Synthesis and characterization of a novel temperature-pH responsive copolymer of 2-hydroxypropyl acrylate and aminoethyl methacrylate hydrochloric salt

Abstract

Abstract. In this investigation, a novel temperature-pH responsive copolymer was prepared by the radical copolymerization between 2-hydroxypropyl acrylate (HPA) and aminoethyl methacrylate hydrochloric salt (AMHS). The molecular structure of the corresponding copolymer has been confirmed by 1 H NMR and FTIR measurements. The results indicated that the lower critical solution temperature (LCST) of the resulting copolymer has shown a considerable dependence on the monomer ratio and pH value in the medium. When the molar ratio of HPA to AMHS unit on polymer chain was fixed at 1.56, 2.25, and 3.01, the LCSTs of copolymers were observed at 36.5, 28.2 and 17.8°C, respectively. For the effect of additive salts, the LCST change of the copolymer was affected by both cations and anions in the following order of Al(NO3)3 > KNO3 > Mg(NO3)2 > NaNO3 and KCl ≈ KSCN > KBr > KNO3 > KI. The copolymer seems to be useful as a candidate for the controlled-drug release carrier by pH and temperature external stimuli.

Poly(meth)acrylates Obtained by Cascade Reaction

“…This suppression of bis(meth)acrylate formation is due to the lower reactivity of the secondary hydroxy group as well as the increased sterical hindrance caused by the vicinity of the two hydroxyl groups. However, the molar ratio of monosubstituted (meth)acrylates is 4:1 (77:21 and 80:20) which is similar to the ratio observed for the chemical synthesis of 2‐hydroxypropyl acrylate from propylene oxide and acrylic acid where 25 mol‐% of the minor isomer (2‐hydroxy isopropylacrylate, 2HIPA) is formed 42, 108. Nonetheless, the chemical route is more demanding and requires high purity reagents, CuCl as inhibitor, pyridine as solvent as well as high temperature108 in comparison to the enzymatic catalyzed reaction.…”

Multifunctionalized Polyamides Prepared by Facile Ugi Reaction as Thermosensitive, Biocompatible and Antibacterial Biomaterials

“…For example, The complete dissolution time of PCA‐800‐Br and PIA‐800‐Br in pure water is much less than that of PCA‐800 and PIA‐800 at a given concentration. Fortunately, some inorganic salts such as NaCl, KCl and KNO 3 acts as “salt out” effect, leading to a increase of hydrophobility of polymer in the solution and decrease of LCST . However, some inorganic salts including NaI, NaNO 3 , and KI acts as “salt in” effect, resulting in decrease of hydrophobility of polymer in the solution and increase of LCST .…”

Preparation and property of starch nanoparticles reinforced aldehyde–hydrazide covalently crosslinked PNIPAM hydrogels

“…Hydrogels based on poly( N ‐isopropylacrylamide) (PNIPAM) have caused great repercussions for their ability to occur a phase transition at 32 °C induced by temperature changes. Also temperature of phase transition could be adjusted by copolymerizing with some hydrophilic comonomers in consistent with in vivo temperatures . Although PNIPAM hydrogels have limited to be used seriously due to unclear clearing mechanism, the excellent stimulative responsibility is enough to make PNIPAM hydrogels or materials based on PNIPAM a qualified candidate for thermosensitive application in vivo …”