Thermo-responsive cellulose hydrogels by grafting low-molecular-weight polymer chains
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Kemian tekniikan korkeakoulu |
Master's thesis
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Authors
Date
2019-06-18
Department
Major/Subject
Chemical and Process Engineering
Mcode
CHEM3043
Degree programme
Master's Programme in Chemical, Biochemical and Materials Engineering
Language
en
Pages
60+5
Series
Abstract
Low-molecular-weight (2.5-10 kDa) thermo-responsive polymers were synthesized through atom transfer radical polymerization (ATRP) and grafted onto carboxymethyl cellulose (CMC) and cellulose nanofibers (CNF) in two different ways. In the first approach, amino-terminated poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA-NH2) and poly(N-isopropylacrylamide) (PNIPAM-NH2) were used to produce graft copolymers with CMC and CNF in water by using water-soluble carbodiimide and N-hydroxysuccinimide as cross-linkers. In the second approach, click chemistry was employed to cross-link alkyne-modified CMC and CNF with azido-terminated PNIPAM (PNIPAM-N3) in the presence of a Cu(II) catalyst. For both synthetic approaches, elemental analysis and infrared spectroscopy were used to confirm polymer grafting. Dynamic light scattering (DLS) and UV-VIS spectroscopy measurements proved that the formed hydrogels exhibited thermo-responsive properties. The rheological behavior of the copolymers was evaluated in water at 25 and 50 °C. The obtained thermo-responsive hydrogels based on natural and biocompatible starting materials pave the way for the design of injectable hydrogels to be used in biomedical applications.Description
Supervisor
Kostiainen, MauriThesis advisor
Heise, KatjaKeywords
cellulose hydrogels, thermoresponsive polymers, modification of polysaccharides, click chemistry, graft copolymers