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In this paper, a series of polyamide derivatives (PAMs) containing morpholine groups were prepared by Ugi polymerization from dialdehyde, diacid, N-(2-aminoethyl)-morpholine and isonitrile compounds as novel multi-responsive fluorescent sensors.

As an important metal element widely existing in nature and the human body, the simple and specific detection of Fe2+ ions has always been of interest.

The pristine carbon materials and traditional electrolytes can not fully meet the increasing practical demand for the high-performance of supercapacitors. Herein, a petal-like multicyclic polycondensate precursor (PCDP) was first prepared by Knoevenagel reaction and amine/aldehyde condensation between 3-aminorhodanine and p-phthalaldehyde. The subsequent activation of PCDP by KOH and final carbonization at different temperatures (600–900 ℃) was performed to get N/S-dual doped porous carbon (N/S-DDPCs) as electrode materials. For N/S-DDPC8 carbonized at 800 ℃, the highest specific surface area was measured as 2047 m2 g− 1, with a large number of interconnected microporous and mesoporous structures and the higher N and S contents of 3.57% and 2.31%, respectively. In addition, Zn(CF3SO3)2 aqueous electrolyte regulated by dimethyl oxalate (DMO) was fabricated in order to further enhance and stabilize the electrochemical performance for N/S-DDPCs. In contrast to the traditional Zn(CF3SO3)2 electrolyte, the energy density and power density of N/S-DDPC8 in DMO-regulated Zn(CF3SO3)2 electrolyte was significantly increased to 36.4 Wh kg− 1 from 11.7 Wh kg− 1 and to 642 W kg− 1 from 250 W kg− 1 at a current density of 0.5 A g− 1, respectively. Most excitedly, N/S-DDPC8-DMO-D can maintain 100% specific capacitance even after 10000 cycles, showing the superhigh electrochemical stability. In brief, N/S-dual doped porous N/S-DDPCs and DMO-regulated electrolyte prepared in this study provides a useful reference for the synergistically enhancing the electrochemical performance for the supercapacitors.

As one of the most investigated conducting polymers, polyaniline (PANI) is considered to be of practical use in many applications. In this study, two new ionic liquids, 1-methylimidazolium hydrogen sulfate ([Hmim]HSO4) and 1-methyl-3-n-butylimidazopersulfate ([C4mim]2S2O8), which were synthesized from 1-methylimidazole ([Hmim]), were used as solvent and dopant, oxidizer, respectively, for in situ polymerization of aniline. Because of the application of the unique structure of ionic liquid, we obtained the ionic liquid–doped polyaniline (IL-PANI) with high solubility (25 mg mL−1 in dimethyl sulfoxide (DMSO)). And by adjusting the ratio of [C4mim]2S2O8 to aniline monomer, the preferred PANI nanofibers could be controlled to form a three-dimensional porous structure. It was found that the ion/electron transport channels could be formed inside the 3D structure. Thus, the redox reactions could occur both at the surface and inside the PANI electrode. Electrochemical characterization showed that the fabricated PANI electrode exhibited a specific capacitance of 489 F g−1 at a current density of 0.5 A g−1. Also, the capacity retention rate reached up to 81% after 4000 cycles investigated at 2 A g−1. In addition, a high-energy density of 80.2 Wh kg−1 was measured when [Hmim]HSO4 was used as an electrolyte. Thus, the present work suggested a new strategy for fabricating high-performance PANI electrode for supercapacitor applications.

We developed a facile synthesis for a series of multifunctionalized polyesters by Passerini three-component polymerization (Passerini-3CP) in a “one-pot” method at room temperature using serial dicarboxylic acids, dialdehyde, and tert-butyl isocyanide as monomers. First, the effects of monomer feed ratio, monomer concentration, and different dicarboxylic acids involved in the polymerization were systematically investigated. The in situ FTIR and GPC measurements have suggested a step-growth mechanism for Passerini-3CP. Second, five succinic acid end-capped polyethylene glycols (S-PEGs) with different molecular weights of 400, 800, 1000, 2000, and 4000 g/mol were prepared and selected as dicarboxylic acids for the subsequent Passerini-3CP to fabricate the thermosensitive and biocompatible polyesters. Among the five resulting polyesters, four polyesters from S-PEG-400, S-PEG-800, S-PEG-1000, and S-PEG-2000 show reversible response to the external temperature, and the lower critical solution temperature (LCST...

