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Multiblock segmented polyurethanes and polyurethane-ureas based on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) macrodiols. Synthesis and characterization

Filip D., Macocinschi D., Ioanid E., Vlad S.

Polimery

2010

T. 55, nr 5

358-365

The amphiphilic behavior of poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) block copolymers has been broadened by introducing new urethane-urea as well as poly(ethylene glycol) co-segments in polyurethane (PUR) and polyurethane-ureas (PURU) materials. Supermolecular organization and self-assembly was confirmed by electron microscopy transmission observations. The driving force for self-assembling is represented by the amphiphilic nature of these materials, the interactional segment length and stabilization through hydrogen bonding. FT-IR spectroscopy was used to investigate the hydrogen bonding related to phase segregation. Phase transitions and phase segregation was evidenced by DSC analyses. The relationship between structure and thermal stability was investigated by thermogravimetric analysis.

Opisano sposób syntezy amfifilowych multiblokowych poliuretanów (PUR) i poliuretano-moczników (PURU) w wyniku wprowadzenia odpowiednich segmentów do łańcucha wymienionych w tytule makrodioli. Scharakteryzowano skład, strukturę oraz wartości Mw i Mw/Mn (tabela 1) uzyskanych PUR (2 typy) oraz PURU (również 2 typy). Przedyskutowano i porównano wyniki ich badania metodami FT-IR (rys. 5), derywatograficzną (rys. 1 i 2), różnicowej analizy termicznej (DSC, rys. 3, tabela 1), rentgenograficzną (rys. 4) i elektronowej mikroskopii transmisyjnej (rys. 6). Zinterpretowano zdolność do samorzutnego tworzenia agregatów przez opisywane produkty, wiążąc ją przede wszystkim z ich amfifilowym charakterem oraz stabilizacją poprzez wiązanie wodorowe. Wyniki uzyskane metodami DSC i FT-IR posłużyły do wyjaśnienia przebiegu zjawisk segregacji fazowej a także przemian fazowych.

Synteza amfifilowych kopolimerów szczepionych metodą kontrolowanej (ko)polimeryzacji rodnikowej hydrofilowego makromonomeru poli(tlenku etylenu)

Neugebauer D.

Wiadomości Chemiczne

2008

[Z] 62, 1-2

49-66

A combination of hydrophilic and hydrophobic characters in one macromolecule of a polymer provides amphiphilic behavior [1, 2]. Such unique properties, which have found significant interest, are exhibited by graft copolymers containing poly(ethylene oxide) (PEO) as side chains attached to the backbone (Scheme 1) [20]. They have greatly expanded a class of materials important for science and biomedicine. This review article describes the PEO graft copolymers prepared by a variety of synthetic procedures used for the atom transfer radical (co)polymerization (ATRP) (Scheme 2) [15-17], i.e. directly by the grafting through, which is also named as the macromonomer method or by the grafting from technique, which requires the use of a multifunctional macroinitiator. Densely homografted copolymers also called molecular brushes [21-25] were obtained by homopolymerization of PEO macromonomer (Scheme 3). The density of PEO grafts was decreased in the copolymerization of PEO macromonomer with a low molecular weight comonomer resulting in loosely grafted copolymers contai-ning uniform PEO side chains (Scheme 4) [46-48]. Consequently, the copolymerization of two macromonomers yielded heterografted brushes (Scheme 5) [21, 23, 26, 45, 53-57]. In this case, the composition of copolymers was designed by the selection of proper comonomers with comparable (rM1 = rM2/rM1 ~ rM2) or different (rM1 > rM2, rM1 < rM2) reactivity ratios, which can form alternating/ random copolymers or spontaneous gradient of PEO chains along backbone, respectively. Using monofunctional macroinitiators with comb or linear composition for polymerization of PEO macromonomer resulted in comb-comb [31] or semi-comb diblock copolymers [21, 23, 27-30]. The reverse structures were also obtained, when the PEO graft copolymers were applied as the monofunctional macroinitiators [31, 32]. The use of polymeric multifunctional macroinitiators (graft or linear) in the polymerization of monomer or macromonomer led to the heterografted copolymers (Scheme 4) [32, 50, 51] or more complexed double grafted copolymers (Scheme 3) [25]. The applications of the PEO graft copolymers in numerous fields are also presented to show their versatile potential [25, 26, 46, 53, 55, 56, 68-76].