Gabriel J. Summers

Chemical modification of polysulfone: anionic synthesis of dipyridyl functionalized polysulfone

Abstract A new method for the synthesis of dipyridyl functionalized polysulfone is described. The functionalization process involves the formation of lithiated polysulfone from polysulfone ( 1 ) and subsequent reaction with 2,2′-vinylidenedipyridine ( 2 ) in tetrahydrofuran at −78°C under argon atmosphere. The dipyridyl functionalized polysulfone ( 3 ) was evaluated for the chelation of trace heavy metal ions such as copper and nickel in aqueous medium. The dipyridyl functionalized polysulfone shows better complexing affinity for nickel ions at specific concentrations of test solutions. Quaternization reactions of dipyridyl functionalized polysulfone with dimethyl sulfate in the presence of perchloric acid quantitatively affords the corresponding polymeric pyridinium perchlorate derivative ( 4 ).

Synthesis of aromatic carboxyl functionalized polymers by atom transfer radical polymerization

The synthesis of aromatic carboxyl functionalized polymers by atom transfer radical polymerization is described. The α-bromo-p-toluic acid (1) initiated polymerization of styrene in the presence of copper(I) bromide and 2,2′-bipyridyl affords quantitative yields of the corresponding aromatic carboxyl functionalized polystyrene (2). Polymerization proceeded via a controlled free radical process to afford quantitative yields of the corresponding aromatic carboxyl functionalized polymers with predictable molecular weights (Mn = 1600–25 900 g mol−1), narrow molecular weight distribution (Mw /Mn = 1.1–1.40) and an initiator efficiency above 0.87. The polymerization process was monitored by gas chromatographic analysis. The functionalized polymers were characterized by thin layer chromatography, size exclusion chromatography, spectroscopy, potentiometry and elemental analysis. © 2000 Society of Chemical Industry

Synthesis and characterization of electrically conductive poly(aniline-co-3-bromoaniline) nanocomposites

Poly(aniline-co-3-bromoaniline) copolymers with varying compositions of the monomers have been prepared in this work by copolymerization of aniline and 3-bromoaniline using ammonium persulphate as oxidant. Structure and morphology of the copolymers have been characterized by XRD, 1H-NMR, UV–Vis, SEM and TEM. Though polyaniline consists of aggregates of nanoparticles, poly(3-bromoaniline) shows plate-like morphology. The copolymers were found to exhibit mixed morphology depending on the composition. Electrical properties such as AC conductivity and dielectric permittivity of the different polymers have been investigated. Conductivity studies reveal that the AC conductivity of the polymers depend on their composition. The poly(3-bromoaniline) shows a conductivity of the order of 10−8 S/cm which is much lesser than polyaniline. However, copolymerization of polyaniline with 10% 3-bromoaniline resulted in a few-fold increase of the conductivity compared to pure polyaniline.

Mechanical properties of ternary blends of ABS + HIPS + PETG

The effect of a commercial styrene/butadiene/styrene-based compatibilizer (Styroflex) on the tensile and impact properties of ternary blends of poly(acrylonitrile-co-butadiene-co-styrene) (ABS), high impact poly(styrene) (HIPS) and poly(ethylene terephthalate-co-cyclohexanedimethanol terephthalate) (PETG) was investigated. The tensile yield strengths and the moduli of the blends were of similar magnitude as the parent polymers. However, notched Charpy impact properties showed significant deviations with high synergy in ABS/PETG blends and strong antagonism in HIPS/PETG blends. Addition of Styroflex improved the impact properties of all blends containing HIPS and ABS. Dynamic mechanical analysis studies confirm the phase separated nature of ABS/PETG binary blends.

Synthesis and Characterization of Polyaniline, Poly(3-fluoroaniline), and Poly(aniline-co-3-fluoroaniline) Derivatives Obtained by Chemical Oxidative Polymerization Methods

ABSTRACT The syntheses of thermally stable, conducting polyaniline, poly(3-fluoroaniline), and poly(aniline-co-3-fluoroaniline) derivatives by chemical oxidative polymerization methods are described. By varying the mol% of 3-fluoroaniline in the monomer feed, a series of new poly(aniline-co-3-fluoroaniline) derivatives with different chemical compositions were prepared by chemical oxidative copolymerization methods using ammonium persulfate as oxidant in the presence of hydrochloric acid as the dopant. The chemical oxidative copolymerization of aniline with 3-fluoroaniline affords poly(aniline-co-3-fluoroaniline) derivatives with increased solubility properties, greater thermal stability, improved morphological control, and enhanced electrical characteristics, which promotes the processibility of the different fluorine-functionalized polyaniline derivatives when compared with the parent polyaniline homopolymer. Poly(3-fluoroaniline) and the different poly(aniline-co-3-fluoroaniline) derivatives show better solubility and thermal stability than the polyaniline homopolymer, due to the incorporation of the F atoms along the fluorine-functionalized polyaniline backbone. Furthermore, the poly(3-fluoroaniline) homopolymer is thermally more stable than the polyaniline homopolymer due to the presence of the C–F bonds of the 3-fluoroaniline units along the polymer backbone. The electrical conductivity of the different poly(3-fluoroaniline) derivatives is dependent on the 3-fluoroaniline content in the polymer derivative and the morphology of the specific copolymer. The poly(3-fluoroaniline) homopolymer exhibits the lowest electrical conductivity. In addition, the electrical conductivity of the different poly(aniline-co-3-fluoroaniline) derivatives decreases with increasing 3-fluoroaniline content in the copolymer. The different polymer derivatives were characterized by proton nuclear magnetic resonance (1H NMR) spectrometry, fourier transform infrared (FTIR) spectroscopy, ultraviolet visible (UV–Vis) spectroscopy, thermogravimetric analyses, scanning electron microscopy, and electrical conductivity measurements. GRAPHICAL ABSTRACT

Tuning the electrical properties of polyaniline by copolymerization with o-bromoaniline

Polyaniline, poly(o-bromoaniline) and poly(aniline-co-o-bromoaniline)s have been prepared by chemical oxidative polymerization methods. A series of poly(aniline-co-o-bromoaniline) derivatives has been prepared by the chemical oxidative copolymerization of aniline with different mole ratio of o-bromoaniline by varying the feed ratios of the monomers with the introduction of o-bromoaniline units along the polymer backbone. The morphology of each poly(aniline-co-o-bromoaniline) derivative is observed as a porous network of aggregated nanoparticles with each nanoparticle having smaller nanoflake structures. Room temperature electrical conductivity studies reveal that polyaniline has a conductivity value of the order of 10−3S/cm. However, the corresponding poly(aniline-co-o-bromoaniline), with 10% o-bromoaniline content, shows a fivefold increase of the electrical conductivity relative to the polyaniline homopolymer. The different polymer derivatives were characterized by 1H NMR spectrometry, Scanning electron...