Preparation and properties of novel water‐soluble surfactants. I. Synthesis and surface activity of polycarboxylated multihydrophilic surfactants

A series of novel surfactants containing multianionic and nonionic hydrophilic moieties were prepared by reacting fumaric acid with polyoxyethylenated stearyl ether in the presence of a peroxy‐type free radical initiator to form a carboxylic‐acid‐group‐containing addition product. The structure of these surfactants was confirmed by infrared, nuclear magnetic resonance, and elemental analysis. These surfactants exhibit excellent functional properties of self‐sequestering. This means that besides good surfactant properties, including surface tension, foaming, and wetting, they possess autonomous sequestering ability without any help of additional sequestering agent. When used in cotton bleaching procedures, these surfactants increase the penetration of the fibers of gray fabrics and increase the whiteness of bleached cotton. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3559–3564, 2006     

Effects of water on the long‐term properties of Bis‐GMA and silylated‐(Bis‐GMA) polymers

Bis‐GMA (2,2‐bis‐[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane) is a viscous hygroscopic monomer which is used with triethyleneglycol‐dimethacrylate (TEGDMA) for dental restorations. Bis‐GMA was silylated with dimethyl‐isopropyl‐siloxane and further polymerized in order to increase water resistance and viscosity. The viscosity of the silylated monomer, Sil·Bis‐GMA, was 50 times lower than that of the parent monomer. After 1 month in water, poly(Bis‐GMA/TEGDMA) absorbed 2.6% water and the silylated polymer, poly(Sil·Bis‐GMA), only 0.56%. During this process water extracted residual monomer from each polymer. The behavior of water sorption and desorption as a function of time in poly(Sil·Bis‐GMA) was completely different from that shown by poly(Bis‐GMA/TEGDMA). The difference is discussed in terms of diffusion coefficients. Initially, water advancing contact angles (θ_ADV) were 75° and 95°, respectively. After 1 month in water both polymers showed a reduction of about 20° in θ_ADV. In poly(Bis‐GMA/TEGDMA), the reduction in θ_ADV obey to water absorption and bulk plasticization; it showed a reduction of 15°C in glass transition temperature, T_g. In contrast, the reduction in θ_ADV in poly (Sil·Bis‐GMA) obeyed to water adsorption and reorientation of the molecules at the surface in contact with the water phase; it only showed a change of 2°C in T_g. Contact angle hysteresis provided further evidence about plasticization. According to our results poly(Sil·Bis‐GMA) is more stable in water than poly(Bis‐GMA/TEGDMA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and application of sulfadiazine surface molecularly imprinted polymers with temperature‐responsive properties

Novel, temperature‐responsive molecularly imprinted polymers (TMIPs) based on potassium hexatitanate whiskers for selectively adsorbing sulfadiazine (SDZ) from aqueous media were prepared with methacrylic acid (MAA) and 4‐vinylpyridine (4‐VP) as cofunctional monomers and N‐isopropyl acrylamide (NIPAM) as a temperature‐responsive monomer. The template–monomer interactions were studied by molecular simulation. In particular, the effects of different kinds of crosslinkers on the selective recognition ability of the TMIPs in water media were investigated. The temperature–responsive adsorption performance and phase behavior of the molecularly imprinted polymers were studied by batch‐mode binding experiments, swelling experiments, and contact angle testing. The results demonstrate that the combination of MAA, 4‐VP, and NIPAM was a favorable temperature‐responsive imprinted system for SDZ in water, and the cocrosslinking agent of ethylene glycol dimethacrylate (EGDMA) and N,N′‐methylene bisacrylamide (MBA) was more suitable compared with either pure EGDMA or MBA. The adsorption kinetics and adsorption isotherms were analyzed by the fitting of different adsorption models. Also, the effect of the temperature on the recovery was investigated by the determination of the spiked SDZ in real‐water samples with solid‐phase extraction and high‐performance liquid chromatography. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41769.     

