Pavel Kratochvíl

Glossary of basic terms in polymer science (IUPAC Recommendations 1996)

Titular Members: G. Allegra (Italy, to 1989); R. E. Bareiss (Germany, to 1993); N. M. Bikales (USA, Secretary to 1987); K. Hatada (Japan, Associate Member from 1987, Titular Member from 1989); A. D. Jenkins (UK, Chairman to 1985, Associate Member to 1987); J. Kahovec (Czech Republic, Associate Member from 1987, Titular Member from 1991); P. Kratochvíl (Czech Republic, Chairman to 1991); E. Maréchal (France, Associate Member from 1991, Titular Member from 1993); W. V. Metanomski (USA, Associate Member from 1987, Titular Member from 1991); I. Mita (Japan, Titular Member to 1989, Associate Member to 1991); C. Noël (France, to 1993); I. M. Papisov (Russia, to 1987, Associate Member to 1991); V. P. Shibaev (Russia, from 1987); R. F. T. Stepto (UK, Associate Member from 1987, Titular Member from 1989, Chairman from 1991); U. W. Suter (Switzerland, to 1991, Associate Member to 1993); W. J. Work (USA, Associate Member from 1985, Secretary from 1987).

Polyaniline dispersions 2. UV—Vis absorption spectra

Optical absorption spectra of polyaniline dispersions in aqueous media have been investigated. Two absorption bands located at 340 and 610 nm are found for blue polyaniline base in ammonia solutions. The spectra of alkalized dispersions are close to those observed for polyaniline base in N-methylpyrrolidone solution (maxima at 332 and 638 nm), but the position of the maxima depends on the nature of the alkali. In the acidic region, three distinct absorption bands of the green protonated polyaniline are observed at 350, 430 and 810 nm. The spectroscopic response to change of pH is fast but additional slow changes occur and may extend for hours when close to neutral media. The absorption coefficient of polyaniline in 1 M hydrochloric acid for a local maximum between 380 and 420 nm is estimated as ϵ=31 500 ± 1700 cm2 per gram of polyaniline hydrochloride. Spectroscopy is used to follow up the dispersion polymerization of aniline. After an induction period, a fast polymerization takes place and the originally colourless solution turns blue. A subsequent change of colour to green indicates termination of polymerization.

The formation of polyaniline and the nature of its structures

The oxidative polymerization of aniline gives rise to polyaniline which exists in a variety of forms, differing in electrical conductivity and in colour. A scheme of interrelated structures which accounts for all the spectroscopic and conductometric observations, is proposed, together with a set of equations summarizing the chemical transformations involved.

Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)

This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into four sections - precursors, gels, solids, and processes - and the terms have been restricted to those most commonly encountered. For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas.

Accelerating effect of some cation radicals on the polymerization of aniline

The chemical oxidation of aniline to polyaniline has been monitored by colour and acidity changes during dispersion polymerization. A small amount of various p-phenylenediamines or benzidine was found to accelerate the formation of polyaniline. The ability of such compounds to form cation radicals upon oxidation allows them to act as mediators in electron-transfer processes. Related chemicals, e.g. o-phenylenediamine, had little effect on polymerization, while m-phenylenediamine caused its retardation.

Polyaniline dispersions: preparation of spherical particles and their light-scattering characterization

Abstract Polyaniline dispersions can be prepared by the oxidative polymerization of aniline in the presence of the steric stabilizer, poly(vinyl alcohol). Dispersion particles are spherical and relatively uniform. Dynamic light scattering was used to determine their hydrodynamic radius and static light scattering to estimate mass-average particle mass. From a series of experiments, a typical example of the preparation and characterization of polyaniline dispersion is described.

Compendium of polymer terminology and nomenclature : IUPAC recommendations 2008

Chapter 1: Glossary of Basic Terms in Polymer Science (1996) Chapter 2: Stereochemical Definitions and Notations Relating to Polymers (1980) Chapter 3: Definitions of Terms Relating to Individual Macromolecules, their Assemblies, and Dilute Polymer Solutions (1988) Chapter 4: Basic Classification and Definitions of Polymerization Reactions (1994) Chapter 5: Definitions Relating to Stereochemically Asymmetric Polymerizations (2002) Chapter 6: Definitions of Terms Relating to Crystalline Polymers (1988) Chapter 7: Definitions of Terms Relating to Low-Molar-Mass and Polymer Liquid Crystals (2001) Chapter 8: Definitions of Terms Relating to the Non-Ultimate Mechanical Properties of polymers (1997) Chapter 9: Definitions of Terms Related to Polymer Blends, Composites, and Multiphase Polymeric Materials (2004) Chapter 10: Terminology of Polymers Containing Ionizable or Ionic Groups and of Polymers Containing Ions (2006) Chapter 11: Definitions of Terms Relating to the Structure and Processing of Sols, Gels, Networks and Inorganic-Organic Hybrid Materials (2007) Chapter 12: Definitions of Terms Relating to Reactions of Polymers and to Functional Polymeric Materials (2003) Chapter 13: Definitions of Terms Relating to Degradation, Aging, and Related Chemical Transformations of Polymers (1996) Chapter 14: Introduction to Polymer Nomenclature Chapter 15: Nomenclature of Regular Single-Strand Organic Polymers (2002) Chapter 16 Nomenclature of Regular Double-Strand (Ladder and Spiro) Organic Polymers (1993) Chapter 17: Structure-Based Nomenclature for Irregular Single-Strand Organic Polymers (1994) Chapter 18: Graphic Representations (Chemical Formulae) of Macromolecules (1994) Chapter 19: Source-Based Nomenclature for Copolymers (1985) Chapter 20: Source-Based Nomenclature for Non-Linear Macromolecules and Macromolecular Assemblies (1997) Chapter 21: Generic Source-Based Nomenclature for Polymers (2001) Chapter 22: Abbreviations

Polystyrene-equivalent molecular weight versus true molecular weight in size-exclusion chromatography

Abstract The evaluation of the size-exclusion chromatography (SEC) concentration elution curves by means of a calibration dependence obtained in a given SEC set for a polymer different from the polymer to be analyzed results in an error in the determination of both molecular weight and molecular-weight distribution (MWD). The problem is analyzed assuming the validity of the universal-calibration concept. The differences between the true and apparent values of molecular weight, MWD and Mw/Mn depend on and are expressed in terms of the parameters of the Mark–Houwink–Kuhn–Sakurada equation, describing the molecular-weight dependence of intrinsic viscosity, for the polymer to be analyzed and the polymer used for calibration. The differences in molecular weight and the Mw/Mn ratio are typically tens of percent and, in extreme cases, can amount up to a factor of three for molecular weight and a factor of two for the Mw/Mn ratio.

Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials

This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into four sections-precursors, gels, solids, and processes- and the terms have been restricted to those most commonly encountered. For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas.

Electrical properties of polyaniline suspensions

Abstract The ordering of electrically conducting polyaniline particles dispersed in a non-conducting liquid, 1,2,4-trichlorobenzene, in a weak electric field (of the order V mm −1 ) has been studied. The time needed for the formation of conducting chains, depending on the applied voltage, the polyaniline concentration and the viscosity of the suspension medium, was used to calculate the effective relative electric permittivity for polyaniline, ɛ p = 4.8, responsible for the dipole-dipole interaction leading to the structure formation. Nonlinear limit current-voltage characteristics typical of electrorheological suspensions were observed. The formation of the conducting chains could be followed in an optical microscope.