Synthesis and Characterization of Novel Biodegradable Di‐ and Tri‐Block Copolymers Based on Ethylene Carbonate Polymer as Hydrophobic Segment

Abstract

Synthesis of novel amphiphilic biodegradable block copolymers based on ethylene carbonate is reported in this study. Polyethylene glycol monomethyl ether (MeO‐PEO) and polyethylene glycol (PEG) of varying molar masses are used as macro‐initiator for ring‐opening polymerization of ethylene carbonate in the presence of sodium stannate trihydrate as a heterogeneous transesterification catalyst. Earlier elution of block copolymer from macro‐initiator in size exclusion chromatography (SEC) indicated the successful synthesis of the block copolymers. Ratios of both types of blocks are varied systematically. Liquid chromatography at critical conditions is used for the analysis of the non‐critical individual blocks, and if there are any critical segments that are not attached to the non‐critical block. To the best of our knowledge, this is the first report on the synthesis of ethylene carbonate‐based amphiphilic block copolymers. Chromatographic critical conditions of the ethylene carbonate polymer are also reported for the first time. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1887–1893

Synthesis and characterization of 4-arm star-shaped amphiphilic block copolymers consisting of poly(ethylene oxide) and poly(ε-caprolactone)

“…At this point, so-called chromatographic critical point, block copolymer is assumed to be eluted exclusively with respect to the functionality/end-group 20,21,24,25 or other block in block copolymer. [26][27][28][29][30][31][32][33][34] A fair estimation of non-critical block length and quantications of critical homopolymers is possible by appropriately applying LCCC. ) were dried by azeotropic distillation with toluene.…”

“…Critical conditions corresponding to PEO has been documented in several articles. 26,28 In this study, critical conditions of MeO-PEO were established on a normal phase plain silica column using a binary mixture of THF and DMF as a mobile phase. THF promotes retention of MeO-PEO onto stationary phase while DMF strongly promotes elution.…”

Chromatographic characterization of amphiphilic di‐ and tri‐block copolymers of poly(ethylene oxide) and poly(ε‐caprolactone)

“…At this compensation point, termed as critical elution point, corresponding polymer becomes "chromatographically invisible", consequently all chains with the same end-functionality elute at same elution time regardless of their molar mass. Hence, separation with regard to other blocks [24][25][26][27][28][29][30][31][32][33][34][35] or end-functionality [36][37][38][39] can be achieved. LCCC has been successfully applied for quantification of critical homopolymers and fair estimation of a non-critical block length in the block copolymer [20,24,40].…”

Analysis of individual block length of amphiphilic di- & tri-block copolymers containing poly(ethylene oxide) and poly(methyl methacrylate)

“…Several different types of block copolymers have been synthesized and exploited for various applications, [26][27][28][29][30][31][32][33][34] however, the number of reports addressing analysis of individual block lengths and presence of unwanted homopolymers in the samples are rather limited. [35][36][37][38][39][40][41][42][43][44][45][46][47] Nonetheless, the length of individual blocks and presence of homopolymers in block copolymer sample can enormously affect the nal application properties, especially in case of amphiphilic block copolymers. The separation of homopolymers from amphiphilic block copolymer samples is a difficult task since products tend to make micelles when dropped in any solvent that has more compatibility for one block.…”

“…37,38 At critical conditions, homopolymers elute near the void volume of the column independent of their molar mass making them so called "chromatographically invisible". Under these conditions separation with regard to end group [61][62][63][64][65] or other block [35][36][37][38][39][40][41][42][43][44][45][46][47] can be realized. LCCC reveals a reasonable estimate of the molar mass distribution of non-critical block, and information with regard to presence or absence of unwanted parent homopolymers in the sample.…”