Preparation of three‐dimensional poly(dimethylsiloxane) (PDMS) with movable cross‐linking

A pentamethylcyclotrisiloxane moiety was introduced into cyclic polystyrene (cPSt) and cyclic PDMS (cPDMS) to obtain noncovalent cross‐linking agents, D₃‐cPSt and D₃‐cPDMS, respectively. Anionic ring‐opening polymerization of octamethylcyclotetrasiloxane (D₄) in nitrobenzene was carried out in the presence of D₃‐cPSt to obtain a cloudy white PDMS gel as a precipitation. On the other hand, bulk copolymerization of D₃‐cPDMS with D₄ proceeded in a homogeneous state to give a colorless transparent PDMS gel in high yield. The formation of mechanically linked PDMS with movable cross‐linking was indicated by control experiment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5882–5890, 2009     

Novel polymer monolith prepared from a water‐soluble crosslinking agent

In this study, we described the fundamental properties of novel polymer monoliths that were prepared from a water‐soluble crosslinking agent. Each monolith was evaluated by scanning electron microscope (SEM) and scanning probe microscope (SPM) to observe the monolithic structure, and the polymer films that were prepared from several monomers were evaluated by the contact angle of water. As results of evaluations, the polymer prepared from a water‐soluble crosslinking agent had high hydrophilicity. Furthermore, SEM evaluations suggested that polymer porogenic solvent (PEG) was contributed to the construction of monolithic structure, and the polymerization degree of PEG was also taken effect of the structural changing by the variation of phase separation. Additionally, the results of SPM evaluations and the differences of monolithic structure were also reflected under water condition although the swelling of polymer was observed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3811–3817, 2007     

Preparation and characterization of crosslinked poly(N,N‐diethylacrylamide‐co‐2‐hydroxyethyl methacrylate) resins and their application as support in solid‐phase peptide synthesis

Novel hydrophilic and thermosensitive poly(N,N‐diethylacrylamide‐co‐2‐hydroxyethyl methacrylate) resins were prepared by inverse suspension polymerization with N,N′‐methylenebis(acrylamide) as a crosslinker. The effects of chemical composition and degree of crosslinking on the polymerization were investigated. The polymer resins were characterized by elemental analysis, infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. The thermosensitivity of the crosslinked resins was demonstrated by their lower critical swelling temperatures. The swelling and deswelling volume of the beads in water varied depending on the molar fraction of the N,N‐diethylacrylamide. These beads swelled extensively in a variety of common solvents. They had high loadings of functional hydroxyl groups and were used as supports in the solid‐phase synthesis of an oligopeptide. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1681–1690, 2003     

Thymine‐based,water‐soluble phototerpolymers: Their preparation and synthesis

Terpolymers of vinylbenzylthymine, vinylbenzyltriethylammonium chloride, and N‐butyl‐N,N‐dimethyl‐(4‐vinylbenzyl)ammonium chloride with different monomer ratios have been prepared, and the effect of the monomer ratios on the properties of the terpolymers has been investigated. These polymers are water‐soluble and, when irradiated with low levels of UV light, undergo a 2π+2π photodimerization reaction of thymine. This photodimerization significantly reduces the water solubility, immobilizing the polymer to the substrate, and shows potential for water‐soluble photoresists. Thermogravimetric analysis has revealed that the terpolymers have two degradation stages corresponding to the quaternary ammonium pendant groups and to the thymine. An evaluation of the contact‐angle measurements has shown that the surface properties and hydrophobicity can be controlled by the variation of the monomer ratios. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1296–1303, 2007     

Modified carrageenan. 5. Preparation,swelling behavior,salt‐ and pH‐sensitivity of partially hydrolyzed crosslinked carrageenan‐graft‐polymethacrylamide superabsorbent hydrogel

