Removal of nonionic surfactant by systems based on polystyrene–polyoxyethylene block copolymers

Three polystyrene (PS)–polyoxyethylene (POE) block copolymers were synthesized: S-114 and S-123 as copolymers of POE–PS–POE type, and S-61-10 as that of type. Although the copolymers themselves did not remove nonionic surfactant, polyethylene glycol mono-p-nonylphenyl ether (NP, n = 10), in water, the copolymers, which were supported on activated alumina, removed the surfactant. The removal rates of NP by the copolymers supported on the alumina were compared. The effect of initial concentration of NP and the effect of the amount of supported copolymer on the amount of NP removed were studied. The Freuindlich adsorption isotherm was observed between the residual concentration of NP and the amount of NP removed. In the three copolymers supported on the alumina, the amount of removal per unit mass was the greatest for the S-61-10.     

Removal of Escherichia coli from water by systems based on insoluble polystyrene–poly(ethylene glycol)s, –polyethylenimines,and –polyethylenepolyamines quaternized

Insoluble polymers adsorbing bacterial cells were prepared by reactions of chloromethylated, divinylbenzene crosslinked polystyrene (CMPS) beads with poly(ethylene glycol) 600 (PEG600), PEG monolaurate (PEGLE), polyethylenimines (PEIs, MW = ca. 300. 600. and 1200, referred to as PEI300, PEI600, and PEI1200, respectively), as well as ethylenediamine (ED) and tetraethylenepentamine (TEP) as polyethylenepolyamines. CMPS-ED and CMPS-TEP were further quaternized with 1-iodooctane (IO) and 1-iodododecane (IDD), respectively. These polymers were brought into contact with Escherichia coli by stirring in sterilized, distilled, and deionized water. Although CMPS-PEG and CMPS-PEGLE did not adsorb the cells, they caused a decrease in the number of viable cells. The decrease seemed to result from the bactericidal action of substances leached from the polymers. CMPS-PEI300, CMPS-PEI600, and CMPS-PEI1200, CMPS-ED-IO, and CMPS-TEP-IDD caused a decrease in the viable cell number by adsorption of the cells to their surfaces. It was observed with a scanning electron microscope that the cells were present on the surfaces of CMPS-PEI600 beads. The decrease coefficient for decrease in viable cell number of E. coli caused by the polymer increased with nitrogen content of the polymer. The adhesion of the cells to CMPS-PEI300, CMPS-PEI600, and CMPS-PEI1200, CMPS-ED-IO, and CMPS-TEP-IDD was due mainly to electrostatic interaction between them.     

Removal of polyethylene glycol mono-p-nonylphenyl ether and dodecylbenzenesulfonate by chloromethylated polystyrene–polyethylenepolyamines and –polyethyleneimines

The reactions of chloromethylated divinylbenzene crosslinked polystyrene (CMPS) with polyethylenepolyamines (PEPA), polyethyleneimines (PEI), 2-methyl-2-oxazoline (MeOZO), and the hydrolysis of CMPS–MeOZO reaction products were carried out. The abilities of these products for removing a nonionic surfactant, polyethylene glycol mono-p-nonylphenyl ether (NP, n=10), solutes in water were investigated. Removal rates of NP by and the amounts of NP removed by CMPS–PEPA, –PEI, –MeOZO, and hydrolyzate of CMPS–MeOZO were compared. The adaptability of removal behavior of the products to the Freundlich's adsorption isotherm and the amounts of NP removed by unit masses of the products were investigated. The products also removed an anionic surfactant, sodium dodecylbenzene sulfonate (DBS), solutes in water. The mechanisms for removing NP and DBS were discussed.     

