Water‐solution properties of a hydrophobically modified poly(N‐isopropylacrylamide)

To study the water‐solution properties of a hydrophobically modified poly(N‐isopropylacrylamide) (PNIPAM) which is temperature‐sensitive, the copolymer of N‐isopropylacrylamide (NIPAM) and octadecyl acrylate (ODA) was synthesized. The aggregation behavior of the copolymer was studied by surface tension and fluorescence probe methods. Simultaneously, the phenomenon of the lower critical solution temperature (LCST) of the copolymer in an aqueous solution with increase of the temperature was also studied using the fluorescence probe method. The results showed that phase separation occurred in an aqueous solution of the copolymer when the temperature was increased to its LCST. The π‐A isotherms for the copolymer molecules, as an insoluble monolayer on the water–air interface, was determined by the Langmuir–Blodgett (L–B) method. The abnormal phenomenon, by which the monolayer of the copolymer molecules became more and more condensed with increase of the temperature, was observed. It further indicated that phase separation of the copolymer occurred by another method. In addition, to prove the thermosensitive effect of the copolymer on the release behavior of liposomes, small unilamellar vesicles entrapped with 5(6)‐carboxyfluorescein [5(6)‐CF] were coated with the copolymer. We found that the coating of the copolymer resulted in the reduction of the release below 30°C and enhancement of the release above 30°C, indicating that there are obvious interactions between the copolymer and the liposomes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 247–255, 2000     

Thermoreversible hydrogels. VII. Synthesis and swelling behavior of poly(N‐isopropylacrylamide‐co‐3‐methyl‐1‐vinylimidazolium iodide) hydrogels

A series of N‐isopropylacrylamide/3‐methyl‐1‐vinylimidazolium iodide (NIPAAm/MVI) copolymer gels were prepared from the various molar ratios of NIPAAm, cationic monomer MVI, and N,N′‐methylene bisacrylamide (NMBA) in this study. The influence of the amount of MVI in the copolymer gels on the swelling behaviors was investigated in various aqueous saline solutions. Results showed that the swelling ratios (SRs) of copolymer gels were significantly greater than those of NIPAAm homopolymer gels, and the higher the MVI content, the higher the volume phase transition temperature. The SRs for the NIPAAm/MVI copolymer gels decreased with an increase of the salt concentration. In various saline solutions, results showed that the effect of divalent ions on the SR was greater than that of monovalent ions for these hydrogels. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3242–3253, 1999     

Synthesis of macromonomer from radical polymerization of styrene with a polymerizable photoiniferter

α‐(Methacrylyoxylethyloxycarbonylmethyl)‐ω‐(N,N‐diethyldithiocarbamyl)polystyrene macromonomers with different molecular weights were prepared by radical polymerization of styrene (St) using β‐methacryloxylethyl 2‐N,N‐diethyldithiocarbamylacetate (MAEDCA) as a polymerizable photoiniferter in toluene under ultraviolet light. The polymerization of St with MAEDCA carried out by a “living” process; that is, both the yield and the molecular weight of the resultant polymers increased with increasing of reaction time, and the resultant polymer was a macromonomer, for example, α‐(methacrylyoxylethyloxycarbonylmethyl)‐ω‐(N,N‐diethyldithiocarbamyl)polystyrene, designated as PSt‐macromonomer. The molecular weight of the PSt‐macromonomer depended on the concentrations of the polymerizable photoiniferter and St, as well as the conversion of St. The PSt‐macromonomer can copolymerize with MMA initiated by AIBN at 65°C to form a graft copolymer (PMMA‐graft‐PSt) with PSt branches randomly distributed along the PMMA backbone. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1350–1356, 2000     

Photorefractive effect in a new composite based on bifunctional host polymer

A new photorefractive composite based on a bifunctional methacrylate copolymer with N‐methacryloxypropyl‐3‐(p‐nitrophenyl)azo carbazole and N‐methacryloxypropyl carbazole as pendant side chains, which has high stability and potential applications, was synthesized. A two‐beam coupling gain coefficient of 9.4 cm⁻¹ and an electrooptic coefficient of 9.3 pm/V were measured at the applied electric field of 92.4 V/μm by a typical two‐beam coupling experiment and a compensation electrooptic measurement technique. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 189–194, 2000     

Volume phase transition behavior of N‐isopropyl acrylamide–N‐cyanomethyl acrylamide copolymer gel particles: The effect of crosslinking density