The polysaccharide, kappa‐carrageenan (κC) was chemically modified to achieve a novel superabsorbent hydrogel via graft copolymerization of methacrylamide (MAM) onto the substrate followed by alkaline hydrolysis. Ammonium persulfate (APS) and N,N′‐methylene bisacrylamide (MBA) were used as a free‐radical initiator and a crosslinker, respectively. The saponification reaction was carried out using sodium hydroxide aqueous solution. Either κC‐g‐PMAM or hydrolyzed κC‐g‐PMAM (PMAM: polymethacrylamide) was characterized by FT‐IR spectroscopy. The effect of grafting variables (i.e. concentration of MBA, MAM, and APS) and alkaline hydrolysis conditions (i.e. NaOH concentration, hydrolysis time and temperature) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling capacity of these hydrogels was also measured in various salt solutions. Results indicated that the swelling ratios decreased with an increase in the ionic strength of the salt solutions. This behavior can be attributed to charge screening effect for monovalent cations, as well as ionic crosslinking for multivalent cations. Absorbency of superabsorbing hydrogels was examined in buffer solutions with pH range 1–13. Also, the pH reversibility and on–off switching behavior, at pH values 3.0 and 8.0, makes the synthesized hydrogels good candidates for controlled delivery of bioactive agents. Finally, swelling kinetics in distilled water and various salt solutions was preliminary investigated. Results showed that the swelling in water was faster than in saline solutions. Copyright © 2004 John Wiley & Sons, Ltd.     

Preparation and microstructural analysis of poly(lactic‐alt‐glycolic acid)

Alternating copolymers of glycolic (G) and lactic (L) acid were prepared by the condensation of the preformed dimers: L_LG and L_racG. By size exclusion chromatography (THF, PS standards), poly(L_LG) exhibited a molecular weight (M_n) of 15.6 kg mol^?1, with a weight average molecular weight (M_w) of 26.9 kg mol^?1 and a PDI of 1.72. The M_n for poly(L_racG) was 9.2 kg mol^?1, with a M_w of 12.9 kg mol^?1 and a PDI of 1.40. The NMR spectra of poly(L_LG) were consistent with an isotactic microstructure. NMR spectra of the racemic poly(L_racG) were consistent with an atactic structure. The methylene region of the ¹H NMR spectrum showed a tetrad level of resolution of the nearby stereochemical relationships, for example, iii. Resonances for other groups in both the ¹H and ¹³C NMR spectra gave only a triad level of resolution. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4704–4711, 2008     

Microwave‐assisted nitroxide‐mediated polymerization for water‐soluble homopolymers and block copolymers synthesis in homogeneous aqueous solution

We performed a critical reinvestigation of microwave enhancement of nitroxide‐mediated polymerization (NMP) of acrylamide (AM) in aqueous media in the dynamic (DYN) mode with a combination of a conventional hydrosoluble radical initiator and a β‐phosphonylated nitroxide (SG1). Based on the results of our previous work, a complementary series of polymerization reactions was carried out between 130 and 160 °C using only the DYN mode to ascertain the existence of a microwave effect. The polymer conversion (p), molar masses, polydispersity index, and viscosity of each sample were measured. The temperature was monitored inside and outside of the vessel using an optical fiber sensor and an IR sensor, respectively. Microwave enhancement of polymerization, temperature control and viscosity of the reaction media were closely related. We also furthered the field of hydrophilic AB diblock copolymer synthesis using a tertiary SG1‐based macroalkoxyamine and directly synthesized both poly(acrylamide‐b‐sodium 2‐acrylamido‐2‐methylpropanesulfonate), a neutral‐b‐anionic diblock copolymer, and poly(acrylamide‐b‐3‐dimethyl(methacrylamidopropyl)ammonium propanesulfonate), a neutral‐b‐zwitterionic diblock copolymer, in homogeneous aqueous media. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and properties of water‐soluble azlactone copolymers

