Angelika Menner

Synthesis and characterization of pyrrole and m-toluidine copolymers

Abstract A series of copolymers were synthesized by chemically oxidative polymerization of pyrrole (PY) and m -toluidine (MT) in hydrochloride aqueous medium at ambient temperature. The yield, intrinsic viscosity, and solubility of the copolymers were studied by changing PY/MT molar ratio from 0/100 to 88/12. The as-prepared PY/MT copolymer bases were characterized by FT–IR, UV–VIS, 1 H NMR, DSC, and wide-angle X-ray diffraction. The results suggested that the oxidative polymerization from pyrrole and m -toluidine is exothermic and the resulting copolymers are more easily soluble in most of the organic solvents than polypyrrole. The polymer obtained is a real copolymer containing pyrrole and m -toluidine units, but the PY content calculated on the basis of the proton NMR spectra is lower than feed PY content.

Synthesis and characterization of pyrrole and anisidine copolymers

Abstract A series of copolymers were synthesized by chemically oxidative polymerization of pyrrole (PY) and o -anisidine (AS) in acidic aqueous medium. The yield, intrinsic viscosity, and solubility of the copolymers were studied by changing the monomer molar ratio, initial polymerization temperature, oxidant, ratio of monomer over oxidant, acidic medium, and adding dodecylbenzene sulfonate. As prepared PY/AS copolymer powder, was characterized by FT-IR, UV–Vis, 1 H NMR, DSC, and TG techniques. The results showed that the oxidative polymerization from PY and o -anisidine is exothermic and the resulting copolymers exhibit an enhanced solubility in most of the organic solvents as compared with polypyrrole. The polymer obtained by the oxidative polymerization is a real copolymer containing pyrrole and o -anisidine units. The PY molar content calculated based on the 1 H NMR spectra is slightly lower than feed PY content when feed PY content is lower than 30xa0mol%. The thermostability of the PY/AS copolymer increases with increasing PY unit content.

Poly(carbazole-co-acrylamide) electrocoated carbon fibers and their adhesion behavior to an epoxy resin matrix

The surface properties of original high strength and preoxidized high modulus carbon fibers were altered by electrocopolymerizing acryl amide and carbazole and therefore depositing a copolymer coating onto the fibers. Scanning electron microscopy and zeta-potential measurements confirmed the presence of a rough but dense and continuous electrocoating with a basic surface character. Therefore, ‘good’ adhesion behavior between the electrocoated carbon fibers and an epoxy resin matrix should be expected. The interfacial adhesion was measured using the single fiber pull-out and single fiber indentation test. It was shown that only ‘intermediate’ adhesion was present between the carbon fibers and the electrocoating, but superior adhesion between the coating and epoxy resin exists. The single fiber model composites always failed at the fiber/electrocoating interface. However, as shown by using the indentation test, the interfacial adhesion between fibers and electrocoating can be significantly improved if preoxidized fibers are used as substrate for electropolymerization. A very high tensile strength for the electrocoating can be expected as derived from the single fiber pull-out tests.

Electrografting of poly (carbazole-co-acrylamide) onto highly oriented pyrolytic graphite. A cyclovoltammetric, atomic force microscopic and ellipsometric study

The electrocopolymerization of carbazole and acrylamide on highly oriented pyrolytic graphite (HOPG) from ACN solutions via cyclovoltammetry (CV) was studied in order to evaluate the possibility to deposit uniform and thin but pinhole-free and still reactive coatings onto graphite-like substrates. The morphology of the coatings was investigated using atomic force microscopy and the coating thicknesses and optical parameters were measured using ellipsometry. It was found that under the chosen conditions thin (coating thickness hf>180 nm) and relatively smooth (root mean square surface roughness RMS 50 nm) no pinholes could be detected. It was found that the thickness of the deposited coatings increases almost linearly with increasing number of CV-cycles while keeping all other experimental parameters (scan rate and comonomer concentration ratio) constant. No influence of the comonomer concentration ratio on the film thickness and coating appearance could be observed, however, at quite low initial concentrations. However, the CV-scanning rate has quite a significant influence on the thickness of the deposited coatings. Higher scan rates (100 mV/s) result in thin (hf≈22 nm) coatings whereas at lower scan rates (<50 mV/s) coatings with thicknesses of approximately 50 nm were obtained. The optical coating parameters (the refractive index n and extinction coefficient k) seem to be independent of the deposition parameters and therefore averaged values of n=1.54±0.03 and k=0.08±0.03 were obtained.

Hybrid sol–gel inorganic/gelatin porous fibres via solution blow spinning

Hybrid sol–gel inorganic–organic fibres offer great potential in tissue engineering and regenerative medicine. A significant challenge is to process them using scalable technologies into useful scaffolds that provide control over fibre diameter, morphology, mechanical properties, ion release, degradation and cell response. In this work we develop formulations that are amenable to processing via solution blow spinning (SBS), a rapid technique using simple equipment to spray nano-/micro-fibres without any electric fields. The technique is extended to produce porous class I and II hybrid fibres using cryogenic SBS, with formulations developed based on tetraethyl orthosilicate/gelatin that are relatively facile to lyophilise. The formulations developed here take advantage of the reversible thermally activated conformation change of gelatin in aqueous solutions from random coil to triple helix to enable viscosity tuning and therefore fibre spinning. Gelatin is functionalised with (3-glycidyloxypropyl)trimethoxysilane to produce class II hybrids which exhibit controllable time- and temperature-dependent viscosity profiles which can be tuned for spinning into highly porous fibres.

New Redoxactive Copolymethacrylate with Side Groups Containing Phenylazoanthraquinone and Phenylbenzotriazol Units

ABSTRACTWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW The radical polymerization of methylmethacrylate (1) intheabsence andpresence of potential transfercompoundssuch as 2-(4-methoxyphenylazo)anthraquinone (4) and2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (5) is described. Neither the phenylazoanthraqui-none nor the phenylbenzotriazol group affect the radicalpolymerization of MMA concerning the polymer proper-ties of the respectively obtained PMMA (P1). Thesynthesis of the copolymer P2 by radical copolymeriza-tion of 3 mol% 2-[4-(6-methacryloyloxyhex-1,6-diy-loxy)-phenylazo]anthraquinone (2) and 97 mol% 2-[3-(2H-benzotriazol-2yl)-4-hydroxyphenyl]ethylmethacry-late (3) is described. The composition of the randomlikecopolymerP2correspondstothemonomerfeed.Sincethemolar mass of P2 is high (M

Emulsion and Foam Templating-Promising Routes to Tailor-Made Porous Polymers

Emulsions, foams, and foamed emulsions have been used successfully as templates for the synthesis of macroporous polymers. Based on this knowledge this Minireview presents strategies to use, optimise, and upscale these templating methods to synthesise tailor-made porous polymers. The uniqueness of such polymers lies in the ability to tailor their structures and, therefore, their properties. However, systematic studies on structure-property relations are lacking mainly because the templating scientific community is split into two: the polydisperse and monodisperse camps. Thus, it is time to build a bridge between the camps, that is, to synthesise porous polymers with very different structures from the same precursors to determine the relationship between the structure and the properties.