Poly(N‐hydroxyethyl acrylamide)‐b‐polystyrene by combination of ATRP and aminolysis processes

Abstract

Block copolymers of very hydrophilic poly(N-hydroxyethyl acrylamide) (PHEAA) with polystyrene (PS) were successfully synthesized by sequential atom transfer radical polymerization of ethyl acrylate (EA) and styrene monomers and subsequent aminolysis of the acrylic block with ethanolamine. Quantitative aminolysis of poly(ethyl acrylate) (PEA) block yielded poly(N-hydroxyethyl acrylamide)-b-polystyrene in well-defined structures, as evidenced by Fourier transform infrared spectroscopy (FTIR) and 1 H-NMR spectroscopy techniques. Three copolymers with constant chain length of PHEAA (degree of polymerization: 80) and PS blocks with 21, 74, and 121 repeating units were prepared by this method. Among those, the block copolymer with 21 styrene repeating units showed excellent micellation behavior in water without phase inversion below 100 C, as inferred from dynamical light scattering, environmental scanning electron microscopy, and fluorescence measurements.

Non‐activated Esters as Reactive Handles in Direct Post‐Polymerization Modification

“…Also the spacer length between the amine and the hydrogen bond donating moiety had a pronounced effect on the reaction rate, reducing the reactivity with increasing spacer length. These observations strongly support the presence of favorable intrachain interactions, hydrogen bonding in this case, affecting the transition states involved in amidation and provide an explanation for previously reported successful uncatalyzed amidations of PMA with ethanolamine [117] . Both reports also provide a basis for the synthesis of poly(acrylamide)s or poly(acrylamide‐ co ‐acrylate) copolymers in a controlled fashion and enable further processing by subsequent reactions, such as thiol‐ene and Alder‐ene reactions [122,146,147] .…”

“…In recent years, however, significant progress in the transesterification and amidation of poly(acrylate)s has been made, as several research groups have reported successful poly(acrylate) modification. [96,[117][118][119][120][121][122][123][124] Several challenges, such as reaching full conversion, controlling the degree of functionalization by partial modification, and conducting selective or simultaneous modifications have been met through the power of catalysis. The means used to overcome these barriers are directly connected to the characteristics of the desired transformation.…”

“…These observations strongly support the presence of favorable intrachain interactions, hydrogen bonding in this case, affecting the transition states involved in amidation and provide an explanation for previously reported successful uncatalyzed amidations of PMA with ethanolamine. [117] Both reports also provide a basis for the synthesis of poly(acrylamide)s or poly(acrylamide-co-acrylate) copolymers in a controlled fashion and enable further processing by subsequent reactions, such as thiol-ene and Alder-ene reactions. [122,146,147] Finally, the reactivity of PMA towards a series of Nsubstituted diamines has also been explored, with the intention of eliminating polymer chain coupling reactions typically observed for modifications performed with ethylenediamine.…”

Preparation of xyloglucan-grafted poly(N-hydroxyethyl acrylamide) copolymer by free-radical polymerization for in vitro evaluation of human dermal fibroblasts

“…The above-described 1 H NMR control signals aligned with those reported for Xy extracted from apple pomace [ 28 ]. The positions of the PHEAA peaks were compared to those of the poly(2-(methacryloyloxy) ethyl trimethyl ammonium-g-N-hydroxyethyl acrylamide) nanogels and PHEAA-grafted polystyrene (PSt), with substantial similarity in the –C-OH, –O-CH 2 , and -CH 2 proton signals [ 29 , 30 ].…”

Direct synthesis of poly(N-alkyl acrylamide) (co)polymers with pendant reactive amino groups by organocatalyzed amidation of polymethylacrylate

“…Although poorly reactive, some recent reports have shown that unactivated ester side-chains of widely available poly(alkyl)acrylates and poly(alkyl)methacrylates could be efficiently converted through transesterification [16][17][18][19][20][21] or amidation [22][23][24][25][26][27][28][29] reactions under mild conditions, assisted by the use of specific reagents, activating agents or catalysts. Metal-based catalysts have been employed by Terashima et al to modify poly(meth)acrylates through transesterification, 17,20 whilst Sumerlin et al, as well as our group employed triazabicyclodecene (TBD) as an organocatalyst for the efficient transesterification or amidation of polyacrylates.…”