Temperature-, pH- and CO2-Sensitive Poly(N-isopropylacryl amide-co-acrylic acid) Copolymers with High Glass Transition Temperatures

نویسندگان

  • Yeong-Tarng Shieh
  • Pei-Yi Lin
  • Tao Chen
  • Shiao-Wei Kuo
  • Jinlian Hu
چکیده

A series of poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAAm-co-PAA) random copolymers were synthesized through free radical copolymerization in MeOH. The incorporation of the acrylic acid units into PNIPAAm tended to enhance the glass transition temperature (Tg), due to strong intermolecular hydrogen bonding between the amide groups of PNIPAAm and the carboxyl groups of PAA, as observed using 1H nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopic analyses. The lower critical solution temperature (LCST) increased upon increasing the pH of the aqueous solution containing PNIPAAm-co-PAA because the COOH groups of the PAA segment dissociated into COO− groups, enhancing the solubility of the copolymer. In addition, high-pressure differential scanning calorimetry revealed that the LCSTs of all the aqueous solutions of the copolymers decreased upon increasing the pressure of CO2, suggesting that CO2 molecules had displaced H2O molecules around the polar CONH and COOH groups in PNIPAAm-co-PAA, thereby promoting the hydrophobicity of the copolymers in the aqueous solution. In addition, the values of Tg of a film sample increased upon treatment with supercritical CO2, implying that intermolecular interactions in the copolymer had been enhanced after such treatment.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

pH Sensitive Hydrogel Based Acrylic Acid for Controlled Drug Release

Hydrogels, due to their unique potentials such as high-water content and hydrophilicity are interest for the controlled release of drug molecules. The present study aims to create a controlled-release system through the preparation and characterization of hydrogels based on pH-sensitive polymers such as poly (acrylic acid). Poly (acrylic acid), p(AA), hydrogel has been synthesized by radical po...

متن کامل

Synthesis, characterization and swelling behavior investigation of gelatin-g-Poly(Acrylic Acid-co-Itaconic Acid)

A novel pH-responsive superabsorbent hydrogel based on gelatin was prepared through crosslinking copolymerization of poly (acrylic acid) and poly (itaconic acid). The copolymerization conditions including monomers, initiator, gelatin and crosslinker concentration, reaction temperature, and neutralization percent were systematically optimized to achieve a hydrogel with swelling capacity as high ...

متن کامل

Synthesis and characterization of poly (AAm-co-AAc)/NaA nanocomposite and removal of methylene blue with it

The nanocomposites of poly (Acryl amide-co-Acrylic acid) with different contents of NaAzeolite were prepared using ammonium persulfate as an initiator and N, N′-methylenebisacrylamide as the crosslinker. The morphology was characterized by SEM and the structure ofnanocomposite materials was studied with XRD and FT-IR that showed the interaction betweenporous materials and poly (AAm-co-Aac). The...

متن کامل

Synthesis and Characterization of Acrylic Copolymers of 4-Chloromethyl Styrene with Incorporation of Phthalimide Groups and Amination of Resulted Polymers

4-ChloroMethyl Styrene (CMS) was copolymerized with different monomers such as Methyl MethAcrylate (MMA), Methyl Acrylate (MA), 2-EthylHexyl Acrylate (EHA) by free radical polymerization method at 70 ±1°C using a,a'-Azobis(IsoButyroNitrile) (AIBN) as an initiator. The copolymer compositions were obtained using related 1HNMR spectra and the poly...

متن کامل

Semicrystalline poly(vinyl alcohol) films and their blends with poly(acrylic acid) and poly(ethylene glycol) for drug delivery applications

Semicrystalline films of poly(vinyl alcohol) (PVA) were prepared by annealing amorphous PVA films at temperatures above the glass transition temperature of 85°C, thus allowing the macromolecules to form crystallites, which stabilized the films and made them behave as if they were chemically cross-linked. Films were prepared by casting a 15% aqueous PVA solution onto glass slides and annealing t...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2016