In this investigation, we described a facile preparation of temperature/photo dual sensitive polymers (PGABs) by Ugi four-component polymerization (Ugi-4CP) at room temperature in “one-pot” method using glutaraldehyde, 4-amido-azobenzene, t-butyl isocyanide and carboxyl-end-capped polyethylene glycols (S-PEG) as monomers. PGABs were found to be reversibly sensitive to the temperature in salt solution, and their lower critical solution temperatures (LCST) can be tuned to the range of 17.2–68.4 °C by changing the structure of PGABs, sort and concentration of salt. The configuration transition of PGABs between cis-form and trans-form was reversibly induced by the alternating radiation at 365 and 254 nm. The rate and conversion of isomerization showed a remarkable dependence on the chemical structure of PGAB. By the photosensitivity, the LCST of PGAB-800 is further regulated in 1.0 °C change because of the hydrophilicity difference of cis-trans-azobenzene moiety. Through the combination of the thermosensitivity and photosensitivity, the particles of PGABs with nano/μm dimension were successfully controlled by the light radiation and temperature change.

Three-dimensional (3D) nanostructured conducting polymer hydrogels represent a group of high-performance electrochemical energy-storage materials. Here, we demonstrate a molecular self-assembly approach toward controlled synthesis of nanostructured polypyrrole (PPy) conducting hydrogels, which was "cross-linked" by a conjugated dopant molecule trypan blue (TB) to form a 3D network with controlled morphology. The protonated TB by ion bonding aligns the free sulfonic acid groups into a certain spatial structure. The sulfonic acid group and the PPy chain are arranged by a self-sorting mechanism to form a PPy nanofiber structure by electrostatic interaction and hydrogen bonding. It is found that PPy hydrogels doped with varying dopant concentrations and changing dopant molecules exhibited controllable morphology and tunable electrochemical properties. In addition, the conjugated TB dopants promoted interchain charge transport, resulting in higher electrical conductivity (3.3 S/cm) and pseudocapacitance for the TB-doped PPy, compared with PPy synthesized without TB. When used as supercapacitor electrodes, the TB-doped PPy hydrogel reaches maximal specific capacitance of 649 F/g at the current density 1 A/g. The result shows that PPy nanostructured hydrogels can be tuned for potential applications in next-generation energy-storage materials.

Self-healing hydrogels with biodegradability have great potential biomedical application in drug loading and delivery, wound dressing and tissue engineering. In this research, biodegradable hydrogels were designed from oxidized CMC (CMC-CHO) and PEO

In this paper, a new class of thermo-sensitive random polyurethanes (PGLDs) have been prepared by polymerization of L-lysineethyl ester diisocyanate with five homologous derivatives of ethylene glycols. The structure and properties of polyurethanes were characterized by various techniques. The molecular weight Mn and structure of polyurethanes are found to be particularly significant factors to their thermo-sensitivity. Four polyurethanes except poly(L-lysine ethyl ester diisocyanate-co-ethylene glycol) show a reversible phase transition at the lower critical solution temperature, which can be easily tuned in the range of 4–35°C by combination of the monomers. Unexpectedly, the increasing number of –CH2CH2O–units in the main-chain of polyurethanes apparently acts as the hydrophobicity in the solution. The catalyst-free-synthesized polyurethanes with Mn of about (1–2) × 104 g/mol responses to the external temperature. Stannous octoate-catalysted polyurethanes with Mn of (3–6) × 104 g/mol exhibit no thermo-sensitivity because of their strong intra/intermolecular interactions. In addition, the viability of HeLa cells in 0.01–100 μg/mL solution reached to 80% after 24 and 48 h of incubation, indicating no cytotoxicity for polyurethanes.

