Biocidal polymers active by contact. V. Synthesis of polysiloxanes with biocidal activity

Polysiloxanes with 3‐(alkyldimethylammonio)propyl pendant groups were synthesized by quaternization of n‐octyldimethylamine or n‐dodecyldimethylamine with linear polysiloxanes containing 3‐chloropropyl groups and/or 3‐bromopropyl groups attached to silicon atoms. The precursor polysiloxanes, poly[(3‐chloropropyl)methylsiloxane] homopolymer and various copolymers containing (3‐halogenopropyl)methylsiloxane and dimethylsiloxane units, were obtained by equilibrium cationic polymerization of linear and cyclic siloxanes with (3‐halogenopropyl)methylsiloxane units. The polysiloxanes bearing quaternary ammonium salts (QAS) showed bactericidal activity against bacteria such as Escherichia coli and Aeromonas hydrophila when incorporated in a polysiloxane network. The activity was retained after 66 days of immersion in water. The QAS‐containing polysiloxanes are also active in aqueous solution. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1005–1012, 2000     

Biocidal polymers active by contact. II. Biological evaluation of polyurethane coatings with pendant quaternary ammonium salts

Films of polyurethane were prepared by reaction of hydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts with an aliphatic triisocyanate. These coatings exhibited high biocidal activity against Gram-positive and Gram-negative bacteria, yeasts, and moulds. It was found that many parameters controlled the bioactivity such as the time of contact between films and bacteria, the [NCO]/[OH] ratio used to prepare the cured polyurethane, the concentration of quaternary ammonium salts in the coating, and the length of the alkyl chain from C₈ to C₁₆ linked to the quaternary nitrogen atom. A secondary phenomenon of diffusion only observed with the shorter alkyl chains (C₈ and C₁₀) was shown to be due to synthesis residues. After these water-soluble impurities are eliminated, the biocidal activity remains excellent: then it is due only to a contact polymer bacteria. © 1993 John Wiley & Sons, Inc.     

Biocidal polymers active by contact. I. Synthesis of polybutadiene with pendant quaternary ammonium groups

Hydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts were successfully synthesized in three steps. The first one was the preparation of 1-(N, N-dimethylaminopropyl) 1,1,3,3-tetramethyldisiloxane (M′₂A) by hydrosilylation. The addition occurred mainly in the terminal position of the double bond, but isomers were formed in small proportion (an isomer resulting from an inverse addition and an isomer resulting from an isomerization of the double bond). The proportion of these isomers increased with the concentration of catalyst (H₂PtCl₆). Similar results were obtained with a Pt (0)-di-vinyltetramethyldisiloxane complex (Pt,DVDS). The second step was the grafting of M′₂A onto the 1,2-units of a hydroxytelechelic polybutadiene by hydrosilylation. The yield of the reaction was higher than 90% and the OH functionality decreased slightly. Here again, different platinum catalysts were compared: initial rates were higher with Pt,DVDS, but the final yields were better with H₂PtCl₆. The last step was the quaternization of the pendant tertiary amino groups in methanol with alkyl bromides from C₈H₁₇Br to C₁₆H₃₃Br. The yield of the reaction was higher than 90% and the OH functionality was not modified. © 1993 John Wiley & Sons, Inc.     

Biocidal polymers (II): Determination of biological activity of novel N-halamine biocidal polymers and evaluation for use in water filters

Novel N-halamine biocidal polymers were prepared by co-polymerizing a heterocyclic ring-based monomer with tolylene-2,6-diisocyanate and toluene-2,4-diisocyanate. The resulting polyurethanes were halogenated; chlorinated, brominated or iodinated. The rate of bacterial killing by the halogenated derivatives was determined both with and without halogen quenching and one of them was evaluated for use in water filters. The effect of these polymers on bacterial growth-rates was also determined.     

