Polymerization Of Hydrophilic Monomers Research Articles

Hydrophilic Microporous Polymer Membranes: Synthesis and Applications.

Ion and water transfer in subnanometer-sized confined channels of hydrophilic microporous polymer membranes show enormous potential in tackling the ubiquitous trade-off between permeability and selectivity for energy and environment-related membrane technologies. To this end, a variety of hydrophilic polymers of intrinsic microporosity (HPIMs) have been developed. Herein, the synthetic strategies toward HPIMs are summarized, including post-synthetic modification of polymers to introduce polar groups (e. g., amines, hydroxy groups, carboxylic acids, tetrazoles) or charged moieties (e. g., quaternary ammonium salts, sulfonic acids), and the polymerization of hydrophilic monomers. The advantages of HPIM membranes over others when employed in energy conversion and storage, acid gas capture and separation, ionic diodes, and ultrafiltration, are highlighted.

Stretchable dual nanocomposite hydrogels strengthened by physical interaction between inorganic hybrid crosslinker and polymers

Stretchable hydrogels have been developed by fabricating a dual nanocomposite structure by polymerization of hydrophilic monomers and sol-gel reaction of tetraethyl orthosilicate (TEOS) in the presence of Laponite. The mechanical enhancement of the hydrogels was markedly influenced by monomer structure and contents of TEOS and Laponite. The strong interaction between N-isopropylacrylamide (NIPAM) and inorganic hybrid crosslinker was examined by dyeing experiment, transparency and fluorescence measurement of Laponite/SiO2/monomer dispersions. This accounted for the excellent mechanical properties of Laponite/SiO2/PNIPAM dual nanocomposite hydrogel. Uniaxial tensile tests showed improved tensile property (elongation at break: 1845±3.46%; fracture stress: 271.41±6.26kPa), and elastic modulus of the hydrogel significantly increased with TEOS contents and reached 26.69±6.13kPa at 10:1.0 of mLaponite:mTEOS. Fracture compression strength could reach 7.06±1.25MPa (fracture energy: 1185.53±5.57Jm−2), meanwhile it showed remarkable fatigue resistance. The embedded nano-SiO2 accounted for the significantly improved stiffness of the hydrogels. Moreover, the dual nanocomposite mechanism (the covalent bonding of SiO2 with Laponite and strong physical interaction of polymer chains with inorganic hybrid crosslinker) made a big contribution to the toughness of the gels. The noncovalent entanglements between SiO2 and polymer chains could promote both strength and elongation of the hydrogel, but the effect is not as notable as the covalent one.

Copper-mediated controlled radical polymerization under biological conditions: SET-LRP in blood serum

The polymerization of hydrophilic monomers is reported utilizing Cu(0)-mediated living radical polymerization, SET-LRP. Highly active Cu(0) is formed in situ as a result of rapid disproportionation of [Cu(I)(Me6-Tren)Br] in serum. Disproportionation and homogenous controlled radical polymerization (PDI 1.09-1.25) are performed for the first time in blood (sheep) serum.

E-Beam Graft Polymerization of Hydrophilic PEG-Methacrylate on the Surface of PMMA

The graft polymerization of hydrophilic monomers on the surface of hydrophobic PMMA was performed using an electron beam (e-beam). The dose of e-beam irradiation, reaction concentration, temperature, and reaction time were used to study the effect of variables on the graft density of poly (ethylene glycol)-methacrylate. The results demonstrated that the weight percentage of graft polymer increased with increasing temperature, time and monomer concentration. However, the weight of the graft polymer did not increase with the increasing dose of e-beam irradiation. The change of the contact angle of the water droplet on the PMMA surface was monitored as a function of a reaction time. The results showed that the contact angle decreased up until a specific time and then leveled off to an approximately constant value after a certain reaction time of the graft polymerization. Transmission electron microscopy proved that the constant value of the contact angle was due to the local survival of surface radicals followed by the perpendicular diffusion of monomers only into the bulk of the surface-modified area on the sheet surface.