Removal of bacteria from water by systems based on insoluble polystyrene–polyethyelnimine

A study was made of the removal of viable bacterial cells from sterilized physiological saline (saline) by insoluble polymer beads. The polymers (CMPS–PEI300 and CMPS–PEI600) were prepared by reactions of chloromethylated, divinylbenzene crosslinked polystyrene (CMPS) beads with polyethyleneimines (PEI) (MW = about 300 and 600). The bacterial strain cells used were Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa). Decrease coefficients (D, which corresponds to adsorption rate constant) for the viable cell numbers of E. coli by CPMS–PEI300 and CMPS–PEI600 were 28 and 120 (mL/gh) in saline, respectively. These D's were less than those (72 and 270 mL/gh) in sterilized, distilled, and deionized water (sterilized water). The D's for S. aureus and P. aeruginosa by CMPS–PEI600 were 46 and 76 (mL/g h), respectively. The D for E. coli by CMPS–PEI600 was compared with R (removal coefficient) for that by pyridinium type polymers. Bactericidal activity of PEI600 was examined on E. coli and P. aeruginosa in saline. Also, that of poly(ethylene glycol) 600 was done on E. coli in saline.     

Synthesis and surface properties of polystyrene‐graft‐poly(ethylene glycol) copolymers

Polystyrene‐graft‐poly(ethylene glycol) copolymers (PS‐g‐PEG) were successfully synthesized using the “grafting‐through” method. The graft copolymers and the surface properties of their coats were characterized by 1 H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), static contact angle measurement, and atomic force microscopy (AFM). Both DSC and TEM indicated that the graft copolymers had a microphase separated structure. AFM showed the microphase separated structure also occurred at the coat surface, especially at high PEG content, which could also be indirectly confirmed by the XPS and contact angle results. The formation mechanism of the microphase separated structure was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1458–1465, 2007     

Kinetic study of emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol,stabilized with poly(ethylene oxide)–block–polystyrene–block–poly(ethylene oxide) triblock copolymer

The kinetics of emulsion copolymerization of ethyl methacrylate (EMA)/lauryl methacrylate (LMA) in propylene glycol is very similar to the emulsion copolymerizations of water‐soluble monomers in water because of the high solubility of EMA/LMA in propylene glycol. The initial rate of polymerization depends only on initiator concentration and is not affected by either monomer concentration or stabilizer concentration. The overall rate of polymerization is only slightly dependent on monomer concentration and stabilizer concentration and is independent of initiator concentration. The final particle number density increases with increasing amount of stabilizer and decreases with increasing monomer concentration. The total surface area increases with stabilizer concentration and is not governed by either initiator concentration or monomer concentration. Homogeneous nucleation is the dominant mechanism of particle nucleation, as shown by the kinetic data on seeded polymerization and monomer partition behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1691–1704, 2001     

Unsaturated polyester based on poly(ethylene glycol)

Unsaturated polyesters were prepared by one-stage melt condensation of maleic anhydride, phthalic anhydride, propylene glycol, and poly(ethylene glycol)s with different molecular weight, and the properties of their castings from styrenated resins were investigated. Tensile and flexural properties decrease with the increase of molecular weight of poly(ethylene glycol), but impact strength, elongation, and water absorption have an inverse effect. This study improves the understanding of the effect of chain length of poly(ethylene glycol) in unsaturated polyester on the properties of its castings.     

Nonaqueous emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol. II. Adsorption of poly(ethylene oxide)–polystyrene–poly(ethylene oxide) triblock copolymer on latex particles

The adsorption behavior of various poly(ethylene oxide)–polystyrene–poly(ethylene oxide) (PEO‐PS‐PEO) triblock copolymer (TBC) s on acrylic latex particles in propylene glycol was studied. The composition of the PEO‐PS‐PEO triblock polymers varied from 41 to 106 in each PEO block length and from 18 to 41 in the PS block length. The location of the PEO‐PS‐PEO TBC was determined by analyzing for the physically adsorbed amount on the latex surface, the anchored mount on the surface, the entrapped amount inside the particle, and the “free” PEO‐PS‐PEO TBCs in the propylene glycol. A contour graph technique was applied to analyze the experimental data, which showed that a minimum existed for the physically adsorbed portion at a PS block length of about 30 units. When the PS block length was less than 30 units, the adsorption decreased with increasing PS block length, indicating rearrangement of mixed PEO brush and adsorbed PS block. When the PS block was greater than 30 units, the adsorption increased with increasing block length because of the poor solvency of the PS block in the propylene glycol medium, resulting in a collapse of the PS chain. Considering the binding energy between the PS block and the latex particle surface, which governs adsorption, it was hypothesized that a lower block length limit exists, below which no adsorption takes place. The solubility of the PS block in propylene glycol guides the important upper block length limit. The anchored fraction of the block copolymer increased continuously with increasing PS block length in the entire region investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1963–1975, 2001     

