Iskanje po katalogu digitalne knjižnice

Opis: The work reported in the present thesis is focused predominantly to investigate how to synthesize random copolymers from ω-pentadecalatone (ω-PDL) and globalide (Gl) by enzymatic ring-opening polymerization (eROP). The reason for choosing this specific theme, i.e. "Functionalized copolymers from macrolactones by enzymatic ring-opening polymerization", was to explore a relatively new concept, in which two cyclic esters (macrolactones) – ω-PDL and Gl were synthesized by a combination of eROP and thiol-ene click reaction using biocatalyst Novozym 435 (lipase B from Candida antarctica). The aim was to position the newborn copolymer from ω-pentadecalactone and globalide among other biomaterials, identify possible applications and prepare nanoparticles that can be used in drug delivery systems. Random copolymers PPDLx-r-PGly with different feed ratios were successfully synthesized and later modified via thiol-ene click reaction when using BAET as a suitable compound for this polymeric functionalization, due to its thiol functionality. Boc-amino deprotection lasted and at the end, graft-copolymers were obtained (PPDLx-r-(PGly-g-PBLGz). Characterization methods were performed on GPC and NMR. The yield for all obtained random copolymers ranged between 67% and 88% and Mn between 14 000 g/mol and 45 000 g/mol depending on feed ratio of random copolymers. Meanwhile, the calculated yield for obtained grafted-copolymers ranged between 63% and 95%. Mn detected by GPC was around 7 000 g/mol for both grafted-copolymers (PPDL90(PGl10-PBLGz) and PPDL50(PGl50-PBLGz)) and Mw between 14 000 g/mol and 21 000 g/mol. Thermal analyses were performed on TGA and DSC. TGA showed that obtained PPDLx-r-PGly copolymers start to decompose at around 400 °C and grafted PPDLx-r-(PGly-g-PBLGz) copolymers at around 250 °C. DSC showed that PPDL and PGl are semicrystalline polymers with Tm ranging between (95 and 96 °C) for PPDL and (41 and 42 °C) for PGl. AFM technique was used for nanoparticles characterization. The resulting surface and deep resolution of PPDL50(PGl50-PBLGz) nanoparticles was between (2 to 88.8 nm) and PPDL10(PGl90-PBLGz) between (2 nm to 94.4 nm).
Ključne besede: ring-opening polymerization, macrolactones, ω-pentadecalatone, globalide, nanoparticles, Novozym 435
Objavljeno v DKUM: 04.10.2018; Ogledov: 1287; Prenosov: 288
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