Radiation Polymerization of Hydrophilic Monomers for Producing Hydrogel Used in Waste Treatment Processes

Co60-γ radiation was used in the synthesis of bipolymer hydrogel, using acrylamide (AAm), acrylic acid (AAc), and sodium acrylate. The parameters affecting preparation of these hydrogels such as monomer ratio, crosslinking agent ratio, and irradiation dose have been studied. The swelling behavior of these hydrogels was studied under different preparation conditions. The experimental results showed that the gel fraction of the produced hydrogel depends mainly on the irradiation dose, and the degree of swelling was intimately related to irradiation dose and blending ratio of the two monomers. Characterization of the obtained hydrogel was carried out using spectroscopic analysis such as infrared (IR) and scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) and the morphology of the prepared hydrogels using X-ray diffraction (XRD) techniques have been studied. The efficiency of these hydrogels for different metal ions adsorption (such as Cu2+, Co2+, Ni2+, and Cr2+) was studied using ICP technique. In addition, the parameters affecting the absorption efficiency, such as time of treatment and pH value were investigated.

Effects of Monomer Organization on the Photopolymerization Kinetics of Acrylamide in Lyotropic Liquid Crystalline Phases

The synthesis of nanostructured polymer gels via polymerization of hydrophilic monomers in lyotropic liquid crystal (LLC) phases has recently been of great interest. This work describes the effects of monomer organization on the photopolymerization kinetics of acrylamide in various LLC phases of surfactant/water systems. Resulting polymer morphology is reported as well. The polymerization rate of acrylamide is significantly enhanced when performed in the presence of various LLC phases. An unprecedented 10-fold increase in polymerization rate is observed in bicontinuous cubic and hexagonal phases as compared to polymerizations in water. This significant increase in polymerization rate is a result of diffusional limitations on the propagating polymer as well as segregation and ordering phenomena induced by the LLC phase. 13C T1 relaxation times and 14N NMR spectra show that the monomer strongly associates with the interface of the surfactant/water assemblies and assumes the orientational order of the LLC phases to some degree. When formed using photopolymerization, the resulting polymer morphology appears to be a direct template of the parent LLC phase.

Morphology Variation of Porous Polymer Gels by Polymerization in Lyotropic Surfactant Phases

Polymerization of hydrophilic monomers, such as acrylamide, in the confinement of lyotropic liquid crystalline phases of nonionic surfactants produces gels with variable pore architecture in the hundreds of nanometers to micrometers size range. The porous gels are characterized by scanning electron microscopy after critical-point drying. The structure of the gels depends on the type of monomer, cross-linking density, and both monomer and surfactant concentration and can be varied systematically to result in different pore morphologies with different pore sizes. In such a way it is possible to build the polymer network structure on a mesoscopic length scale, optimizing different network properties which are otherwise coupled in an opposite fashion; e.g., polymer networks with very large pore size and high mechanical stability can be made.

Polymer Gels with a Micron-Sized, Layer-like Architecture by Polymerization in Lyotropic Cocogem Phases

Polymerization of hydrophilic monomers, such as acrylamide, in the aqueous lyotropic phases of counterion-coupled gemini surfactants (“cocogems”) results in highly ordered gels with a layerlike architecture between the submicrometer and micrometer length scale. The order of such gels is preserved even after removing the templating surfactant. The evolution of the gels is monitored using polarized light optical microscopy, rheology, small-angle X-ray scattering, and scanning electron microscopy (SEM). The synthesis envokes structural changes of the templating lyotropic phase structure as well as demixing of the gelling polymer and the surfactant phase. The overall gel morphology is, however, still controlled by the anisotropy of the surfactant assembly. Hence, the polymer gel is not a direct cast of the original phase structure, but its growth is indirectly controlled by the ordered arrays. The persistence of the lyotropic liquid crystalline phases of cocogems is high enough to preserve a layered order, however with the characteristic size of a demixing structure rather than that of the parental lyotropic phase. Chemical functionalization of these gels is easily achieved by copolymerizing functional comonomers, such as acrylic acid or dimethylaminoethyl methacrylate. It is expected that these ordered gels, simple to prepare and inexpensive, will find a number of applications in various fields of modern materials science, such as for the construction of size-selective membranes or high-performance material hybrides.

Durable, hydrophilic surface modification of polypropylene films by plasma graft polymerization of glycidyl methacrylate

The plasma graft polymerization of glycidyl methacrylate (GMA) was investigated to obtain hydrophilic surface. The combination of the argon plasma and GMA vapor exposures leaded to graft polymerization of GMA at the surface of polypropylene films. This graft polymerization was initiated by the argon plasma exposure for 2 min, and was accomplished with the GMA vapor exposure for 2 min. The GMA graft polymerization made polypropyrene surface hydrophilic. The surface energy was 55.8 mJ/m2. The hydrophilicity introduced by the GMA graft polymerization remained for at least 3 weeks. The graft polymerization of hydrophilic monomers was a good means of hydrophilic surface modification.