Photochemical surface modification of polymers for improved adhesion

A method using photoactivatable reagents is described to modify organic polymer surfaces without changing the bulk properties of the material. The reagents contain a benzophenone or other photoactivatable group which, when exposed to light of appropriate wavelength, generates highly reactive intermediates that covalently bond with nearly any organic material. Some general surface characteristics that can be achieved by this approach, on a wide range of materials, are good wettability, good lubricity, passivation, and priming for either adhesion or immobilization of other molecules. This technology provides tremendous flexibility for tailoring surface characteristics for a broad range of applications. Some materials that have desirable bulk properties for specific applications, however, have surface characteristics that make bonding them to other materials difficult. By photocoupling water-soluble polymers onto the surfaces of such materials, the surface properties can be modified to achieve greatly increased bond strengths with conventional adhesives. For example, using such techniques, the strength of bonding two pieces of high-density polyethylene to each other using a cyanoacrylate adhesive was increased by about 17-fold. Similarly, in preliminary experiments, the bond strengths of silicone rubber to polyvinyl chloride, using cyanoacrylate adhesive, were increased by more than 18-fold. This technology offers great potential for surface modification for improved adhesion.     

Surface modification with acrylic polyampholytes 1, adsorption of acrylic polyampholytes on fiberglass reinforced plastics,and characterization of the polymer adsorbed surfaces

The adsorption of acrylic polyampholytes on fiberglass reinforced plastics (FRP) was investigated using random copolymers derived from (dimethylamino)ethyl methacrylate (DM), methacrylic acid, and t‐butyl methacrylate (t‐BMA). The effect of the copolymer structure changes on the adsorption and the interactions between the copolymers and the surface were assessed using ζ‐potential and contact angle measurements, NMR, and ESCA. The copolymer having the composition of 58 mol % pDM, 38 mol % pMMA, and 4 mol % pt‐BMA was adsorbed on the FRP surface at pH 7, and it formed the highest hydrophilic surface among the tested copolymers. An analysis by use of atomic force microscope revealed that the copolymer afforded a uniform 4–6 nm thick coverage on the FRP. We concluded that the interactions between the copolymer's cationic sites and the anionic FRP surface are important as well as the hydrophobic interaction for adsorption. Furthermore, it is suggested that the hydrophilicity of the copolymer's adsorbed surfaces is related to the density of the copolymer's anionic sites. These results indicate that the ampholytic structure of the polymers would be essential for the surface modification on the FRP. The effect of functional groups of surfaces on the acrylate adsorption was also assessed using surface plasmon resonance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4454–4461, 2006     

Modification of polyolefin films surface with sodium hypochlorite

Surface modification of high‐density‐polyethylene (HDPE) and linear‐low‐density polyethylene (LLDPE) films is promoted by sodium hypochlorite solutions using two different processes (I and II). Such an oxidation system introduces limited amounts of carbonyl–carboxyl and hydroxyl groups onto the surface of hydrocarbon polymers. FTIR, XPS, and SEM were used to assess the efficiency of the oxidation. The hydrophilicity of the studied surfaces was investigated by the sessile drop technique and the Wilhelmy plate and a plausible oxidation mechanism is proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1184–1197, 2006     

Recent biomedical advances with polyampholyte polymers

Polyampholyte polymer systems are composed of varying mixtures of charged monomer subunits. These polymeric systems have gained increasing attention because it is possible to design the final material properties through careful selection of the charged monomer subunits and controlling the polymer architecture. Characteristics that have been manipulated include the hydration, mechanical properties, pH responsive swelling, temperature responsive swelling, resistance to nonspecific protein adsorption, and protein conjugation capability. This had led researchers to propose the use of polyampholyte polymers as biosensor platforms, fouling release membranes, drug delivery vehicles, and tissue engineering scaffolds. This review is focused on advances that have been made over the last 5 years to develop polyampholyte polymers for these biomedical applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40069.     

Influence of low‐temperature plasma conditions on wicking properties of PA/PU knitted fabric

Plasma surface treatment has been extensively applied in the textile industry for the modification of polymer materials. In this study low‐temperature plasma (LTP) is used for surface treatment of polyamide/polyurethane (PA/PU) knitted fabric. The envisaged plasma effect is an increase in the surface energy of the treated textile, leading toward improved hydrophilic properties. The knitted fabric was treated by LTP using three non polymerizing gases: oxygen, air, and carbon dioxide. After plasma treatment, wettability of samples was tested through their wicking properties measuring capillary rise after water bath contact. The PA/PU knitted fabric samples treated with different plasma gases exhibited different hydrophilic performances. The influence of plasma variables (discharge power, time, pressure) was investigated. Although the chemical characteristics of elastan (PU) and nylon (PA) threads are different, the study has demonstrated that plasma treatment can in the same time alter the surface‐wetting behavior of both the components of the knitted fabric. It was also shown how these treatments can be regulated to produce the desired level of hydrophilicity dependently on the request application. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Influence of amino group pKa on the properties of stimuli‐responsive piperazine‐based polymers and hydrogels

