PHOTOCOPOLYMERIZATION OF MALEIC ANHYDRIDE AND VINYL ACETATE IN TETRAHYDROFURAN~*

The copolymerization of maleic anhydride and vinyl acetate in tetrahydrofuran was studied. Results show that the maximum copolymerization rate is in 0.6 mole fraction of maleic anhydride, indicating the involvement of maleic anhydride-tetrahydrofuran charge transfer complex in the chain initiation process. ESR study provides collateral evidence for the formation of maleic anhydride radical and tetrahydrofuran radical.     

CHARGE-TRANSFER AND ENERGY-TRANSFER IN THE PHOTO-INDUCED COPOLYMERIZATION OF 2-VINYLNAPHTHALENE WITH MALEIC ANHYDRIDE

The initiation mechanism of the copolymerization of 2-vinylnaphthalene with maleic anhydride was studied under irradiation of 365 nm. The excited complex was formed from (1) the local excitation of 2-vinylnaphthalene followed by the charge-transfer interaction with maleic anhydride and (2) the excitation of the ground state charge-transfer complex, and then it collapsed to 1,4-tetramethylene biradical for initiation. A1: 1 alternating copolymer was formed in different monomer feeds. Addition of benzophenone could greatly enhance the rate of copolymerization through energy-transfer mechanism.     

Synthesis and study of MPNS/SMA nano-composite tanning agent

The radical polymerization of maleic anhydride（MA）,styrene（ST）with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica（MPNS）was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.     

CHARACTERIZATION AND THERMAL STABILITY OF PMR POLYIMIDES USING 7-OXA-BICYCLO[2,2,l]HEPT-5-ENE-2,3-DICARBOXYLIC ANHYDRIDE AS END CAPS

An anhydride monomer containing ether oxide bridge,7-oxa-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic anhydride (ONA),was successfully synthesized by Diels-Alder reaction of furan and maleic anhydride.The ONA was also studied as an end-cap for the polymerization of monomer reactant(PMR) type polyimides.Three molecular weight levels of the ONA end-capped PMR resins were evaluated.The effects of process conditions of these novel PMR resins on thermal and mechanical properties were investigated.It was demonstr...     

Synthesis and Characterization of a Novel Biomaterial： Maleic Anhydride-modified Poly（dl-lactic acid）

A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA‘s hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, ^13 C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.     

Preliminary study of extractable protein binding using maleic anhydride copolymer

A preliminary study of using maleic anhydride copolymer for protein binding has been carried out.The polymeric films were prepared by compression of the purified resin and annealing the film to induce efficient back formation of the anhydride groups.The properties of the film surface were analyzed by attenuated total reflection Fourier transforms infrared spectroscopy and water contact angle measurements.The protein content was determined by Bradford assay.To obtain optimum conditions,immersion time for protein binding was examined.Results revealed that proteins can be successfully immobilized onto the film surface via covalent linkage.The efficiency of the covalent binding of the extractable protein to maleic anhydride-polyethylene film was estimated at 69.87μg/cm~2,although the film had low anhydride content(3%) on the surface.     

Synthesis and characterization of biodegradable materials： PDLLA-（MAh-Diol）n-PDLLA copolymer

The novel biodegradable copolymer PDLLA-(MAH-Diol)_n-PDLLAwith unsaturated bond was synthesized by copolymerizing lactide and prepolymer, which was prepared by the polycondensation of maleic anhydride and poly(ethylene glycol), using p- toluene sulphonic acid as catalyst. The new copolymer has improved hydrophilicity and fexibility. The structure and properties of the novel polymers were studied by FTIR, NMR, GPC-MALLS and DSC.     

Characterization and thermal stability of PMR polyimides using 7-oxa-bicyclo[2,2,1]hept-5-ene-2, 3-dicarboxylic anhydride as end caps

An anhydride monomer containing ether oxide bridge,7-oxa-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic anhydride (ONA),was successfully synthesized by Diels-Alder reaction of furan and maleic anhydride.The ONA was also studied as an end-cap for the polymerization of monomer reactant(PMR) type polyimides.Three molecular weight levels of the ONA end-capped PMR resins were evaluated.The effects of process conditions of these novel PMR resins on thermal and mechanical properties were investigated.It was demonstrated that the imidized prepolymers using the end-cap have good processability,and the cured polyimide specimens exhibited good thermal stability.The initial decomposition temperature, T_d(ca.580℃) and glass transition temperature,T_g(330℃) of the novel resin(PI-20),prepared under optimum process conditions,compare favorably with the T_d(ca.620℃) and T_g(ca.348℃) of the state-of-the-art resin(PI’-20),respectively.     