A random poly(L-alanine-co-L-lactic acid) (PAL) with excellent thermo-sensitivity and no cytotoxicity was synthesized by the structure-controlled polycondensation from natural L-alanine and L-lactic acid. Only those PALs in which the contents of L-alanine structural unit are rigidly controlled in the smaller range of 53–65% show a reversible lower critical solution temperature of 35–60°C. The change of secondary structure in poly(L-alanine) segments by the introduction of L-lactic acid structural unit plays a decisive role in regulating the thermo-sensitivity of PAL. The viability of HeLa cells exposed to PAL reaches up to 91–116% after incubation of 24 and 72 h, indicating no cytotoxicity. Furthermore, PAL can easily form curcumin-loaded nano-carriers through its thermo-sensitivity and self-assembly. The curcumin-loaded PAL nano-particles are observed to clearly internalize into the cells by confocal laser-scanning microscopy, and thus can be used as a potential nano-drug-carrier.

“Self-healable” materials can recover their structures and functions upon injury, which is extremely attractive for emerging biomedical applications. In this research, P(N-isopropyl acrylamide-co-4-formylphenyl acrylate) P(NIPAM-co-FPA) with a pendant benzaldehyde group though connection with a base-labile phenolic ester bond was designed, and polymer gels were prepared with PEO dihydrazide as a cross-linker. The polymer gels formed automatically by self-catalysis but their self-healing property was dependant on cross-linking density. The self-healing property of the polymer gel improved with decreasing cross-linking density based on decreasing FPA composition, increasing molecular weight of the cross-linker, and decreasing gelator concentration. Based on the reversibility of the acylhydrazone bond, the polymer gel showed gel–sol–gel transition by variation of acidity and group ratios. Furthermore, the gels could be degraded by Na2CO3 solutions because the phenolic ester bond is base-labile.

In this paper, a series of monomers (M1-M7) were facilely synthesized by Passerini reaction and the subsequent in-situ polymerization led to the formation of the conductive poly(indole/thiophene)s (P1-P7). Among P1-P7, it was found through the comparison that P7-P with a higher conjugated system exhibits an outstanding specific capacitance of 1170 F g−1 (scan rate 1 mV s−1), power density of 2614.4 W kg−1 and energy density of 56.5 Wh kg−1 (5 A g−1). The capacitance performance of P7-P complexed with Fe3+ system is further increased by 130 F g−1 because of the redox reaction of Fe3+. Using the chronoamperometry, the minimum detection limit of polymer P7-P for Fe3+ is 3 × 10−5 M. In summary, the facile synthesis of the conductive poly(indole/thiophene) polymers, their excellent energy storage and Fe3+ detection performance, open an opportunity for functional polymers in the energy storage and sensor applications.

Non-cytotoxicity or good biocompatibility is an essential requisite for the thermo-sensitive polymeric materials used in the biomedical fields. In this study, a new poly(N-acetyl-L-glutamic acid-co-lysine ester) (PGAL) with excellent thermo-sensitivity and biocompatibility is synthesized from natural lysine and glutamic acid. The chemical structures of the monomers and polymers are determined by 1H NMR, FTIR spectrum, and GPC. PGAL shows a reversible lower critical solution temperature (LCST) of 17.3–31.7 °C, and the thermo-sensitivity is affected by its molecular weight, structure, and concentration. The viability of HeLa cells in 0.01–10 μg/mL PGAL solution is found to be in a range of 98–110 % after 24, 48, and 72 h of incubation. To sum up, this new thermo-sensitive PGAL has excellent biocompatibility that makes it a promising material in the biomedical fields.

A pH/thermo-responsive hydrogel with porous structure (HME), composed of poly(N-acryloylglycine methyl ester), poly(N-acryloylglycine ethyl ester) and sodium alginate (SA) was prepared for the controllable drug carrier. The resultants, CO2 and CaCl2 from the reaction of CaCO3 particles and HCl act as pore-forming and crosslinking of SA, respectively. The porous HME was characterized by differential scanning calorimetry, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and surface area and porosity analysis. The sheet, porous structure was clearly observed by the SEM measurement and the specific surface area of HME was evidently increased with an increase of CaCO3 content. At pH 2.1 phosphate buffered saline (PBS), the release amount of caffeine at room temperature was only 7.2 % within 600 min, while this value approached to 65.3 % at pH 7.4 PBS. Additionally, the cumulative release at 37 °C is much higher than that at room temperature due to the thermo-sensitivity of HME. The experimental results indicated that porous HME has a potential to be used as the promising release-controlled drug carrier in the biomedical fields.