Displacement of poly(ethylene oxide) adsorbed on silica by a nonionic surfactant studied by spin labeling

Poly(ethylene oxide) chains labeled at one end by a nitroxide free radical were adsorbed on silica. The electron paramagnetic resonance spectrum is mainly sensitive to the local Brownian motion and shows lines typical of two different environments, namely, loops and tails protruding in solution with a fast motion, and trains adsorbed on the solid with a hindered motion. When a solution of nonionic Triton surfactant with different concentrations is put in contact with the coated surface, the polymer segments are progressively removed from the surface and the chains extend into solution. This displacement is recorded as a function of temperature and concentration and follows a well-defined smooth path.     

Phase separation of poly(ethylene glycol)-water-salt systems

Phase separation temperatures, each corresponding to lower critical solution temperature (LCST) for solutions of poly(ethylene glycol) (PEG) in water-sodium chloride (NaCl) and in water-propionic acid-sodium salt (Pro-Na), have been determined for PEG with molecular weights of M_η = 2.18 × 10³, 8 × 10³ and 719 × 10³ over concentration ranges from 0–1.09 M (mol/1000 g solvent) NaCl and 1.02 M Pro-Na. The phase separation temperature decreases with an increase of salt concentration and depends on polymer molecular weight. The thermal pressure coefficient, thermal expansion coefficient, and density have been determined from 20° to approximately 60°C for ethylene glycol-water solutions over the entire concentration range and also for aqueous salt solutions over the concentration ranges from 0–1.7 M NaCl and 0–0.5 MPro-Na. The excess thermal pressure coefficient, γ^E_V, excess thermal expansion coefficient, α^E, and excess of temperature dependence of γ_V, [$\text{(}\text{?}{}_{\mathrm{\gamma V}}\text{?T}\text{)}{}^{\mathrm{E}}{}_{\mathrm{?}}$], for the EG-water system are all positive, while the excess volume of mixing V^E is negative. The thermal pressure coefficient and thermal expansion coefficient for aqueous salt solutions water-Pro-Na and water-NaCl increase with an increase of salt concentration. The behaviour of the two polymer-salt-water solutions is discussed in terms of a thermodynamic equation of state, and a shortcoming of the usual formulation of the corresponding states theory of polymer solutions is pointed out.     

Synthesis of monomethoxy poly(ethylene glycol) without diol poly(ethylene glycol)

Since monomethoxy poly(ethylene glycol) (mPEG) inevitably contains diol PEG and is difficult to get high molecular weight through traditional synthesis at high temperature under high pressure, a novel synthetic technique via anionic solution polymerization was reported in this study. With a new initiating system, potassium naphthalene and methanol, was introduced, the polymerization proceeded at ambient temperature and side reactions were well restrained. Furthermore, a slight excess of potassium naphthalene can effectively remove the trace of water and oxygen in the reaction system. Under this condition, mPEG was nearly quantitatively obtained without containing diol PEG. Its Mn ranged from 1 to 30 kDa and the polydispersity was kept lower than 1.07. Characterization of the mPEG obtained was carried out using GPC to determine the content of diol PEG and ¹H‐NMR and MALDI‐ToF MS spectroscopic analysis to confirm the exact structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Drug release from poly(ortho esters)–poly(ethylene glycol) polyblend

