Ring‐Opening Polymerization of a Benzyl‐Protected Cyclic Ester towards Functional Aliphatic Polyester^†

Abstract

Comprehensive Summary Monomer design strategy has become a powerful tool to access polymers with desired and diverse functionalities. Here, we designed a novel monomer 2‐((benzyloxy)methyl)‐1,4‐oxathiepan‐7‐one (BTO) via installing a benzyl ether side chain to the structure of 1,4‐oxathiepan‐7‐one (OTO). The ring‐opening polymerization of BTO with Zn1 as the catalyst demonstrated the characteristics of living polymerization with turnover frequency (TOF) up to 2520 h−1. With a [BTO]0/[Zn1]0/[I]0 feed ratio of 2000/2/1, polymer with high number‐average molecular weight (Mn = 536 kDa) and narrow dispersity (Ð = 1.06) was obtained. The produced polymer with a glass transition temperature of ‐17°C behaved as an elastomer at room temperature. Consequently, the monomer BTO was copolymerized with L‐LA to modulate the mechanical properties of P(L‐LA). When the BTO content is 10%, the copolymer exhibits excellent strength (24 MPa) and elongation at break (270%), affording a crystalline, hard, and tough plastic material that combines the high ductility of P(BTO) and the high modulus of P(L‐LA). In addition, the oxidation of P(BTO) to P(BTO)‐SO2 led to an improvement of Tg from ‐17°C to 38°C. Debenzylation of P(BTO)‐SO2 afforded P(BTO)‐SO2‐OH containing free hydroxyl groups. Ultimately, P(BTO) could be hydrolyzed under a base condition to recover the corresponding hydroxyl acid intermediate, which could be used to prepare the monomer again and complete the closed‐loop from monomer to polymer to monomer.

cis-Fused cyclohexane promoted the chemical recycling of polycarbonate to monomer

“…Copolymerization has served as an important strategy to adjust polymer properties. [53][54][55][56][57] Next, copolymerization of C6DO with L-lactide (L-LA) was studied to explore new copolymers with aliphatic carbonate linkages and ester moieties. A one-pot copolymerization of a mixture of C6DO and L-LA in a [C6DO]/[L-LA]/[Zn1]/[I] ratio of 500/500/1/1 was first conducted at room temperature (Table 2).…”

Tailoring the Properties of Polyhydroxyalkanoates from Plastics to Elastomers via Stereoselective Copolymerizations of rac‐β‐Butyrolactone and β‐Propiolactone

“…Copolymerization serves as a straightforward and effective strategy to tailor the properties of polymers by adjusting the composition ratio of monomers. [ 28‐35 ] For example, the copolymerization of rac ‐8DL Me and various lactones, such as 7‐heptanolactone, ε ‐caprolactone, and γ ‐butyrolactone, has been utilized to toughen the brittle isotactic P3HB and regulate its thermal properties by modifying polymer's structure and adjusting the component ratio. [ 36‐37 ] Similarly, copolymerization of rac ‐ β ‐BL and lactide (LA) was employed to modulate the thermal properties according to their composition in the resultant gradient copolymer.…”

Leveraging the monomer structure for high-performance chemically recyclable semiaromatic polyesters

“…To further develop the PDHB system to meet practical applications as chemically recyclable polymers, we aimed to enhance its thermal and mechanical properties by leveraging the monomer structure. Motivated by our previous monomer design strategy based on epoxides, [64][65][66] we were able to take advantage of the inexpensive and bio-derived salicylic acid and epoxides to synthesize DHB-Me and DHB-Et using a convenient two-step method. Furthermore, 3-substituted 2,3dihydro-5H-naphthodioxepin-5-ones (DHN-R, R = Me, Et) were also prepared from 3-hydroxy-2-naphthoic acid and epoxides (Fig.…”