Tailoring Polymer Molecular Weight Distribution and Multimodality in RAFT Polymerization Using Tube Reactor with Recycle

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/mren.201700023. RAFTPolymerization Solution reversible addition fragmentation chain transfer (RAFT) polymerization of butyl acrylate in 50 wt% toluene, initiated with 2,2′-azobisisobutyronitrile and mediated with 3-benzyltrithiocarbonyl propionic acid, is carried out in a tube reactor of 1.65 mm inner diameter. The tube reactor is operated in three modes: batch tube reactor (inlet and outlet closed, recycle open), continuous tube reactor (inlet and outlet open, recycle closed), and loop tube reactor (inlet, outlet, and recycle all open). The effects of inlet and outlet flow rates, residence time, and recycle ratio on the polymerization rate and polymer molecular weight distribution (MWD) are systematically investigated. The dynamic and steady state kinetics of the three modes of operation are analyzed and compared. Polymer samples having multimodal MWD are generated using the loop reactor. It is found that the MWD and multimodality can be readily controlled by residence time (τ) and recycle ratio.

Enabling technologies in polymer synthesis: accessing a new design space for advanced polymer materials

“…Telescoping has been used to allow sequential insertion of blocks for block copolymers 55,56 , or chemical modification of synthesised polymers 57 , and to enable real-time analysis through dilution and sampling. 58 Furthermore, inventive injection routines, such as tube-in-tube injection for synthesis of gradient copolymers, 59 or recycling through the reactor to tailor MWDs 60 demonstrate that the possibilities are not only limited to what might be achieved by sequential addition to a flask. The construction of flow-reactors also offers opportunities for attempting processes which would otherwise be extremely laborious in batch, for example Lin et al prepared block copolymers via ring-opening polymerisation which involved a telescoped catalyst switch to ensure optimum conditions for each monomer (Figure 3).…”

“Living” Polymer Dispersity Quantification for Nitroxide-Mediated Polymerization Systems by Mimicking a Monodispersed Polymer Blending Strategy

“…22−24 Zhu et al tailored polymer MMD in RAFT polymerization by adjusting the tube reactor configurations. 25 Recently, Goto et al adopted a strategy that can regulate Đ in any segment of block copolymers by adding a small amount of comonomer with different temperaturedependent reactivities in a reversible complexation-mediated polymerization. 26 In addition to experimental approaches, both analytical solutions and numerical methods have been widely proposed to capture full MMD and the evolution of Đ in RDRP systems.…”

“…For example, Boyer et al manipulated MMD shape through blending polymer samples with different molecular properties prepared by the reversible addition fragmentation chain transfer (RAFT) technique . Anastasaki et al adopted RAFT by mixing RAFT agents with different reactivities to tailor Đ . , The same group also employed photo-induced atom transfer radical polymerization (ATRP) to modulate the width of MMD by altering the concentration of an activator. , Fors et al reported a temporal initiation modular strategy to control the shape, width, and skew of MMD in nitroxide-mediated polymerization (NMP). − Zhu et al tailored polymer MMD in RAFT polymerization by adjusting the tube reactor configurations . Recently, Goto et al adopted a strategy that can regulate Đ in any segment of block copolymers by adding a small amount of comonomer with different temperature-dependent reactivities in a reversible complexation-mediated polymerization …”

All-aqueous continuous-flow RAFT dispersion polymerisation for efficient preparation of diblock copolymer spheres, worms and vesicles

“…24 Using a similar concept, postpolymerisation chemistry such as the removal of the RAFT endgroup post synthesis and the use of thiolto functionalise polymers is easily achieved [25][26][27] and modules which enable processes such as degassing, precipitation, dialysis and UV detection 27 can also be integrated into platforms. 28 The precision control has also enabled the synthesis of more complex architectures such as forced gradient 29 polymers, the ability to control the polymer MW distribution [30][31][32] and the easily tuneable synthesis of highly branched polymers. 33 Heterogeneous RAFT polymerisation technologies have been widely reported over the last 15 years or so and are popular since they allow rational production of a variety of block copolymer nanoparticles via polymerisation-induced selfassembly (PISA).…”