Synthesis and antibacterial activities of water‐soluble methacrylate polymers containing quaternary ammonium compounds

New water‐soluble methacrylate polymers with pendant quaternary ammonium (QA) groups were synthesized and used as antibacterial materials. The polymers with pendant QA groups were obtained by the reaction of the alkyl halide groups of a previously synthesized functional methacrylate homopolymer with various tertiary alkyl amines containing 12‐, 14‐, or 16‐carbon alkyl chains. The structures of the functional polymer and the polymers with QA groups were confirmed with Fourier transform infrared and ¹H and ¹³C NMR. The degree of conversion of alkyl halides to QA sites in each polymer was determined by ¹H NMR to be over 90% in all cases. The number‐average molecular weight and polydispersity of the functional polymer were determined by size exclusion chromatography to be 32,500 g/mol and 2.25, respectively. All polymers were thermally stable up to 180 °C according to thermogravimetric analysis. The antibacterial activities of the polymers with pendant QA groups against Staphylococcus aureus and Escherichia coli were determined with broth‐dilution and spread‐plate methods. All the polymers showed excellent antibacterial activities in the range of 32–256 μg/mL. The antibacterial activity against S. aureus increased with an increase in the alkyl chain length for the ammonium groups, whereas the antibacterial activity against E. coli decreased with increasing alkyl chain length. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5965–5973, 2006     

Design and synthesis of ninhydrin-based cyclophanes as potential neutral receptors for quaternary ammonium cations

Four ninhydrin-based cyclophanes 4a, 4b, 6a, and 6b were designed and synthesized. Two rectangular type cyclophanes (4a and 4b) and two square type cyclophanes (6a and 6b) were prepared in 8-43% yields.     

Functionalization of polypropylene by hydroboration

This article relates to functionalized polypropylene with high molecular weight and high crystallinity. The chemistry involves the hydroboration of poly(propylene-co-1,4-hexadiene) with borane reagents, such as diborane and 9-BBN. In turn, the borane-containing polymers are very versatile and can be easily converted to various functionalized polymers under mild reaction conditions. Despite the heterogeneous reaction conditions, both hydroboration and interconversion reactions were very effective using appropriate solvents. Apparently, the double bonds in the side chains are located in the amorphous phase and are ready for reaction with reagents. Overall, this functionalization process preserves the molecular weight and most of the crystallinity of poly(propylene-co-1,4-hexadiene). © 1993 John Wiley & Sons, Inc.     

TG characterization of organically modified montmorillonite

Montmorillonite was modified with octadecyltrimethylammonium chloride, under different reaction conditions, as evidenced by TG and XRD. TG curves presented two degradation peaks (295 and 395°C). At low salt concentrations, only the 395°C-degradation appeared, which increased with reaction time to the limit of 9 g of salt/100 g of clay. The second peak presented a limit at 17/100 m/m of salt/clay ratio. XRD analysis confirmed clay organic modification as the basal distance increased, showing greater reaction time effect than the salt mass effect, and with only one d-spacing. This suggested that an intercalation complex was formed but also that octadecyltrimethylammonium was adsorbed on the external surfaces of clay particles. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis by ATRP and effects of molecular weight on photomechanical properties of liquid crystalline polymers containing side-chain azobenzene chromophores

The synthesis of a series of azobenzene containing liquid crystalline methacrylic homopolymers, poly(4-ω-methacryloyloxy-hexyloxy-4′-ethoxyazobenzene) [Poly(M6A)], with distinct average chain lengths and low polydispersity has been achieved by Atom Transfer Radical Polymerization (ATRP) in THF solution using allyl 2-bromoisobutyrate as initiator and Cu(I)Br as catalyst. Under the adopted conditions the living centers concentration is found to be constant throughout the polymerization process and well defined chain end-groups are obtained. All the obtained polymeric samples, having average molecular mass ranging from 3300 to 14000 g/mol, exhibit smectic and nematic liquid-crystalline phases on heating, with transition temperatures strongly dependent on polymerization degree, as characterized by differential scanning calorimetry and polarized optical microscopy.The photomechanical effects (i.e. the dependence of volume and density) exhibited upon trans-to-cis and cis-to-trans photoisomerization of the azobenzene mesogenic groups have been investigated by ellipsometry and related to molecular weight, with particular attention to important parameters for potential applications such as the relative variation of total volume, response time, stability and reproducibility.     

