Highly Active Pandanus Nanocellulose-Supported Poly(amidoxime) Copper (II) Complex for Ullmann Cross-Coupling Reaction

The transition metal-catalyzed chemical transformation of organic electrophiles, and organometallic reagents have turned up as an exceedingly robust synthetic tool. The evolution of transition metal catalysts has attained a stage of civilization that authorizes for an extensive scope of chemical bonds formation partners to be combined efficiently. The applications of Cu-based nanoparticles have received great attention owing to the earth-abundant, low toxicity and inexpensive. Due to these characteristics, copper nanoparticles have generated a great deal of interest especially in the field of catalysis. In this study, poly(acrylonitrile) was synthesized by undergoes free-radical initiation process and followed by Beckmann rearrangement with hydroxylamine solution converted into the poly(amidoxime) ligand and anchored the copper onto poly(amidoxime). Cu(II)@PAM was characterized using different techniques such as FTIR, FESEM, EDX, TEM, TGA, DSC, ICP-OES, and XPS analyses. The Cu(II)@PAM showed high stability and high catalytic activity in a wide variety of electrophilic substituted phenols with substituted aryl/benzyl halides. 0.15 mol%, ±3 mg of Cu(II)@PAM could efficiently promote Ullmann reaction to give the corresponding coupling product up to 99 % yields. The complex was easy separated and recovered from the reaction mixture by simple filtration.

New functional copolymers of 1-vinyl-1,2,4-triazole with allylamine

New water-soluble functional copolymers based on 1-vinyl-1,2,4-triazole and allylamine were synthesized under the action of free-radical initiation conditions and azobisisobutyric acid dinitrile. Сopolymers of various compositions with a molecular weight of 1287–30204 Da were obtained by varying reaction conditions. The structure, molecular weight and physicochemical properties of the copolymers were determined using elemental analysis, IR and NMR 1H-spectroscopy, gel permeation chromatography, potentiometric and turbidimetric titration, as well as dynamic light scattering and thermogravimetric analysis. It was established that the obtained copolymers, exhibiting the properties of high-resistance organic semiconductors, are characterized by a specific electrical conductivity of 10-13 – 10-14 S/cm and high resistance to thermal destruction (up to 260–280 °C). These copolymers are promising as stabilizing polymer matrices in the formation of biologically active water-soluble hybrid organic-inorganic nanocomposites.

Determination of homopolymerization kinetics and copolymerization with methyl methacrylate of diethyl 9-(methacryloyloxy)-2-oxo-nonylphosphonate, 9-(methacryloyloxy)-2-oxo-nonylphosphonic acid and diethyl 9-(methacryloyloxy)-nonylphosphonate

The three polymerizable monomers diethyl 9-(methacryloyloxy)-2-oxo-nonylphosphonate M1, 9-(methacryloyloxy)-2-oxo-nonylphosphonic acid M2 and diethyl 9-(methacryloyloxy)-nonylphosphonate M3 are examined for their free radical polymerization and copolymerization activity in methanol between 40 and 65°C. Polymerization proceeds readily through a thermal free radical initiation. The intensity exponents for the monomer and initiator are only slightly over 1 and approximately 0.5, respectively. This is in accordance with the results typically observed for an ideal free radical polymerization with bimolecular termination. The kinetics of copolymerization with methyl methacrylate (MMA) are monitored by online 1H nuclear magnetic resonance (NMR) spectroscopy. Two copolymerization reactions for each pair of co-monomers are sufficient to evaluate the kinetic data using the Jaacks method, the Fineman-Ross method and the nonlinear least squares method. All three methods give similar results for particular monomer/MMA couples.

Effect of Chitosan-Grafted-Poly (Methyl Methacrylate) Content on Mechanical Properties and Thermal Degradation of Poly (Vinyl Chloride) Composites

The graft copolymerization was carried out under nitrogen atmosphere using the free radical initiation technique. The blend formulations were first dry blended using a mixer before being milled into sheets on a two-roll mill at 170°C, and then hot pressed into composites specimens at 175°C for 10 min. The objective of this study to investigate the mechanical and thermal properties of PVC blends. The flexural strength and modulus of ungrafted composites increased with increasing filler content from 2 to 10 part per hundred resin (phr) while the grafted composites also increased only from 2 to 6 phr filler content. The flexural modulus of ungrafted was higher compared to the grafted composites whereas the grafted showed good flexural strength than ungrafted composites. The impact strength of both composites decreased with increasing filler content but the ungrafted composites showed good toughness than grafted composites. The thermal stability of both composites increased compared to unfilled PVC.

A Novel Biomaterial from Acrylamide Graft on NaOH-Urea Modified Rice Husk

Rice husk is a plentiful agricultural byproduct. In this paper, rice husk (RH) surface was first treated by NaOH/urea into a modified-rice husk(MRH), then the MRH was used as a new template for polymerization of acrylamide(AM) on MRH, as a result, the product named as MRH-g-AM, was formed by the free-radical initiation in aqueous solution using ammonium persulfate as an initiator. The polymer grafted on the MRH was considered as a novel copolymer which was thereafter analyzed by FTIR and SEM. The product was washed thoroughly with distilled water to remove all unreactive chemicals. The results showed that MRH was successfully reacted with AM. The SEM images indicated that MRH-g-AM appeared distinct cracks and formed a loosen structure in comparison with RH, indicating the facilitation of heavy metal ion adsorption in the future wastewater treatment.

Effect of poly (methyl methacrylate)-grafted-talc content on mechanical properties and thermal degradation of poly (vinyl chloride) composites

The influence of talc and poly (methyl methacrylate) (PMMA)-grafted (g)-talc on the mechanical properties of poly (vinyl chloride) (PVC) was investigated. The graft copolymerization was carried out under nitrogen atmosphere, using the free radical initiation technique. The blend formulations were first dry blended using a mixer before being milled into sheets on a two-roll mill at 165°C, and then hot pressed into composites at 190°C. The flexural modulus of both composites increased with increasing filler content from 0 to 20 part per hundred resin (phr), however the increment of grafted (57.7%) was higher than ungrafted composites (48.5%). A similar trend has also been observed for thermal stability. The impact strength of grafted was increased by 45.82%, whereas 18.96% in reduction was observed for the ungrafted composites. The decrement of flexural strength by 16.6% and 21.1% of grafted and ungrafted, respectively, has also shown the improvement in mechanical properties of grafted composites.

Synthesis of Konjac Glucomannan-Graft-Methacrylic Acid Copolymer

Konjac glucomannan is a kind of natural polysaccharides with excellent biocompatibility and biodegradable activities. In this paper, a series of Konjac glucomannan-graft-methacrylic acid copolymers were prepared by the free-radical initiation grafting Konjac Glucomannan (KGM) with methacrylic acid(MA). The reaction conditions such as reaction temperature, KGM and MA ratio and initiator concentration, were investigated, and chemistry of KGM and its MA grafted copolymers were characterized using FTIR.