MPSA. Under optimal conditions, the currents increased with the increasing LH level in the sample, and exhibited a linear range from 0.25 to 240mIUmL−1 with a detection limit of 0.08mIUmL−1 LH at 3sB. The precision, reproducibility, and specificity were acceptable. No obvious difference was encountered in the analysis of spiking LH samples into newborn calf serum with the referenced values.