Synthesis and characterization of hyperbranched copolymers hyper-g-(NIPAAm-co-IAM) via ATRP

Autor: Kuei-Ting Shu, Shu-Mei Chang, Tun-Fun Way, Whe-Yi Chiang, Wei-Chu Pan, Syang-Peng Rwei
Rok vydání: 2015
Předmět:
Zdroj: Colloid and Polymer Science. 294:291-301
ISSN: 1435-1536
0303-402X
DOI: 10.1007/s00396-015-3775-5
Popis: A hyperbranched copolymer, hyperbranched-g-(N-isopropylacrylamide-co-itaconamic acid) (“hyperbranch-g-(NIPAAm-co-IAM)”), serving as a pH- and thermo-responsive material, was synthesized via atomic transfer radical polymerization (ATRP) and characterized in this study. A macroinitiator was prepared from a commercially available hyperbranched polymer, “hyperbranched bis-(methylol)propionic acid (bis-MPA) polyester-16-hydroxyl, generation 2” (hyperbranch-OH) and used as a core structure of the hyperbranched copolymer. The hyperbranch-OH has 16 hydroxyl groups; among them, 12 arms were derived from substitution of the hydroxyl groups with poly(NIPAAm-co-IAM) by ATRP. The polydispersity index (PDI) of the newly synthesized hyperbranched copolymer can be controlled to be less than 1.4. The hyperbranched copolymer shows more significant size change as the environmental pH value changes, compared to the linear random poly(NIPAAm-co-IAM). The particle size decreases with temperature but increases with the pH value. As the molar fraction of IAM in the hyperbranched copolymer increases, the lower critical solution temperature (LCST) increases. Hyperbranch-g-(NIPAAm-co-IAM) with a molar ratio of NIPAAm/IAM equaling to 3:1 shows a LCST of the aqueous solution close to the body temperature, indicating potential use in biomedical applications such as drug release.
Databáze: OpenAIRE
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