SYNTHESIS OF POLYURETHANE MODIFIED BISMALEIMIDE (UBMI) AND POLYURETHANE-IMIDE ELASTOMER

Urethane modified bismaleimide(UBMI)was synthesized by the reaction of maleic anhydride(MA)with NCO group terminated polyurethane prepolymer(PUP)in presence of acetone.The product was determined by infrared analysis. Then ultrasonic assistant process was introduced into the solvent removal of the prepolymer mixture of UBMI and PUP. Polyurethane-imide(PUI)elastomer was synthesized from the above PUP-UBMI prepolymer mixture by the infusion technology with 2,5-dimethyl-2,5-bis(tert-butylperoxy)-hexane(B25)a...     

Synthesis and characterization of biodegradable polymer： Poly （ethene maleic acid ester-co-D,L-lactide acid）

A novel biodegradable polymer--poly （ethene maleic acid ester-co-D,L-lactide acid） was synthesized by copolymerizing lactide and prepolymer, which was prepared by the condensation of maleic anhydride and glycol, using p-toluene sulphonic acid as a catalyst, attempting to improve the hydrophilicity, increase flexibility and modulate the degradation rate. FTIR,^1H NMR, MALLS and DSC were employed to characterize these polymers.     

Isobaric vapor–liquid equilibria of the binary system maleic anhydride and di-isobutyl hexahydrophthalate at 2.67, 5.33 and 8.00 kPa

Isobaric vapor–liquid equilibrium (VLE) data for the binary system maleic anhydride (MAN) + di-isobutyl hexahydrophthalate (DIBE) at 2.67, 5.33 and 8.00 kPa were measured with a modified ebulliometer. Also, saturated vapor pressures of pure DIBE were measured and Antoine constants were obtained. These data were used to calculate equilibrium vapor and liquid compositions for this binary system using the NRTL model. Prediction of the VLE was done with the universal quasi-chemical functional-group activity coefficients (UNIFAC) model. The predicted results generally agree with those from experiment.     

Influence of maleic anhydride grafted polypropylene on the miscibility of polypropylene/polyamide-6 blends using ATR-FTIR mapping

In this work we describe an approach to study the influence of the compatibilizer, maleic anhydride grafted polypropylene (PP-g-MAH), on the miscibility of polypropylene/polyamide-6 blends (PP/PA6) using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopic mapping. In measurement, the image area for each blend was 100 μm × 100 μm. Different amounts of PP-g-MAH were introduced into the polymer blends, and the miscibility was characterized by the spatial distribution of PA6 in the image based on the corrected absorbance at 1640 cm^?1. It was found that small quantities of the compatibilizer could significantly improve the miscibility of the two immiscible polymers. Furthermore, our results proved that blend with 6 parts of PP-g-MAH by weight exhibited an optimal miscibility behavior. This paper demonstrates that ATR-FTIR mapping is a direct method to visualize the miscibility of polymer blends.     

Characterization of pp/regenerated tire-rubber blends using proton spin-lattice relaxation time

Proton spin-lattice relaxation time (T₁H) in the solid state was used to determine the molecular mobility of PP/regenerated tire-rubber blends (PP/RgR), employing low-field NMR. The blends were prepared with different quantities of regenerated rubber (5, 10, 15 and 20 wt%). The addition of 5 wt% maleic anhydride functionalized polypropylene (PP-g-MAH) was carried out to evaluate the processing behavior of the reclaimed material. Important differences were observed concerning the molecular mobility according to the content of regenerated rubber. A decrease in the relaxation time of the blends with an increase in PP-g-MAH content indicates that enhanced mobility of PP/regenerated tire-rubber blends was obtained and, thus, PP-g-MAH acts as a plasticizer and/or impact modified.     

Reactive poly（divinyl benzene-co-maleic anhydride） nanoparticles：Preparation and characterization

Polymeric nanoparticles（NPs）have drawn great interest in the past few years due to their potential applications in the felds of biomedical and optical technologies.However,it is still a challenge to prepare functional polymeric NPs,especially for particle diameters smaller than 50 nm.In this work,we demonstrate a one-pot method to fabricate reactive poly（divinyl benzene-co-maleic anhydride）NPs（PDVBMAH NPs）through a self-stable precipitation polymerization process.The size and morphology of these PDVBMAH NPs were characterized in detail by scanning electronic microscopy,and their chemical structure was determined by IR.The results showed that these NPs were highly cross-linked and their diameter was about 30 nm with narrow distribution.Additionally,the DVB and MAH endow the NPs with reactive surface anhydride and pendant vinyl groups,and these particles could be further functionalized through reaction of these groups.A plausible pathway was proposed for the formation of PDVBMAH NPs.     

