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Thermoplastic elastomers (TPEs) have long been used in a wide range of industries. However, most existing TPEs are petroleum-derived polymers. To realize environmentally benign alternatives to conventional TPEs, cellulose acetate is a promising TPE hard segment because of its sufficient mechanical properties, availability from renewable sources, and biodegradability in natural environments. Because the degree of substitution (DS) of cellulose acetate governs a range of physical properties, it is a useful parameter for designing novel cellulose acetate-based TPEs. In this study, we synthesized cellulose acetate-based ABA-type triblock copolymers (AcCelx-b-PDL-b-AcCelx) containing a celloologosaccharide acetate hard A segment (AcCelx, where x is the DS; x = 3.0, 2.6, and 2.3) and a poly(δ-decanolactone) (PDL) soft B segment. Small-angle X-ray scattering showed that decreasing the DS of AcCelx-b-PDL-b-AcCelx resulted in the formation of a more ordered microphase-separated structure. Owing to the microphase separation of the hard cellulosic and soft PDL segments, all the AcCelx-b-PDL-b-AcCelx samples exhibited elastomer-like properties. Moreover, the decrease in DS improved toughness and suppressed stress relaxation. Furthermore, preliminary biodegradation tests in an aqueous environment revealed that the decrease in DS endowed AcCelx-b-PDL-b-AcCelx with greater biodegradability potential. This work demonstrates the usefulness of cellulose acetate-based TPEs as next-generation sustainable materials.

Silver nanoparticles (AgNPs) are practically valuable in biological applications. However, no steady PEGylation has been established, which is essential for internal use in humans or animals. In this study, cyclic PEG (c-PEG) without any chemical inhomogeneity is physisorbed onto AgNPs to successfully PEGylate and drastically enhance the dispersion stability against physiological conditions, white light, and high temperature. In contrast, linear HO-PEG-OH and MeO-PEG-OMe do not confer stability to AgNPs, and HS-PEG-OMe, which is often used for gold nanoparticles, sulfidates the surface to considerably degrade the properties. TEM shows an essentially intact nanostructure of c-PEG-physisorbed AgNPs even after heating at 95 degrees C, while complete disturbance is observed for other AgNPs. Molecular weight- and concentration-dependent stabilization by c-PEG is investigated, and DLS and zeta-potential measurements prove the formation of a c-PEG layer on the surface of AgNPs. Furthermore, c-PEG-physisorbed AgNPs exhibit persistent antimicrobial activity and cytotoxicity.

Hyperbranched polyesters (HBPEs) are well-known interesting materials used in many fields.

Bacterial cellulose (BC), which is produced by bacteria, is a biodegradable and biocompatible natural resource. Because of its remarkable physicochemical properties, BC has attracted attention for the development and manufacture of biomedical and industrial materials. In the BC production system, the enzyme endo-β-1,4-glucanase, which belongs to glycoside hydrolase family 8 (GH8), acts as a cleaner by trimming disordered cellulose fibers to produce high-quality BC. Understanding the molecular mechanism of the endo-β-1,4-glucanase would help in developing a reasonable biosynthesis of BC. Nevertheless, all of the steps in the reaction of this endo-β-1,4-glucanase are not clear. This study confirms the BC hydrolytic activity of the endo-β-1,4-glucanase from the BC-producing bacterium Enterobacter sp. CJF-002 (EbBcsZ) and reports crystal structures of EbBcsZ. Unlike in previously reported GH8 endo-β-1,4-glucanase structures, here the base catalyst was mutated (D242A) and the structure of this mutant bound to cellooligosaccharide [EbBcsZ(D242A)CPT] was analyzed. The EbBcsZ(D242A)CPT structure showed two cellooligosaccharides individually bound to the plus and minus subsites of EbBcsZ. The glucosyl unit in subsite −1 presented a distorted 5 S 1 conformation, a novel snapshot of a state immediately after scissile-bond cleavage. In combination with previous studies, the reaction process of endo-β-1,4-glucanase is described and the β-1,4-glucan-trimming mechanism of EbBcsZ is proposed. The EbBcsZ(D242A)CPT structure also showed an additional β-1,4-glucan binding site on the EbBcsZ surface, which may help to accept the substrate.

