Polyglycolic acid from the direct polymerization of renewable C1 feedstocks

Abstract

Potentially sustainable C1 feedstocks carbon monoxide and formaldehyde are subjected to cationic alternating copolymerization to yield polyglycolic acid.

Polyglycolic acid copolymers from one‐step cationic polymerization of formaldehyde, carbon monoxide, and epoxides derived from PEG

“…Reaction temperature and epoxide weight ratio had profound impacts on the physical properties of the obtained copolymers. The influence of CO pressure was already reported in our previous work, and optimum CO pressure had been found to be 800 psi. The polymerization yield was lower for below 800 psi CO pressure and did not change above 800 psi CO pressure.…”

“…Various reaction conditions including different epoxide weight ratios and reaction temperatures were employed to optimize polymerization conditions. A series of copolymers was synthesized by using the same reaction conditions for PGA homopolymer synthesis as previously reported . As seen in Table , the copolymerization affords products in very high yields.…”

“…Another important finding is that the melting temperatures of the obtained copolymers were significantly decreased with increasing epoxide weight ratios (Figure ). For example, while PGA homopolymer synthesized at 170°C melted around 195°C, copolymer melting temperatures with addition of only about 5 weight % of epoxide comonomers in the reaction were around 170°C to 180°C (the decrease of the copolymer melting temperatures was different for each epoxide comonomer, and there was no relationship established between the melting temperatures and epoxide structures). No relationship can also be addressed between the glass transition temperatures of the obtained copolymers and the reaction temperatures or epoxide weight ratios.…”

“…After cooling to room temperature, the pressure was released, and the mixture was poured into cold basic methanol. The product was isolated by filtration, and washed with methanol and DCM, and dried under vacuum …”

“…Recently, we reported an alternative method for the synthesis of PGA from the perfectly alternating copolymerization of formaldehyde (from trioxane) and carbon monoxide (CO) as illustrated in Figure . PGA was successfully obtained in only one step with yields up to 92% using triflic acid (TfOH) catalyst . Although very high conversion and yield were achieved with this method, the poor physical properties of PGA (insolubility in many organic solvents, brown color, etc.)…”