Abstract
This work aims at modeling in detail the polymerization of non-ionized acrylic acid in aqueous solution. The population balances required to evaluate the main average properties of molecular weight were solved by the method of moments. The polymerization process considered is initiated by a persulfate/metabisulfate redox couple and, in particular, the kinetic scheme considers the possible formation of mid-chain radicals and transfer reactions. The proposed model is validated using experimental data collected in a laboratory-scale discontinuous reactor. The developed kinetic model is then used to intensify the discontinuous process by shifting it to a continuous one based on a tubular reactor with intermediate feeds. One of the experimental runs is selected to show how the proposed model can be used to assess the transition from batch to continuous process and allow faster scale-up to industrial scale using a literature approach.
Highlights
Poly(acrylic acid) (PAA) is a widely produced polymer with a growing, global annual production of 1.58 × 109 kg as of 2008 [1] and with applications in many industrial sectors
The application is determined according to the molecular weight of the produced polymer: low molecular mass PAA is used as sequestrant, mid-low mass (20–80 kDa) PAA is adopted in paints, mid-high mass (0.1–1 MDa) PAA is useful in the textile and paper industry, and high weight
The synthesis of PAA is almost exclusively run in aqueous solutions through free-radical polymerization of acrylic-acid (AA) at 40–90 ◦C in batch (BR) or semi-batch (SBR) chemical reactors
Summary
Poly(acrylic acid) (PAA) is a widely produced polymer with a growing, global annual production of 1.58 × 109 kg as of 2008 [1] and with applications in many industrial sectors. The application is determined according to the molecular weight of the produced polymer: low molecular mass (less than kDa) PAA is used as sequestrant, mid-low mass (20–80 kDa) PAA is adopted in paints, mid-high mass (0.1–1 MDa) PAA is useful in the textile and paper industry, and high weight (larger than 1 MDa). A SBR starved process is generally adopted to achieve such control in a monomer-depleted environment. This way AA is consumed at a faster rate than its dosing and no dangerous accumulation of monomer is taking place. This kind of process may require long reaction times and proper disposal of the high amount of water used
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