Preparation and study of a series of copolymers incorporating 2‐vinyl‐4,4‐dimethylazlactone (VDMA) is reported. The reactivity ratios for photo‐initiated free radical copolymerization of VDMA with methacrylic acid (MAA), acrylic acid (AA), acrylamide (AAm), dimethylacrylamide (DMAA), hydroxyethyl methacrylate (HEMA), methoxy poly(ethylene glycol) methacrylate (MPEG₃₀₀MA), and 2‐methacryloyloxyethyl phosphorylcholine (MPC), were determined by fitting comonomer conversion data obtained by in situ ¹H NMR to a terminal copolymerization equation. Semi‐batch photo‐copolymerizations were then used to synthesize the corresponding VDMA copolymers with constant composition. Their solubility and dissolution behavior, as well as their hydrolysis half‐lives under physiological conditions, were determined. P(VDMA‐co‐MAA) copolymers with 52 to 93 mol % VDMA showed decreasing initial solubility and increasing hydrolysis half‐lives with increasing VDMA content. VDMA copolymers with nonionic monomers AAm and DMAA were water soluble only at VDMA contents of 41 and 22 mol % or less, respectively, and showed longer hydrolysis half‐lives than comparable MAA copolymers. VDMA copolymers with HEMA and MPEG₃₀₀MA were found to crosslink during storage, so their hydrolysis half‐lives were not determined. VDMA copolymers with 18% zwitterionic MPC showed a much longer half‐life and superior initial solubility compared to analogous p(VDMA‐co‐MAA), identifying this copolymer as a promising candidate for macromolecular crosslinkers in, for example, aqueous layer‐by‐layer co‐depositions with polyamines. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Interfacial living radical copolymerization of oil‐ and water‐soluble comonomers to form composite polymer capsules

The suspension copolymerization of methyl methacrylate with hydroxy‐functional poly(ethylene glycol) monomethacrylate (PEGMA) by atom transfer radical polymerization (ATRP) yielded soluble, controlled‐molecular‐weight amphiphilic copolymers (weight‐average molecular weight/number‐average molecular weight <1.3). Despite extensive partitioning of PEGMA into the water phase, copolymers containing up to 24 mol % PEGMA were formed in the oil phase, from comonomer feeds containing 30 mol % PEGMA. Conversions by suspension polymerization were comparable to those obtained by solution polymerization, at over 70%. Suspension copolymers with high PEGMA contents contained high‐molecular‐weight polymer formed by uncontrolled polymerization, unless poly(vinyl pyrrolidone) was added to displace the growing polymer from the interface. The addition of diethylene glycol dimethacrylate gave capsules at 17 mol % PEGMA with ATRP, whereas conventional free‐radical polymerization required 24 mol % PEGMA to form capsules. The lower PEGMA level required for capsule formation with ATRP was attributed to the lower rates of propagation and crosslinking and to improved incorporation of PEGMA into the final gels. Suspension ATRP with 24 mol % PEGMA in the feed gave two‐layer capsule walls consisting of an inner layer visible by transmission electron microscopy and an outer layer visible by both transmission electron microscopy and environmental scanning electron microscopy, which indicated a compositional gradient across the capsule wall. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 156–171, 2006     

不同交联剂含量对戊二醛交联壳聚糖膜结构与性 能影响的研究

仔细研究壳聚糖膜的结晶度、溶胀度及其对二价铜离子的吸附量与交联剂戊二醛含量(特别是在戊二醛含量较低时)的关系。结果发现膜的结晶度、溶胀度以及对铜离子的吸附量均在戊二醛摩尔分数为0.25%时达到极大值。结晶度的增大可归结于轻度交联能使壳聚糖分子链在成膜时排列更为有序;而溶胀度和对铜离子吸附量的增加则可认为是交联能使壳聚糖中原先被氢键作用所束缚的氨基获得了自由。     

Synthesis of water‐soluble conductive copolymer based on polyaniline

Synthesis and characterization of polyaniline‐grafted poly(styrene‐alt‐maleic anhydride) (PANI‐g‐PSMA) was carried out to obtain conductive comb copolymers with highly improved processability. First, polyaniline (PANI) was prepared in nano‐scale by chemical synthesis under ultrasonic irradiation. Then the poly(styrene‐alt‐maleic anhydride) (PSMA) was synthesized by free radical polymerization. Moreover, the PANI was grafted on the PSMA backbone to prepare a comb‐like conductive copolymer for improving its processability as a new method. The products were characterized by Fourier transform infrared, ultraviolet–visible spectroscopy and X‐ray diffraction patterns. Morphology of the samples was also investigated by scanning electron microscopy images. Finally, the solubility and conductivity of the products were studied, and it resulted in high solubility of the products in water and other common organic solvents in comparison to the pure PANI. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and polymerization of 5‐(methacrylamido)tetrazole,a water‐soluble acidic monomer

