Using poly(N,N-dimethylaminoethyl methacrylate)/polyacrylonitrile composite membranes for gas dehydration and humidification

The transport of water vapor through a composite membrane consisting of hydrophilic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) as the active layer and polyacrylonitrile (PAN) as the substrate was investigated, and the performance of the membrane for gas dehydration and humidification applications was evaluated. For gas dehydration, methane/water vapor mixtures were used as feed and vacuum was applied on the downstream side. The feed composition and operating temperature were found to have a significant effect on the membrane performance. The PAN substrate had little effect on the permeation of methane, but the resistance of the substrate to water vapor permeation was significant because of the substantially higher permeability of water vapor in the membrane. For gas humidification, liquid water was brought to be in contact with the active layer of the membrane and nitrogen gas flowed on the other side. With an increase in the gas flow rate, the mass transfer rate of water through the membrane to reach the gas stream increased, and the humidity level of the gas stream decreased. The humidification can be enhanced significantly by operating at a higher temperature. A phenomenological mass transfer equation was derived for membrane humidifiers to correlate the overall mass transfer coefficient and membrane area, and this equation could be used in process design and scale up.     

Composite membranes from polyacrylonitrile with poly(N,N-dimethylaminoethyl methacrylate)-grafted silica nanoparticles as additives

Polyacrylonitrile (PAN)-based composite membranes were prepared by immersion precipitation method by using poly(N,N-dimethylaminoethyl methacrylate)-grafted silica (PDMAEMA@SiO₂) nanoparticles as hydrophilic additives. The molecular weight of PDMAEMA were controlled by the surface initiated atom transfer radical polymerization of N,N-dimethylaminoethyl methacrylate on SiO₂ nanoparticles. The synthesized nanoparticles have a typical core–shell structure as characterized in detail by FT-IR, TEM, DLS and GPC. The prepared PAN-based composite membranes have higher porosity and water permeation flux than those of the pure PAN membranes. They also show high rejection (⩾90%) to bovine serum albumin and high flux recovery ratio (⩾90%) to water permeation. These improved performances are attributed to the good hydrophilicity of PDMAEMA@SiO₂ nanoparticles. The results suggest that PDMAEMA@SiO₂ nanoparticles are suitable for the property optimization of PAN-based composite membranes.     

Solute transport in poly(2-hydroxyethyl methacrylate) hydrogel membranes

The swelling, permeation, and release characteristics for benzoic acid, caffeine, propranolol hydrochloride, and diclofenac sodium in crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels were examined. Increasing polymer crosslinking density resulted in decreases in the degree of swelling, drug loading, the diffusivity of solute in the hydrogels, and in the rate of drug release. Diclofenac sodium led to an abnormally large degree of swelling as the maximum value is given as 6.5, while the highest for the other three was 1.07. That the logarithmic drug diffusivity was proportional to the reciprocal of hydration indicates that the free volume theory accounts for the transport of solute in the gels. Increasing the concentration resulted in increases in the diffusivities, solubilities, and permeabilities of the solutes in the hydrogels. The drug release kinetics from most wet hydrogel samples can be well-fitted by a Fickian diffusion model. Near zero-order release is observed only for dry samples with caffeine of low loading.     

Plasma graft polymerization of N,N-dimethylaminoethyl methacrylate and water–ethanol separation by pervaporation through the grafted membranes

N,N-dimethylaminoethyl methacrylate was graft-polymerized onto the porous polypropylene films of Celgard 2400 and 2500 which have been previously surface-activated by glow discharge plasmas. The grafting was dependent on various factors both in the plasma pretreatment and the post-polymerization with the monomer. The reaction was discussed from the aspects of the dependences of graft polymerization on discharge power, plasma pretreatment period, etc. When the grafting exceeded a critical amount depending on the size of pores on the substrate film, pervaporation of water-ethanol separation functioned through these grafted membranes. The water permselectivity was improved by the ammonium ionization of the pendant N,N-dimethylamino group using dimethyl sulfate or chloroacetic acid, although the increase of prevaporation performance was not so high as those previously obtained by the grafted poly(sodium acrylate) -type membranes. Pervaporation characteristics of these membranes were discussed from the ionized states of the permselective layers analyzed by IR and ESCA.     

