Ring-opening polymerization of l-lactide in supercritical carbon dioxide using PDMS based stabilizers

Ring-opening copolymerization of L-lactide and ɛ-caprolactone in supercritical carbon dioxide using triblock oligomers of caprolactone and PEG as stabilizers

“…In the related literature, similar results were obtained. Ganapathy et al 8 investigated the polymerization of LLA with a PDMS-based SB in scCO 2 . Without the SB, they reported that an aggregated morphology for PLLA was produced with 78% yield at the end of the polymerization process (80 1C, 207 bar, 47 h).…”

“…[20][21][22][23] One of the main (target) issues is to reach high molecular weights and polymerization yields without any aggregation in the end product, which could be achieved by using proper stabilizers (SBs) and initiator systems. Ganapathy et al 8 reported the use of a poly(dimethyl siloxane) (PDMS)-based structure as a SB in the polymerization of LLA. Although PDMS-b-poly(methacrylic acid) and PDMS-b-poly(acrylic acid) formed discrete (PLLA) microparticles, acetylated PDMS-based copolymers could not stabilize the polymerization and produced hard agglomerates.…”

“…2 There are a number of studies on the synthesis, processing, modification and purification of synthetic and natural polymers in scCO 2 . [3][4][5][6][7][8] Polymers obtained at the end of polymerization have low solubilities in scCO 2 . This issue has brought about many heterogeneous polymerization processes, such as precipitation, emulsion, suspension and dispersion polymerizations.…”

“…This issue has brought about many heterogeneous polymerization processes, such as precipitation, emulsion, suspension and dispersion polymerizations. 8 One of the major areas of study in the heterogeneous polymerization in scCO 2 is radical polymerization. 9,10 Different types of heterogeneous radical polymerizations such as nitroxide-mediated polymerization, [11][12][13] atom transfer radical polymerization [14][15][16] and reversible addition fragmentation chain transfer 17,18 polymerization have been investigated in scCO 2 .…”

“…All of these linear aliphatic polyesters are biodegradable and widely used in a variety of medical applications, such as controlled drug release, absorbable sutures and scaffolds. 8,19 There are many routes for the polymerization of these monomers. The ring-opening polymerization of these lactones is the most popular polymerization protocol.…”