Linear homopolymers of N‐acryloyl‐N′‐alkyl piperazine (N′‐alkyl: methyl, ethyl, or propyl) and their corresponding crosslinked hydrogels were prepared. The polymers showed good responses to changes in the pH of the medium due to the presence of tertiary amine functions that could be protonated at a low pH. The nature of the N′‐alkyl group attached to the piperazine amino nitrogen greatly affected the pK_a of the amino group. This in turn influenced the solution behavior of the polymers and was studied with light scattering, potentiometry, and viscosity measurements. The basicity of the polymers increased with an increase in the chain length of the N′‐alkyl substituent. The intrinsic viscosity of the polymers in a good polar organic solvent such as dimethylformamide decreased slightly with increasing temperature because of decreased thermodynamic affinity (interaction) at high temperatures. The viscosity behavior of the polymers in sodium chloride solutions was similar to that of classical polyelectrolytes. The swelling property of the hydrogels was studied with water sorption measurements, and the swelling was by anomalous (non‐Fickian) transport. The diffusion coefficient of the gels in solutions of pH 2.6 increased with increasing N′‐alkyl chain length, whereas at neutral pH, the effect was reversed. This behavior was attributed to the increase in both the basicity and hydrophobicity of the gels with an increase in the chain length of the N′‐alkyl groups. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Antimicrobial effect of monomers and polymers with azole moieties

Five monomers with azole moieties were synthesized and their antimicrobial activities were investigated. The antimicrobial activity of the monomers was evaluated by the halo zone test method. The results strongly depended on the chemical structure of the group attached to the azole moieties. Polymers with (benzimidazol‐2‐yl)thio groups and with (5‐methyl‐1,3,4‐thiadiazol‐2‐yl)thio groups were synthesized. The shake flask test showed that the two polymers possessed excellent antimicrobial activity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2933–2937, 2003     

A robust and coarse surface mesh modified by interpenetrating polymer network hydrogel for oil‐water separation

A robust and coarse surface mesh was fabricated by introducing a hydrogel coating with interpenetrating polymer network (IPN) structure on stainless steel mesh. The IPN hydrogel was prepared by crosslinking polymerization of acrylic acid (AA) followed by condensation reaction of polyvinyl alcohol (PVA) and glutaraldehyde (GA) at room temperature. As a result, the roughness of modified mesh was enhanced obviously and oil droplet underwater showed a larger contact angle. The hydrogel‐coated surface showed an underwater superoleophobicity with an oil contact angle of 153.92 ± 1.08^°. Besides, stable wettability was observed. The mesh can selectively separate oil from water with a high separation efficiency of above 99.8%. This work provides a facile method to strengthen the coating and enhance the efficiency of oil‐water separation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41949.     

Dielectric properties of epoxy/graphite flakes composites: Influence of loading and surface treatment

Epoxy-rich carbon-based composites are well recognized materials in industries owing to their good mechanical properties and thermal stability. Here, dielectric properties of composites based on bisphenol-A-epoxy resin loaded with 5, 6, 10, and 15 wt% of graphite flakes (GF) have been studied. The frequency and temperature dependence of the dielectric permittivity, dielectric loss, and ac conductivity have been examined in temperature (−103 to 97°C) and frequency (20 Hz–200 kHz) range. Influence of the filler surface chemistry have been studied for composites loaded with 5 wt% GF obtained: (i) under wet milling, without or with adding Triton-100x as a surfactant, or (ii) under dry milling in the presence of KOH. The composite made of epoxy loaded with 5 wt% exfoliated expanded graphite flakes (EEG), was also prepared. The surface treatment with KOH notably increased dielectric constant of the composite, keeping low dielectric loss, while treatment with Triton-100x significantly increased tanδ. The composite loaded with exfoliated expanded graphite shows higher ac conductivity than those obtained with flaky graphite, GF. Possibility to change dielectric properties of the composites without changing the loading content can be used as an approach in tailoring one with desired dielectric properties.     

