Automated Continuous Online Monitoring of Polymerization Reactions (ACOMP) and Related Techniques

Abstract

Automatic continuous online monitoring of polymerization ( ACOMP ) is a widely applicable platform for monitoring and potentially controlling polymerization reactions. It relies on the continuous extraction, dilution, and conditioning of a small sample stream from the reactor on which measurements by various combinations of detectors are made. By combining simultaneous data from multiple detectors, continuous monitoring of salient reaction characteristics can be made, such as kinetics, conversion of comonomers, composition drift, evolution of molecular mass and intrinsic viscosity, and detection of unusual phenomena, such as microgelation and runaway reactions. Typical detectors include light scattering, UV /visible spectrophotometry, viscometry, refractivity, and polarimetry. Recent additions to ACOMP include the ability to use multiple similar sensors to detect the onset and evolution of polymer‐stimuli‐responsive behavior during synthesis, for example, copolymer compositions at which a lower critical solution temperature occurs. ACOMP has been applied to free radical, controlled free radical, and condensation reactions, to micellar, emulsion, and inverse emulsion polymerization, to postpolymerization and derivitization reactions, and to batch, semibatch, and continuous reactors. While ACOMP is not inherently a chromatographic method, its continuous stream can be used in automatic conjunction with gel permeation chromatography ( GPC ) and other separation chromatographies. A growing area for ACOMP is its integration into predictive and closed‐loop reaction control.

Towards improving the biocompatibility of prosthetic eyes

“…It is important to note that water absorption was very low in all materials tested and any potential effect that water absorption might have on dimensional stability, plasticity or strength would not affect the application of 50% EGDMA to prosthetic eyes. Further, it is known that crosslinking PMMA, by addition of a compound such as EGDMA yields a more ductile polymer which helps to reduce the brittleness of PMMA polymer [ 35 ].…”

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

“…ACOMP was first introduced in 1998 [35] and was recently reviewed in detail [36]. It has been used in many scenarios including free radical copolymerization [37,38], copolyelectolytes [39], branching reactions [40], emulsion [41] and inverse emulsion [42] reactions, in batch, semi-batch [43] and continuous reactors [44], for aqueous and organic solvents, for post-polymerization and derivitization reactions [45], and for the controlled radical polymerization routes nitroxide-mediated polymerization (NMP) [46], atom transfer radical polymerization (ATRP) [47], reversible addition fragmentation transfer polymerization (RAFT) [48], and ring opening metathesis polymerization (ROMP) [49].…”

Automatic Control of Polymer Molecular Weight during Synthesis

“…Use of UV absorption, viscosity, and MALS to compute monomer and polymer concentration, reduced viscosity, η r , M w , and z -average mean-square radius of gyration ⟨ S 2 ⟩ z has been detailed in previous ACOMP publications. , For the latter, the usual Zimm equation was used, , where I R (θ) is the excess Rayleigh scattering ratio from the polymer solution at scattering angle θ where C p is polymer concentration and q s is the magnitude of the scattering vector K is an optical constant, given for vertically polarized incident light by where d n /d C p is the differential index of refraction for the polymer in a solvent of refractive index n , N A is Avogadro’s number, and λ is the vacuum wavelength of the incident laser. For Am in water d n /d c = 0.181 cm 3 /g was used, n = 1.333, and λ = 660 nm from a 35 mW Laser Max linearly polarized miniature diode laser.…”

“…Automatic continuous online monitoring of polymerization reactions (ACOMP) was introduced in 1998 and first used to monitor the free radical polymerization of vinylpyrrolidone . Since then, it has been used in a wide variety of reactions including step growth, emulsions and inverse emulsions, and batch, semibatch, and continuous reactors, and in many of the above-mentioned controlled radical polymerization, including ATRP, NMP, , RAFT (reversible addition–fragmentation transfer), and ROMP (ring-opening metathesis polymerization) …”