The reaction of methacryloyl chloride with 5‐aminotetrazole gave the polymerizable methacrylamide derivative 5‐(methacrylamido)tetrazole ( 4 ) in one step. The monomer had an acidic tetrazole group with a pK_a value of 4.50 ± 0.01 in water methanol (2:1). Radical polymerization proceeded smoothly in dimethyl formamide or, after the conversion of monomer 4 into sodium salt 4‐Na , even in water. A superabsorbent polymer gel was obtained by the copolymerization of 4‐Na and 0.08 mol % N,N′‐methylenebisacrylamide. Its water absorbency was about 200 g of water/g of polymer, although the extractable sol content of the gel turned out to be high. The consumption of 4‐Na and acrylamide (as a model compound for the crosslinker) during a radical polymerization at 57 °C in D₂O was followed by ¹H NMR spectroscopy. Fitting the changes in the monomer concentration to the integrated form of the copolymerization equation gave the reactivity ratios r _4‐Na = 1.10 ± 0.05 and r_acrylamide = 0.45 ± 0.02, which did not differ much from those of an ideal copolymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4333–4343, 2002     

Magnetic field effects on the copolymerization of water‐soluble and ionic monomers

The effect of magnetic field (MF) on the radical copolymerization of a series of water‐soluble and ionic monomers is presented including acrylamide (AM), acrylic acid (AA), its ionized form acrylate (A^?), and diallyldimethylammonium chloride (DADMAC). The following combinations have been studied: AM/AA, AM/A^?, AM/DADMAC, and AA/DADMAC. In addition to the MF, strong electrostatic interactions are present for the majority of monomer combinations and conditions. Although the monomer consumption rate (R_p) increased up to 65% applying a MF of 0.1 Tesla, the composition of the resulting copolymers was not affected under such conditions. Despite this increase of R_p by MF, the electrostatic repulsion between ionic monomers and charged growing radicals dominates R_p and governs the copolymer composition with and without MF. The order of the experimentally obtained reactivity ratios reflects the extent of electrostatic interaction: r_AM/AA (1.41) < r (3.10) < r_AA/DADMAC (4.25) < r_AM/DADMAC (6.95) and r_AA/AM (2.20) > r_DADMAC/AA (0.25) > r (0.17) > r_DADMAC/AM (0.03). Overall, weak MF offers to reduce the production time without modifying the product composition. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 373–383, 2009     

Preparation of amphiphilic statistical copolymers of 2‐hydroxyethyl methacrylate with 2‐diethylaminoethyl methacrylate,precursors of water‐soluble copolymers

Statistical copolymers of 2‐hydroxyethyl methacrylate (HEMA) and 2‐diethylaminoethyl methacrylate (DEA) were synthesized at 50 °C by free‐radical copolymerization in bulk and in a 3 mol L^?1 N,N′‐dimethylformamide solution with 2,2′‐azobisisobutyronitrile as an initiator. The solvent effect on the apparent monomer reactivity ratios was attributed to the different aggregation states of HEMA monomer in the different solvents. The copolymers obtained were water‐insoluble at a neutral pH but soluble in an acidic medium when the molar fraction of the DEA content was higher than 0.5. The quaternization of DEA residues increased the hydrophilic character of the copolymers, and they became water‐soluble at a neutral pH when the HEMA content was lower than 0.25. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2427–2434, 2002     

Enzymatic‐catalyzed polymerization of water‐soluble electrically conductive polymer PEDOT:PSS

Water‐soluble electrically conductive polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) was synthesized by the enzymatic‐catalyzed method using 3,4‐ethylenedioxythiophene (EDOT) as monomer, poly(styrenesulfonate) (PSS) as water‐soluble polyelectrolyte, horseradish peroxidase enzyme as catalyst, and hydrogen peroxide (H₂O₂) as oxidant. Fourier transform infrared spectra and UV–vis absorption spectra confirm the successful enzymatic‐catalyzed polymerization of PEDOT. Dynamic light scattering data confirm the formation of a stable PEDOT:PSS aqueous dispersion. The thermo gravimetric data show that the obtained PEDOT is stable over a fairly high range of temperatures. The atomic force microscopy height images show that the PEDOT:PSS aqueous dispersion can form excellent homogeneous and smooth films on various substrates by conventional solution processing techniques, which renders this PEDOT:PSS aqueous dispersion a very promising candidate for various application in electronic devices. This enzymatic polymerization is a new approach for the synthesis of optical and electrical active PEDOT polymer, which benefits simple setting, high yields, and environmental friendly route. Copyright © 2014 John Wiley & Sons, Ltd.     