We prepared submicron‐sized N‐isopropyl acrylamide (NIPA)–N‐cyanomethyl acrylamide (NCMA) copolymer gel particles by precipitation polymerization. Volume phase transition behaviors of gel particles with various compositions and crosslinking density were observed by using photon correlation spectroscopy (PCS). The experimental data showed that both the volume transition temperature and the swelling ratio of copolymer gel particles were varied with the mole ratio of NCMA and NIPA. We compared the swelling behaviors of given systems with the thermodynamic model based on the extended Flory–Huggins theory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1091–1099, 1999     

Synthesis of poly[(2‐oxo‐1,3‐dioxolan‐4‐yl)methyl vinyl ether‐co‐N‐phenylmaleimide] and its miscibility in blends with styrene‐acrylonitrile or poly(vinyl chloride)

The aim of the study was to investigate the synthesis of a copolymer bearing cyclic carbonate and its miscibility with styrene/acrylonitrile copolymer (SAN) or poly(vinyl chloride) (PVC). (2‐Oxo‐1,3‐dioxolan‐4‐yl)methyl vinyl ether (OVE) as a monomer was synthesized from glycidyl vinyl ether and CO₂ using quaternary ammonium chloride salts as catalysts. The highest reaction rate was observed when tetraoctylammonium chloride (TOAC) was used as a catalyst. Even at the atmospheric pressure of CO₂, the yield of OVE using TOAC was above 80% after 6 h of reaction at 80°C. The copolymer of OVE and N‐phenylmaleimide (NPM) was prepared by radical copolymerization and was characterized by FTIR and ¹H‐NMR spectroscopies and differential scanning calorimetry (DSC). The monomer reactivity ratios were given as r₁ (OVE) = 0.53–0.57 and r₂ (NPM) = 2.23–2.24 in the copolymerization of OVE and NPM. The films of poly(OVE‐co‐NPM)/SAN and poly(OVE‐co‐NPM)/PVC blends were cast from N‐dimethylformamide. An optical clarity test and DSC analysis showed that poly(OVE‐co‐NPM)/SAN and poly(OVE‐co‐NPM)/PVC blends were both miscible over the whole composition range. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1809–1815, 2000     

Studies on the microstructure of vinyl/N‐phenylmaleimide copolymers by NMR and their applications

The micro‐ and stereostructures and sequence distribution of methyl methacrylate (MMA)/N‐phenylmaleimide (PMI) and styrene (St)–PMI copolymers were studied in detail with NMR spectroscopy. The MMA–PMI copolymer was in a random sequence distribution and the St–PMI copolymer was alternating in structure. Some micro‐ and stereoinformation of the MMA–PMI copolymers could be obtained from ¹H‐NMR spectra. The average number sequence length obtained from the copolymer triad by ¹³C‐NMR spectra was in agreement with that calculated from the reactivity ratios measured by an elemental analyzer. From the triad fraction of the copolymer measured by ¹³C‐NMR, the copolymer chain of MMA–PMI was proved to be a one‐order Markov chain. More suitable propagation reactions were proposed from the deviation of sequence distribution of the St–PMI copolymer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2581–2587, 2000     

Synthesis and characterization of biodegradable block copolymer pluronic‐b‐poly(L‐lysine)

This study presented the investigations on the synthesis of a novel biodegradable block copolymer of pluronic‐b‐poly(L ‐lysine) (pluronic‐b‐PLL), which combined the characteristics of aliphatic polyester and poly(amino acids). The synthesis work started with end‐capping of pluronic with N‐t‐butoxycarbonyl‐L ‐phenylalanine using dicyclohexylcarbodiimide in the presence of 4‐dimethylaminopyridine, followed by a deprotection process to obtain the amino‐terminated pluronic; the new primary amino group in the modified pluronic initiated ring‐opening polymerization of amino acid N‐carboxyanhydride, which afforded the pluronic‐b‐poly(N^ε‐(Z)‐L ‐lysine) block copolymer. Finally, removal of the side‐chain N^ε‐(carbonybenzoxy) end protecting groups yields the block copolymer of pluronic‐b‐PLL. The products were characterized by ¹H‐NMR, FTIR, DSC, and GPC. The block copolymer micelle containing the anticancer drug paclitaxel was prepared by the double emulsion method. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of N‐ and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]

Poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] was synthesized in an aqueous hydrochloric acid medium with a determined feed ratio by chemical oxidative polymerization. This polymer was used as a functional conducting polymer intermediate because of its side‐group reactivity. To synthesize the alkyl‐substituted copolymer, the initial copolymer was reacted with NaH to obtain the N‐ and O‐anionic copolymer after the reaction with octadecyl bromide to prepare the octadecyl‐substituted polymer. The microstructure of the obtained polymers was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray diffraction. The thermal behavior of the polymers was investigated by thermogravimetric analysis and differential scanning calorimetry. The morphology of obtained copolymers was studied by scanning electron microscopy. The cyclic voltammetry investigation showed the electroactivity of poly [aniline‐co‐N‐(2‐hydroxyethyl) aniline] and N and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]. The conductivities of the polymers were 5 × 10^?5 S/cm for poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] and 5 ×10^?7 S/cm for the octadecyl‐substituted copolymer. The conductivity measurements were performed with a four‐point probe method. The solubility of the initial copolymer in common organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylformamide was greater than polyaniline. The alkylated copolymer was mainly soluble in nonpolar solvents such as n‐hexane and cyclohexane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Temperature‐responsive alginate‐g‐poly(N,N‐diethylacrylamide) copolymer: Synthesis,characterization, and swelling behavior

Temperature‐responsive polymers have recently gained importance due to their applications in drug delivery. Herein, temperature‐responsive graft copolymer (Alg‐g‐PDEAAm) of alginate and N,N‐diethylacrylamide was synthesized by microwave‐assisted copolymerization using potassium persulfate/N,N,N′,N′‐tetramethylethylenediamine initiator system. The reaction conditions for the best grafting (331%) have been optimized by changing microwave irradiation time, temperature, N,N‐diethylacrylamide, and alginate concentrations. The spectroscopic characteristic, thermal properties, and surface morphology of the copolymers were investigated by FTIR, ¹H‐NMR, DSC/TGA, XRD, gel permeation chromatography, and SEM. Furthermore, low critical solution temperatures of Alg‐g‐PDEAAm copolymers were detected by UV spectroscopy. Swelling ratio of graft microspheres was carried out at 25, 32, and 37 °C, and microspheres were found exhibiting temperature‐responsive property. Cytotoxicity test indicated the Alg‐g‐PDEAAm copolymer and its microsphere were biocompatible. Therefore, based on the results the synthesized temperature‐responsive copolymer could be considered as a promising biomaterial. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46688.     

Copolymerization of styrene with an α‐olefin via atom transfer radical polymerization

This investigation reports the preparation of styrene–α‐olefinic random copolymers, using 1‐octene as an α‐olefin, via atom transfer radical polymerization. Atom transfer radical copolymerization of styrene with 1‐octene was successfully carried out using phenylethyl bromide as initiator and CuBr as catalyst in combination with N, N, N′, N″, N″‐pentamethyldiethylenetriamine as ligand. The copolymers had controlled molecular weight, narrow dispersity and well‐defined end groups with significant 1‐octene incorporation in the polymer. Incorporation of 1‐octene in the copolymers was confirmed using ¹H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectroscopy. An increase in 1‐octene content in the monomer feed led to an increase in the level of incorporation of the α‐olefin in the copolymer. An increase in the concentration of 1‐octene led to a decrease in the rate of polymerization and an increase in dispersity. The glass transition temperature of the copolymer gradually decreased as the incorporation of 1‐octene increased. Copyright © 2011 Society of Chemical Industry     

Functional polymers for colloidal applications. XIV. Syntheses of styrene–maleic anhydride copolymers with different charges and their ability to disperse kaolinite particles

Four kinds of styrene/maleic–anhydride (SMA) copolymer‐derived dispersants with different charged forms were synthesized and characterized with ¹H‐NMR. These four different dispersants contained carboxylic acid groups and exhibited characteristics indicative of anionic, cationic, zwitterionic, or nonionic surfactants as pH was changed. The charge properties of these copolymers changes with pH, and their ability to disperse clay particles under low and high pH were assessed by measuring viscosity or sedimentation, as well as Scanning Electron Microscopy (SEM). The results showed that the dispersing abilities are functions of pH of the system. It was found that SMA‐N [Poly(styrene‐co‐β‐N,N‐dimethylpropylamino) maleic acid, sodium salt)] exhibits the best dispersing ability, the fastest rate of sedimentation, and the smallest sedimentation volume at pH = 2, and SMA‐Na [poly(styrene‐co‐maleic acid, disodium salt)] exhibits the better dispersing ability at pH = 7 and 12. In addition, the aggregation behavior of the dispersants characterized by fluorescence spectroscopy revealed that the degree of aggregation for all dispersants at high concentration increases in the order: SMA‐Na < SMA‐B [poly(styrene‐co‐B‐imino‐propyl‐N‐trimethylammonium acetate) maleic acid, disodium salt)] < SMA‐N < SMA‐Q [poly(styrene‐co‐β‐imino‐propyl‐N‐trimethylammonium sulfate) maleic acid, sodium salt)]. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 592–602, 2000     

