Preparation and Properties of High Performance Multilayered PANi/PMMA/PPG-b-PEG-b-PPG/FGHMDA Nanocomposites via in Situ Polymerization

In this attempt, novel conjugated polymer/graphite nanocomposites with exposed surface area were fabricated by in situ polymerization using polyaniline, poly(methyl methacrylate) and poly(propylene glycol)-block-poly(ethylene glycol) block- poly(propylene glycol) as matrices and functionalized graphite as a filler. Structural and morphological analysis revealed the modification of graphite as well as oxidative polymerization of numerous matrices over the surface of modified graphite ensuing multilayered nanocomposites. The increased values of T_g (59 and 103°C) obtained from thermal analysis reflect the improved thermal stability of prepared nanocomposites and exhibit better adsorption capacity (35.5cm³/g). Maximum electrical conductivity (7.4 S/cm) was also observed for multilayered nanocomposite.     

在大孔硅基囊泡材料孔道内原位接枝有机聚合物

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物（P123）为模板剂、正硅酸甲酯（TMOS）为硅源,采用水热法合成出孔径大于100 nm的硅基囊泡材料。同时采用两步法合成出带有硅烷偶联基团的有机自由基引发剂2-溴-2-甲基丙酸丁酯基三乙氧基硅烷（BPE）和2-溴-2甲基丙酸丁酯基二甲基氯硅烷（BPCM）。再利用偶联基团与囊泡材料孔道内表面的硅羟基偶联反应将自由基引发剂BPE和BPCM分别接枝到囊泡内表面,元素分析发现BPCM具有更高的接枝效率。然后在囊泡孔道内分别引发烯烃单体甲基丙烯酸甲酯（MMA）和甲基丙烯酸丁酯（BMA）的原子转移自由基聚合（ATRP）反应,使单体在表面自由基上逐一反应形成聚合物刷。透射电镜（TEM）表征结果表明,孔道内表面接枝上了聚合物后囊泡保持较为完好。通过化学方法将聚合物切割下来,凝胶渗透色谱（GPC）分析发现接枝的PMMA和PBMA的数均分子量（M_n）分别为7600和11400,分子量分布指数（PDI）均为1.25。     

Preparation of Nano Carbonate-Substituted Hydroxyapatite from an Amorphous Precursor

Carbonated amorphous calcium phosphate (CACP) precursors were precipitated by the wet chemical method at 5°C in the presence of poly(ethylene glycol) and carbonates. The nano carbonate-substituted hydroxyapatite (HAp) was obtained after heat treat CACP precursors at a low temperature (800°C) for 3 h. The calcium phosphates were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma, thermal gravimetric and differential thermal analysis, transmission electron microscopy, and scanning electron microscopy. The results show that calcium phosphate particles with a Ca/P molar ratio of 1.73 are AB-type carbonate-substituted HAp with about 50 nm in diameter.     

Processing and properties of nano‐ and macro‐hydroxyapatite/poly(ethylene‐co‐acrylic acid) composites

Hydroxyapatite (HAp)/poly(ethylene‐co‐acrylic acid) composites have been synthesized by a solution‐based method, using nanosized (n‐HAp) and coarse hydroxyapatite (c‐HAp) particles, respectively. X‐ray diffraction study has indicated the development of compressive and tensile stresses in composites because of the thermal expansion mismatch between the particles and polymer matrix. Fourier transform infrared absorption spectra and thermal analysis have showed the presence of strong interfacial bonding between the particles and polymer. The surface roughness and the homogeneous dispersion of HAp particles in the polymer matrix have been observed by scanning electron microscopy. A comparison in mechanical properties between composites prepared with n‐HAp and c‐HAp particles, respectively, has been studied. Nanosized particles contribute excellent improvement of mechanical properties of the composites rather than the coarse particles. The uniform dispersion of HAp particles, followed by the improvement in mechanical properties of the composite, provides a means of preparing HAp/polymer composites for low load‐bearing implant applications. POLYM. COMPOS., 27:633–641, 2006. © 2006 Society of Plastics Engineers     

Poly(ethylene glycol) electrolyte gels prepared by condensation reaction

Poly(ethylene glycol) electrolyte gels were prepared by condensation reaction in the presence of tetraethoxysilane. Differential scanning calorimetry and X‐ray diffraction spectroscopy were used to investigate the thermal transition behavior and crystalline structure of polymer gels prepared. Both formation of crosslinks and incorporation of salts or plasticizers reduced the development of crystalline structure of poly(ethylene glycol)s. Cyclic voltammetric and ion‐conducting behaviors of polymer gels were analyzed using potentiostat and impedance spectroscopy, and those were also considerably affected by the crosslinking density of polymers and the concentration of electrolyte salt or plasticizers incorporated. Poly(ethylene glycol) gels possessing certain levels of electrolyte salt and plasticizer were expected to have applications of solid electrolytes for lithium polymer secondary batteries. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 948–956, 2002     