Thermogravimetric analysis of calcium montmorillonite treated with hexamethylene diisocyanate

The product of the reaction between calcium montmorillonite and hexamethylene diisocyanate in acetone, catalyzed with dibutyltin dilaurate, was studied by thermogravimetry to determine the amount of polymer produced. The method developed to determine polymer content in the clay possessed excellent accuracy and precision, and produced more consistent results than traditional gravimetric methods.This research originated as a portion of the author's Master's degree research undertaken at California State Polytechnic University Pomona, and conducted at the Getty Conservation Institute (GCI). The author is indebted to the following colleagues at the GCI for providing advice and direction: Neville Agnew, Charles Selwitz, Dusan Stulik, James Druzik, David Scott and William Ginell. Consolidated adobe samples were prepared at the GCI by Richard Coffman, and by Dr. Michael Geis, department of Chemistry, Loyola University. Much valuable information and technical assistance was provided by Dr. Hans Wiedemann and Genia Paul, both of Mettler Instrument Corporation.     

Preparation and characterization of side-chain liquid crystalline polymers containing chenodeoxycholic acid residue

A series of new side-chain liquid crystalline polymers containing chenodiol residue derived from 24-[4′-hydroxybiphenyl-4-yl-4-(allyloxy)benzoyloxy]-3α,7α-di{n-[4′-(4-ethoxybenzoyloxy)biphenyl-4-yloxy]-n-oxoalkanoyloxy}-5β-cholane was designed and prepared. The chemical structures of the monomer and polymer were confirmed by Fourier transform infrared and ¹H NMR spectra. The mesomorphic properties of monomer and polymer were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X-ray diffraction. The side-chain liquid crystalline polymers revealed wide mesophase temperature range and high thermal stability, and they showed nematic liquid crystalline phase. The influence of flexible space group length on thermal properties and specific rotation was examined.     

Synthesis and properties of hydroxide conductive polymers carrying dense aromatic side-chain quaternary ammonium groups

A series of hydroxide conductive polymers QTBMs carryingdense aromatic side-chain quaternary ammonium groups has been synthesized by using a new monomer of 3,3′-di(3′′,5′′-dimethylphenyl)-4,4′-difluorodiphenyl sulfone and other commercial monomers via polycondensation reaction, and subsequent bromination, quaternization and alkalization.The chemical structures of the ionomers were confirmed by ~1H-and ~(13)C-NMR spectroscopy. Water uptake, swelling ratio, hydroxide conductivity, the number of bonded water per ammonium group(λ), volumetric ion exchange capacity(IEC_(Vwet)), mechanical and thermal properties, and chemical stability were systematically evaluated for the series of QTBMs membranes. QTBMs showed IECs ranging from1.02 meq·g~(-1)to 2.11 meq·g~(-1); in particular, QTBM-60 membrane with the highest IEC(2.11 meq·g~(-1)) had very high hydroxide ion conductivity of 131.9 m S·cm~(-1) at 80 °C, which was attributed to the well assembled nano-channels with distinct phase separation evidenced by small-angle X-ray scattering(SAXS). It was found that the hydrated QTBMs membranes were mechanically stable with moderate water uptakes and swelling ratios, high chemical stability under the harsh alkaline conditions. This work provides a facile way to prepare anion exchange membranes(AEMs) with high performances for the application in alkaline fuel cells.     

