Automatic continuous online

Because the reaction medium is normally quite concentrated, however, rheological and other measurements often only indirectly measure molecular mass and other single chain properties, because the interactions between polymer chains often dominate signals from undiluted reactor contents. Automatic continuous online monitoring of polymerization reactions (ACOMP) provides a solution for this. ACOMP is covered in Chapters 11-13. 

It is important to emphasize that the development of fiber optics technology is a fundamental cornerstone that allowed for the development of real in-line and in-situ monitoring spectroscopic techniques, as the sampling device can be placed at very harmful environments, while the spectrometer still sits in a process control room. Without the support of fiber optics technology, samples have to be prepared and placed inside the illuminated chambers (as performed in the lab since the nineteenth century) or pumped through sampling windows (as performed in advanced systems intended for process and product development, such as automatic continuous online monitoring of polymerization reactions (ACOMP) [37- 1] in order for spectral data to be obtained. 

Alb AM. Automatic Continuous Online Monitoring of Polymerization Reactors (ACOMP) Progress in Characterization of Polymers and Polymerization Reactions. PhD Thesis, Tulane University, New Orleans. 

Alb AM, Reed WF. Recent advances in Automatic Continuous Online, Monitoring of Polymerization reactors (ACOMP). Macromol Symp 2008 271 15-25. 

Florenzano FH, Enohnyaket P Fleming V, Reed WF. Coupling of near infrared spectroscopy to automatic continuous online monitoring of polymerization reactions. Eur Polym J 2005 41 535-545. 

AUTOMATIC CONTINUOUS ONLINE MONITORING OF POLYMERIZATION REACTIONS (ACOMP)... 

Automatic continuous online monitoring of polymerization reactions surmounts this problem and allows to be measured in a single solvent because the instantaneous composition of copolymers can be determined during synthesis, which, together with the hght scattering data stream yields M at each instant. 

Automatic continuous online monitoring of polymerization reactions allows all the required variables to be measured at each point in time total comonomer conversion f apparent... 

Mignard E, Guerret O, Berlin D, Reed WF. Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) of high viscosity reactions. Polym Mat Sci Eng 2003 88 314-316. 

Composition Drift and Sequence Length Distributions Automatic continuous online monitoring of polymerization continuous measurements of comonomer concentrations can be used to compute the average instantaneous molar fraction of a comonomer A in the copolymer chain formed at any given moment F based on ... 

FIGURE 12.7 Automatic Continuous Online Monitoring of Polymerization Reactions detectors response (LS90 ° and viscosity) to the different components of the diluted, phase inverted polyacrylamide emulsion (top) determination of dissolution time, from RI data for polyacrylamide in emulsion and in dry form. Reprinted (adapted) with permission from Alb AM, Farinato F, Calbick J, Reed WF. Online monitoring of polymerization reactions in inverse emulsions. Langmuir 2006 22 831-840. 2006 American Chemical Society. 

Automatic continuous online monitoring of polymerization joins other techniques to study and quantify RAFT polymerization kinetics under different conditions [75-77]. The utility of the technique for monitoring RAFT polymerization and to chart changes in kinetics and molar mass evolution as the concentration of RAFT agent is varied was recently demonstrated [78]. 

Novel approaches in the online monitoring of the synthesis of the amphiphilic copolymers by Automatic continuous online monitoring of polymerization were recently reported by Alb et al. [23]. The ACOMP monitoring platform was used to follow in real time the synthesis of 2-(dimelhylamino)ethyl acrylate (DMAEA)/styrene (sty) copolymers by RAFT. 

Automatic continuous online monitoring of polymerization multiple detection offers flexibility in choosing the most appropriate method to compute the comonomer concentrations during a reaction. In this case, the authors used, as a novel featiire, an altemate route to follow DMAEA concentration by the use of the monitored conduc-... 

Mignard E, Lutz J-F, Leblanc T, Matyjaszewski K, Guerret O, Reed WF. Kinetics and molar mass evolution during atom transfer radical polymerization of n-butyl acrylate using automatic continuous online monitoring. Macromolecules 2005 38 9556-9563. 

As shown in Chapter 1, the initiation step in free radical polymerization can be rate limited either by decomposition of the initiator or diffusion-controlled initiation of decomposed radicals with the first monomer. Automatic continuous online monitoring of polymerization reactions (ACOMP) was used to experimentally observe the crossover between decomposition control and diffusion control of the initiation step. The crossover was observed both among potassium persulfate initiated acrylamide (Am) free radical polymerization reactions at different concentrations of Am and in single reactions. There is no appreciable chain transfer in this particular polymerization. 

There are many subtleties inherent in treating solution conductivities involving polyelectrolytes, and Kreft and Reed [30] developed a simple model for interpreting the marked nonlinearities of a versus [VB]. Automatic Continuous Online Monitoring of Polymerization Reactions data can serve as grist for more refined and rigorous models. In Reference [30], t) is the fraction of noncondensed Na counterions, is the conductivity due to added salt in the reactor at the reaction temperature, which is constant during the reaction, is the specific conductivity of free VB (it includes both the conductivities of the anionic monomer and its free Na" counterions), is the specific conductivity of Na", and is the specific conductivity of VB in the poly electrolyte (i.e., the conductivity of a VB monomer incorporated into a copolymer chain). (0 was computed from o(0 by ... 

Automatic Continuous Online Monitoring of Polymerization Reactions was adapted to monitoring a homogeneous continuous stirred tank reactor (HCSTR) to verify the quantitative predictions concerning f, M, and r, as a function of the flow and kinetic parameters, to determine the kinetic parameters themselves, to ascertain the ideality of mixing in the reactor, to assess the effects of feed and reactor fluctuations, and to approximate a fully continuous tube-type reactor [38],... 

The preceding two chapters have focused on the capabihties of automatic continuous online monitoring of polymerization reactions (ACOMP) in the area of polymerization monitoring. Related characterization challenges include time-dependent processes apart from polymerization reactions, behavior of multicomponent systems, and the issue of particulates coexisting with polymers. Recent methods for dealing with these issues are presented in this chapter. 

As previously discussed in Chapters 11-13, the automatic continuous online monitoring of polymerization reactions (ACOMP) technology has been used successfully to monitor a wide range of polymerization reactions in work dating back to 1998 [1], Nnmerons examples have been given in the previous three chapters (Chapters 11-13) [2-7]. 

Automatic Continuous Online Monitoring of Polymerization Reactions... 

Reed and coworkers developed a strategy for automatic continuous online monitoring of polymerization (ACOMP). The method may be used during the initial development of the polymerization process, its optimization and monitoring of the continuous reaction. ACOMP automatically dilutes samples from the reactor and measures its properties, e.g., refractive index, near infrared (NIR) spectra, LSc, [ ]], etc., from which it computes evolution of MW, MWD, degree of conversion, copolymer composition (in copolymerization) and others. The method has been applied to a variety of the free radical homo- and co-polymerizations, including the reactions in emulsion or suspension. ... 

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