Potentiometric studies of oxidation–reduction reactions with redox copolymers

Polymeric oxidants in the bead form that were macroporous styrene/divinylbenzene copolymers containing N‐chlorosulfonamide functional groups (in sodium or hydrogen form) or N‐bromosulfonamide groups (in sodium form) were synthesized and investigated to determine their oxidizing powers. The redox potentials of the N‐chlorosulfonamide/sulfonamide and N‐bromosulfonamide/sulfonamide systems were determined by potentiometric studies at different pH values with aqueous solutions of Na₂SO₃, KCN, and KSCN as reducers. The formal redox potentials of the N‐chlorosulfonamide copolymers were 0.79, 0.44, and ?0.12 V at pH's of 1.8, 8.45, and 13.6, respectively. The formal redox potential of the N‐bromosulfonamide copolymer was about 100 mV higher in comparable conditions and in solutions over pH = 5 (e.g., 0.56 V at pH = 8.56). The comparatively higher oxidizing power of the N‐bromosulfonamide copolymer was particularly evident in a strong alkaline medium (in which the N‐chlorosulfonamide copolymer was not reactive). In contrast, the N‐chlorosulfonamide copolymer showed strong oxidative properties in acidic media (in which the N‐bromosulfonamide copolymer decomposed itself). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Copolymerization and addition of styrene and N‐phenylmaleimide in the presence of nitroxide

The copolymerization and addition reaction of styrene (S) with N‐phenylmaleimide (PMI), either neat or in xylene, have been found to proceed at 125°C in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxy (TEMPO) radicals. TEMPO‐terminated alternating S‐PMI copolymers and comonomer adducts were obtained. The amounts of the low molecular weight compounds increased with the increasing content of PMI in the initial mixture. The reaction suggests formation of monofunctional unimolecular initiators. In the autopolymerization of neat comonomers, a mediating role of TEMPO was observed. The synthesized copolymers containing TEMPO end groups were used as macroinitiators to initiate polymerization of styrene. The molecular weight distributions of resulting poly(styrene‐alt‐N‐phenylmaleimide)‐block‐polystyrene copolymers indicated the presence of both low molecular weight termination products and some copolymer precursor. The copolymers and comonomer adducts were characterized using the nitrogen analysis, size‐exclusion chromatography (SEC), and NMR spectroscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1093–1099, 2000     

Synthesis of a glycosaminoglycan polymer mimetic using an N‐alkyl‐N,N‐linked urea oligomer containing glucose pendant groups

The synthesis of a glycosaminoglycan polymer mimetic is reported. An isopropylidene protected glucose methacrylate monomer was copolymerized under reversible addition fragmentation chain transfer polymerization control with an azido‐containing comonomer to a molecular weight of 29 000 g mol^?1 with polydispersity of 1.21. The comonomer ratio was determined to be 15:1 based on ¹H NMR spectroscopy. This copolymer was coupled to sugar‐functionalized N‐alkyl‐N,N‐linked urea oligomers using a copper catalyzed alkyne/azide cycloaddition reaction. The reaction efficiency was 100% as monitored by ¹H NMR spectroscopy. The isopropylidene protecting groups on the polymer and N‐alkyl‐N,N‐linked urea oligomers were removed using acid hydrolysis to give the final polysaccharide mimetic. It is expected that these polymers will have applications in a variety of future therapeutic applications. © 2013 Society of Chemical Industry     

Synthesis of poly(β‐pinene)‐g‐polystyrene from allylic brominated poly(β‐pinene)

Poly(β‐pinene) was brominated by N‐bromosuccinimide on the allylic carbons. Then the brominated product was activated by AlEt₂Cl to initiate the polymerization of styrene to give a β‐pinene/styrene graft copolymer. AlEt₂Cl was selected because it alone could not initiate the polymerization of styrene. The obtained graft copolymer was characterized by GPC, ¹H‐NMR, and DSC measurements, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 599–603, 2000     