The acidity of analogous ammonium cations: A description of the solvent effect through the attainment of hydration clusters using the AGOA methodology

The optimized geometries of ethylaminium (1), ethyldiaminium (2), n-butylaminium (3) and tri-ethylaminium (4) cations were calculated using the B3LYP/6-311++G(d,p) theoretical level. Subsequently, the hydration clusters of these structures were explored using the AGOA methodology. Analysing the molecular electrostatic potential of the solute and using the TIP4P model to orient the water molecules around the ammonium cations, systematic increases were observed in hydration energy, from 1 to 4. This result does not correlate with the experimental acidity of 1–4, suggesting that the AGOA methodology is not efficient in modelling cationic structures in an aqueous medium. The AGOA hydration clusters were, therefore, re-optimized (AGOA-OPT) using the B3LYP/6-311++G (d,p) theoretical level. This new AGOA-OPT procedure revealed the hydration energy of the 1, 2, 3 and 4 cations to be in accordance with the experimental acidity.     

Functional benzoxazines containing ammonium salt of carboxylic acid: Synthesis and highly activated thermally induced ring‐opening polymerization

1,3‐Benzoxazine monomers having ammonium salt of carboxylic acid have been developed. These 1,3‐benzoxazines 1a and 1b were easily synthesized from the corresponding tetrabutylammonium salts of glycine and β‐alanine, respectively. The glycine‐derived benzoxazine 1a exhibited remarkably high reactivity, which allowed its thermally induced ring‐opening polymerization in bulk at 100 °C, at which N‐methyl‐1,3‐benzoxazine 1d did not undergo the polymerization at all. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Calixarenes as hosts for ammonium cations: a quantum chemical study and mass-spectrometric investigations

Host-guest complexes of tetramethylcavitand with different ammonium cations were investigated by using a quantum chemical method at the density functional level (BP86, B3 LYP). The NH4+ cation is strongly bound to the host. Increasing methyl substitution at the cation decreases its inclination towards the complex formation. The calculated data are in line with results from electrospray ionization mass spectrometry (ESI-MS) experiments. They reveal stable aggregates only for the NH4+ cation and for the primary alkylammonium cations.     

超吸水聚丙烯酰胺/蒙脱土复合材料力学性质的研究

利用紫外线照射方法合成了超吸水聚丙烯酰胺／蒙脱土复合材料(SAPC)。力学性质研究表明其吸水膨胀时可以做功。做功能力和效率取决于其形状。材料越薄,膨胀速率越快,单位质量材料产生功率越大。改变溶液pH值可以改变SAPC的膨胀能力。     

Stability of Na-montmorillonite suspension in the presence of different cations and valences

The aim of this study was to investigate the effects of inorganic cations (Na⁺, Ca²⁺, and Al³⁺) with different valences and concentrations on the stability of Na-montmorillonite (Na-MMT) suspension. The stability was studied by turbidity and zeta potential measurements and adsorption thermodynamics. The results showed that the Na-MMT particles coagulated at pH 3–4.8, the stability of which was much inhibited by cations with higher concentration and higher valence. This was caused by the adsorption of cations and the reduction of electrostatic repulsion. Adsorption of Ca²⁺ on Na-MMT surface fits the Freundlich curve model well. Furthermore, the adsorption reduced the zeta potential of Na-MMT and then the energy barrier between the particles which well obeyed the classic DLVO theory.     

Thermo-XRD analysis of the adsorption of Congo-red by montmorillonite saturated with different cations

The adsorption of the organic anionic dye Congo red (CR) by montmorillonite saturated with Na⁺, Cs⁺, Mg²⁺, Cu²⁺, Al³⁺ and Fe³⁺ was investigated by XRD of unwashed and washed samples after equilibration at 40% humidity and after heating at 360 and at 420°C. The clay was treated with different amounts of CR, most of which was adsorbed. Clay samples, untreated with CR, after heating showed collapsed interlayer space. Unwashed and washed samples, which contained CR, before heating were characterized by three peaks or shoulders, labeled A (at 0.96-0.99 nm, collapsed interlayers), B (at 1.24-1.36 nm) and C (at 2.10-2.50 nm). Peak B represents adsorbed monolayers of water and dye anions inside the interlayer spaces. Peak C represents interlayer spaces with different orientations of the adsorbed water and organic matter. Diffractograms of samples with small amounts of dye were similar to those without dye showing peak B whereas diffractograms of most samples with high amounts of dye showed an additional peak C. Heated unwashed and washed samples were also characterized by three peaks or shoulders, labeled A' (at 0.96 nm), B' (at 1.10-1.33 nm) and C' (at 1.61-2.10 nm), representing collapsed interlayers, and interlayers with charcoal composed of monolayers or multilayers of carbon. When the samples were heated from 360 to 420°C some of the charcoal monolayers underwent rearrangement to multilayers. In the case of Cu the charcoal decomposed and oxidized. The present results show that most of the adsorbed dye was located inside the interlayer space.This revised version was published online in November 2005 with corrections to the Cover Date.     