Encapsulation of polymer electrolytes into hectorite

Poly (ethylene oxide) (PEO), polyvinylpyrrolidone (PVP), methyl cellulose (Mcel), poly [oligo(ethylene glycol)-oxalate] (POEGO), poly[oxymethylene-(oxyethylene)] (POMOE), and poly[bis-(methoxyethoxyethoxy)phosphazene] (MEEP) were intercalated into hectorite. The intercalated hectorites were characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and infra-red spectroscopy. The interlayer expansion depended on the amount of polymer added as well as on its dimension. The polymer-intercalated materials exhibited higher thermal stability when compared to the bulk polymers.     

Preparation of pH-sensitive amphiphilic block star polymers,their self-assembling characteristics and release behavior on encapsulated molecules

Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG-b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using ¹H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG-b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG-b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG-b-PEEGE) are attractive candidates as anticancer drug delivery carriers.     

Partially graphitized carbon filaments from as-synthesized silica/surfactant composite

The carbonization behavior of surfactants templated within mesoporous silica is studied in detail. Cetyltrimethylammonium bromide and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123) are used as the structure-directing agents for MCM-41 and SBA-15 synthesis, respectively. Thermal treating the as made silica/surfactant composites under argon flow at 900 °C produces partially graphitized carbon filaments as a result of the carbonization of the surfactants within the mesopores. Furthermore, the carbon materials derived from P123 in SBA-15 yield a more developed graphite structure than the carbon obtained from CTAB in MCM-41, as evidenced by the narrower X-ray Bragg reflections in the powder XRD and larger I_G/I_D ratio in the Raman spectra.     

Synthesis and characterization of star-shaped poly(d,l-lactide)-block-poly(ethylene glycol) copolymers

Star-shaped hydroxy-terminated poly(d,l-lactide) (s-PDLLA), with arms of different lengths, were obtained by ring-opening polymerization (ROP) of d,l-lactide (LA) initiated by varied contents of pentaerythritol (PETH) in the presence of stannous octoate (Sn(Oct)₂), and were condensed with carboxyl-terminated poly(ethylene glycol) methyl ether (CT-mPEG, M _n = 850 and 2,000) to afford four-arm star-shaped poly(d,l-lactide)-block-poly(ethylene glycol) copolymer (s-PDLLA-b-PEG). The polymers, including s-PDLLA, CT-mPEG, and s-PDLLA-b-PEG, were characterized and confirmed by ¹H-NMR and ¹³C-NMR spectroscopy, fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC).     

氯化聚丙烯接枝聚乙二醇的合成与性能

以用等规聚丙烯改性氯化制得的氯化聚丙烯（MCPP）与聚乙二醇（PEG）为原料,在金属钠作用下,合成了以MCPP为主链、PEG为支链的梳形结构的两亲性高聚物。用傅里叶变换红外光谱、核磁共振氢谱和核磁共振碳谱表征了高聚物的结构,并测试了MCPP接枝前后的吸水性和水在其表面的接触角。结果表明,两亲性高聚物的吸水性能随着PEG含量的增加而增强,水在其表面的接触解随着PEG含量的增加而减少。     

Synthesis and characterization of interpenetrating polymer networks from polyurethane and poly(ethylene glycol) diacrylate

Interpenetrating polymer networks (IPNs) combining polyurethane (PU) and poly(ethylene glycol) diacrylate (PEGDA) networks were prepared with simultaneous polymerization. PU was synthesized from biocompatible and biodegradable poly(ε-caprolactone) diol, and the hydroxyl group of poly(ethylene glycol) was substituted with a crosslinkable acrylate group. The effects of the PU/PEGDA compositions and the crosslink density of PU and PEGDA on the thermal properties, swelling ratio, surface energy, mechanical properties, and morphologies were investigated. The mechanical properties of PEGDA networks were improved by the presence of PU networks, particularly in the 75% PU/25% PEGDA IPNs. All PU/PEGDA IPNs showed a microphase-separated structure with cocontinuous morphology, as observed by atomic force microscopy, which was in agreement with the results of swelling ratio and dynamic mechanical thermal analysis measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Mesoporous carbon membranes from polyimide blended with poly(ethylene glycol)

