Terminology for chain polymerization (IUPAC Recommendations 2021)

Chain polymerizations are defined as chain reactions where the propagation steps occur by reaction between monomer(s) and active site(s) on the polymer chains with regeneration of the active site(s) at each step. Many forms of chain polymerization can be distinguished according to the mechanism of the propagation step (e.g., cyclopolymerization – when rings are formed, condensative chain polymerization – when propagation is a condensation reaction, group-transfer polymerization, polyinsertion, ring-opening polymerization – when rings are opened), whether they involve a termination step or not (e.g., living polymerization – when termination is absent, reversible-deactivation polymerization), whether a transfer step is involved (e.g., degenerative-transfer polymerization), and the type of chain carrier or active site (e.g., radical, ion, electrophile, nucleophile, coordination complex). The objective of this document is to provide a language for describing chain polymerizations that is both readily understandable and self-consistent, and which covers recent developments in this rapidly evolving field

Terminology for chain polymerization (IUPAC Recommendations 2021)

Chain polymerizations are defined as chain reactions where the propagation steps occur by reaction between monomer(s) and active site(s) on the polymer chains with regeneration of the active site(s) at each step. Many forms of chain polymerization can be distinguished according to the mechanism of the propagation step (e.g., cyclopolymerization – when rings are formed, condensative chain polymerization – when propagation is a condensation reaction, group-transfer polymerization, polyinsertion, ring-opening polymerization – when rings are opened), whether they involve a termination step or not (e.g., living polymerization – when termination is absent, reversible-deactivation polymerization), whether a transfer step is involved (e.g., degenerative-transfer polymerization), and the type of chain carrier or active site (e.g., radical, ion, electrophile, nucleophile, coordination complex). The objective of this document is to provide a language for describing chain polymerizations that is both readily understandable and self-consistent, and which covers recent developments in this rapidly evolving field

Terminology for chain polymerization (IUPAC Recommendations 2021)

Chain polymerizations are defined as chain reactions where the propagation steps occur by reaction between monomer(s) and active site(s) on the polymer chains with regeneration of the active site(s) at each step. Many forms of chain polymerization can be distinguished according to the mechanism of the propagation step (e.g., cyclopolymerization – when rings are formed, condensative chain polymerization – when propagation is a condensation reaction, group-transfer polymerization, polyinsertion, ring-opening polymerization – when rings are opened), whether they involve a termination step or not (e.g., living polymerization – when termination is absent, reversible-deactivation polymerization), whether a transfer step is involved (e.g., degenerative-transfer polymerization), and the type of chain carrier or active site (e.g., radical, ion, electrophile, nucleophile, coordination complex). The objective of this document is to provide a language for describing chain polymerizations that is both readily understandable and self-consistent, and which covers recent developments in this rapidly evolving field

Terminology for chain polymerization (IUPAC Recommendations 2021)

Chain polymerizations are defined as chain reactions where the propagation steps occur by reaction between monomer(s) and active site(s) on the polymer chains with regeneration of the active site(s) at each step. Many forms of chain polymerization can be distinguished according to the mechanism of the propagation step (e.g., cyclopolymerization – when rings are formed, condensative chain polymerization – when propagation is a condensation reaction, group-transfer polymerization, polyinsertion, ring-opening polymerization – when rings are opened), whether they involve a termination step or not (e.g., living polymerization – when termination is absent, reversible-deactivation polymerization), whether a transfer step is involved (e.g., degenerative-transfer polymerization), and the type of chain carrier or active site (e.g., radical, ion, electrophile, nucleophile, coordination complex). The objective of this document is to provide a language for describing chain polymerizations that is both readily understandable and self-consistent, and which covers recent developments in this rapidly evolving field

Reconsidering terms for mechanisms of polymer growth: The “Step-Growth” and “Chain-Growth” Dilemma

© 2022 The Authors. Published by Royal Society of Chemistry. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1039/D2PY00086EThe terms “step-growth polymerization” and “chain-growth polymerization” are used widely in both written and oral communications to describe the two main mechanisms of polymer growth. As members of the Subcommittee on Polymer Terminology (SPT) in the Polymer Division of the International Union of Pure and Applied Chemistry (IUPAC), we are concerned that these terms are confusing because they do not describe the fundamental differences in the growth of polymers by these methods. For example, both polymerization methods are comprised of a series of steps, and both produce polymer chains. In an effort to recommend comprehensive terms, a 1994 IUPAC Recommendation from the then version of SPT suggested polycondensation and polyaddition as terms for the two variants of “step-growth polymerization”, and similarly chain polymerization and condensative chain polymerization for two variants of “chain-growth polymerization.” However, these terms also have shortcomings. Adding to the confusion, we have identified a wide variety of other terms that are used in textbooks for describing these basic methods of synthesizing polymers from monomers. Beyond these issues with “step-growth” and “chain-growth,” synthesis of polymers one monomer unit at a time presents a related dilemma in that this synthetic strategy is wholly encompassed by neither of the traditional growth mechanisms. One component of the mission of IUPAC is to develop tools for the clear communication of chemical knowledge around the world, of which recommending definitions for terms is an important element. Here we do not endorse specific terms or recommend new ones; instead, we aim to convey our concerns with the basic terms typically used for classifying methods of polymer synthesis, and in this context we welcome dialogue from the broader polymer community in a bid to resolve these issues.We acknowledge IUPAC for support of this work through project 2019-027-1-400. We thank the members of SPT for helpful discussions and critical feedback in the preparation of this manuscript