水溶性聚合物和两亲聚合物:14.丙烯酰胺/2-丙烯酰胺基十六烷磺酸铵无规共聚物

水溶液中用硫酸亚铁-异丙苯过氧化氢氧化还原引发体系合成了丙烯酰胺(AM)/2-丙烯酰胺基十六烷磺酸铵(AMC_(16)SNH_4)无规共聚物。用元素分析、IR、~(13)C-NMR和~1H-NMR对其进行了表征。对水溶液性质的研究结果表明,与部分水解聚丙烯酰胺相比,这种新型共聚物有着优异的耐盐性、耐温性和贮存稳定性。     

Polymers containing quaternary ammonium groups based on poly(N-vinylimidazole)

A poly(N-vinylimidazole) (PNVI)—based poly(carboxybetaine) with two methylene groups between the opposite charges was achieved by the nucleophilic addition reaction of the mentioned aminic polymer to the carbon-carbon double bond of acrylic acid (AA). Treatment of poly(carboxybetaine) with concentrated HCl (2 N) for long time leads to the corresponding cationic polyelectrolyte. The poly(carboxybetaine) is soluble in both water and aqueous solutions of salts such as: LiCl, NaCl, NaHCO₃, CaCl₂, Na₂SO₄. In water and in the first three salts, poly(carboxybetaine) exhibits a non-polyelectrolyte behaviour (a linear dependence of reduced viscosities on polymer or salt concentration), while in the remaining two salts, a slight polyelectrolyte behaviour is observed. The cationic polyelectrolyte is soluble in water and aqueous solutions of LiCl, NaCl, CaCl₂ and NaHCO₃, except Na₂SO₄. It has a polyelectrolyte behaviour in all solutions. Also, the binding trends of the added salts by polymers are discussed.     

Interaction of long chain alkylammonium cations with reduced charge montmorillonite

Reduced charge montmorillonites (RCM) were prepared using lithium thermal treatment. The sorption of octylammonium (OA), dodecylammonium (DDA) and hexadecylammonium ions (HDA) on differently charged samples were studied. The amounts of DDA and HDA sorbed on each RCM exceed the cation exchange capacity (CEC) but that of OA exceeds only the CEC of samples with the lowest CEC. The sorption is affected not only by the layer charge but also by the formation of collapsed interlayer spaces in the lowest charged montmorillonites. X-ray measurements confirmed the decrease of the layer charge after lithium thermal treatment and the layer charge heterogeneity in RCMs.     

Synthesis and characterization of azobenzene-containing side-chain photorefractive polymers

The synthesis and characterization of some new high-T_g photorefractive polymers, polyphosphazene P3-P8, were described. They were obtained via a post-azo coupling reaction. The resulting materials have been characterized by means of ¹H NMR, ³¹P NMR, FT-IR, UV-vis, GPC and DSC. Chromophore contents up to 14 mol% have been realized. The polymers had high glass transition temperatures and good optical transparency. Measurements reveal that they possess relatively large magnitude of photoinduced birefringence.     

超声波合成温敏型聚合物——聚(N-异丙基丙烯酰胺)

以N-异丙基丙烯酰胺为单体,N,N′-亚甲基双丙烯酰胺为交联剂,THF为溶剂,采用超声辐照聚合法合成了一种温敏型聚合物——聚(N-异丙基丙烯酰胺)(1),其结构经FT-IR表征.用UV-Vis研究了1的热相转变性能.结果表明,1具有温度敏感性,其最低临界共溶温度为34℃.