Determination of Lower Critical Solution Temperatures of a Series of Novel Poly(2- hydroxypropyl acrylate)-based Copolymers

In this study, the lower critical solution temperatures of a series of poly(2-hydroxypropyl acrylate) (PHPA) copolymers prepared by adding different acrylamide derivatives were determined. This study aims to demonstrate the tunability of cloud points by controlling the molecular structure of HPA copolymers through changes in the composition of acrylamide derivative comonomers. In this context, first of all, N -isobutoxymethyl acrylamide (IBMAAm), N -(3-methoxypropyl)acrylamide (MPAAm), acrylamide (AAm), N -(2-hydroxyethyl)acrylamide (HEAAm), and methacrylamide (MAAm) were used as comonomers to obtain P(HPA-co-IBMAAm), P(HPA-co-MPAAm), P(HPA-co-AAm), P(HPA-co-HEAAm), and P(HPA-co-MAAm) statistical copolymers, respectively. The structural and thermal characterization of the products was achieved using standard polymer characterization methods, including elemental analysis, FTIR, ¹H-NMR, GPC, DSC, and TGA. The lower critical solution temperatures of the statistical copolymers based on PHPA were determined to be 7.5 to 48.2 ^o C, depending on the comonomer polarity and its quantity in the copolymer.