A Safety Strategy for Producing Poly(Acrylic Acid) of Low Molar Mass

The synthesis of poly(acrylic acid) (PAA) of low molar mass under safe conditions is difficult due to the high polymerization rate of acrylic acid (AA) and the fast heat generation. The aqueous‐solution “semibatch” polymerization of non‐ionized AA in almost starved conditions involves high initiator...

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Bibliographic Details
Published in:Macromolecular reaction engineering 2017-06, Vol.11 (3), p.n/a
Main Authors: Montenegro, Gerardo Cáceres, Gutierrez, Carolina G., Vaillard, Santiago E., Minari, Roque J., Vega, Jorge R., Gugliotta, Luis M.
Format: Article
Language:English
Subjects:
Acrylic acid
Acrylics
Chain transfer
chain transfer agent
Chains (polymeric)
Feeding
Heat generation
Isopropanol
Loads (forces)
Mathematical analysis
Mathematical models
molar mass distribution
poly(acrylic acid)
Polymerization
Safety
Strategy
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Summary:The synthesis of poly(acrylic acid) (PAA) of low molar mass under safe conditions is difficult due to the high polymerization rate of acrylic acid (AA) and the fast heat generation. The aqueous‐solution “semibatch” polymerization of non‐ionized AA in almost starved conditions involves high initiator loads when low molar masses are required. This article proposes the simultaneous feeding of AA and nonconventional chain transfer agents (CTA) as a strategy aimed at controlling both the molar masses and the generated heat rate. Three CTAs are investigated: 2‐mercaptoethanol, thioglycolic acid, and isopropyl alcohol. Even when PAA of relatively low molar mass can be produced by adequately selecting the flow rates and concentrations of both AA and CTA, it is found that the nature of CTA can have a significant effect on the polymerizations kinetics. The mechanisms responsible for these effects are discussed with the help of a representative mathematical model. Poly(acrylic acid) of low molar mass is produced by a semicontinuous polymerization with water‐soluble chain transfer agent (CTA). Although sulfidryle‐containing CTAs reduce molar masses, they can cause initiator depletion and incomplete AA polymerization. The proposed model adequately predicts these effects.
ISSN:1862-832X
1862-8338
DOI:10.1002/mren.201600049