Poly(vinyl alcohol) separators improve the coulombic efficiency of activated carbon cathodes in microbial fuel cells

High-performance microbial fuel cell (MFC) air cathodes were constructed using a combination of inexpensive materials for the oxygen reduction cathode catalyst and the electrode separator. A poly(vinyl alcohol) (PVA)-based electrode separator enabled high coulombic efficiencies (CEs) in MFCs with activated carbon (AC) cathodes without significantly decreasing power output. MFCs with AC cathodes and PVA separators had CEs (43%–89%) about twice those of AC cathodes lacking a separator (17%–55%) or cathodes made with platinum supported on carbon catalyst (Pt/C) and carbon cloth (CE of 20%–50%). Similar maximum power densities were observed for AC-cathode MFCs with (840 ± 42 mW/m²) or without (860 ± 10 mW/m²) the PVA separator after 18 cycles (36 days). Compared to MFCs with Pt-based cathodes, the cost of the AC-based cathodes with PVA separators was substantially reduced. These results demonstrated that AC-based cathodes with PVA separators are an inexpensive alternative to expensive Pt-based cathodes for construction of larger-scale MFC reactors.     

Electro-electrodialysis of hydriodic acid using the cation exchange membrane cross-linked by accelerated electron radiation

Electro-electrodialysis (EED) of hydriodic acid with HI molality of ca. 9.5 mol/kg was examined in the presence of iodine using a commercial cation exchange membrane (CMB) as a separator. For the increase of the selectivity of proton permeation, the membrane was cross-linked by accelerated electron radiation. The membrane properties (area resistance, ion exchange capacity (IEC), water content) of the cross-linked membranes were measured. The area resistance in 2 mol/dm³ KCl solution of the cross-linked membranes decreased as compared with that of the non-cross-linked membrane (original of CMB membrane). The IEC and water content of cross-linked membranes at each dose rate had almost the same value as that of non-cross-linked membrane. Electro-electrodialysis of hydriodic acid with HI molality of ca. 9.5 mol/kg was examined at 75 °C with 9.6 A/dm². The cross-linked cation exchange membrane by accelerated electron radiation had higher selectivity of the proton permeation by cross-linking structure of polymer than that of the non-cross-linked membrane.     

Isothermal (vapor + liquid) equilibria of maleic anhydride + di-isobutyl hexahydrophthalate and maleic anhydride + di-n-butyl phthalate systems at T = (413.2, 433.2 and 453.2) K

Isothermal (vapor + liquid) equilibrium for the two binary systems (maleic anhydride + di-isobutyl hexahydrophthalate and maleic anhydride + di-n-butyl phthalate) at T = (413.2, 433.2, and 453.2) K were determined using the ebulliometric method. The parameters of the NRTL model for the two binary systems were obtained from the correlation of the experimental data.     

Influences of surfactant (PVA) concentration and pH on the preparation of copper nanoparticles by electron beam irradiation

Electron beam irradiation method was successfully applied to the preparation of Cu nanoparticles in aqueous solution under room temperature and ambient pressure using polyvinyl alcohol (PVA) as the surfactant. The influences of the pH on the products were studied by X-ray diffraction (XRD), and those of the surfactant PVA concentration on the particle size and agglomeration by ultraviolet–visible spectrophotometry (UV–vis) and laser scattering particle size distribution analysis (LSPSDA). The products were characterized by XRD and transmission electron microscopy (TEM). The results showed that the grain size of Cu nanoparticles, within a certain range, can decrease with increasing PVA concentration. Pure Cu nanoparticles with the grain size distribution of 5–50 nm were prepared when the pH was adjusted between 5.0 and 9.0, and the PVA concentration was 2.20 g/100 mL.     

Uranyl ion uptake capacity of poly (N-isopropylacrylamide/maleic acid) copolymeric hydrogels prepared by gamma rays

The effect of gel composition, absorbed dose and pH of the solution on the uranyl ion uptake capacity of N-isopropylacrylamide/maleic acid copolymeric hydrogels containing 0–3 mol% of maleic acid at 48 kGy have been investigated. Uranyl uptake capacity of hydrogels are found to increase from 18.5 to 94.8 mg [UO₂²⁺]/g dry gel as the mole % of maleic acid content in the gel structure increased from 0 to 3. The percent swelling, equilibrium swelling and diffusion coefficient values have been evaluated for poly(N-isopropylacrylamide/maleic acid) hydrogels at 500 ppm of uranyl nitrate solution.     

Effect of separating layer in pervaporation composite membrane for MTBE/MeOH separation

The composite membranes with polyvinylalcohol (PVA) as separating layer material and polyacrylonitrile (PAN) or cellulose acetate (CA) as supporting layer material were prepared for separating methyl tert-butyl ether (MTBE)/MeOH mixture by pervaporation (PV). The results showed that PV performance of the composite membrane with PVA membrane as separating layer was superior to that with CA membrane as separating layer, and the PV performance of PVA/CA composite membrane with CA membrane as supporting layer was better. The parameters to prepare the composite membrane remarkably affected PV performance of the composite membrane. The permeate flux of both composite membranes of PVA/PAN and PVA/CA was over 400 g/m² h, and the concentration of MeOH in the permeate reached over 99.9 wt.% for separating MTBE/MeOH mixture.