A polyblend of poly(ortho esters)–poly(ethylene glycol) (POE–PEG) was prepared. The release behavior of the acetanilide‐loaded film of the POE–PEG polyblend was studied. Blending POE with water‐soluble PEG can promote the release of drug in pH 7.4 PBS buffer at 37°C, while POE has plasticizing effect on PEG. Infrared and X‐ray diffraction studies reveal that there is some interaction between POE and acetanilide. The SEM micrographs disclose that the porosity of the drug‐loaded film enhances with an increase immersing time. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 303–309, 1999     

Comparison of interdiffusion at polystyrene–poly(vinyl methyl ether) and polystyrene–poly(isobutyl vinyl ether) interfaces

The effect of polymer–polymer compatibility on interdiffusion at polymer interfaces with dissimilar mobilities was investigated by attenuated total internal reflectance infrared spectroscopy. The polymer pair consisting of polystyrene and poly(vinyl methyl ether) was used to study interdiffusion at the interface of compatible polymers. The polymer pair consisting of polystyrene and poly(isobutyl vinyl ether) was used to study interdiffusion at the interface of incompatible polymers. Results indicate that the extent of interdiffusion is controlled by the polymer–polymer compatibility parameter, irrespectively of the differences in the mobility of the polymers.     

Antielectrostatic poly(ether ester) block copolymer of poly(ethylene terephthalate‐co‐isophthalate)–poly(ethylene glycol)

Poly(ethylene terephthalate) (PET) fiber has a low moisture regain, which allows it to easily gather static charges, and many investigations have been carried out on this problem. In this study, a series of poly(ethylene terephthalate‐co‐isophthalate) (PEIT)–poly(ethylene glycol) (PEG) block copolymers were prepared by the incorporation of isophthalic acid (IPA) during esterification and PEG during condensation. PEG afforded PET with an increased moisture affinity, which in turn, promoted the leakage of static charges. However, PET also then became easier to crystallize, even at room temperature, which led to decreased antistatic properties and increased manufacturing inconveniences. IPA was, therefore, used to reduce the crystallinity of the copolymers and, at the same time, make their crystal structure looser for increased water absorption. Moreover, PET fibers with incorporated IPA and PEG showed good dyeability. In this article, the structural characterization of the copolymers and antistatic and mechanical properties of the resulting fibers are discussed. At 4 wt % IPA, the fiber containing 1 mol % PEG with a molecular weight of 1000 considerably improved antistatic properties and other properties. In addition, the use of PEIT–PEG as an antistatic agent blended with PET or modified PET fibers also benefitted the antistatic properties. Moreover, PEIT–PEG could be used with another antistatic agent to produce fibers with a low volume resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1696–1701, 2003     

Properties of poly(ethylene glycol)‐based bioelastomers

In this article, a series of poly(ether ester) bioelastomers, poly(PEG‐co‐CA)s (PECs), were synthesized by the melt polycondensation of citric acid (CA) and poly(ethylene glycol) (PEG) with molecular weights of 150, 200, 300, and 400. The measurements of the mechanical properties of the PEC series testified that these polymers were elastomers with a low hardness and high elongation, and the hydrolytic degradation of polymer films in a buffer of pH 7.4 at 37°C showed that the PECs had excellent degradability. The molecular weight of PEG had a strong influence on the degradation rates, water absorption rates, and mechanical performance of the PECs. The materials are expected to be useful for pressure hemostasis implementation in lacuna and other biomedical applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Associative properties of perfluorooctyl end‐functionalized polystyrene–poly(ethylene oxide) diblock copolymers

The synthesis of 2,2,3,3‐tetrahydro‐perfluoroundecanoyl end‐functionalized polystyrene–poly(ethylene oxide) block (PS‐block‐PEO‐R_F) copolymers and their matching PS‐block‐PEO diblock copolymers was carried out by sequential anionic polymerization. Viscometry and ¹⁹F NMR studies show that the PS‐block‐PEO copolymers, in contrast to their matching PS‐block‐PEO‐R_F copolymers, exhibit a micellar rather than the associative behavior seen for the latter. However, the presence of an excess of fluorinated acid, used for end‐functionalization, produces a reduction of the associative behavior above the overlap concentration, with the fluorinated acid acting like a surfactant. A competition may also occur between PS—and R_F—mediated micellization. Copyright © 2004 Society of Chemical Industry     