A pH/temperature and degradable-responsive hydrogel (PSMEA) was prepared from chitosan (CS), N-acryloylglycine methyl ester (NAGME), N-acryloylglycine ethyl ester (NAGEE), acrylic acid (AA), and N-methylenebisacrylamide (NMBA). The swelling properties of PSMEA were systematically investigated at different temperatures, pH, and CS contents. It was found that the PSMEA demonstrated obvious pH and temperature-responsive natures. The caffeine-release behaviors showed that only 42.9% caffeine was released from PSEMA in pH 2.1 phosphate buffer solution (PBS) after 360 min, whereas more than 71.5% caffeine was gradually diffused into pH 7.4 PBS over the same time interval. In addition, the caffeine release was much higher at 37.0°C than that at 14.0°C in PBS medium. The apparent degradability of PSMEA was also observed in the pH 7.4 PBS at 37.0°C through the chemical cleavage of CS. As seen from the results, PSEMA seems to be a potential application in the drug-delivery system controlled by the external pH value and temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In this study, a pH/temperature sensitive bead with core-shelled structure, as a drug carrier, was prepared by grafting of N-acryloylglycinates on the surface of sodium alginate beads. The pH and temperature sensitivity of the beads originate from sodium alginate (SA) and copoly(N-acryloylglycinates), respectively. Here, indomethacin (IMC) was selected as a drug model molecule and loaded in SA beads. The release of IMC was systematically investigated as a function of temperature, pH, and SA concentration. The amount of IMC released from beads was as high as 61.6%in pH = 7.4 phosphate buffer solution (PBS) over 620 min, whereas only 27.9% IMC diffused into the pH = 2.1 PBS. In addition, the release rates of IMC at 37.5°C were faster than that at 20.0°C and decreased with increasing SA concentration in the beads. The result indicates that the sensitive beads have the potential to be used as an effective pH/temperature-controlled delivery system in the biomedical fields.

In this article, poly(N-methyl acryloylglycine methyl ester) (PNMAME) was prepared as a novel thermosensitive material with a lower critical solution temperature (LCST) at around 49.5°C. The chemical structures of the monomer NMAME and PNMAME were characterized by 1H NMR and IR measurements. The LCST was investigated systematically as a function of PNMAME concentration, inorganic salt solution and pH value. The results indicated that LCST of PNMAME was obviously dependent on PNMAME concentration and pH. The LCST was increased with a decrease in pH value and PNMAME concentration. To obtain a thermo-sensitive hydrogel with the phase transition temperature close to human body temperature, the copolymerization was conducted between NMAME and N-acryloylglycine ethyl ester (NAGEE). The release behavior of caffeine was evaluated at different temperatures and contents of cross-linkers (N, N-methylenebis(acrylamide) (NMBA)). The increase of cross-linker content led to a decrease in the release rate of caffeine due to higher crossing density in the hydrogel network. In addition, a faster release of caffeine from the hydrogel with 3% NMBA at 37°C was found in contrast to that at 18°C.

In this work, a pH/temperature responsive hydrogel (PMEA) from N-acryloylglycine methyl ester (NAGME), N-acryloylglycine ethyl ester (NAGEE), and acrylic acid (AAc) was synthesized by free radical polymerization. The swelling behaviors and drug release properties of hydrogels were systematically investigated at different temperature, pH, and AAc content. It was found that the hydrogel PMEA demonstrated pH and temperature responsive nature. The caffeine-release behaviors showed that only 49.1% caffeine was released from PMEA in pH 2.70 phosphate buffer solution (PBS) after 500 minutes, whereas more than 93.9% caffeine was gradually diffused into the medium in pH 7.49 PBS over the same time interval. In addition, the caffeine release was much higher at 37°C than that at 14°C in deionized water. As seen from the results, the PMEA seems to be a potential drug carrier with pH-temperature responsiveness.