Synthetic amphoteric copolymer as a dispersant for aqueous barium titanate slurries

An amphoteric water‐soluble copolymer, i.e., poly(methacrylate‐co‐N‐(4‐vinylbenzyl)‐N,N‐dimethylglycinate) (PMV) was synthesized and used as a dispersion agent for barium titanate (BaTiO₃) (BT) particles. PMV was prepared from methacrylic acid and N‐(4‐vinylbenzyl)‐N,N‐dimethylglycinate in basic conditions through free radical polymerization. The structure of this copolymer was verified by its IR and ¹H‐NMR spectra. The dispersing effects of PMV were examined and evaluated through viscosity and sedimentation measurements. The results indicate that this copolymer could uniformly disperse the particles, make the resulting suspensions less viscous and more stabilized. The dispersing ability of PMV is better than that of a commercial dispersant, ammonium polymethacrylate (PMAAN). Accordingly, the BT compacts with PMV exhibit higher dielectric constant values than those with PMAAN. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

N‐halamine‐modified polyglycolide (PGA) multifilament as a potential bactericidal surgical suture: In vitro study

In this study, new cationic homopolymer and anionic copolymer were synthesized, and deposited onto polyglycolide sutures using a layer‐by‐layer assembly technique. The coated sutures were rendered antibacterial by chlorinating with dilute solution of household bleach solution at pH 7. The chlorination treatment transformed the N? H groups of anionic copolymer into N‐halamine structures. The N‐halamine‐modified sutures were challenged with Staphylococcus aureus and Escherichia coli O157:H7 bacteria at different contact times. The suture with chlorine loading of 0.22% completely inactivated both bacterial strains in 30 min contact time. Fourier transform infrared spectroscopy, scanning electron microscopy, and analytical titration confirmed the successful deposition of the N‐halamine multilayers. The effect of layer‐by‐layer coatings of polyelectrolytes on the chlorine loading and antibacterial efficacy of sutures was evaluated. The straight‐pull and knot‐pull strength tests performed on the sutures reported slight decline in tensile properties after chlorination treatment. The in vitro hemolysis and cytocompatibility tests revealed that the N‐halamines‐based antibacterial sutures were biocompatible. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42483.     

Synthesis and characterization of the copolymer of dodecyl methacrylate/styrene containing an amidine functional group

A copolymer of dodecyl methacrylate/styrene (DMA/St) containing the amidine functionality was synthesized and characterized. The one‐step solution copolymerization process was carried out using a mixed solvent, high temperature, and a functional azo initiator, 2,2′‐azobis[N,N′‐dimethylene isobutyramidine]. Copolymers with different compositions (DMA/St 10/1 to 1/2), molecular weight (M_n 2000–9000), and functionality (1.0–2.0) were prepared and characterized by NMR, FTIR, DSC, and elemental analysis. The molecular weight of the copolymers could be controlled by the amount of the initiators. Copolymer composition depends on the feed molar ratio of comonomers. The amidine functionality of the copolymers was determined by elemental analysis. It was found that 72% of the polymer chain has one functionality. The T_g of the copolymer depends on the feed molar ratio. This copolymer could be used as a potential dispersant for lubricant oil. Published 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1684–1691, 2002     

Poly(sulfobetaine)s and corresponding cationic polymers. IX. Synthesis and aqueous solution properties of zwitterionic poly(sulfobetaine) derived from a styrene–N,N‐dimethylaminopropyl maleamidic acid copolymer

A styrene–N,N‐dimethyl(maleamidic acid)propyl ammonium propane sulfonate (SDMMAAPS) copolymer was synthesized through an amidoacidation reaction of a styrene–maleic anhydride alternating copolymer with N,N‐dimethylaminopropylamine (ring‐opening reaction) and then reacted with propane sultone. The cloud point and minimum salt concentration (msc) of this ampholytic SDMMAAPS copolymer were determined in aqueous salt solutions. The effects of counterions on the cloud point and msc of SDMMAAPS were not entirely the same as those of other zwitterionic poly(sulfobetaine)s. The greatest difference from other poly(sulfobetaine)s, such as styrene–N,N‐dimethyl(maleimido propyl)ammonium propane sulfonate copolymers, was the carboxylic group on the polymer chain unit of SDMMAAPS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1884–1889, 2003