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Öğe Alternative Approach for Synthesizing Polyglycolic Acid Copolymers from Cl Feedstocks and Fatty Ester Epoxides(Amer Chemical Soc, 2019) Reyhanoglu, Yusuf; Sahmetlioglu, Ertugrul; Gokturk, ErsenOver the past couple of years, replacement of petroleum-based products with biodegradable and biorenewable is an emerging topic in polymer science. Biodegradable polyglycolic acid (PGA), the simplest aliphatic linear polyester, can traditionally be synthesized through the ring-opening polymerization of glycolide. Our previous studies revealed that PGA can alternatively be produced via one-step cationic polymerization of formaldehyde from trioxane and carbon monoxide (CO), which are potentially sustainable C1 feedstocks, under Bronsted acidic conditions. In this study, trioxane, CO, and a minor amount of fatty ester epoxides are copolymerized to improve on the physical properties of PGA, such as solubility and appearance, under the same reaction conditions for PGA homopolymer synthesis (in DCM, at 800 psi CO, with triflic acid catalyst, reaction duration of 72 h). The results have shown that the addition of minor quantities of epoxide comonomers vastly improved the solubility and decreased the melting temperature of the PGA. The melting temperatures of the obtained copolymers decreased by increasing incorporation percentages of the epoxide comonomers and decreasing polymerization temperatures. The solubility of the copolymers increased with incorporation of the epoxides in the PGA backbone.Öğe One-Step Solvent-Free Synthesis of Polyglycolic Acid from Sustainable C1 Feedstocks(Wiley-V C H Verlag Gmbh, 2021) Reyhanoglu, Yusuf; Kalayci, Berkant; Gokturk, ErsenPolyglycolic acid (PGA) is an aliphatic biodegradable polyester commonly synthesized through the ring opening polymerization of glycolide using mostly tin (II) octoate catalyst. Previously, a very convenient method for the synthesis of PGA from the cationic alternating copolymerization of formaldehyde (from trioxane) and carbon monoxide (CO) with triflic acid (TfOH) catalyst in dichloromethane (DCM) at 170 degrees C is described with 92% of yield. The need of using harmful DCM solvent for this polymerization directs to discover solvent-free polymerization of formaldehyde and CO. Here, one-step solvent-free synthesis of PGA from the cationic alternating copolymerization of formaldehyde and CO is presented. Unlike the polymerization carried out in DCM solvent, optimum polymerization in solvent-free conditions with TfOH catalyst is achieved in 80% of yield at 130 degrees C. It is considered that utilization of solvent-free conditions and lower reaction temperatures compared to the previous report provides a more green and economic way of the synthesis of PGA. The method is also extended to copolymerization strategy by adding a minor amount of an epoxide compound to the reaction mixture, and PGA-based copolymer with improved physical properties (such as solubility and appearance) is obtained in solvent-free conditions.Öğe Polyglycolic acid copolymers from one-step cationic polymerization of formaldehyde, carbon monoxide, and epoxides derived from PEG(Wiley, 2019) Reyhanoglu, Yusuf; Gokturk, ErsenBiodegradable polyglycolic acid (PGA) is conventionally produced via the ring-opening polymerization of glycolide, the cyclic dimer form of glycolic acid, in the presence of mostly tin-based catalyst initiators which are rather known to be cytotoxic materials. Our previous studies revealed an alternative method for the synthesis of PGA from the perfectly alternating copolymerization of formaldehyde (from trioxane) and carbon monoxide (CO) under Bronsted acidic conditions. The poor physical properties of PGA (insolubility in many organic solvents, brown color, etc.) limit its use in other marketing applications in the industry. To improve on the physical properties of PGA, such as solubility and appearance, copolymerization of trioxane, CO, and a minor amount of epoxides derived from polyethylene glycol (PEG) were performed under the same reaction conditions for PGA synthesis (in DCM, at 800 psi CO pressure, with triflic acid catalyst, reaction duration of 72 hours). The results have shown that the addition of minor quantities of epoxide comonomers vastly improves the appearance of the obtained PGA copolymers and allows for the control of the polymeric properties, such as solubility and melting temperature.Öğe Synthesis of polyglycolic acid copolymers from cationic copolymerization of C1 feedstocks and long chain epoxides(Elsevier, 2019) Reyhanoglu, Yusuf; Gokturk, ErsenPolyglycolic acid (PGA), which is an important biodegradable polymer, can traditionally be synthesized through the ring opening polymerization of glycolide (with mostly using tin octanoate catalyst). Our previous studies revealed that PGA was alternatively synthesized with one-step cationic polymerization of formaldehyde from trioxane and carbonmonoxide (CO), sustainable Cl feedstocks obtainable from biomethanol or biogas. PGA and its copolymers can be mainly used for the biomedical applications due to their biocompatibility and biodegradability. In order to utilize PGA in other marketing materials such as packaging, PGA should be specifically engineered to improve its physical properties by a copolymerization strategy utilizing appropriate comonomers since PGA displays brown or beige color and is not soluble in most organic solvents due to its very high crystallinity. In this study; to improve on the physical properties of PGA, such as melting temperature and solubility, polymerizations of trioxane, CO and a minor amount of epoxides with long side chains were performed under the same reaction condition as PGA homopolymer synthesis (DCM solvent, at 800 psi, with trifle acid catalyst, reaction time of 72 h). The results have shown that optimum polymerizations were achieved at lower reaction temperatures than that of PGA homopolymer synthesis (110 degrees C versus 170 degrees C). The melting temperatures of all copolymers are lower, and the colors of the copolymers have become lighter than that of PGA homopolymer. The solubilities of obtained copolymers also increased by increasing side chain length of epoxides in the polymer backbone. (C) 2019 King Saud University. Production and hosting by Elsevier B.V.