Although polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is the most widely employed template and scaffold for constructing nanoscale patterns, its relatively small Flory-Huggins interaction parameter makes it challenging to realize microphase-separated structures with a periodicity (or domain spacing) of less than 20 nm. The direct post-polymerization modification of PS-b-PMMA can resolve this issue. In this study, we present the PS block post-polymerization modification of commercially available PS-b-PMMA through a metal-free Friedel-Crafts alkylation reaction with adamantanols to modulate its microphase-separated morphology and dimensions. The adamantyl group can be easily installed on the PS benzene ring, which increases the incompatibility with the PMMA block, enabling ordered microphase-separated structures, including lamellar, gyroid and hexagonally close-packed cylindrical structures, from low-molecular-weight PS-b-PMMA. Notably, a periodicity as low as approximately 16 nm was realized with this strategy, which is much lower than the lowest accessible periodicity of pristine PS-b-PMMA. Furthermore, we observed additional benefits from the installation of the adamantyl group, such as increased thermal stability, glass transition temperature and etching contrast.

Naturally occurring polysaccharides, such as cellulose, hemicellulose, and chitin, have roles in plant skeletons and/or related properties in living organisms. Their hierarchically regulated produc...

This work reports a facile and versatile ring-opening metathesis polymerization of three- and four-armed star-shaped poly(epsilon-caprolactone) (PCL) macromonomers bearing a norbornenyl group at each chain end using Grubbs' third-generation catalyst under diluted condition to obtain graft polymers (GPs) comprising densely arrayed three- and four-armed cage-shaped grafted PCLs (GPCLs) with narrow dispersity (1.19-1.35) and a controllable number of cage repeating units up to 40 (molecular weight: similar to 320 000 g mol(-1)). The GPCLs were characterized using nuclear magnetic resonance spectroscopy, size exclusion chromatography, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The cyclopolymerization proceeded via repetitive rapid intramolecular reactions to form cage-shaped units followed by slow intermolecular propagation. This synthesis was applicable to star-shaped poly(L-lactide), poly(trimethylene carbonate), and poly(ethylene glycol). Investigating the structure-property relationships regarding crystallization behavior, hydrodynamic diameter, and viscosity revealed that cage-shaped topological side chains reduced the chain dimensions and mobility compared to their linear and cyclic counterparts.

Developing an efficient and versatile process to transform a single linear polymer chain into a shape-defined nanoobject is a major challenge in the fields of chemistry and nanotechnology to replicate sophisticated biological functions of proteins and nucleic acids in a synthetic polymer system. In this study, we performed one-shot intrablock crosslinking of linear block copolymers (BCPs) to realize single-chain nanoparticles (SCNPs) with two chemically compartmentalized domains (i.e., Janus-shaped SCNPs). Detailed structural characterizations of the Janus-shaped SCNP composed of polystyrene- block -poly(glycolic acid) revealed its compactly folded conformation and compartmentalized block localization, similar to the self-folded tertiary structures of natural proteins. Versatility of the one-shot intrablock crosslinking was demonstrated using several different BCP precursors. We further discovered the excellent self-assembling behavior of the Janus-shaped SCNP to produce miniscule microphase-separated structures, representing the significant potential of the presented compartmentalization protocol, for developing biomimetic synthetic-systems, as well as for industrial nanofabrication applications.

Carbohydrates are key building blocks for advanced functional materials owing to their biological functions and unique material properties. Here, we propose a star-shaped discrete block co-oligomer (BCO) platform to access carbohydrate nanostructures in bulk and thin-film states via the microphase separation of immiscible carbohydrate and hydrophobic blocks (maltooligosaccharides with 1-4 glucose units and solanesol, respectively). BCOs with various star-shaped architectures and saccharide volume fractions were synthesized using a modular approach. In the bulk, the BCOs self-assembled into common lamellar, cylindrical, and spherical carbohydrate microdomains as well as double gyroid, hexagonally perforated lamellar, and