Polymer electrolytes based on poly(ethylene glycol) and cyanoresin

Polymer electrolytes based on a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresins with lithium salt and plasticizer were prepared with an in situ blending process to improve both the mechanical properties and the ionic conductivity (σ). The PEG/lithium perchlorate (LiClO₄) complexes, including blends of cyanoethyl pullulan (CRS) and cyanoethyl poly(vinyl alcohol) (CRV), exhibited higher σ's than a simple PEG/LiClO₄ complex when the blend compositions of CRS/CRV were 5 : 5 or 3 : 7 or than CRV alone. When the CRS/CRV blend was compared with a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) (CRM) in the same molar ratio, the σ values of the polymer electrolytes containing the CRM copolymer series were slightly higher than those of the CRS/CRV blends containing PEG/LiClO₄ complexes. Moreover, the addition of cyanoresin to PEG/LiClO₄/(ethylene carbonate–propylene carbonate) polymer electrolytes provided better thermal stability and dynamic mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2402–2408, 2007     

Biodegradability of poly(ethylene terephthalate) copolymers with poly(ethylene glycol)s and poly(tetramethylene glycol)

Poly(ethylene terephthalate) copolymers were prepared by melt polycondensation of dimethyl terephthalate and excess ethylene glycol with 10–40mol% (in feed) of poly(ethylene glycol) (E) and poly(tetramethylene glycol) (B), with molecular weight (MW) of E and B 200–7500 and 1000, respectively. The reduced specific viscosity of copolymers increased with increasing MW and content of polyglycol comonomer. The temperature of melting (T_m), cold crystallization and glass transition (T_g) decreased with the copolymerization. T_m depression of copolymers suggested that the E series copolymers are the block type at higher content of the comonomer. T_g was decreased below room temperature by the copolymerization, which affected the crystallinity and the density of copolymer films. Water absorption increased with increasing content of comonomer, and the increase was much higher for E1000 series films than B1000 series films. The biodegradability was estimated by weight loss of copolymer films in buffer solution with and without a lipase at 37°C. The weight loss was enhanced a little by the presence of a lipase, and increased abruptly at higher comonomer content, which was correlated to the water absorption and the concentration of ester linkages between PET and PEG segments. The weight loss of B series films was much lower than that of E series films. The abrupt increase of the weight loss by alkaline hydrolysis is almost consistent with that by biodegradation.     

Porous poly(ethylene glycol)–polyurethane hydrogels as potential biomaterials

We report the synthesis of porous poly(ethylene glycol)–polyurethane (PEG‐PU) hydrogels using PEG‐4000 as a soft segment and 4,4′‐methylenebis(cyclohexylisocyanate) as a hard segment. The degree of swelling in the hydrogels could be controlled by varying the amount of crosslinking agent, namely 1,2,6‐hexanetriol. Structural characterization of the hydrogels was performed using solid‐state ¹³C NMR and Fourier transform infrared spectroscopy. Wide‐angle X‐ray diffraction studies revealed the existence of crystalline domains of PEG and small‐angle X‐ray scattering studies showed the presence of lamellar microstructures. For generating a porous structure in the hydrogels, cryogenic treatment with lyophilization was used. Scanning electron microscopy and three‐dimensional micro‐computed tomography imaging of the hydrogels indicated the presence of interconnected pores. The mechanical strength of the hydrogels and xerogels was measured using dynamic mechanical analysis. The observed dynamic storage moduli (E′) for the equilibrium swollen and dry gels were found to be 0.15 and 4.2 MPa, respectively. Interestingly, the porous PEG‐PU xerogel also showed E′ of 5.6 MPa indicating a similar mechanical strength upon incorporating porosity into the gel matrix. Finally, preliminary cytocompatibility studies showed the ability of cells to proliferate in the hydrogels. These gels show promise for applications as scaffolds and implants in tissue engineering. © 2014 Society of Chemical Industry