Synthesis and responsive behavior of poly(N,N-dimethylaminoethyl methacrylate) brushes grafted on silica nanoparticles and their quaternized derivatives

Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) was grafted onto the surface of silica nanoparticles via surface-initiated atom transfer radical polymerization to form temperature- and pH-responsive PDMAEMA brushes (silica-g-PDMAEMA). The resultant samples were characterized via ¹H NMR, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Their molecular weights and molecular weight distributions were determined by gel permeation chromatography analysis after silica content etching. The control of brush thickness and the responsive behavior were systematically investigated. Dynamic light scattering (DLS) results indicate that the brush thickness can be controlled by changing the polymerization time and the DMAEMA, initiator, and THF concentrations. According to DLS and zeta potential results, the lower critical solution temperature (LCST) of the PDMAEMA brushes shifts to a higher temperature with decreasing solution pH, which is attributed to the weak charge of the polyelectrolyte brushes. When the temperature is kept above the transition temperature, the silica-g-PDMAEMA nanoparticles aggregate into clusters and disaggregate during the cooling process. Moreover, with the heating/cooling step increasing, the aggregation and disaggregation temperatures are decreased. Meanwhile, when the molecular weight is increased from 13.6 × 10⁴ to 23.1 × 10⁴ g/mol, a decrease in the LCSTs at constant pH is observed. The related properties of the corresponding quaternized analog, poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI) brushes, were also discussed. The hydrodynamic radius of the silica-g-PMETAI nanoparticles decreases with increasing ionic strength, and a salting-out/salting-in effect is observed when the ionic strength is adjusted using NaI instead of NaCl.     

紫外光引发甲基丙烯酸-N,N-二甲氨基乙酯溶液聚合的研究

研究了甲基丙烯酸 -N ,N -二甲氨基乙酯的紫外光引发自由基溶液聚合的条件 ,包括引发剂安息香乙醚用量、单体浓度、光引发时间及其对聚合速率、产率与相对分子质量的影响 ,实验确定了制备线型聚甲基丙烯酸 -N ,N -二甲氨基乙酯聚合物的工艺及方法。采用膨胀计法研究了聚合反应 ,其反应速率与单体浓度呈 1.91级关系 ,结果表明 ,单体可能同时参与了光引发过程     

Rate of radical polymerization of N,N-dimethylaminoethyl methacrylate in cyclohexane

Summary Anions of propene, isobutylene and cycloheptatriene have been prepared using Lochmann's Base. Star polymers in the form of one arm star, two arm star and three arm star polymers of styrene have been synthesized from the allyl anion (2), 2-methylenepropylenyl dianion (4) and the cycloheptatrienyl trianion (6) respectively, with acid end groups by quenching the living polymers with carbon dioxide. The number average molecular weight has been determined by stoichiometry, HPSEC and end group analysis by titration.     

The transport phenomena of some model solutes through postcrosslinked poly(2-hydroxyethyl methacrylate) membranes with different tactic precursors

Two series of membranes of various degree of hydration have been prepared by postcrosslinking highly syndiotactic and isotactic poly(2-hydroxyethyl methacrylate) [P(HEMA)] with various amounts of hexamethylene diisocyanate (HMDIC). The equilibrium water content, the partition coefficient, and the permeability of the model solutes such as urea, acetamide, NaCl, 2-propanol, and isobutanol for these membranes were measured. In addition, differential scanning calorimetry (DSC) study for the membranes was performed. The membranes of the isotactic precursor are more hydrated at 25°C compared to the ones of its syndiotactic counterpart. This may be due to the more hydrophobic nature of syndiotactic P(HEMA). The partition coefficient data show that the solutes of urea, acetamide, and NaCl are partitioned only into the water-containing region, whereas the alcohol solutes are preferentially sorbed on to polymer matrix. The permselectivity data of urea to NaCl reveal that the permselectivity of crosslinked isotactic P(HEMA), (ISO) membranes increases as the amount of HMDIC is increased from 2.5 to 10 mol %, while the trend is reversed for crosslinked syndiotactic P(HEMA), (SYN) membranes. The apparent diffusivity order of urea, acetamide, and NaCl is not the same in those two characteristic membranes: the order is urea > NaCl > acetamide for highly crosslinked ISO membranes, and NaCl > urea > acetamide for all SYN membranes, which was compared with the free diffusion data in aqueous solution and interpreted in terms of the water-structural orderlines within membranes.     