A series of cyclic surfactants were synthesized from a poly(ethylene glycol) (PEG) homopolymer and Pluronic surfactants L35, L64, P123, F68, 10R5, and 17R4, and their interfacial activity depending on the topology, chain ends, and block sequence was investigated. The cyclization was performed in a single step through etherification of the PEG homopolymer and the hydrophilic-hydrophobic-hydrophilic (ABA type) poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG), while the hydrophobic-hydrophilic-hydrophobic (BAB type) PPG-PEG-PPG was cyclized via acetalization. The cyclized surfactants were rigorously characterized by nuclear magnetic resonance spectroscopy and size exclusion chromatography. Cyclization of the surfactants induced a significant decrease in the hydrodynamic volume, which was more pronounced than that of the PEG homopolymer. Surface tension (γ) measurements indicated that the interfacial activity of the cyclized surfactants is stronger than their corresponding linear precursors, due to the increase in the surfactant density at the air-water interface as a consequence of the decreased molecular occupational area (A) upon cyclization. In the case of the PEG homopolymer, A considerably decreased from 410 A2 for the linear PEG prepolymer to 100 A2 for the cyclized PEG product. While the effects of chain-end groups were found to be limited to surfactants of relatively small molecular weights, the influence of cyclization depended strongly on the hydrophilic/hydrophobic ratio; the higher the PEG composition the surfactants had, the larger the decrease in γ and A; in other words, stronger enhancement in the interfacial activity was observed.

The mechanical properties and structural design flexibility of charge-trapping polymer electrets have led to their widespread use in organic field-effect transistor (OFET) memories. For example, in the electrets of polyfluorene-based conjugated/insulating block copolymers (BCPs), the confined fiberlike polyfluorene nanostructures in the insulating polymer matrix act as effective hole-trapping sites, leading to controllable memory performance through the design of BCPs. However, few studies have reported intrinsically stretchable charge-trapping materials and their memory device applications, and a practical method to correlate the thin-film morphology of BCP electrets with their charge-trapping ability has not yet been developed. In this study, a series of new conjugated/insulating BCPs, poly(9,9-di-n-hexyl-2,7-fluorene)-block-poly(δ-decanolactone)s (PF-b-PDLx, x = 1-3), as stretchable hole-trapping materials are reported. The linear and branched PDL blocks with comparable molecular weights were used to investigate the effect of polymer architecture on morphology and device performance. Moreover, the coverage area of the polyfluorene nanofibers on the BCP films was extracted from atomic force microscopy images, which can be correlated with the trapping density of the polymer electrets. The branched PDL segments not only improve stretchability but also tailor crystallinity and phase separation of the BCPs, thus increasing their charge-trapping ability. The OFET memory device with PF-b-PDL3 as the electret layer exhibited the largest memory window (102 V) and could retain its performance at up to 100% strain. This research highlights the importance of the BCP design for developing stretchable charge-trapping materials.

The development of eco-friendly fiber-reinforced composite resins is an important objective from an environmental perspective, and nanofibrillated bacterial cellulose (NFBC), with extremely long high-aspect-ratio fibers, is a filler material with high potential for use in such composite resins. In this study, we investigated chemical modification of the surfaces of NFBC fibers by coupling with (3-aminopropyl)trimethoxysilane and fabricated nanocomposite materials using the prepared surface-modified NFBC. The product prepared by the one-pot reaction of (3-aminopropyl)trimethoxysilane with NFBC microfibrils dispersed in aqueous acid retained the same nanofibril structure as the intact NFBC. The degree of molar substitution and the silicon states on the surface of the product depended on the NFBC/(3-aminopropyl)trimethoxysilane ratio. The thermal analysis revealed that the thermal degradation temperature of the products increases with an increase of degree of molar substitution. Highly transparent (78–89% at 600 nm) poly(methyl methacrylate)-based nanocomposites were prepared by solvent casting; the nanocomposite containing 1.0 wt % (3-aminopropyl)trimethoxysilylated NFBC was only 8% less transparent than neat poly(methyl methacrylate) at 600 nm. In addition, the tensile strength of the nanocomposite was more than twice that of neat poly(methyl methacrylate) when 1 wt % of the surface-modified NFBC was added. The surface-modified NFBC is expected to be a reinforcing nanofiber material that imparts excellent physical properties to fiber-reinforced resins.

Surface modification of nanofibrillated bacterial cellulose (NFBC) with methyltrimethoxysilane was performed in water to hydrophobize its surface. A series of cellulose samples with different degre...