A brief guide to polymer characterization: structure (IUPAC technical report)

To bolster the series of Brief Guides released by International Union of Pure and Applied Chemistry (IUPAC), here we introduce the first Brief Guide to Polymer Characterization. This article provides a concise overview of characterization methods for teachers, students, non-specialists, and newcomers to polymer science as well as being a useful manual for researchers and technicians. Unlike pure low molar mass chemical substances, polymers are not composed of identical molecules. The macromolecules which comprise a single polymer sample vary from one another, primarily in terms of size and shape, but often also in the arrangement or positioning of atoms within macromolecules (e.g., chain branching, isomerism, etc.). Polymer properties are often drastically different from those of other substances and their characterization relies on specialist equipment and/or common equipment used in a specialized way (e.g., particular sample preparation or data analysis). This Brief Guide focuses uniquely on the structural characterization (i.e., analyzing the molecular and multi-molecular aspects) of polymers. The complex nature of the structural variables possible in macromolecular materials often presents a challenge with regard to the detailed structural characterization of polymers. This Brief Guide provides a useful starting point to direct the reader to the most commonly used and useful techniques to characterize these structural variables

An exercise-based international polymer syllabus

The IUPAC Subcommittee on Polymer Education has been pursuing the development of a compact syllabus covering the essential topics required for a tertiary education in polymer science, with numerical and short answer exercises addressing each topic. The primary goal of the document is to provide a framework for a complete course made freely available worldwide so that any educator can implement a professionally-curated course in polymer science for their students without needing expensive textbooks or reliable internet access. An important secondary goal is to popularize the use of approved IUPAC terminology in polymer science by using it consistently throughout the document and providing references to IUPAC source documents. Professor Melissa Chin Han Chan was an active and enthusiastic participant in the project who played a significant role in its design and implementation. The late Professor Richard ‘Dick’ Jones also had a keen interest in the project and had a great influence on its direction and structure. This brief note is dedicated to these two illustrious polymer scientists

The Role of Solubility in Thermal Field Flow Frac-tionation – A Revisited Theoretical Approach for Tuning the Separation of Chain-Walking Polymerized Polyethylene

The influence of the polymer solubility on the separation efficiency in thermal field-flow fractionation (ThFFF) was investigated for a polymer model system of differently branched chain walking polyethylenes in five different solvents, which were selected depending on their physical parameters. The understanding of polymer thermal diffusion has been elucidated using a revisited approach based on the latest thermal diffusion prediction model by Mes,Kok and Tijssen combined with the Hansen solubility theory. Thereby, a significant improvement in the precision of the thermal diffusion prediction and the separation efficiency has been achieved by implementation of the temperature dependency on Hansen solubility parameters. In addition, we demonstrate a method for validation of the segmental size of polymer chains with varying topology by using the revisited thermal diffusion prediction approach in inverse mode and experimental thermal diffusion data

Control of morphology in olefin polymerization catalyzed by nickel diimine complexes encapsulated into polybutadiene based support

commercially available hydroxyl terminated low molecular cis-1,4-polybutadiene was modified by carboxylic functions and used as an effective support in single-site alpha-olefin polymerization. Dynamic light scattering analysis of support solution in heptane confirmed increased ability to self-assembly of modified polybutadienes in the presence of methylaluminoxane cocatalyst (MAO). alpha-Diimine nickel and bis(indenyl) zirconium dichloride catalysts activated by trimethylaluminium or MAO cocatalysts were encapsulated into polymer micellar aggregates and used for ethylene and octadec-1-ene polymerization. Furthermore, the effects of cocatalyst type and concentration on the micelle-formation process, activity and morphology of polyethylene (polyoctadec-1-ene) particles were investigated. In the presence of polybutadiene supports, formation of spherical micrometric PE beads was observed during MAO cocatalyzed ethylene polymerization, whereas the activity of polymerization was not decreased

Polymerization of hex-1-ene initiated by diimine complexes of nickel and palladium

The effect of monomer concentration, reaction temperature and initiator structure on the activity, molar mass, branching and thermal properties of poly(hex-1-ene)s was investigated for the polymerization of hex-1-ene initiated by four alpha-diimine complexes of nickel and palladium. Hex-1-ene polymerization exhibits an apparent negative kinetic order with respect to monomer concentration. Polymerization of hex-1-ene initiated by MAO activated 1,4-bis(2, 6-diisopropylphenyl)acenaphtenediiminenickel(II) dibromide (1a/MAO) proceeds in living-like fashion not only at sub-zero temperatures but even at 20degreesC. However, molar masses of the polymers are higher than predicted values in agreement with an initiator efficiency lower than one