二(N,N-二甲基胺基乙基)己二酸酯的合成

采用二月桂酸二丁基锡为催化剂,通过己二酸二甲酯与N,N-二甲基乙醇胺进行酯交换反应合成了二(N,N-二甲基胺基乙基)己二酸酯.实验考察了反应温度、催化剂量、反应时间及物料配比等因素对反应收率的影响.最佳工艺条件为:温度120℃,反应时间5h,n(己二酸二甲酯):n(二甲胺基乙醇):n(二月桂酸二丁基锡)=1:6:0.048.在优化条件下,产品收率为81.6%(以己二酸二甲酯计),产物经IR、'HNMR表征了结构.     

Complexes of poly(2-N,N-dimethylaminoethyl) methacrylate with heavy metals I. Preparation and properties

The present paper studies the synthesis of complexes of poly(2-N,N-dimethylaminoethyl) methacrylate with aqueous solutions of of salts of FeSO₄.2H₂O; CoCl₂.6H₂O; CuCl₂.2H₂O; VOSO₄.5H₂O; Na₂MoO₄.2H₂O and Na₂WO₄.2H₂O. The introduction of metal ions depends on the content of crosslinking agent and was in the range from 1.18 to 59.63 mg metal ion/g polymer carrier. The study of polymer complexes by IR and Moesbauer spectroscopy, as well as EPR, provides possibilities to suggest the probable co-ordination structure of the compounds.     

The transport of methyl methacrylate monomer in poly(methyl methacrylate)

The absorption kinetics and equlibria of methyl methacrylate monomer into poly(methyl methacrylate) were studied over a range of penetrant activities. The interval sorption kinetics at elevated activities were determined, compared, and contrasted with the integral sorption experiments in previously unpenetrated film samples. The sorption kinetics in previously unpenetrated films were predominantly case II or relaxation controlled at high activities. A Fickian contribution to the overall kinetics was apparent at lower activities. In contrast, interval sorption, at elevated activities in previously equilibrated and plasticized samples, followed Fickian kinetics rather closely, whereas resorption, over an activity range which involved a traversal of the effective T_g, was characterized by more complicated kinetics involving a super case II mechanism at long times. These composite results reinforce the notion that the kinetics describing penetration of a single penetrant into a single polymer are extremely sensitive to the boundary condition imposed upon the polymeric sorbent.     

Preparation of poly (N,N‐dimethylaminoethyl methacrylate) (PDAEM) membranes: Application for water purification

The present work concerns a development of new membranes for performing ions separation. These membranes were prepared by solution casting followed by solvent evaporation, using a commercial cellulose triacetate (CTA), synthesized poly (N,N‐dimethylaminoethyl methacrylate), macrocylic polyethers (15‐crown‐5 and Dibenzo‐24‐crown‐8) as carrier and dioctylphtalate as plasticizer. Different Polymer Inclusion Membranes were characterized using physical and chemical techniques as well as Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. Transport of lead and cadmium in aqueous solution has been studied using these systems. The selective separation of these membranes is accomplished by the presence of specific compounds, called carriers, in the membrane phase. The carriers are responsible to facilitate the transport of the target component across selective membranes. The influence of the membrane nature has been studied using some supports of different physical characteristics. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46592.     