The development of precise folding techniques for synthetic polymer chains that replicate the unique structures and functions of biopolymers has long been a key challenge. In particular,spiro-type (i.e., 8-, trefoil-, and quatrefoil-shaped) polymer topologies remain challenging due to their inherent structural complexity. Herein, we establish a folding strategy to producespiro-type multicyclic polymers via intramolecular ring-opening metathesis oligomerization of the norbornenyl groups attached at predetermined positions along a synthetic polymer precursor. This strategy provides easy access to the desiredspiro-type topological polymers with a controllable number of ring units and molecular weight while retaining narrow dispersity (& x189; < 1.1). This effective strategy marks an advancement in the development of functionalized materials composed of specific three-dimensional nanostructures. Intramolecular ring-opening metathesis oligomerisation is a useful method for constructing multicyclic polymer cages. Here, it is applied to the synthesis of spirocyclic polymers with figure-8, trefoil, and quatrefoil structures with low polydispersity.

A series of fully bio-based block copolymers (BCPs) consisting of maltooligosaccharides (maltose, maltotriose, maltotetraose, and maltohexaose; A block) and poly(delta-decanolactone) (PDL; B block), with ABA-, A(2)BA(2)-, A(3)BA(3)-, A(BA)(2)-, and A(2)(BA)(2)-type architectures, were synthesized to demonstrate the potential of oligosaccharides as novel hard segments for biobased elastomers. To understand the correlation between the BCP molecular structure and material properties, the BCPs were designed to have comparable molecular weights (ca. 12K) and total numbers of glucose units (12). Morphological analysis revealed the formation of body-centered-cubic sphere and hexagonally close-packed cylinder (HEX) morphologies depending on the branched architecture (interdomain distance 9.7-14.4 nm). While the PDL homopolymer is a viscous liquid due to its low T-g and amorphous nature, all BCPs exhibited elastomeric properties, confirming that the oligosaccharide blocks segregated to form the hard domains to cross-link the rubbery PDL chains. Tensile testing revealed that the mechanical properties of the BCPs were mainly determined by the microphase-separated structure and less affected by the length of each oligosaccharide chain. The HEX-forming A(2)BA(2)- and A(3)BA(3)-type BCPs exhibited Young's moduli of similar to 6 MPa, which is comparable to well-known styrene-based thermoplastic elastomers. Furthermore, a readily available polydisperse maltooligosaccharide was employed to synthesize an A(2)BA(2)-type BCP with a higher molecular weight PDL block (20K), which exhibited a Young's modulus of similar to 6 MPa and an elongation at break of similar to 700%. These results demonstrate that oligosaccharides are a sustainable alternative to the petroleum-derived synthetic hard segments (e.g., polystyrene), thereby opening up a new avenue for fully bio-based soft material design.

High-chi (where chi is the Flory-Huggins interaction parameter) block copolymers (BCPs) have great potential to achieve ultra-small microphase-separated structures with domain spacings (d) of

The highly asymmetric lamellar (A-LAM) nanostructure is one of the most important template geometries for block copolymer (BCP) lithography. However, A-LAM is unattainable from conventional BCPs, and there is no general molecular design strategy for A-LAM-forming BCP. Herein, a nanoparticle-linear hybrid BCP system is reported, which is designed based on the intramolecular crosslinking technique, as a remarkably effective platform to obtain the A-LAM morphology. The hybrid BCPs consisting of polystyrene single-chain nanoparticles and linear polylactide segments show a remarkable capability to form the A-LAM morphology in bulk, where a maximum width ratio of 4.1 between the two domains is obtained. This unusual phase behavior is attributed to the bulky and rigid characteristics of the nanoparticle block. Furthermore, the thin films of these hybrid BCPs show perpendicularly oriented A-LAM morphology on a chemically modified Si substrate, allowing promising application in the fabrication of asymmetric line-and-space nanopatterns.