Star oligomers and hyperbranched polymers in low VOC polyurethane coatings: Part III

Conclusion  In this paper the effects of the functionality of hydroxyl functional star oligomers and dendritic polys have been demonstrated in a low VOC clear 2-component clear coat crosslinked with a polysocyanate. At a fixed initial composition of the overall system and with the same reactivity of hydroxyl and isocyanate functional groups, the molecular weight increase as a function of time and the conversion can be calculated using the theory of branching processes. The study has shown that the practical results agree quite well with theory and that the potlife is shortened in case of higher functionality as well as in the case of a broad functionality distribution. The hardness in such a system is not only the effect of functionality, but also of solvent evaporation during crosslinking. If the molecular weight increase upon drying is too fast due to a high functionality (and/or distribution), early gel formation can result in a low film glass transition temperature and hardness due to solvent entrapment.     

Ozone treatment of water-soluble polymers. III. Ozone degradation of polyacrylamide in water

Polyacrylamide (MW 350,000) was ozonized at pH 2 and pH 10 buffer solution. There was little ozonization at pH 2, but at pH 10 the COD and the viscosity of the solution decreased upon ozonization, and a linear relationship existed between the ozone consumed and the number of breaks calculated from the viscosity. This relationship apparently indicated that 45 molecules ozone were consumed for one cleavage of the polymer chain. Such random cleavage was confirmed also by the observation of molecular weight distribution by means of gel filtration chromatography. The amide group decreased scarcely by the ozonization, while a small amount of aldehyde was observed in the ozonized solution. No remarkable change was observed in the IR spectra of the ozonized sample, except for a weak absorption band at 1725 cm^?1 which arose from the carbonyl of aldehyde or ketone. Although no variation was observed in the ¹³C NMR spectra either, a strong absorption peak at 266 nm appeared in the UV spectra of the ozonized solution and increased with the ozonization time. This phenomenon was presumed to be due to the formation of a certain ring structure between the amide group and the small amount of ketone produced in the main chain. However, the details of the ozonization mechanism could not be ascertained.     

Fabrication of active corrosion protection waterborne polyurethane coatings using cerium modified palygorskite nanocontainers

The development of eco-efficient and environmental friendly active anti-corrosion coatings for metallic substrates represents a fundamental milestone in many engineering applications. Herein, a new type of active corrosion protection coating was successfully synthesized simply based on waterborne polyurethane (WPU) and nanocontainer of Ce³⁺ modified palygorskite (Ce-PAL). Particularly, the nanocontainer of Ce-PAL was achieved via a facile and green process by cation exchange in water. Inductively coupled plasma atomic emission spectrometry (ICP) revealed that Ce³⁺ had successfully incorporated into PAL nanofibers with a loading amount of 10.334 g/kg. The salt immersion test, electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy (EIS) demonstrated that the incorporation of Ce-PAL only with 2 wt% into WPU led to a significant improvement of their corrosion protection properties. Finally, according to the results of scanning electron microscopy with energy dispersive X-ray spectroscopy, the active anti-corrosion mechanism of Ce-PAL/WPU coating was proposed.     

Intumescent flame retardant for polymers. III. The polypropylene–ammonium polyphosphate–polyurethane system

The action of some mixtures of ammonium polyphosphate (APP) and polyurethanes (PUr) as flame retardant (FR) agents for polypropylene (PP) was examined. The APP–PUr systems behave as intumescent flame retardant (IFR) formulations. The IFR action of these systems is described by the comparison of the oxygen index (OI) values measured on molded pellets and on molded rods, by measurements of the polymer temperature just below the burning surface and by visual observations. A strong synergism between APP and some polyurethanes, having piperazine units in the polymer chain, was ascertained with a maximum 3:1 ratio. Our results also indicate that only polyurethanes with specific structure, in combination with APP, are active as IFR agents on PP combustion.     