Contribution of hydrogen and/or covalent bonds on reinforcement of natural rubber latex films with surface modified silica

A macromolecular coupling agent containing hydrophilic and hydrophobic groups is made to react with precipitated silica. Interfacial interactions between  OH groups of silica and  COOH groups of macromolecule are found to be created through either hydrogen bonds alone or through hydrogen bonds and covalent bonds. Aqueous dispersions of unmodified and modified silica are prepared and the colloidal stability and particle size distribution of the dispersions are observed. The dispersions at neutral pH are incorporated into vulcanized/unvulcanized natural rubber latex. The formation of hydrogen bonds and/or covalent bonds is studied via FTIR spectroscopy and their contribution in encouraging filler‐rubber interactions is emphasized through mechanical and swelling properties. Uniform distribution and dispersion of modified filler particles throughout the rubber matrix is confirmed by the microstructures of the latex films cast from filler added natural rubber latex. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40380.     

Characterization of the surface energies of functionalized multi-walled carbon nanotubes and their interfacial adhesion energies with various polymers

The surface energies of pristine multi-walled carbon nanotubes (MWCNTs) and MWCNTs functionalized with carboxylic acid (MWCNT-COOH), acyl chloride and ethyl amine were characterized, and the effects of the changes in MWCNT surface energies on the interfacial adhesion and reinforcement of the composites were explored. When the surface energy of pristine MWCNTs was compared to that of functionalized MWCNTs, a decrease in the dispersive surface energy and an increase in the polar surface energy were observed. Interfacial adhesion energies between MWCNTs and various polymers were estimated from surface energy values of MWCNTs and various polymers. Among the MWCNTs, polyethylene, polystyrene and bisphenol-A polycarbonate (PC) had the highest interfacial energy with pristine MWCNTs, while nylon 6,6 and polyacrylamine exhibited the highest interfacial energy with MWCNT-COOH. When tensile properties and adhesion at the interface of PC and nylon 6,6 composites containing MWCNTs were examined, composites having high interfacial adhesion energy exhibited greater adhesion at the interface and reinforcement.     

Soluble network polymers based on trifluoropropyl-substituted open-cage silsesquioxane: Synthesis,properties, and application for surface modifiers

Fluorinated completely condensed polyhedral oligomeric silsesquioxanes (F-CC-POSSs) are widely utilized as surface modifiers for polymeric materials because of their polyhedral and fluorine-rich structures, which generate polymers with lower surface energies under molecular-level control. In contrast, their derivatives, fluorinated incompletely condensed or open-cage POSSs (F-IC-POSSs), have similarly intriguing structures, but their utilization for polymer synthesis remains undeveloped. Herein, fluorinated network polymers were prepared based on a 3,3,3-trifluoropropyl-substituted IC-POSSs via hydrosilylation polymerization with isobutyl- and phenyl-substituted IC-POSS under optimized conditions. In addition to their good thermal stability and tunable refractive indices, these polymers exhibited solution processability and their casting films showed excellent optical transparency, indicating their potential for constructing fluorinated polymers. Their utilization as surface modifiers was examined by addition to poly(methylmethacrylate) (PMMA) films. Intriguingly, modified PMMA films with 2.0 and 0.5 wt% addition showed similar hydrophobicity and surface energies to the films prepared with only fluorinated network polymers.     

含辣素衍生结构疏水缔合聚合物的制备及性能

为了改进聚丙烯酰胺在原油三次采收领域存在的耐温耐盐性能差等问题，采用无助溶剂的无皂乳液聚合方式，以微量（0.05mol%）辣素衍生单体N-[3-（丙烯酰氨基甲基）-2-羟基-4,5-二甲基苄基]-丙烯酰胺（HMMAM）为功能性单体，与甲基丙烯酸十八烷基酯（SMA）、甲基丙烯酸异冰片酯（IBOMA）等共聚合成新型疏水缔合聚合物PACSAM和PACIAM以提高聚丙烯酰胺的各项耐受性能。采用FTIR、1HNMR、TGA、SEM等进行结构和形貌表征；探讨聚合物的疏水缔合特性、耐温耐盐性、溶解性及缓蚀性能等。结果表明，PACIAM和PACSAM存在稳定的三维网状结构，临界缔合浓度分别为4.5 × 10-3 g/mL和4 × 10-3 g/mL，微量辣素衍生单体的引入使0.01 g/mL聚合物溶液在30℃下表观黏度提升至776 mPa·s和1224 mPa·s，90 ℃黏度保留率为37.57%和41.44%，在0.01 g/mL的NaCl溶液中黏度保留率为37.57%和42.12%，溶解速率为25 min和27 min，4 × 10-3 g/mL的聚合物溶液的缓蚀效率可达96.76%和97.28%，表明微量HMMAM的引入大大增加了聚合物的各项性能。     