The control of the mesoporous structure in a carbon membrane from a poly(ethylene glycol)/polyimide‐blended polymer was investigated. The size of the pores tends to become large with increase of the content of poly(ethylene glycol) against polyimide, that is, the mesoporous structure could be controlled by the composition of the blended polymers. On the other hand, the average molecular weight of poly(ethylene glycol) has little effect from the viewpoint of the control of the pore structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 836–841, 2001     

Influence of nonionic polymers on the rheological and electrical properties of Egyptian bentonite

The rheological properties of Egyptian bentonite suspensions in the presence of nonionic polymers were investigated. Two different types of nonionic polymers were studied: poly(ethylene glycol) (molecular weight = 6000 g/mol) and poly(vinyl pyrrolidone) (molecular weight = 40,000 g/mol). The rheological properties (plastic viscosity, apparent viscosity, and yield point) of concentrated clay suspensions (6–8% w/w) at different temperatures after 24 h were determined. As the nonionic polymer concentrations increased, the rheological properties of the bentonite suspensions showed a slight increase, especially at an 8% clay content. The electrical properties (electrophoretic mobility and ζ potential) of Egyptian bentonite in the presence of different nonionic polymers were measured with a ζ meter. The results showed that the ζ potential of this bentonite was higher with 200 mg/L poly (vinyl pyrrolidone) than with 1000 mg/L poly(ethylene glycol). Potential energy profiles for bentonite suspensions for these nonionic polymers were constructed to show that the net energy barrier for bentonite suspensions followed repulsion or attraction between particles. These profiles showed that the potential energy profile of a bentonite suspension with 200 mg/L poly(vinyl pyrrolidone) produced a high repulsion potential energy between clay surfaces; that is, the suspension stability improved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

On the polymerization of acrylamide in methanol in presence of poly(ethylene glycol)

Acrylamide was polymerized in presence of poly(ethylene glycol)-200 (PEG), with persulphate as initiator, in methanol as reaction medium, with varying monomer concentrations. The polymers obtained were finely divided powders and readily soluble in water, unlike pure polyacrylamide. The incorporation of PEG into the polymers was demonstrated by nitrogen determination, IR, and NMR studies. PEG does not covalently link to the polyacrylamide chains, but forms a blend with the polymer.     

pH-sensitive and bioadhesive poly(β-amino ester)-poly(ethylene glycol)-poly(β-amino ester) triblock copolymer hydrogels with potential for drug delivery in oral mucosal surfaces

A series of novel pH-sensitive triblock copolymers composed of poly(β-amino ester)-poly(ethylene glycol)-poly(β-amino ester) (PAE-PEG-PAE) were synthesized by conjugating poly(β-amino ester) to poly(ethylene glycol). The resulting polymers were characterized by ¹H and ¹³C NMR in CDCl₃ and gel permeation chromatography in tetrahydrofuran. The concentrated polymer solutions (30 wt%) exhibited a gel-to-sol transition in the pH range 6.4-7.8. The gel window spanned physiological conditions (37 °C, pH 7.4). After injection into a rat, the copolymer solution (30 wt%) changed to a gel in a short time. This copolymer hydrogel showed bioadhesive properties and in vitro release of lidocaine was controllable.     

Preparation and characterization of novel crosslinked poly[glycidyl methacrylate–poly(ethylene glycol) methyl ether methacrylate] as gel polymer electrolytes

In this study, glycidyl methacrylate was copolymerized with poly(ethylene glycol) methyl ether methacrylate to obtain a copolymer {poly[glycidyl methacrylate–poly(ethylene glycol) methyl ether methacrylate] [P(GMA–PEGMA)]}, which was crosslinked with α,ω‐diamino poly(propylene oxide) (Jeffamine) at various weight ratios and molecular weights to form novel gel polymer electrolytes (GPEs). The crosslinked copolymers were characterized by Fourier transform infrared spectroscopy and thermal analysis. The crosslinked polymers were amorphous in the pristine state and became crystallized after they were doped with lithium electrolyte. Furthermore, the crosslinking degree of the crosslinked polymers increased with increasing weight ratio of Jeffamine, and both the swelling properties and mechanical behaviors of the crosslinked polymers were heavily affected by the weight ratio and molecular weight of Jeffamine. The ionic conductivity (σ) of the GPEs from the crosslinked copolymers was determined by alternating‐current impedance spectroscopy. A higher molecular weight and increased weight ratio of Jeffamine resulted in a higher σ. The GPE based on P(GMA–PEGMA) crosslinked with an equal weight of Jeffamine D2000 exhibited the highest σ of 8.29 × 10⁻⁴ S/cm at 25°C and had a moderate mechanical strength. These crosslinked copolymers could be potential candidates for the construction of rechargeable lithium batteries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of hydroxyapatite/poly(vinyl alcohol phosphate) nanocomposite and its characterization