In this study, a novel pH-temperature-responsive copolymer was first synthesized by the radical copolymerization between HPA (2-hydroxypropyl acrylate and 2-hydroxyisopropyl acrylate) and AMHS (aminoethyl methacrylate hydrochloric salt). The molecular structure of the corresponding copolymer has been confirmed by 1 H-NMR and FTIR. The lower critical solution temperature of the resulting copolymer exhibited a considerable dependence upon the ratio of monomers and pH value in the medium. On the basis of the copolymer, a hydrogel as drug release carrier was prepared via the introduction of a crosslinker, N,N'-methylenebisacrylamide. The swelling behaviors of hydrogel in the different pH value, temperature, and NaCl concentration have indicated that the hydrogel showed a remarkable phase transition at 31.5°C. The swelling ratio was increased with an increasing of pH value, especially in the greater pH values. By the use of caffeine as a model drug, we investigated the caffeine-controlled release from hydrogel systematically as a function of pH value, temperature, and crosslinker content. The caffeine release was sensitive to the temperature. Only 55% caffeine was released from the hydrogel at room temperature, whereas ∼ 92% caffeine diffused into the medium at 37°C.

In this investigation, a novel temperature-pH responsive copolymer was prepared by the radical copolymeriza- tion between 2-hydroxypropyl acrylate (HPA) and aminoethyl methacrylate hydrochloric salt (AMHS). The molecular structure of the corresponding copolymer has been confirmed by 1H NMR and FTIR measurements. The results indicated that the lower critical solution temperature (LCST) of the resulting copolymer has shown a considerable dependence on the monomer ratio and pH value in the medium. When the molar ratio of HPA to AMHS unit on polymer chain was fixed at 1.56, 2.25, and 3.01, the LCSTs of copolymers were observed at 36.5, 28.2 and 17.8°C, respectively. For the effect of addi- tive salts, the LCST change of the copolymer was affected by both cations and anions in the following order of Al(NO3)3 > KNO3 > Mg(NO3)2 > NaNO3 and KCl ≈ KSCN > KBr > KNO3 > KI. The copolymer seems to be useful as a candidate for the controlled-drug release carrier by pH and temperature external stimuli.

Using potassium diperiodatonickelate (Ni (IV)) as an efficient initiator, the graft copolymerization of methyl acrylate (MA) onto organophilic montmorillonite (OMMT) was successfully performed in an alkaline medium. Three grafting parameters were systematically evaluated as functions of the temperature, the initiator concentration, reaction time, pH value, and the ratio of MA to OMMT substrate. The structure of the titled graft copolymers (OMMT-g-PMA) were confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermo-gravimetric analysis (TGA). It was found that Ni (IV) was a highly efficient initiator for graft copolymerization of the MA onto OMMT, i.e., grafting efficiency is as high as 95% and grafting percentage can be facilely controlled within 700% in this study. In addition, the highest grafting efficiency and grafting percentage were obtained when temperature adopted was over 40°C and pH was about 10.3. A single-electron-transfer mechanism was proposed to illustrate the formation of radicals and the initiation reaction. Copyright © 2008 John Wiley & Sons, Ltd.

Melting behavior, nonisothermal crystallization and isothermal crystallization kinetics of polypropylene (PP) with metallocene-catalyzed linear low density polyethylene (mLLDPE) were studied by differential scanning calorimetry (DSC). The results show that PP and mLLDPE were partially miscible. The Avrami analysis was applied to analyze the nonisothermal and isothermal crystallization kinetics of the blends, the Mo Z.S. method was used to take a comparison in nonisothermal kinetics. Values of Avrami exponent indicate the crystallization nucleations of both pure PP and PP in the blends were heterogeneous, the growth of spherulites is tridimensional and the spherulites in the blends were more perfect than that in pure PP. The crystallization activation energy was estimated by Kissinger method and Arrhenius equation and the two methods draw similar results. The mLLDPE increased the crystallization rate of PP in nonisothermal crystallization process and decreased it in isothermal process. The results from nonisothermal crystallization and isothermal crystallization kinetics were not consistent because the two processes were completely different. Addition of minor mLLDPE phase favors to increase the overall crystallinity of PP, showing the mLLDPE entered the PP crystals. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