Effect of interfacial pretreatment on the properties of montmorillonite/poly(vinyl alcohol) nanocomposites

This work explores the factors that control the dispersion of exfoliated montmorillonite (MMT) in poly(vinyl alcohol) (PVOH) during solution blending and solvent evaporation. Nanocomposite films were prepared by solution blending of aqueous PVOH solutions with dilute suspensions of fully exfoliated MMT platelets (as confirmed by AFM). Dynamic light scattering (DLS) indicates that addition of MMT suspensions to PVOH solutions results in undesired particle aggregation and thus poor MMT dispersion in cast films (as evidenced by transmission electron microscopic images and gas permeation measurements). We believe that PVOH bridging induces MMT platelet aggregation. To counteract bridging aggregation, we explore the novel idea of pretreating the MMT surface with a small amount of compatible polymer prior to solution blending with PVOH. We hypothesize that “pretreating” the MMT platelet surfaces with adsorbed polymer in dilute suspensions will protect the platelets from bridging aggregation during solution blending and solvent evaporation. MMT/PVOH composite films have been prepared using low‐molecular‐weight PVOH as the pretreatment polymer; and low‐, medium‐, and high‐molecular‐weight PVOH as the matrix polymer. A PEO‐PPO‐PEO triblock copolymer (F108 from the Pluronics^® family) was also evaluated as the pretreatment polymer. DLS shows that pretreated MMT platelets are less susceptible to aggregation during blending with PVOH solutions. Results compare the crystalline structure, thermal properties, dynamic mechanical properties, gas permeability, and dissolution behavior of MMT/PVOH films incorporating untreated versus pretreated MMT. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41867.     

Sorption and desorption properties of random copolymer hydrogels of N‐isopropylacrylamide and N‐ethylacrylamide: Effect of monomer composition

Random copolymer hydrogels of N‐isopropylacrylamide and N‐ethylacrylamide (NEAM) were prepared using different monomer compositions in 1:1 methanol–water mixtures. The samples were characterized by cononsolvency study in methanol‐water mixtures at various temperatures, swelling properties measurements, scanning electron microscopy. With changing ratio of the monomers in the reaction mixture, the thermal, morphological and swelling properties, varied significantly. The change in the properties with monomer composition variation are interpreted based on the different thermoresponsive characteristics and interactions of gels of N‐isopropylacrylamide and NEAM (homo‐ and copolymer gels) in water and different methanol‐water mixtures, their variable compositions in the synthesis mixtures, and their morphologies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45176.     

One‐Pot Preparation of Organic–Inorganic Composite Microspheres Comprising Silica Nanoparticles and End‐Functionalized Polymers

Colloidal assemblies of inorganic nanoparticles dispersed in liquid media hold particular promise for the creation of a unique class of functional materials with innovative applications. In the present report, “compound‐eye”‐like core–shell and Janus‐type silica and amino‐terminated 1,2‐polybutadiene (PB‐NH₂) and polystyrene (PS) composite microspheres are successfully prepared by simply mixing an aqueous dispersion of silica particles into a tetrahydrofran (THF) solution of PB‐NH₂, and PB‐NH₂ and PS blends, followed by evaporation of the THF. This co‐precipitation process provides a new approach for producing organic–inorganic composite particles without the need for surface modification of the inorganic nanoparticles.

     

Investigations on the surface structure and properties of silica‐polyamine composites on the nanoscales and microscales

The structure and properties of silica polyamine composites (SPC) made from microparticles of amorphous silica gel (300–600 microns) and silica nanoparticles (10–20 nm) modified with aminopropyltrimethoxysilane (APTMS), poly(allylamine) (PAA) or poly(ethyleneimine) (PEI) have been studied. The APTMS nano‐hybrids showed batch capacities for copper equal to or better than the corresponding polymer‐based micro‐hybrids. Loading of the PEI on the nanoparticles was independent of molecular weight of the polymer. Dynamic light scattering measurements showed that the SiO₂ nanoparticles and the composites made from them aggregate in water and the degree of aggregation is dependent on the surface modification. All of the amine‐modified materials were catalysts for the Knoevenagel reaction but interestingly, the microparticles modified with APTMS were better catalysts than the corresponding nanoparticles or the polyamine modified composites. Solid‐state ¹⁹Si NMR has been used to elucidate the surface structure of the various composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42271.