Precipitation polymerization of aniline in the presence of water‐soluble organic acids

The precipitation polymerization of aniline in the presence of organic acids, including toluene‐4‐sulfonic acid, phenylphosphonic acid, 4‐aminophenylphosphonic acid, and acetophosphonic acid, led in one step to conductive polyaniline. The polyaniline showed very good affinity for water and was easily modified to be water‐soluble. In comparison with the widely studied postpolymerization of doped polyaniline, this reaction allowed reasonably good conductivity to be achieved at a lower acid/polyaniline ratio. Moreover, the easy in situ incorporation of the dopant into the polymer structure caused high stability of the created salt; that is, no dedoping was observed after it was washed with water, methanol, or other solvents. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3562–3569, 2002     

Preparation,characterization, and properties of fast‐responding bulk hydrogel and treated bleached banana pulp

The reaction between bleached banana pulp and pure maleic anhydride (MA) was investigated. The reaction was conducted in a reactor in the presence of xylene used as a solvent and sodium hypophosphite as catalyst. The appearance of infrared absorption bands at 1891 and 1708 cm^?1 indicated that MA chemically reacted by esterification with bleached banana pulp. However, evidence of an esterification reaction was obtained between cellulose and MA. The production of fast‐responding bulk hydrogel with a high swelling ratio was also investigated. This hydrogel was synthesized first by the formation of maleated acrylamide particles and then by the graft copolymerization of the particles with cellulose. The maleated acrylamide particles were characterized with mass spectroscopy, and the formed hydrogl was characterized by FT‐IR. The esterification reaction between bleached banana pulp and maleated acrylamide was also studied. Steam absorption for bulk hydrogel, maleated acrylamide‐treated bleached banana pulp, MA‐treated cellulose and bleached banana pulp is higher than the steam absorption for untreated cellulose and bleached banana pulp. Compared with treated bleached banana pulp and cellulose, the hydrogel had very high swelling ratios and much faster swelling rates attributed to the collaboration of the ionized particles and bulk hydrogel. The number of ionic maleated acrylamide groups in the hydrogel affected the swelling behavior. Copyright © 2004 John Wiley & Sons, Ltd.     

In situ polymerization and morphology of polypyrrole obtained in water‐soluble polymer templates

Several water‐soluble polymers were used as templates for the in situ polymerization of pyrrole to determine their effect on the generation of nanosized polypyrrole (PPy) particles. The polymers used include: polyvinyl alcohol (PVA), polyethylene oxide (PEO), poly(vinyl butyral), polystyrene sulfonic acid, poly(ethylene‐alt‐maleic anhydride) (PEMA), poly(octadecene‐alt‐maleic anhydride), poly(N‐vinyl pyrrolidone), poly(vinyl butyral‐co‐vinyl alcohol‐co‐vinyl acetate), poly(N‐isopropyl acrylamide), poly(ethylene oxide‐block‐propylene oxide), hydroxypropyl methyl cellulose, and guar gum. The oxidative polymerization of pyrrole was carried out with FeCl₃ as an oxidant. The morphology of PPy particles obtained after drying the resulting aqueous dispersions was examined by optical microscopy, and selected samples were further analyzed via atomic force microscopy. Among the template polymers, PVA was the most efficient in generating stable dispersions of PPy nanospheres in water, followed by PEO and PEMA. The average size of PPy nanospheres was in the range of 160 nm and found to depend on the molecular weight and concentration of PVA. Model reactions and kinetics of the polymerization reaction of pyrrole in PVA were carried out by hydrogen ¹H NMR spectroscopy using ammonium persulfate as an oxidant. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012