Swelling of hydrophilic polymers. III

The total volume change included gel and surrounded water with the swelling of five types of speherical cross-linked dextran (Sephadex) that are either nonionic (G) or possess one of four different ionic groups in the same molecular skeleton: CM: sodium carboxymethyl, SP: sodium sulphopropyl, DEAE: diethylaminoethyl chloride, and QAE: diethyl-(2-hydroxypropyl) aminoethyl chloride. All have been studied by dilatometry. The total volume decreased with the swelling of all Sephadexes. The maximum changes of total volume with the swelling in water were all negatives of CM, G, SP, (DEAE, QAE), which decrease in that order. These values did not depend on the concentration of sodium chloride and were closely related to the maximum heats of swelling. Total volume changes occurred by the dissociation of the ionic group of dextran derivatives that subtracted the total volume change due to hydration of Sephadex skeleton from the total volume change: ?21.6 ± 3.1 μL mmol^?1 for CM, ?2.8 ± 8.0 μL mmol^?1 for SP, +13.2 ± 4.4 μL mmol^?1 for DEAE, and +15.4 ± 4.6 μL mmol^?1 for QAE. These values are assumed to be reflected in the quantities of ions-water interaction of Sephadexes. © 1994 John Wiley & Sons, Inc.     

Light stabilisation of polymers by radiation-cured acrylic coatings

The light stability of macromolecular materials has been substantially increased by protecting their surface with a UV-cured acrylic coating containing both a UV absorber and a HALS. The liquid resin, made of a telechelic polyurethane-acrylate, was transformed into a highly crosslinked polymer within a fraction of a second upon intense illumination. The cure kinetics was followed in real-time by infrared spectroscopy. Acylphosphine oxide compounds proved to be the most efficient photoinitiators. The light-fastness of the UV-cured polymer was evaluated by monitoring the chemical modifications occurring upon accelerated QUV ageing. It was greatly increased by the addition of small amounts of a HALS radical scavenger. Clear poly(vinyl chloride) plates have been effectively protected against photodegradation by a 50 μm thick UV-cured coating. The greatest stabilisation efficiency was obtained by using as UV absorber either a hydroxyphenyltriazine or an in situ photogenerated hydroxyphenylbenzotriazole. An additional advantage of this method of photostabilisation is an improvement in the surface properties of the coated material, which becomes more resistant to solvents, chemicals as well as to abrasion and scratching     

水性双组分氟丙烯酸—聚氨酯涂料的研制及性能测试

介绍了水性双组分氟丙烯酸-聚氨酯涂料所用原料及其预处理,水性双组分氟丙烯酸-聚氨酯涂料的羟基组分采用两步法合成:第一步合成了具有大分子表面活性剂性能的水性聚氨酯,在合成的过程中引入了双键和羟基组分;然后采用无皂乳液聚合的方法合成了以氟丙烯酸酯为核、聚氨酯为壳的水性树脂。并列举了采用该树脂与水性固化剂配合研制的清漆的性能指标,该清漆有着非常广泛的用途,讨论了影响涂料性能的各种因素。该双组分清漆水性含氟丙烯酸酯-聚氨酯清漆具有优异的综合性能。     

Biocidal polystyrene beads. III. Comparison of N‐halamine and quat functional groups

A comparison has been made between the biocidal efficacies of N‐chlorinated polymeric beads and two derivatives of polyquat beads. Biocidal effects were measured after brief contact exposures of aqueous suspensions of either Staphylococcus aureus or Escherichia coli to the water‐insoluble beads. The polymeric backbone was held the same in all three types of beads, so they differed only in their biocidal derivative moieties. In all cases, functionalization of crosslinked chloromethylated polystyrene beads was performed to introduce the biocidal properties. Synthetic methods and test data will be presented. The most effective biocide, as measured by degree of inactivation in the shortest contact time of the two species of bacteria, was the N‐chlorinated hydantoinyl derivative of methylated polystyrene. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 363–367, 2004     

Durability of radiation-sterilized polymers III. Oxidation layer determined by chemiluminescence

Chemiluminescence (CL) analysis was used for determining the oxidation layer formed by the irradiation of polypropylene for medical supplies. The depth of the oxidation layer from the surface depended on dose rate and increased with decreasing dose rate. The oxidation occurred remarkably at a region near the surface area of the film where the diffusion of oxygen is more sufficient. On the contrary, there was very little oxidation in the interior portion. The oxidation layers of polypropylene samples irradiated with electron beam showed U-shaped profiles in the cross-section of film as did as a sample irradiated with γ-rays. However, the degree of oxidation by irradiation with electron beam was very small; CL intensity at the surface area was only one-third that for the γ-irradiated samples.     