In this study, we demonstrated that the Suzuki–Miyaura catalyst transfer polycondensation (SCTP) of the triolborate-type fluorene monomer, viz. potassium 2-(7-bromo-9,9-dihexyl-9H-fluorene-2-yl)triolborate, can be an efficient and versatile approach to the precise synthesis of poly[2,7-(9,9-dihexylfluorene)]s (PFs) and PF-containing block and graft copolymers. SCTP of the triolborate-type monomer proceeded rapidly in a THF/H2O mixed solvent at −10 °C using an iodobenzene derivative/Pd2(dba)3·CHCl3/t-Bu3P initiating system. Kinetic and post-polymerization experiments revealed that SCTP proceeded via the chain-growth and living polymerization mechanisms. The most important feature of the present polymerization system is that only a small amount of base and water can sufficiently promote the reaction. The well-controlled nature of this polymerization system enabled the synthesis of high-molecular-weight PFs (Mn = 5–69 kg mol−1) with narrow dispersity (ĐM = 1.14–1.38) and α-end-functionalized PFs. Most importantly, PF-containing block and graft copolymers were successfully synthesized, beginning with various iodobenzene-functionalized macroinitiators; this was difficult to achieve by the conventional SCTP of pinacolboronate-type fluorene monomer. One of the key factors for the successful block and graft copolymer syntheses is the reduced water content in the polymerization medium, which suppressed the potential precipitation/aggregation of the macroinitiators.

The alternating copolymer of lactic acid and glycolic acid (PLGA) is a highly promising next generation biodegradable material for biomedical and pharmaceutical applications due to its uniform degradation behaviors in addition to its ability to form stereocomplexes. However, versatile synthetic methods toward the narrowly dispersed alternating PLGAs with controlled molecular weights and desired end functionalities have been largely unexplored. Herein, we report the organocatalytic regioselective ring-opening polymerization (ROP) of optically active methylglycolides (l- andd-MGs) to produce highly alternating PLGAs. The ROP ofl-MG using a phosphazene base P-2-t-Bu/alcohol system in THF at -78 degrees C achieved the highest regioselectivity (P= 0.95) as well as a good control over the molecular weight (M-n= 6.6-15.6 g mol(-1)), with a relatively narrow dispersity (D= 1.21-1.29). Furthermore, alternating PLGA diol as well as azido-, ethynyl-, and poly(ethylene glycol) monomethyl ether-end-functionalized alternating PLGAs was successfully obtained by employing the corresponding functional alcohol initiators. An enantiomeric 1 : 1 blend of PLGAs prepared froml- andd-MGs formed a stereocomplex with a crystallinity and melting point comparable to the reported data for the stereocomplex from the perfectly alternating PLGAs producedviaa polycondensation approach, which implies the high degree of the alternating sequence of the obtained copolymers.

This study attempts to clarify the basic material properties of in-vivo-fabricated hyaluronan (HA)/bacterial cellulose (BC) nanocomposites prepared previously. BC membranes (pellicles) generated by Gluconacetobacter hansenii (G. hansenii) are promising biomaterials owing to their outstanding biocompatible properties. Recently, specific demands for biomedical applications of BC have increased owing to its excellent mechanical properties. Although many techniques have been developed to improve the biofunctional properties of BC pellicles, such modifications remain limited owing to technical difficulties in the modulation of complex biosynthetic processes. Therefore, we previously developed an in vivo modification technique to produce nanocomposite pellicles composed of BC and HA (in vivo HA/BC), which are directly secreted from genetically engineered G. hansenii. In the present study, the HA extractability and content rate, physical characteristics, and cytocompatibility of in vivo HA/BC have been investigated in comparison to conventional in situ HA/BC and native BC pellicle. The results suggested that HA more strongly adsorbed to the solid BC surface of in vivo HA/BC than that of in situ HA/BC, which possibly affected the dynamic viscoelastic characteristics. Furthermore, in vivo HA/BC showed remarkably high human epidermal cell adhesion. These results indicate the great potential of in vivo modification to expand the usefulness of BC-based biomaterials.

Unique physical and chemical properties arising from a polymer topology recently draw significant attention. In this study, cyclic poly(ethylene glycol) (

Naturally occurring polysaccharides, such as cellulose, hemicellulose, and chitin, have roles in plant skeletons and/or related properties in living organisms. Their hierarchically regulated production systems show potential for designing nanocomposite fabrication using engineered microorganisms. This study has demonstrated that genetically engineered

