The Effect of Methacrylic Acid and Maleic Acid on the Isothermal Kinetics of Acrylic Acid Crosslinking Co-polymerization under Conventional and Microwave heating

The kinetics of free-radical crosslinking co-polymerization(FRCCP)of acrylic acid(AA)with both methacrylic acid(MA)(PAMA hydrogel)and maleic acid(MAL)(PAMAL hydrogel)was investigated under the conditions of isothermal conventional heating(CH)and under the conditions of microwave heating(MWH)with controlled cooling.The kinetics curves of FRCCP of PAMA and PAMAL hydrogels under the conditions of CH are described with the kinetics model of second order chemical reaction,whereas the kinetics curves under the conditions of CH are described with the kinetics model of Polany-Winger.It is proved that MWH leads to the changes in the rate of FRCCP and to the changes in the values of the kinetic parameters activation energy(Ea)and pre-exponential factor(lnA).It was found the existence of relationship between the values of the kinetic parameters calculated for MWH and CH for PAMA and PAMAL hydrogel synthesis process,which is well-known as compensation effect.The effect of MWH on the kinetics of FRCCP for PAMA and PAMAL hydrogel formation were explained by applying the model of activation by selective energy transfer(SET).The changes in kinetics model,rate of FRCCP and kinetics parameters,caused with the MWH can found wide application in designing novel technologies for obtaining polymers and for synthesis of polymers with novel physico-chemical properties.The suggested mechanism of activation for polymerisation under the conditions of MWH also enables development of novel reaction systems and technologies for polymers productions.

Synthesis, Characterization of Cellulose Grafted N-Oxide Reagent and Its Application in Oxidation of Alkyl/Aryl Halides

Oxidation of aliphatic and aromatic halides by N-oxide functionalities supported on 4- vinyl pyridine, (4-VP), grafted cellulose is reported in the present manuscript. Synthesis of graft copolymer of cellulose and poly 4-vinyl pyridine, poly(4-VP), has been carried out using ceric ions as redox initiator. Post-grafting treatment of CellO-g-poly (4-VP) with 30% H2O2 in acetic acid gives Cellulose-g-poly (4-VP) N-oxide, the polymeric supported oxidizing reagent. The polymeric support, CellO-g-poly (4-VP) N-oxide, has been used for oxidation reactions of different alkyl / aryl halide such as 1-bromo-3-methyl butane, 2-bromo propane,1-bromo heptane and benzyl chloride. The polymeric reagent was characterized by IR and thermo-gravimetric analysis. The oxidized products were characterized by FTIR and H1NMR spectral methods. The reagent was reused for the oxidation of a fresh alkyl / aryl halides and it was observed that the polymeric reagent oxidizes the compounds successfully but with little lower product yield.

Open tubular capillary electrochromatography with block co-polymer coating for separation of β-lactam antibiotics

A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reversible addition fragmentation chain transfer radical polymerization method was used to synthesize poly (maleic anhydride-styrene-N-isopropylacrylamide). The prepared block copolymer coating was characterized with NMR, fourier transform infrared spectroscopy and scanning electron microscope. Several key separation factors of OT-CEC, which including polymer amount,stability of the coating, temperature, species of organic additives, buffer pH and concentration, were investigated in detail. Our results indicated that the separation efficiency was improved greatly with the coating capillary and the three test analytes could be baseline separated. Then, the separation mechanism was briefly explored. Moreover, the proposed OT-CEC method displayed promising quantitative analysis property of the three test analytes with good linearity (R2>0.99), repeatability (relative standard deviations <0.9%) and high recovery (95.4%-106.2%). Further, the assay was applied in monitoring the three test β-lactam antibiotics (cephradine, cephalexin and amoxicillin) in serum samples, providing a useful platform for construction of novel polymer coatings in OT-CEC system and for analysis of drugs in real bio-samples.

HALF-TITANOCENE CHLORIDES 2-(BENZIMIDAZOL-2-YL)QUINOLIN-8-OLATES: SYNTHESIS, CHARACTERIZATION AND ETHYLENE (CO-)POLYMERIZATION BEHAVIO

A series of half-titanocene chloride 2-（benzimidazol-2-yl）quinolin-8-olates C1-C6 were synthesized by treating the lithium salts of the ligand with CpTiCI3. All the complexes were characterized by 1H-NMR, 13C-NMR and elemental analyses, and the crystal structure of C3 and C6 was measured by X-ray. These half-titanocene complexes showed moderate catalytic activities toward ethylene polymerization （up to 1840 kg·mol-1（Ti）·h-1） when activated with MMAO, affording the high molecular weight polymers. And they also exhibited good activity for copolymerization of ethylene and a-olefin with low content of co-monomer.

Preparation of High-performance Polyimide Fibers with Wholly Rigid Structures Containing Benzobisoxazole Moieties

In this work, a fully rigid coplanar symmetric heterocyclic unit was introduced into the rigid polyimide macromolecular backbone structure to prepare high-performance polyimide fibers. The novel co-polyimide(co-PI) fibers based on 3,3',4,4'-biphenyltetracarboxylic anhydride(BPDA), p-phenylenediamine(PDA) and 2,6-(4,4'-diaminodiphenyl) benzo[1,2-d:5,4-d'] bisoxazole(PBOA) were fabricated via a twostep wet-spinning method. The effects of benzobisoxazole moiety on spinnability, aggregation structure, and mechanical properties of fibers were systematically discussed. The detailed structural analysis revealed that the well-defined aggregation structures of co-PI fibers were obtained from initial amorphous structure when post hot-drawing temperature was higher than 460 ℃ under proper drawing ratio, and the incorporation PBOA into BPDA-PDA structures produced more compact structural co-PI fiber than homo BPDA-PDA fiber. The BPDA-PDA/PBOA co-PI fibers exhibited optimum tensile strength and modulus of 2.65 and 103 GPa, which increased by 182% and 84% compared to the homo BPDA-PDA fiber, respectively.

Effect of GMA Polymer Compatibilizers on Highly Filled Composites of Low Density Polyethylene/Magnesium Hydroxide

Functional polymers such as polyethylene grafted glycidyl methacrylate （PE-g-GMA） and ethylene-methyl acrylate-glycidyl methacrylate terpolymer （E/MA/GMA） were used as compatibilizers in the preparation of highly filled composites of polyethylene/magnesium hydroxide（PE/MH）. Comparative studies were performed on the effect of magnesium hydroxide and stearic acid on the interface within polymer and magnesium hydroxide composites. The effect of polymeric compatibilizers on the properties of the composites was studied using tensile and impact tests, torque rheological analysis, differential scanning calorimetry and environmental scanning electron microscopy （ESEM）. The microstructure of highly filled PE/MH composites changed after the addition of functional polymers. The mechanical properties of the composite material increased after compatibilization. The compatibilization processes of PE-g-GMA and E/MA/GMA were different. The grafted polymer was more compatible with polyethylene, which led to a polar polymer phase. In contrast, the tercopolymer tended to adhere to the surface of MH particles.