State‐of‐the‐Art and Progress in Method of Moments for the Model‐Based Reversible‐Deactivation Radical Polymerization

Abstract

polymerization (FRP). However, because of the slow initiation, rapid propagation, and termination involving many different chain lengths, FRP is difficult to control over the polymer architectures and the minimum dispersity of the molar mass distribution is 2. [4,5] What's exciting is that controlled radical polymerization (also termed as reversible-deactivation radical polymerization (RDRP)) was discovered about two decades ago. [6,7] In most of RDRP systems, the initiation or degeneratively exchange is fast, propagation is relatively slow, and termination is suppressed per present chain, referring to the dominance of dormant chains in the final mixture. As a result, polymerization proceeds in a controlled manner, allowing one to prepare various well-defined block copolymers, stars, bottlebrushes, and hybrid materials. [6] Therefore, RDRP has attracted increasing interest from both academic and industrial fields. [8][9][10] Facing the increasing demand on high qualified and tailor-made polymeric materials, despite the technological promise, there are only limited products and investigations based on RDRP techniques at industrial scale. This can be attributed to the limited commercial RDRP agents Reversible-deactivation radical polymerization (RDRP) techniques have received lots of interest for the past 20 years, not only owing to their simple, mild reaction conditions and broad applicability, but also their accessibility to produce polymeric materials with well-defined structures. Modeling is widely applied to optimize the polymerization conditions and processes. In addition, there are numerous literatures on the kinetic and reactor models for RDRP processes, which show the accessibility on polymerization kinetics insight, process optimization, and controlling over chain microstructure with predetermined molecular weight and low dispersity, copolymer composition distribution, and sequence distribution. This review highlights the facility of the method of moments in the modeling field and presents a summary of the present state-of-the-art and future perspectives focusing on the model-based RDRP processes based on the method of moments. Summary on the current status and challenges is discussed briefly.in large quantities at reasonable costs and the extra cost of the polymer purification processes. [10] From the view point of chemical engineering, the productivity and quality of the polymer products, as well as the polymer chain composition and chain topology, are largely influenced by the engineering problems, such as micromixing, residence time distribution of reactor, mass and heat transfers. It normally takes a long time to obtain an optimized operation condition and products only through practices. The ongoing paradigm of polymerization processes begins to shift from process design and operation by experiments and empirical methods to one by the combination of experiments and mathematical models. [11,12] In order to speed up the industrialization of RDRP techniques, the polymerization engineers can take advant...

Nano‐Star‐Shaped Polymers for Drug Delivery Applications

“…NMRP utilizes alkoxyamines as the initiators for polymerization. [104][105][106][107][108][109] These compounds undergo homolysis at the CO bond under certain conditions, producing two radicals, a nitroxide radical and a carbon radical. [110] NMRP then functions on the basis of the persistent radical effect (PRE), observable in some radical systems where the formation of one product is highly favored because of the stability of one of the radical species, nitroxide.…”

An Update on the Pivotal Role of Kinetic Modeling for the Mechanistic Understanding and Design of Bulk and Solution RAFT Polymerization

“…To obtain a fast simulation of the RAFT polymerization kinetics, the deterministic method of moments, as originally proposed by Bamford et al, [65] has been most frequently used. [38,46,61,64,[66][67][68] This simplified method allows to calculate average characteristics such as x n , Đ, and EGF as a function of reaction time and monomer conversion. Most focus has been on linear homopolymers, although the method of moments has been also considered for the simulation of RAFT polymerizations aiming at the synthesis of nonlinear polymers and copoly mers.…”

“…Several research groups have focused on this important research task, both experimentally and via computer simulations. [25,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] However, the number of kinetic studies considering the simultaneous impact and interaction of all relevant process parameters is limited.…”

A detailed mechanistic study of bulk MADIX of styrene and its chain extension

“…For the deterministic modelling, the so-called extended method of moments [78][79][80][81][82] is used, allowing the simulation of the evolution of the monomer and R 0 X conversion and average polymer characteristics such as the number and mass average chain length (x n/m ), Đ, and EGF. Since this method is very fast it facilitates the estimation of the RAFT exchange parameters (cf.…”