In this study, potassium diperiodatocuprate (Cu3+) was selected as an initiator to prepare poly(methyl methacry- late)/organo-montmorillonite composites (OMMT-g-PMMA) by in situ graft copolymerization. Three synthetic parameters were systematically evaluated as a function of the temperature, the concentration of initiator, pH and the ratio of MMA to OMMT. It was found that Cu3+ was a highly efficient initiator for the preparation of OMMT-g-PMMA i.e., monomer con- version and grafting efficiency were as higher as 95%. The X-ray diffraction measurement showed the intercalation of PMMA chains into OMMT layers on base of an increasing basal spacing after polymerization. FTIR analysis also sug- gested that the PMMA chains were effectively grafted onto OMMT substrate. The enhanced thermal stabilities of OMMT- g-PMMA composites were confirmed by the thermal gravimetric analysis (TGA). Finally, a single-electron-transfer mechanism was proposed to illustrate the formation of radicals and the preparation process of OMMT-g-PMMA compos- ites. Cu3+ can be used as an effective and practical initiator in preparing the organic/inorganic composite due to its high

Block copolymers of methyl methacrylate (MMA) and poly(diethylene glycol Phthalic Anhydride) (PPAG) was synthesized using a novel redox system—potassium diperiodatonickelate(IV) [DPN]/PPAG system in an alkaline medium. Block copolymers with high percentage of blocking were obtained, which indicated that DPN/PPAG redox system was an efficient initiator for this blocking. Effects of different factors on the blocking parameters were examined. The overall activation energy of this blocking was calculated to be 55.12 kJ/mol. The structure of the block copolymer was determined by infrared, X-ray diffraction, and scanning electron microscope (SEM). A mechanism is proposed to explain the generation of radicals and the initiation of block copolymerization. The block copolymer was used as the compatibilizer in blends of PMMA and Nylon6. The SEM photographs show that the block copolymer greatly improved the compatibility of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1312–1317, 2006

Block copolymers of methyl acrylate (MA) and poly(ethylene glycol) (PEG) have been obtained using a novel redox system—potassium diperiodatocuprate(III)[DPC]/PEG system in alkaline aqueous medium. Block copolymers with a high percentage of blocking were obtained, which indicated that the DPC/PEG redox system was an efficient initiator for this blocking. Effects of different conditions (concentration of reactants, temperature, concentration of the DPC, and reaction time) on the total conversion, percentage of blocking, and intrinsic viscosity were examined. The effects of different monomers and various PEGs with different molecular weight on the total conversion were also examined. A mechanism is proposed to explain the generation of radicals and the initiation of block compolymerization. Some basic properties of the block copolymers were also studied by thermogravimetry and scanning electron microscope. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2139–2145, 2005

The graft copolymerization of methyl methacrylate (MMA) onto starch with potassium ditelluratocuprate(III) (DTC)–starch redox system as initiator was studied in alkaline medium. The grafting parame...

The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) using potassium diperiodatoargentate(III) [Ag(III)]–PVA redox system as initiator was studied in an alkaline medium. Some structural features and properties of the graft copolymer were confirmed by Fourier-transfer infrared spectroscopy, scanning electron microscope, X-ray diffraction and thermogravimetric analysis. The grafting parameters were determined as a function of concentrations of monomer, initiator, macromolecular backbone (Xn = 1750, M = 80 000 g mol−1), reaction temperature and reaction time. A mechanism based on two single-electron transfer steps is proposed to explain the formation of radicals and the initiation profile. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n-butyl acrylate, were also used to produce graft copolymerizations. It has been confirmed that grafting occurred to some degree. Thermogravimetric analysis was performed in a study of the moisture resistance of the graft copolymer. Copyright © 2004 Society of Chemical Industry

A novel efficient redox system—potassium diperiodatoargentate [Ag(III)]-chitosan—was employed to initiate the graft copolymerization of methyl acrylate (MA) onto chitosan in aqueous alkali solution. The effects of reaction variables such as monomer concentration, initiator concentration, reaction time, and temperature were investigated and the grafting conditions were optimized. The structures and the thermal stability of chitosan and chitosan-g-PMA were characterized by infrared spectroscopy (IR) and thermogravimetric analysis (TGA). The solubility of chitosan-g-PMA in some mixed solvent was tested. The graft copolymer was shown to be an effective compatibilizer in blends of poly(vinyl chloride) (PVC) and chitosan. Finally, a mechanism is proposed to explain the formation of radicals and the initiation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 799–804, 2006

A novel redox system, potassium diperiodatocuprate(III) [Cu (III)]-poly(vinyl alcohol) (PVA) redox system, was employed to initiate the graft copolymerization of methyl acrylate (MA) onto PVA in al...

The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) with a potassium diperiodatonickelate(IV) [Ni(IV)]–PVA redox system as an initiator was investigated in an alkaline medium. The grafting parameters were determined as functions of the temperature and the concentrations of the monomer and initiator. The structures of the graft copolymers were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The Ni(IV)–PVA system was found to be an efficient redox initiator for this graft copolymerization. A single-electron-transfer mechanism was proposed for the formation of radicals and the initiation. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate, n-butyl acrylate, and n-butyl methacrylate, were used as reductants for graft copolymerization. These reactions definitely occurred to some degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 529–534, 2003

The novel redox system, potassium diperiodatonickelate (Ni(IV))–casein, was used to initiate graft copolymerization of butyl acrylate onto casein under heterogeneous conditions in aqueous 5% potassium hydroxide solution, which showed high grafting efficiency and percent grafting. FT i.r. spectroscopy, thermal analysis and scanning electron microscopy characterized the structures and properties of the grafted copolymer. The effects of synthesis variables in the graft copolymerization have been discussed in the light of grafting efficiency, percent grafting and the rate of polymerization. A possible initiation mechanism is proposed.

A novel redox system, potassium diperiodatonickelate [Ni (IV)]‐chitosan, was employed to initiate the graft copolymerization of methyl acrylate (MA) onto chitosan in alkali aqueous solution. The effects of reaction variables such as monomer concentration, initiator concentration, reaction time, pH and temperature were determined. By means of a series of copolymerization, the grafting conditions were optimized. The maximum grafting percentage obtained was 404.1% when 0.3 g chitosan was copolymerized with 1.8 mL monomer at 35°C for 5 hours with [Ni (IV)]=9.4×10−4 M and the total volume was 20 mL. Ni (IV)-chitosan system is found to be an efficient redox initiator for this graft copolymerization. A single electron transfer mechanism is proposed to explain the formation of radicals and the initiation. The grafted copolymers were characterized by IR and X-ray diffraction diagrams. The thermal stability of chitosan and chitosan-g-PMA was studied by thermogravimetric analysis (TGA).

In this investigation, a group of poly(l-malic acid acetate-co-l-lysine ester)s (PMALs) with excellent thermo-sensitivity and non-cytotoxicity were prepared by an optimized synthetic route from natural l-malic acid and l-lysine. The structure and properties of PMALs including monomers were systematically characterized by FTIR, 1H NMR, UV, gel permeation chromatograph, scanning electron microscope, contact angle measurement, cell counting kit assess (CCK-8), and confocal laser scanning microscopy (CLSM). Three PMALs show a reversible lower critical solution temperature of 8–36 °C depending on their chemical structure. The contact angle measurement revealed a considerable discrepancy in the hydrophilicity/hydrophobicity of PMALs and further influence on their thermo-sensitivity. The viability of HeLa cells exposed to 0.2–100 μg/mL PMALs solution was found to be in a range 80–103% after 24, 48, and 72 h of incubation, indicating no cytotoxicity. Moreover, a spherical nanocarrier with core-shell structure was facilely fabricated via the thermo-sensitivity of PMALs and hydrophobicity of drug. CLSM observations manifested that the hydrophobic-curcumin-enwrapped nanocarriers can clearly internalize into the cellular inside. The sustained release of curcumin from nanocarriers in vitro provided a possibility of depressing fast hydrolytic degradation at physiological pH or other side-effects. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45984.

In this article, the graft copolymerization of methyl acrylate (MA) onto nylon1010 by using potassium diperiodatonickelate(IV) [Ni(IV)]–nylon1010 redox system as initiator was studied in alkaline medium. The effect of different factors on grafting parameters was investigated. The structure of the graft copolymer was determined by infrared (IR), X-ray diffraction, and scanning electron microscope (SEM). It was found that Ni(IV)–nylon1010 system is an efficient redox initiator for this graft copolymerization. A single-electron transfer mechanism is proposed to explain the formation of radicals and the initiation. The graft copolymer was used as the compatibilizer in blends of poly(methyl methacrylate) (PMMA) and nylon1010. The SEM photographs indicate that the graft copolymer greatly improved the compatibility of the blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2636–2640, 2001