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A novel kind of AgNPs catalyst was synthesized by in-situ reduction method using poly(2-acrylamido-2-methyl propyl sulfonic acid-co-2-hydroxyethyl methclate) [short as P(AMPS-co-HEMA)] hydrogel as matrices and AgNO3as a metal precursor. The structure of the composite hydrogel was characterized by Scan Electrical Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The results showed that AgNPs were binded with end group and most of the particles were isolated and uniformly distributed on the P(AMPS-co-HEMA). The catalytic properties in the reduction reaction of 4-nitrophenol(shorted as 4-NP) to 4-aminophenol(shorted as 4-AP) were studied in detail, and the result showed that conversion rate and conversion efficiency attained 97.56% and 0.9671 mmol/g·min when the amount of AgNPs was 9mg, [NaBH4] was 2.0×10−1mol/L, [4-NP] was 2.0×10−2mol/L and the total volume of solution was 50 mL, respectively.

A semi-interpenetrating network hydrogel with pore structure (P-S-IPN) was prepared by solution polymerization with 4-acetyl acryloyl ethyl acetate (AAEA) and crylic acid (AA) as monomers, polyvinylpyrrolidone (PVP) as the second network and polyving akohol 2000(PEG2000) as a pore-foaming agent. Gold nanoparticle composite hydrogel (GNPs gel) was obtained through in-situ reduction reaction by using P-S-IPN as a template. P-S-IPN exhibits excellent mechanical strength, the maximum compressive strength is 14.0 Mpa. The influence of the dosage of PEG2000 on the swelling/deswelling properties of P-S-IPN and GNPs gel was investigated. The pore structures could shorten the time that P-S-IPN takes to reach swelling equilibrium from 170min to 75min, improve the ability of P-S-IPN to absorb AuCl4-. The swelling/deswelling properties of GNPs gel under an applied voltage showed when the concentration of NaCl solutions exceed 0.025mol/L, the hydrogel swells, when the concentration of NaCl solutions is below 0.025mol/L, it deswells.

In order to extract tea polyphenols (TPs) by water under room temperature, the mechanochemical methodology was used for leaching process, and then TPs was purified from leaching solution by ethanol and ammonium sulfate aqueous two-phase system. The optimum parameters of mechanochemical methodology leaching TPs were determined by response surface methodology (RSM), which optimum parameters were: Na2CO3content 25~27wt%, solid material particle size D9540~45μm, liquid/solid mass ratio55~60, leaching time 16~18min. The TPs leaching rate was 16.46%. When ammonium sulfate mass composition0.2, ethanol mass composition0.35 as the composite of the extraction system, TPs maximum extraction rate was 93.4%. The maximum yield of TPs was 15.25% on the average, with average purity was 96.54% ultimately. Under such technology, water is only solvent used in TPs leaching at room temperature, and aqueous two-phase system extraction system under mild conditions, avoid the use of toxic solvent, is a green technology for extracting TPs.

P(DMAA-co-AM)hydrogel; adsorption method; a-amylase; Immobilized enzyme. Abstract. P(DMAA-co-AM)hydrogel was prepared by aqueous solution polymerization with N,N-dimethylacrylamide(DMAA) and acrylamide(AM) as monomers.,taking the P(DMAA-co-AM) hydrogel as carrier, a-amylase was immobilized by adsorption method.The investigation of effection of temperature and pH on enzymatic activity exhibites that the optimum temperatures are 50°C for both free and immobilized enzyme,the maximum activity is observed at pH 6.0 for both free and immobized enzyme. The activity of immobilized a-amylase remaines higher 40% at sixth run. Kinetic studies demonstrate that: Km values are 5.15749 and 1.44479 mg/mL for free and immobilized enzyme, Vmax values are 2.56082 and 0.58272 mg/mL min-1 for free and immobilized enzyme.

The effects of ethylene vinyl acetate grafting maleic anhydride (EVA-g-MAH )as a compatilizer on the mechanical properties, compatibility and morphological structure of thermoplastic Polyurethane and poly(vinyl chloride) blends were studied. The blends were prepared and characterized by mechanics properties test, scanning electron microscopy(SEM,)dynamic mechanical properties (DMA) and thermogravimetry(TG) . Mechanical properties indicate that the hardness, tensile strength, breaking elongation of the blends are greatly improved by EVA-g-MAH, when the critical EVA-g-MAH content at about 4 wt%.SEM micrographs reveal that EVA-g-MAH could bring down the diameter of dispersed , change brittle fracture into ductile fracture, and promote adhesion of phase interface. The glass transition temperature change by DMA proves that the addition of the EVA-g-MAH improved the compatibilization of blends. And the results of TG experiment show that EVA-g-MAH greatly improve the thermal stability of the blends.

Using N, N′-methylene bisacrylamide as crosslinking agent and potassium peroxydisulfate as initiator, the temperature-sensitive hydrogels were prepared with organic monomer N-isopropylacrylamide (NIPAAm) and acrylic amide and inorganic material ethyl orthosilicate (TEOS). The structure of hybrid hydrogels was represented by scanning electron microscopy and Fourier transform infrared spectroscopy. The volume phase transition temperature (VPTT) of hybrid hydrogels was determined by differential scanning calorimetry thermograms of the swollen hydrogel. The results showed that the VPTT of the hydrogels increased with the increasing of TEOS dosage. When the temperature was lower than VPTT, the hydrogels exhibited excellent temperature sensitivity and kept at a swelling state, but when the temperature was higher than VPTT, the hydrogels deswelled significantly. In addition, the compressive strength of hydrogels was studied, the results showed that hybrid hydrogels had more ideal mechanical properties than organic hydrogels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Polyacrylamide and poly(2-acrylamido-2-methyl propyl sulfonic acid) co-polymer[short as P(AM-co-AMPS)] superabsorbent materials were synthesized using 2-acrylamido-2-methyl propyl sulfonic acid and acrylamide as monomers, and P(AM-co-AMPS)/SiO2 hybrid superabsorbent materials were prepared using P(AM-co-AMPS) as the organic phase and SiO2 as the inorganic phase. The absorbent properties of these two kinds of superabsorbent materials were investigated. Fourier-transform infrared (FT-IR) and scanning electron microscopes (SEM) were used to characterize these two kinds of superabsorbent materials. The result shows that the SiO2 can disperse in P(AM-co-AMPS) polymer networks homogeneously. The water-absorbent ability of P(AM-co-AMPS)/SiO2 and P(AM-co-AMPS) is similar, but P(AM-co-AMPS)/SiO2 exhibits better acid, base, salt, organic solvents, and temperature tolerance than the P(AM-co-AMPS) dose. In addition, the swelling speed of P(AM-co-AMPS)/SiO2 is larger than that of P(AM-co-AMPS).

A modified seed-mediated growth method was developed for in situ controllable preparation of gold nanoparticles (GNPs) within P(AMPS-co-HEMA) hydrogel networks. When the time of cycles absorbing procedure increased in mother solutions under given temperature during the processing stage, the number of GNPs was significantly increased and networks were utilized for in situ nanoparticles synthesis by reduction of glod ion absorbed. TEM images confirmed that GNPs were between 100 and 200 nm in size and distributed uniformly in gel. The network embedded GNPs also endows the composite gel with selective catalytic activity for selective catalysis in the reduction of nitro compound (2-NP, 3-NP and 4-NP). The kinetics of the reduction reaction were investigated under the same condition, the result showed the GNPs gel system was found to have an excellent catalytic activity and high conversion for 4-NP reduction among nitrophenol homologue, the nitrophenol hydrogenation rate got to 6.63 mol/g min for reducing of 4-NP compared to 3.69 mol/g min, the rate of 2-NP. It was almost zero for 3-NP implying no catalytic activity, even though they were isomeride.

P(AA-co-DMAA) superporous drug-loaded hydrogels containing berberine hydrochloride were prepared by dispersion polymerization in foam system with acrylic acid (AA) and N,N-dimethyl acrylamide (DMAA) as monomers. Then sodium alginate (SA) as the second network was added to the system, and P(AA-co-DMAA)/SA interpenetrating polymer network (IPN) hydrogels were formed. The effects of pH value, reaction time between SA and glutaric dialdehyde (GA), the concentration of SA and GA on release behavior of berberine hydrochloride were discussed. The FT-IR spectra showed that P(AA-co-DMAA)/SA IPN hydrogels were synthesized successfully. The inverted fluorescence micrograph of P(AA-co-DMAA)/SA showed that some part of the superporous structures were still retained.The cumulative release profiles showed that the release rates were slightly higher in pH=6.8 phosphate buffer solution (PBS) than the one in pH=1 HCl solution. The release rate was the slowest in distilled water, only 7.3% within 24h. When the reaction time between SA and GA was shortened, the release speed of berberine hydrochloride became faster. The pore size of P(AA-co-DMAA) hydrogels was reduced with the concentration of SA and GA increased, and the release rate decreased due to the more dense network structures.

A novel monomer called 4-acetyl acryloyl ethyl acetate (AAEA) was synthesized from acetoacetic ester and acryloyl chloride. Copolymerization was carried out between AAEA and acrylic acid (AA) using azoisobutyronitrile as initiator and N,N′-methylene bis(acrylamide) as crosslinking agent. The novel monomer and the hydrogel were characterized using 1 H NMR and FT-IR. A peak at 17.78 ppm in the 1 H NMR spectra and an absorption band at 1584 cm −1 in the FT-IR spectra of AAEA indicated that AAEA mainly existed as enol forms. In the IR spectra of P(AAEA-co-AA), no peak was observed at around 1600 cm −1 confirmed that copolymerization between AAEA and AA was carried out successfully. The volume phase transition temperature (VPTT) of the hydrogels was determined by their respective DSC thermograms of swollen hydrogel specimens. The results showed that the VPTT of the hydrogels ranged from 50.3 to 61.8 °C, and increased significantly with the increasing dosage of AA. These series of hydrogels exhibited good thermo-sensitivity. When the temperature was higher than the critical temperature, the hydrogels deswelled significantly. Moreover, the critical temperature of the hydrogels increased significantly with the increasing dosage of AA. The pH sensitivity of the hydrogels was also studied. The results indicated that the hydrogels exhibited a discontinuous volume change at around pH = 9.5.