Polymerization of a new thermo-responsive copolymer with N-vinylcaprolactam and its application in recyclable aqueous two-phase systems with another thermo-responsive polymer

Abstract

Background

The recovery characteristics of phase-forming polymers are essential for aqueous two-phase systems (ATPS) to recycle in bioseparation engineering.

Results

A new thermo-responsive copolymer (P_VBAm) is suggested based on N-vinylcaprolactam, acrylamide, and butyl methacrylate. Together with another thermo-responsive polymer, poly (N-isopropyl acrylamide) (P_N), it has been applied to form a recyclable ATPS. P_VBAm and P_N were designed to obtain structures and molecular weights allowing a lower critical solution temperature (LCST). By polymerization optimization, both P_N and P_VBAm were obtained with recoveries 98.5% and 95% above their LCST (i.e., P_N 32.5 °C and P_VBAm 40.5 °C), respectively, which allows each ATPS phase to be effectively recycled. The recycled ATPS based on P_VBAm and P_N was applied to the partitioning of vitamin B₁₂. Under optimized conditions (5% PVBAm/3.5 %PN ATPS, in the presence of 0.8 M KCl, pH 4.0), the partition coefficient of vitamin B₁₂ reached a value of 5.81.

Conclusion

The new ATPS based on the thermo-responsive copolymer P_VBAm/P_N possessed appropriate recycling characteristics regarding LCST, as well as recovery and phase separation characteristics.

Keywords

Aqueous two-phase systems / Thermo-responsive polymer / N-isopropyl acrylamide / N-vinylcaprolactam

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Funding

Natural Scientific Foundation of China (No. 21376078)