Synthesis of poly(N,N-dimethylaminoethyl methacrylate) nanogels in reverse micelles for delivery of plasmid DNA and small interfering RNAs into living cells

Hydrogel nanoparticles of poly(N,N-dimethylaminoethyl methacrylate) with hydrodynamic radii of 40?C50 nm are synthesized via the copolymerization of a water-soluble monomer and N,N??-methylenebis(acrylamide) in a solution of Brij-97 reverse micelles in cyclohexane. All amino groups of nanoparticles are protonated in a weakly acidic solution; however, almost one-third of them remain inaccessible to a flexible polystyrenesulfonate polyanion, while almost two-thirds of them remain inaccessible to rigid double-helical DNA. Complexes of nanogels with plasmid DNA carrying the firefly luciferase gene transfect eukaryotic cells in a cultural medium, and the products of interaction of nanogels with small interfering RNAs suppress expression of the marker enzyme. In both systems, the replacement of linear polyamine with nanogel significantly increases the efficiency of delivery. The activity of nanogels in transfection experiments depends in an extremum pattern on the crosslink degree and achieves a maximum value at a crosslinking-agent concentration of 5 mol %. The results of this study suggest that the developed procedure offers promise for the synthesis of cationic nanogels as vectors for delivery of genetic material into living cells.     

Grafting of pH-sensitive poly (N,N-dimethylaminoethyl methacrylate-co-2-hydroxyethyl methacrylate) onto HNTS via surface-initiated atom transfer radical polymerization for controllable drug release

Copolymer brushes composed of N,N-dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) were tethered on the surface of HNTs (HNTs) through surface-initiated atom transfer radical polymerization (SI-ATRP). ATRP initiator was anchored to surface and copolymers were synthesized from surface with different compositions of monomers. Successful grafting of copolymer brushes was approved by FTIR, TGA, XPS, FE-SEM, TEM, and N₂ adsorption-desorption.¹H NMR was used to determine the composition of copolymers. pH-sensitive properties of copolymer-grafted nanotubes were investigated by UV-visible absorbance in different pH values. Finally, loading and in vitro drug release from neat and copolymer-grafted HNTs were investigated using diphenhydramine hydrochloride as a model drug. Incorporation of DMAEMA to structure of polymers led to pH sensitivity of grafted-copolymers and controlled release of drug upon varying the pH of release medium. pH-dependent drug release showed that drug release was increased by decreasing pH of release medium and increasing DMAEMA content.     

Miscibility of poly(methoxymethyl methacrylate) and poly(methylthiomethyl methacrylate) with poly(methyl methacrylate)

Summary Poly(n-propyl methacrylate) is known to be immiscible with poly(methyl methacrylate) (PMMA). However, we have found that poly(methoxymethyl methacrylate) is miscible with PMMA, indicating the importance of ether oxygen atoms in achieving miscibility. On the other hand, poly(methylthiomethyl methacrylate) is immiscible with PMMA.     

Controlled radical polymerization of N,N-dimethylaminoethyl methacrylate using triazolinyl as counter radical

Summary The role of the triazolinyl radical as additive for controlled radical polymerisation is investigated for N,N-dimethylaminoethyl methacrylate (DMAEMA) as polar monomer. A linear increase of the molecular weight with conversion and first-order kinetics are observed proving the controlled behaviour of the polymerization. The end-functionalisation of the obtained polymers was proven by both GPC und UV-spectroscopy. Furthermore, various amphiphilic block copolymers were obtained by chain extension with styrene, methyl methacrylate and ethyl methacrylate. In all cases monomodal GPC curves were obtained indicating an almost quantitative reinitiation.     

A study of electrostatically stabilized poly(methyl methacrylate) latex

Poly(methy methacrylate) latex with various solid contents, stabilized electrostatically, was studied. The hydrodynamic layer (H.L.) extends rapidly at volume fraction larger than 0.35. The agglomeration of particles was found. When the reduced thickness (δ/r) of H. L. exceeds 3.0, particle agglomeration becomes more serious and the gel-like product forms. In comparison, the value of (δ/r) is much smaller than 3.0 when the H. L. begins to contact each other. Using a higher amount of emulsifier, the thickness of H. L. decreases. This is attributed to the fact that more free emulsifier presenting in the aqueous phase leads to more depletion stabilization. Meanwhile, in the presence of unreacted monomer, the use of the monomer-swollen volume fraction is suggested to replace the unswollen volume fraction. © 1994 John Wiley & Sons, Inc.