At-Line Monitoring of Conversion in the Inverse Miniemulsion Polymerization of Acrylamide by Raman Spectroscopy

Abstract

This work studied the at-line Raman spectroscopy monitoring for the inverse miniemulsion polymerization of acrylamide. The conversion was determined from the Raman spectra without previous calibration using the peaks corresponding to CH 2  and CC functional groups of acrylamide. Gravimetric data was used to validate the results of conversion obtained with the Raman spectra. Dynamic light scattering was used to measure the particle size. The results show that high energy in the homogenization step increases the surface area of the droplets and generates a lack of surfactant, which results in larger diameters. It is possible to make at-line monitoring of monomer conversion directly from the Raman spectra without using calibration models. The data obtained show an incomplete conversion that is also confirmed by gravimetric analysis.

Mathematical Modeling of Inverse Miniemulsion Polymerization of Acrylamide with an Oil-Soluble Initiator

“…These inverse polymerization reactions follow the same methodology studied previously. , Briefly, the continuous phase was prepared by dissolving the surfactant in cyclohexane. To prepare the aqueous disperse phase, acrylamide and costabilizers were dissolved in distillated water.…”

“…The gravimetric data were obtained by calculating the ratio between the dry polymeric mass and the unreacted monomer mass. , Dynamic light scattering (DLS) was used to measure the average particle diameter using Beckmann Coulter N4 Plus equipment; the samples were diluted in cyclohexane.…”

“…The literature addresses the inverse polymerization of acrylamide with respect to heterogeneous synthesis, − monitoring, , and kinetics − reasonably well. Despite the increasing and promising applications of inverse latexes, there are few studies focused on the mathematical modeling of miniemulsion inverse polymerization, particularly of acrylamide (AAm).…”

In Situ Raman Spectroscopy Real-Time Monitoring of a Polyester Polymerization Process for Subsequent Process Optimization and Control

“…Since the Raman spectrum of water only shows a very small band between 1600 and 1800 cm –1 , it is better suited to systems that contain water, such as esterification and polyesterification. − Raman spectroscopy also allows for noncontact and rapid analysis and is widely used in several fields. − Indeed, the hardware of real-time Raman spectroscopy is technically mature enough. When it comes to monitoring the quality index of a specific product in real time, its quantitative determination based on spectra generated by the hardware may not need prior calibration in some cases − and is required in some other cases.…”

Unprecedented Acid‐Promoted Polymerization and Gelation of Acrylamide: A Serendipitous Discovery

“…[18] Commercial high molecular weight polyacrylamide is obtained from conventionalr adical polymerization. [19,20] It can be made in aqueous solution, [21] in emulsions, [22] in polar organic solvents [19] or solvent-free in bulk. [23] Polymerization by redox-o rp hoto-initiators is generally preferred over the use of thermali nitiators because the reaction can be initiated at lower temperatures with better conversion.…”