Hydroxyapatite (HAp)/poly(vinyl alcohol phosphate) (PVAP) nanocomposite has been prepared using a solution‐based method varying HAp from 10 to 60% (w/w). X‐ray diffraction, Fourier transform infrared absorption spectra (FTIR), and thermal analysis have indicated the presence of bonding between HAp particles and PVAP matrix. Transmission electron microscope analysis shows the needle‐like crystals of HAp powder having a diameter of 6–10 nm and a length of 26–38 nm. The surface roughness and the homogeneous dispersion of HAp particles in the polymer matrix have been observed by scanning electron microscopy. Particle size distribution analysis shows the narrow distribution of hydrodynamic particles in the polymer matrix. The tensile stress–strain curves show the improvement in mechanical properties of the composites with increase in amount of HAp particles loading. The composites along with polymer are highly hemocompatible. The use of PVAP promotes the homogeneous distribution of particles on the polymer matrix along with strong particle–polymer interfacial bonding, which has supported the improvement in mechanical properties of the composites. The prepared HAp/PVAP composite with uniform microstructure would be effective to act as a potential biomaterial. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Synthesis and characterization of amine‐functionalized amphiphilic block copolymers based on poly(ethylene glycol) and poly(caprolactone)

A series of amine‐functionalized block copolymers, poly(caprolactone)‐block‐poly(ethylene glycol) (PCL‐b‐PEG), were synthesized by ring‐opening bulk polymerization (ROP) of ε‐caprolactone (ε‐CL) initiated through the hydroxyl end of the amino poly(ethylene glycol) (PEG) used as a macroinitiator in the presence of stannous 2‐ethylhexonoate [Sn(Oct)₂]. The polymerization and end functionality of the polymer were studied by different physicochemical techniques (¹H NMR, Fourier transform infrared and X‐ray photoelectron spectroscopy, gel permeation chromatography and thermogravimetric analysis). Thermal, crystalline and mechanical properties of the polymer were thoroughly analyzed using differential scanning calorimetry, wide‐angle X‐ray diffractometry and tensile testing, respectively. The results showed a linear improvement in crystallinity and mechanical properties of the polymer with the content of PEG. Thus the synthesized functional polymers can be used as excellent biomaterials for the delivery of polyanions, as well as macroinitiators for the synthesis of A–B–C‐type block copolymers. Copyright © 2006 Society of Chemical Industry     

Synthesis of poly(urethane-urea) varnish bearing azobenzene chromophoric pendants

A new diol with azoaromatic pendant was prepared by N-phenyl-4-amido-3,4-dichloromaleimide with 2-mercaptoethanol in the presence of NaOH, and used to obtain photosensible poly(urethane-urea) varnish. A poly(urethane-urea) varnish bearing azobenzene chromophores, based on a poly(ethylene adipate)diol (average molecular weight—2000), 4,4′-dibenzyldiisocyanate, diethylene glycol, trimethylolpropane, and afore-mentioned diol, were prepared and characterized. The polymers were characterized by FTIR spectroscopy, thermal analysis (DMA, DSC, and TGA), and the photochromic behavior by UV irradiation of thin films was discussed.     

Effect of γ‐irradiation on the physical properties and dyeability of poly(vinyl butyral) blends with polystyrene and poly(ethylene glycol)

Cast films of polymer blends essentially based on poly(vinyl butyral) (PVB) and equal ratios of polystyrene (PS) and poly(ethylene glycol) (PEG) were prepared from benzene and butyl alcohol solutions of the individual polymers. The effect of γ‐irradiation on the thermal decomposition and tensile mechanical properties was investigated. Moreover, the effect of γ‐irradiation on the dye affinity of PVB/PS and PVB/PEG for basic and acid dyestuffs was studied. The thermogravimetric analysis (TGA) study showed that the unirradiated PVB polymer films prepared in benzene displayed higher thermal stability than the same polymer films prepared in butanol. However, in all cases the thermal stability was found to increase with increasing γ‐irradiation dose. On the other hand, PVB/PS blend possesses higher thermal stability than PVB/PEG, as shown from the determination of the weight loss (%) at different heating temperatures, the temperatures of the maximum rate of reaction and the activation energy. While, pure PS films showed the stress‐strain behavior of brittle polymers, PVB/PS films showed the behavior of tough polymers with yielding properties. The results of dyeing clearly showed that the solvent type, blend composition, and irradiation dose are determining factors for the dye affinity for basic or acid dyes. For example, unirradiated PVB films prepared from butanol displayed a higher affinity for the basic and acid dyes than the same polymer prepared from the same benzene. However, PVB prepared from butanol showed higher affinity to the dyes than PS prepared from the same solvent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers