Development of Urease Immobilization Using Poly（acrylonitrile）/Chitosan Composite Materials

PANCHI （poly（acrylonitrile）/chitosan） composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of poly（acrylonitrile） and PANCHI membranes were determined by SEM analyses It was found that the membrane coated with 1.0% chitosan shows the maximum reduced pore size. The amounts of the functional groups and the degree of hydrophilicity of PANCHI composite membranes were determined. Urease was covalently immobilized onto all kinds of PANCHI membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity （92.96%） was measured for urease bound to PANCHI （1%） membranes. The basic characteristics of optimum conditions （pH and temperature）, heat inactivation and storage stability of immobilized urease were determined. Immobilization improved the thermal, pH and storage stability of the enzyme. The obtained results show that the poly（acrylonitrile）/chitosan composite materials are suitable for urease immobilization.

Polymerization of Acrylonitrile Initiated by Di（2，6－di－tert－butyl－4－methylphenoxo） Samarium Complex

The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect of polymerization conditions on catalytic activity of the title complex and molecular weight of the polymers produced have been studied.

Preparation and Characterization of Carboxyl-terminated Poly(butadiene-co-acrylonitrile)-epoxy Resin Prepolymers for Fusion-bonded-epoxy Powder Coating

Liquid carboxyl-terminated poly（butadiene-co-acrylonitrile）（CTBN）-epoxy resin（EP） prepolymers were prepared with different contents of CTBN.The chemical reactions between EP and CTBN were characterized by Fourier ransform infrared（FTIR） spectroscopy and gel permeation chromatography（GPC）.The scanning electron micrograph（SEM） and dynamic mechanical analysis（DMA） of curing films showed phase separation,and the rubber particles were finely dispersed in the epoxy matrix.Mechanical properties analysis of curing films showed that impact strength and elongation at break increased significantly upon the addition of CTBN,indicating good toughness of the modified epoxy resins.Thermogravimetric analysis（TGA） showed that the incorporation of CTBN had little effect on the thermal stability of EP.Fusion-bonded-epoxy（FBE） powder coatings modified with CTBN-EP prepolymers were prepared.The experimental results demonstrate the ability of CTBN-EP prepolymers,toughening technology to dramatically enhance the flexibility and impact resistance of FBE coatings without compromising other key properties such as corrosion protection.

Synthesis and Characterization of the Polyacrylonitrile-block- poly(methyl acrylate) by RAFT Technique

Polyacrylonitrile-block-poly（methyl acrylate）（P（AN-b-MA）） was synthesized by reversible addition-fragmentation chain transfer （RAFT） polymerization employing macro-RAFT agent （PAN-RAFT） as the chain transfer agent and azobis（isobutyronitrile） （AIBN） as the initiator. A linear relationship between ln（[M]0/[M]1） and reaction time was observed. The molecular structure of P（AN-b-MA） was characterized by ^1H-NMR, element analysis, FTIR and SEC. The molecular weight distribution （MWD） was less than 1.40, the Mn could be controled from 0.733 to 4.834×10^4, and the molar content of MA in P（AN-b-MA） were from 15.6 to 75.0 percentage, respectively.

REDUCING NONSELECTIVE PROTEIN ADSORPTION AND CELL ADHESION ON POLYACRYLONITRILE FILMS BY COPOLYMERIZATION OF ACRYLONITRILE WITH α-ALLYL GLUCOSIDE

In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contactangle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorptionamount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly withincreasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both thehydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizin gacrylonitrile with vinyl carbohydrates.

Electrospinning organic solvent resistant preoxidized poly(acrylonitrile)nanofiber membrane and its properties

A high performance preoxidized poly(acrylonitrile)(O-PAN)nanofiber membrane with excellent solvent resistance,thermal stability and flexibility was fabricated by the preoxidation of electrospun PAN nanofiber membrane.The performance of resultant O-PAN nanofiber membrane was optimized by altering the PAN concentration and preoxidation temperature.The results showed that the O-PAN nanofiber membrane which made from PAN concentration of 14%(mass)and preoxidation temperature of 250.0
℃ have a more optimal comprehensive performance.In the long-term separation test of SiO2 particle(1 μm)in DMAc suspension,the permeate flux of O-PAN nanofiber membrane stabilized at 227.91 L·m^(-2)·h^(-1)(25
℃,0.05 MPa)while the SiO2 rejection above 99.6%,which showed excellent solvent resistance and separation performance.In order to further explore the application of the O-PAN nanofiber membrane,the OPAN nanofiber membrane was treated with fluoride and used in oil/water separation process.The O-PAN nanofiber membrane after hydrophobic treatment showed excellent hydrophobicity and good oil/water separation performance with the permeate flux about 969.59 L·m^(-2)·h^(-1)while the separation efficiency above 96.1%.The O-PAN nanofiber membrane exhibited a potential application prospect in harsh environment separation.

Molecular Imprinting Fibrous Membranes of Poly(acrylonitrile-co-acrylic acid) Prepared by Electrospinning

IntroductionOver the past few decades, molecular imprinting has been described as a technology for preparing ＂molecular doors＂ which can be matched to ＂template keys＂. It has been found to be a simple and effective approach to introduce specific recognition sites into synthetic polymers, namely, to create molecular imprinting polymers Remarkable features such as stability, ease of preparation and low cost, have made molecular imprinting polymers particularly attractive in chemical sensors, catalysis, drug delivery, and dedicated separations. Practical applications of molecular imprinting polymers require accessible sites, fast mass transfer, and quick binding. However, present techniques used to prepare molecular imprinting polymers most often result in materials exhibiting a high affinity and selectivity but a low capacity and poor site accessibility for the target molecules. It is also very difficult to remove the imprinted molecules located in these molecular imprinting polymers because the highly cross-linked structures do not allow the templates to move freely. To some extent, combining molecular imprinting technology with membrane separation and surface imprinting can overcome the shortcomings, such as mass transfer limitations and non-quantitative recovery of the template molecules seen for imprinted materials fabricated by conventional bulk methods. In that ease, it appears to us that molecular imprinting polymers with high surface area to volume ratios are particularly desirable for largescale applications. Eleetrospun nano and ultrafine fibrous membranes are the most suitable materials due to advantages such as： （1） large specific surfaces, providing relatively high imprinting sites per unit mass; （2） fine porous structures, resulting in the accessibility of imprinting sites and low diffusion resistance necessary for high efficiency; and （3） easy recoverability from practical operation or applicability for continuous usages. Therefore, in this work, we prepared a unique kind of imprinted material--molecularly imprinted fibrous membranes of poly （ acrylonitrile-co-acrylic acid） fabricated by means of an electrospinning process.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL POLYMER ELECTROLYTE BASED ON ACRYLONITRILE/N-[4-(AMINOSULFONYL)PHENYL]ACRYLAMIDE COPOLYMERS

Acrylonitrile/N-[4-（aminosulfonyl）phenyl]acrylamide （AN/ASPAA） copolymers were synthesized and used as a host of lithium ion conducting electrolytes. The composition, molecular weight and molecular weight distribution of AN/ASPAA copolymers were determined, and the influence of copolymer composition on the glass temperature of AN/ASPAA copolymers and the ion conductivity of electrolytes were investigated. The molecular weights of AN/ASPAA copolymers were lower than those of AN and ASPAA homopolymers due to the cross-termination reaction. The glass temperatures of AN/ASPAA copolymers increased as the molar fraction of ASPAA units in copolymers increased. The lithium ion conductivities of the polymer electrolytes increased initially as the molar fraction of ASPAA units in copolymers increased, and a maximum conductivity was achieved when the molar fraction of ASPAA in the copolymer was 16.8%.

Effect of Methyl Methacrylate– Acrylonitrile -Butadiene–Styrene (MABS) on the Mechanical and Thermal Properties of Poly (Methyl Methacrylate) (PMMA)-Fly Ash Cenospheres (FAC) Filled Composites

With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by preparation of polymer blends gives rise to new materials with tailored properties. More complex, three-component systems, obtained by the addition of polymeric modifier to polymer filled composites may be of interest. Use of Fly ash cenospheres is very attractive because it is inexpensive and its use can reduce the environmental pollution to a significant extent. In the present study, Poly (Methyl Methacrylate) (PMMA)-Fly ash cenospheres composites were prepared using extrusion followed by Injection molding. The effect of matrix modification with Methyl methacrylate– acrylonitrile -butadiene–styrene (MABS) on the performance of PMMA- Fly ash cenospheres compositions was also, studied. It was found that with the addition of Fly ash cenospheres particulate as filler in PMMA showed marginal reduction in Tensile Strength, % Elongation and Impact strength and improvement in Flexural Strength, Heat Deflection Temperature and Vicat Softening Point. Compared with PMMA-cenospheres composites, the notched Impact Strength of the PMMA/MABS/cenospheres composites showed marginal enhancement in values at higher loading of cenospheres. The optimum performances in mechanical and thermal properties were obtained when the ratio of MABS to cenospheres was 1:2.

Performance of CTBN(carboxyl-terminated poly (butadiene-co-acrylonitrile))-EP(diglycidyl ether of bisphenol-A (DGEBA)) Prepolymers and CTBN-EP/polyetheramine (PEA) System

CTBN-EP prepolymers were synthesized from CTBN and epoxy resin under the catalysis of HTMAB. FTIR analyses indicate the formation of ester group between the carboxyl group of CTBN and the oxirane group of epoxy resin. The viscosity of modified prepolymer increases with CTBN content increasing, but the epoxy value of the prepolymer decreases greatly. DSC analyses verify that CTBN affects the curing process of CTBN-EP/PEA system. Mechanical testing presents the improved toughness of CTBN-EP/PEA curings for the decrease of tensile strength, flexural strength and compressive strength, and increase of impact strength and elongation-at-break with the CTBN content increasing. SEM micrographs show the rubber phase with many holes in diameter about 0.5-1.5 μm is formed when CTBN content is lower than 10 phr. However, the pattern of SEM graph shows some stalactite-like strips when CTBN content is higher than 15 phr. Furthermore, the SEM image of 25 phr CTBN sample forms a kind of co-continuous structure.

Synthesis and Characterization of Proton-conducting Polymer Electrolytes Based on Acrylonitrile-Styrene Sulfonic Acid Copolymer/Layered Double Hydroxides Nanocomposltes

Acrylonitrile-sodium styrene sulfonate copolymer/layered double hydroxides nanocomposites were prepared by in situ aqueous precipitation copolymerization of acrylonitrile （AN） and sodium styrene sulfonate （SSS） in the presence of 4-vinylbenzene sulfonate intercalated layered double hydroxides （MgA1-VBS LDHs） and transferred to acrylonitrile-styrene sulfonic acid （AN-SSA） copolymer/LDHs nanocomposites as a proton-conducting polymer electrolyte. MgA1-VBS LDHs were prepared by a coprecipitation method, and the structure and composition of MgAl-VBS LDHs were determined by X-ray diffraction （XRD）, infrared spectroscopy, and elemental analysis. X-ray diffraction result of AN-SSS copolymer/LDHs nanocomposites indicated that the LDHs layers were well dispersed in the AN-SSS copolymer matrix. All the AN-SSS copolymer/LDHs nanocomposites showed significant enhancement of the decomposition temperatures compared with the pristine AN-SSS copolymer, as identified by the thermogravimetric analysis. The methanol crossover was decreased and the proton conductivity was highly enhanced for the AN-SSA copolymer/LDHs nanocomposite electrolyte systems. In the case of the nanocomposite electrolyte containing 2% （by mass） LDHs, the proton conductivity of 2.60×10^- 3 S·m^-1 was achieved for the polymer electrolyte.

Phase Partition of Acrylonitrile(AN)in Vinylidene Chloride(VDC)/Water System and Its Effect on VDC-AN Copolymer Composition

Phase partition of acrylonitrile in the vinylidene chloride/water system at different temperature and under pressure was studied. A calculation method for average VDC-AN copolymer composition with AN phase partition considered was proposed. The calculated results are in good agreement with the experimental data nearly the entire conversion range. VDC-AN copolymer with narrower composition distribution can be prepared in the suspension process and interpreted with dynamic equilibrium of AN between the oil and water phases continuously.

An Affordable and Easily Accessible Approach for Acrylonitrile Monomer Purification through a Simple Column Technique

This manuscript presents a dataset detailing a method for purifying monomers. Purification plays a crucial role in every chemical process, as it leads to an improvement in product quality through the removal of impurities. The primary method for monomer purification, like acrylonitrile (AN), is the distillation technique. However, this technique is unsafe and hard to set up or handle. A straightforward, risk-free, low-cost method like the column technique resolves these issues. A simple column technique demonstrated the successful execution of purifying AN. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed that AN was successfully purified, with purity reaching 99.8%. FTIR spectra revealed changes in the position and intensity of the stretching vibration peaks after purification. Also, the functional groups of the inhibitor monomethyl ether of hydroquinone (MeHQ) were undetected after purification. Furthermore, after purification, NMR spectra revealed the absence of aromatic protons and carbons associated with MeHQ. In conclusion, the column technique is a successful and inexpensive way to purify AN monomers. This makes it useful for a wide range of applications, especially in polymerization reactions where MeHQ needs to be removed to prevent self-polymerization during the initiation process.

Synthesis and Characterization of a Novel Acrylonitrile Copolymer Containing Glucose Pendants

In this work, a novel sugar-containing copolymer was synthesized by the copolymerization of a-allyl glucoside (AG) with acrylonitrile (AN). The copolymers were characterized by NMR spectroscopy. It was found that acrylonitrile-based copolymers containing as high as 22wt.% of a-allyl glucoside can be synthesized by the free radical solution copolymerization of the two monomers in DMSO with AIBN as initiator.

Polymerization of Acrylonitrile with(Diisopropylamido) Bis(indenyl) Lanthanides

The polymerization of acrylonitrile was studied using (diisopropylamido)bis(indenyl) lanthanides, Ind 2LnN(i Pr) 2(Ln=Y, Yb) as a single component catalyst. The effects of the amount of catalyst, monomer concentration and polymerization temperature on catalytic activity and molecular weight of polyacrylonitrile(PAN) were studied. The results show that the catalytic activity is raised obviously with rising polymerization temperature. The monomer conversion reaches 64% under polymerization temperature, monomer concentration and catalyst concentration are 50 ℃, 5.1 mol·L -1 and 0.3%(molar ratio) sequentially. The conversion and molecular weight of the polymer increase appreciably with adding additive, PhONa. When the molar ratio of PhONa to the catalyst is three, the conversion and the molecular weight is 76% and 1.32×10 4, respectively. The initiation mechanism for the polymerization of acrylonitrile was proposed.

TEMPERATURE AND pH RESPONSE,AND SWELLING BEHAVIOR OF POROUS ACRYLONITRILE-ACRYLIC ACID COPOLYMER HYDROGELS

Macroporous acrylonitrile-acrylic acid （AN-AA） copolymer hydrogels were synthesized by flee-radical solution polymerizations, using ammonium persulfate （APS）/N,N,N＇,N＇-tetramethylethylenediamine （TEMED） redox initiator system and alcohols porogens. The morphology, temperature and pH sensitive swelling behavior, and swelling kinetics of the resulting hydrogels were investigated. It was found that alcohol type and concentration had great influences on the pore structure and porosity of hydrogels. The pore size of hydrogel increases with the moderate increase of the length of alcohol alkyl chain. However, a further increase of alkyl length would result in the formation of cauliflower-like structure and the decrease of pore size. The porosity of hydrogels increases with the increase of porogen concentration in the polymerization medium. The hydrogels with macroporous structure swell or shrink much faster in response to the change of pH in comparison with the conventional hydrogel without macroporous structure. Furthermore, the response rate is closely related to the porosity of the hydrogels, which could be easily controlled by modulating the concentration of the porogen in the medium. The circular swelling behavior of hydrogels indicated the formation of a relaxing three-dimensional network.

STUDY ON THE POLYMERIZATION OF ACRYLONITRILE INITIATED BY POLYPROPYLENE-BASED VANADYL POLYIMIDODIACETATE——THIOUREA REDOX SYSTEM

The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the temperature range from 25 to 40℃. The polymerization rate was measured by varying the concentrations of monomer, vanadyl polyimidodiacetate, thiourea and sulfuric acid. The overall rate of polymerization was summarized asRp=2.2×10~5e^(-6.560/RT) [AN]^(1.0)[PV]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)The molecular weight of polyacrylonitrile based on the experimental data was:(?)=k 1/T [pv]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)These results indicated that the chain radicals are terminated by combination and/or disproportionation rather than chain transfer. The cooperation effect of carboxylic groups and the macromolecular field effect of polymer supporter are the characters of vanadyl polyimidodiacetate such as the case reported in early paper.

BARRIER PROPERTY AND STRUCTURE OF ACRYLONITRILE/ACRYLIC COPOLYMERS

A series of acrylonitrile (AN) copolymers with methyl acrylate (MA) or ethyl acrylate (EA) as comonomer (5-23 wt%) was prepared by free-radical copolymerisation. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor also measured at 100% relative humidity and at 30 degrees C. All the AN/acrylic copolymers are semicrystalline. As the acrylate content increase, the permeability coefficients of the copolymers to oxygen and carbon dioxide are increased progressively, but those to water vapor are decreased progressively. The gas permeability coefficients of the polymers were correlated with free-volume fractions or the ratio of free volume to cohesive energy.

"CAGE" VANADYL POLYCARBOXYLATE-THIOUREA COMPLEX FOR THE POLYMERIZATION OF ACRYLONITRILE

The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by ' cage ' vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate ofpolymerization isThe relationship between the induction period (τ) and the temperature of polymerization as well as the concentrations of reactants can be expressed as follows :The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreases with increasing temperature of polymerization and concentrations of vanadyl polycarboxylate and thioureaThe polymerization mechanism was proposed and discussed.

SUPPRESSION OF CELL ADHESION ON POLYACRYLONITRILE-BASED MEMBRANES BY THE ANCHORING OF PHOSPHOLIPID MOIETIES

In this work, the membrane surface of poly（acrylonitrile-co-2-hydroxyethyl methacrylate） （PANCHEMA） was chemically modified by anchoring of phospholipid moieties. The process involved the reaction of hydroxyl groups on the membrane surface with 2-chloro-2-oxo-1,3,2-dioxaphospholane （COP） followed by the ring-opening reaction of COP with trimethylamine. Chemical differences between the original and the modified membranes were characterized by FT-IR and XPS, It was found that the amount of macrophage adhered on the modified membrane surface is substantially lower than that on polyacrylonitrile （PAN） and PANCHEMA membranes under the same condition, The morphological change of the adherent cell is also suppressed by the generation ofphospholipid moieties on the membrane surface.