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Polybutadiene chemical modification to amine terminated polybutadiene, polyurea and magnetic nanocomposite was settled as the aim of current report. In this regard, amine terminated polybutadiene synthesized through a two consecutive oxidation and amination reactions on polybutadiene. In situ polymerization method was used to prepare polybutadiene-based polyurea. Magnetic nanocomposite synthesized with loading 1-3 weight percent of surface modified magnetite (Fe3O4@Si-NH2) nanoparticle in one-pot reaction of amine terminated polybutadiene with toluene diisocyanate. 1H NMR and FT-IR spectroscopy methods were approved correct synthesize of amine functionalized polybutadiene, polyurea and magnetic nanocomposites. Thermal degradation and characteristics investigated using TGA/DTG and DSC techniques; lower degradation rates with improved thermal stabilities and superior thermal properties with wider thermal service range observed especially in 3 weight percent nanocomposite in comparison with pristine polyurea. In addition to, successful nanocomposite synthesis and fine nanoparticle dispersion confirmed by XRD and SEM methods, remarkable chain orderings of magnetic nanocomposite observed. VSM magnetization characterization proved superparamagnetic characteristics of nanocomposites with direct relationship to the magnetic nanoparticle content. [ABSTRACT FROM AUTHOR]

Surface modification of fumed nanosilica was performed by using n-(2-aminoethyl)-3-ammopropyrtrime-thoxysilane as a coupling agent. Then, modified nanosilica was utilized in the preparation of polyurethane rigid foam. The characterization and the study of properties were done by some techniques, such as Fourier transform infrared spectroscopy, thermogravi-metric analysis, scanning electron microscopy, dynamic mechanical analysis, and thermomechanical analysis. Also, tensile test was examined to evaluate the static mechanical properties. With the increasing of modified nanosilica, thermal and static mechanical properties were enhanced, but dynamic mechanical behavior was different from static mechanical behavior because of the different properties of interfacial domain and bulk matrix. The presence of functional groups on the nanosilica surface affected stoichiome-try and reduced hard phase formation in bulk polymer. The decrease in glass transition temperature ([T.sub.g]) confirmed this statement. POLYM. ENG. SCI., 50:468-473, 2010. [C] 2009 Society of Plastics Engineers, INTRODUCTION Polyurethanes (PUs) are unique polymer materials with a wide range of physical and chemical properties. With well-designed combination of monomeric materials, PUs can be tailored to meet the diversified [...]

Poly(urethane-imide)/Fe3O4@SiO2-NH2 nanocomposites were synthesized by the reaction of 4,4′-diphenylmethane diisocyanate (MDI), polypropylene glycol (PPG), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride and Fe3O4@SiO2-NH2 nanoparticles in propylene carbonate (PC) as an alternative green solvent. Poly(urethane-imide)s combined with Fe3O4@SiO2-NH2 nanoparticles (NPs) at various NPs ranging from loadings levels of 0.5 and 3.5 pbw were prepared and characterized by fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and vibrating sample magnetometery (VSM). The results showed the performances of Fe3O4@SiO2-NH2 nanoparticles in improving of thermal resistance and magnetic properties of PUI/Fe3O4@SiO2-NH2 in comparison with pristine poly(urethane-imide). [ABSTRACT FROM AUTHOR]

In the electronic industry, there is an enormous request for high thermal conductivity polymer. In this regard, we propose a novel synthesis route to produce magnetically alignable 2D-nanofiller. In our work, surface modification of boron nitride nanosheets (BNNs) with polyacrylamide brushes are explored. For this purpose, the post-polymerization reaction of BNNs is followed by the redox polymerization of acrylamide onto the surfaces of already hydroxyl-functionalized BNNs. Afterward, magnetic iron oxide nanoparticles are contributed to modified BNNs through polyacrylamide chelating effect. Finally, to provide high thermal conductive and magnetic responsive nanocomposites, the functionalized Fe3O4/BNNs are dispersed in epoxy matrix and aligned under an external magnetic field. According to the results of thermal conductivity studies, thermal transport of the nanocomposites increases to 0.37 W/mK by adding only 10% of functionalized Fe3O4/BNNs (at 25 °C). Mechanical and thermal properties of these nanocomposites are compared with the pristine epoxy polymer as a control sample. [ABSTRACT FROM AUTHOR]

Polybutadiene (PB) and hydroxyl-terminated PB were epoxidized using in situ-generated dimethyl dioxirane as an oxidant in the attendance of different concentrations of copper and lead (2-guanidinobenzimidazoliume) (GBH) complexes as the catalyst at 25°C. The potential of cis, trans, and vinyl double bonds toward epoxidation was considered in detail at various reaction times. The products were characterized using proton nuclear magnetic resonance and Fourier transform infrared spectroscopy techniques and data revealed that the formation of desired products were obtained without any side reaction. The results indicated the performance of calculated 0.252 mmol of GBH complexes in obtaining maximum epoxidation yield as well as selectivity in the epoxidation of cis double bonds in comparison with trans and vinyl ones. [ABSTRACT FROM AUTHOR]