Biodegradable Ionomers

• Several telechelic anionic or cationic ionomers were synthesized starting from poly(trimethylene carbonate) diols (PTMC) of different molecular weight, ranging from 1000 to 12 000 g/mol. In the synthesis of the anionomer, addition of sulfur trioxide trimethylene complex to the PTMC end-group hydroxyls and subsequent ion exchange afforded a disulfate monoester sodium salt. The cationomer was synthesized in two steps. Acylation of the PTMC diol using 4-chlorobuturyl chloride was followed by displacement of the alkyl chloride with trimethylamine to give a quaternary ammonium salt. These ionomers showed excellent swelling properties, up to around 500% in H2O, while the unfunctionlized PTMC did not swell at all. The lowest molecular weight ionomers were soluble in both water and chloroform. The physical properties of the ionomers were analyzed with oscillating rheological experiments. Interestingly, the ionomers displayed "rubbery plateau". The mechanical and swelling properties may be linked to phase separation resulting in ionic aggregates within the bulk, which may function as physical cross-links. At ambient temperatures, the PTMC starting material behaved like a highly viscous fluid, while the ionomers behaved as elastomers. In a hydrophilic environment, the ionomers displayed a surface rearrangement making the surface of the ionomer hydrophilic by allowing the ionic end groups to appear at the water ionomer interface. In air or vacuum all the ionic groups were found in the bulk of the material as analyzed by XPS or contact angle measurements. Finally, we showed that with the specific ionic groups it was possible to complex specific molecules to the ionomers.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

Nyckelord

Inorganic chemistry

Oorganisk kemi

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