Heat-resistant polymers containing the low molecular weight closo-carboranes. III. The preparation of polycarboranesiloxane polymers by alcoholysis

A new synthesis for carboranesiloxane polymers has been discovered. It involves the alcoholysis of the bischlorodimethylsilylcarborane monomers and the generation of the HCl catalyst in situ. Alcoholysis is applicable to the synthesis of most carborane-siloxane polymers, with the probable exception of the SiB-1 homopolymers of the larger carboranes. The attack of the B? H moieties in the carborane cage can be minimized both by the utilization of a tertiary alcohol and by the addition of excess acid when a primary alcohol is employed.     

Diffusion coefficients of polyurethane coatings by swelling experiments using dielectric spectroscopy

The present work describes the use of dielectric analysis (DEA) for comparison of swelling kinetics of two polyurethane coating recipes, R1702 and R1703, with varied hardener amount by swelling in ethanol. For this purpose, a rapid swelling test, simulating a cleaning process of coated polymer housings, was created and the diffusion coefficients of different coating compositions were calculated. These diffusion coefficients were compared with diffusion coefficients determined from the classical swelling experiment. Besides this, the internal comparison of swelling kinetics after repeated exposure of coatings to ethanol was made. Subsequently, the coating compositions with the most resistant against swelling were determined. For the fitting of desorption curves, received from DEA measurements, a fit function based on the solution of the second Fick´s law and Doolittle like equation was used. The DEA can be successfully used for comparison of desorption processes in polyurethane coatings and for the calculation of diffusion coefficients.     

Ageing behavior of acrylic polyurethane varnish coating in artificial weathering environments

Polyurethane-based coatings reinforced by ZnO nanoparticles (about 27 nm) were prepared via solution blending. The ZnO/PU films and coats were fabricated by a simple method of solution casting and evaporation. The mechanical properties of the films were investigated by a universal material test, and the abrasion resistance of the prepared coats was evaluated by a pencil-abrasion-resistance tester. It was found that significant improvement of the PU films in Young’s modulus and tensile strength was achieved by incorporating ZnO nanoparticles up to 2.0 wt%, and that the abrasion resistance of the PU coats was greatly enhanced due to the addition of ZnO nanoparticles. Moreover, the antibacterial property test was carried out via the agar dilution method and the result indicated that PU films doped with ZnO nanoparticles showed excellent antibacterial activity, especially for Escherichia coli.     

超支化聚合物在涂料中的应用

介绍了超支化聚合物在涂料中的应用 ,包括超支化聚合物的特性以及可应用于涂料树脂的不同结构的超支化聚合物     

Ageing properties of polyurethane methacrylate and off‐stoichiometry thiol‐ene polymers after nitrogen and argon plasma treatment

Proprietary mixture of polyurethane methacrylate (PUMA) and off‐stoichiometry thiol‐ene (OSTE‐80) are evaluated as two possible polymeric substrates to prototype microfluidic biochips. Because of their lack of biocompatibility, PUMA and OSTE‐80 are modified by argon (Ar) or nitrogen (N₂) plasma treatment to introduce nitrogen moieties that are highly polar and conducive for cell attachment and growth. XPS and water contact angle measurement show that these nitrogen groups are relatively stable in the plasma‐treated PUMA and OSTE‐80 in spite of the hydrophobic recovery and volatilization of nitrogen moieties during air ageing for 15 days. This stability can be attributed to their high degree crosslinking that is reflected by the increase of elastic modulus of PUMA and OSTE‐80 during their air ageing. These results show that Ar and N₂ plasma‐treated PUMA and OSTE‐80 possess the necessary physical and chemical properties to be evaluated further to develop microfluidic biochips for biological applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44107.     

Osmotic effects in water absorption by polymers

The absorption of liquids by polymers which contain liquid-soluble inclusions is described. It is shown that the equilibrium uptake of liquid can be calculated if several properties of the inclusion such as solubility as well as the modulus of the polymer are known.