Herein, we compared the microphase-separation behavior and mechanical properties of cellulose- and amylose-based block copolymers (BCPs). Various cellooligosaccharide triacetate-b-poly(δ-decanolactone)-b-cellooligosaccharide triacetates (AcCel n-b-PDL-b-AcCel ns), which are cellulose-based ABA-type BCPs, with PDL molecular weights of approximately 5, 10, and 20 kg mol -1and PDL volume fractions of 0.65, 0.77, and 0.87, were synthesized from α,ω-diazido-end-functionalized PDLs and propargyl-end-functionalized cellooligosaccharide triacetates via click chemistry. We adopted the cellodextrin-phosphorylase-mediated oligomerization of α-glucose-1-phosphase in the presence of a propargyl-end-functionalized cellobiose primer to synthesize the functional cellooligosaccharide segment. The maltooligosaccharide triacetate-b-poly(δ-decanolactone)-b-maltooligosaccharide triacetate (AcMal n-b-PDL-b-AcMal ns) amylose counterparts were also synthesized in a similar manner. Small-angle X-ray scattering experiments and atomic force microscopy revealed that AcCel n-b-PDL-b-AcCel ns are more likely to microphase-separate into ordered nanostructures compared to AcMal n-b-PDL-b-AcMal ns, despite their comparable chemical compositions and molecular weights. Furthermore, AcCel n-b-PDL-b-AcCel ns exhibited significantly superior mechanical performance compared to their amylose counterparts under tensile testing, with Young’s modulus and stress at break of AcCel n-b-PDL 10k-b-AcCel nbeing 2.3 and 1.8 times higher, respectively, than those of AcMal n-b-PDL 10k-b-AcMal n. The enhanced microphase-separation and mechanical properties of AcCel n-b-PDL-b-AcCel ns were found to be attributable to the stiffness and crystalline nature of the AcCel nsegments. These results demonstrate the advantages of using cellulose derivatives to synthesize novel biofunctional materials.

Cellulose is produced by all plants and a number of other organisms, including bacteria. The most representative cellulose-producing bacterial species is Gluconacetobacter xylinus (G. xylinus), an acetic acid bacterium. Cellulose produced by G. xylinus, commonly referred to as bacterial cellulose (BC), has exceptional physicochemical properties resulting in its use in a variety of applications. All cellulose-producing organisms that synthesize cellulose microfibrils have membrane-localized protein complexes (also called terminal complexes or TCs) that contain the enzyme cellulose synthase and other proteins. The bacterium G. xylinus is a prolific cellulose producer and a model organism for studies on cellulose biosynthesis. The widths of cellulose fibers produced by Gluconacetobacter are 50‒100 nm, suggesting that cellulose-synthesizing complexes are nanomachines spinning a nanofiber. At least four different proteins (BcsA, BcsB, BcsC, and BcsD) are included in TC from Gluconacetobacter, and the proposed function of each is as follows: BcsA, synthesis of a glucan chain through glycosyl transfer from UDP-glucose; BcsB, complexes with BcsA for cellulose synthase activity; BcsC, formation of a pore in the outer membrane through which a glucan chain is extruded; BcsD, regulates aggregation of glucan chains through four tunnel-like structures. In this review, we discuss structures and functions of these four and a few other proteins that have a role in cellulose biosynthesis in bacteria.

Alkali metal carboxylates, including sodium acetate, sodium benzoate, and sodium sorbate, which are all readily available and widely used as food additives, were found to promote the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) to produce poly(trimethylene carbonate) (PTMC). The sodium acetate-catalyzed ROP of TMC proceeded in the presence of an alcohol initiator under solvent-free conditions at 70 °C, even at very low catalyst loadings of 0.01–0.0001 mol%. The controlled nature of this ROP system enabled the synthesis of PTMCs with predicted molecular weights ranging from 2400 to 11 700 g mol−1 and narrow dispersities (~1.23). Importantly, ROP is initiated by an alcohol initiator, allowing PTMC production with desired functional groups, such as azido, alkyne, and methacrylate groups, at the α-chain end. Furthermore, the poly(l-lactic acid)-b-PTMC-b-poly(l-lactic acid) triblock copolymer, a biodegradable thermoplastic elastomer, was successfully synthesized in one pot via the sodium acetate-catalyzed ring-opening block copolymerization of TMC and l-lactide with a 1,3-propanediol initiator. Alkali metal carboxylates, which are readily available and widely used as food additives, were found to promote the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) to produce poly(trimethylene carbonate) (PTMC). The sodium acetate-catalyzed ROP of TMC proceeded in the presence of an alcohol initiator under solvent-free conditions, even at very low catalyst loadings of 0.01–0.0001 mol%. This ROP system enabled the synthesis of PTMCs with predicted molecular weights ranging from 2400 to 11 700 g mol−1 and narrow dispersities (~1.23).