High Molar Mass Research Articles

Computational and Experimental Study of PVA with F127 and Citric Acid for Electrospinning

Despite the widespread application of electrospun membranes across various scientific fields, there remains a need for a deeper understanding of the molecular interactions between polymers and other compounds in precursor solutions for electrospinning. This study evaluates the molecular conformations of poly(vinyl alcohol) (PVA) with different degrees of hydrolysis (PVA87 and PVA99) and high molar mass, crosslinked with citric acid (CA), using molecular modeling. The solution properties, including rheology and conductivity, were compared to obtain electrospun nanofibers. Additionally, Pluronic-F127® (F127) was incorporated into the PVA/CA system for advanced applications. The molecular modeling results indicate that the degree of hydrolysis affects the intermolecular forces of PVA and the effective binding of CA to the polymer chain. The interactions within the PVA/CA/F127 system vary with the degree of hydrolysis. The high viscosity of PVA99, due to inter- and intramolecular bonds, negatively impacts fiber morphology and formation. Thermal and Raman analyses confirmed crosslinking. Under the conditions used, the PVA99/CA/F127 system is unsuitable for electrospinning. In contrast, the electrospinning and crosslinking of PVA87/CA/F127 with high molar mass yielded better results, enhancing the potential of these nanofibers for drug delivery applications.

Characterization of Hydrocolloids Extracted from Fenugreek and Sweet Basil Seeds and Their Effect on Rheological Properties of Wheat Starch Paste

Starch-hydrocolloid systems are crucial texturizing agents, ingredients and additives in many food products. The aim of this work was to investigate the effect of extraction temperature on the composition and properties of hydrocolloids extracted from milled fenugreek and sweet basil seeds, as well as the effect of the obtained non-starch polysaccharide preparations on the rheological properties of wheat starch paste. Hydrocolloids were extracted from milled seeds of fenugreek and sweet basil at room temperature (PFRT and PSBRT, respectively) and at 70 °C (PF70 and PSB70, respectively), with the extraction yields ranging from 32 to 47%. Extracted hydrocolloids contained polysaccharides (mainly high molar mass galactomannan) and protein. Preparations extracted at 70 °C from fenugreek (PF70) and sweet basil (PSB70) seeds were characterized by a higher content of polyphenols (16.2% and 50.9%, respectively), as well as higher antioxidant properties compared to preparations extracted at room temperature (PFRT and PSBRT). The 6% share of the fenugreek and sweet basil seed preparations obtained by extraction at room temperature increased the consistency index and reduced the flow behavior index compared to the starch paste without the preparations. The share of fenugreek seed and sweet basil preparations increased (p < 0.05) the tan δ parameter of the starch paste compared to the starch paste without the preparations.

Reversible Addition-Fragmentation Chain-Transfer Polymerization in Supercritical CO2: A Review.

The development of cleaner, more environmentally friendly processes in polymerization technology is crucial due to the prevalent use of volatile organic solvents (VOCs), which are harmful and toxic. Future regulations are likely to limit or ban VOCs. This review explores the use of supercritical solvents, specifically supercritical CO2 (scCO2), in polymerization processes. The study focuses on reversible addition-fragmentation chain-transfer (RAFT) induced homo-polymerization of various monomers using specific chain transfer agents (CTAs) in scCO2. RAFT polymerization, a reversible deactivation radical polymerization (RDRP) polymerization, relies heavily on the choice of CTA, which significantly influences the dispersity and molar mass of the resulting polymers. Stabilizers are also crucial in controlling product specifications for polymerizations in supercritical CO2, except for fluor-based polymers, although they must be removed and preferably recycled to ensure product purity and sustainability. The review notes that achieving high molar mass through RAFT polymerization in scCO2 is challenging due to solubility limits, which lead to polymer precipitation. Despite this, RAFT polymerization in scCO2 shows promise for sustainable, circular production of low molar mass polymers, although these cannot yet be fully considered green products.

Riboflavin‐Catalyzed Photoinduced Atom Transfer Radical Polymerization

AbstractThe photoATRP of methyl acrylate (MA) is investigated using riboflavin (RF) and CuBr2/Me6TREN as a dual catalyst system under green LED irradiation (λ ≈ 525 nm). Both RF and CuBr2/Me6TREN enhanced oxygen tolerance, enabling effective ATRP in the presence of residual oxygen. High molar mass polymers (up to Mn ≈ 129 000 g·mol−1) with low dispersity (Đ ≤ 1.16) are prepared, and chain‐end fidelity is confirmed through successful chain extension. The molecular masses of the obtained polymer increased linearly with conversion and showed high initiation efficiency. Mechanistic studies by laser flash photolysis reveal that the predominant activator generation mechanism is reductive quenching of RF by Me6TREN (83%, under [CuBr2]/[Me6TREN] = 1/3 condition), supported by polymerization kinetics and thermodynamic calculations.

DMTMM-mediated amidation of sodium alginate in aqueous solutions: pH-dependent efficiency of conjugation

DMTMM-mediated amidation of sodium alginate is one of the methods used for the chemical modification of alginate with amines. However, there is a limited understanding of how the reaction conditions, particularly the pH value, influence the conjugation efficiency (CE) and the resulting degree of substitution (DS). In this study, we investigated the effect of the pH during the reaction, focusing on both neutral and weakly basic conditions, using water and buffer as solvents. Two model amines with high pKaH values were selected, furfurylamine (FFA, pKaH = 9.12) and 4-(2-aminoethyl)morpholine (AEM, pKaH = 9.93). Sodium alginate with a high mannuronate content (60 mol%) and molar mass of 168 kg·mol−1 was used for amidation. Our results show that both FFA and AEM effectively conjugate to sodium alginate under the selected reaction conditions. We found that pH significantly affects both CE and DS, which varied between 2 % to 40 % and 3 % to 53 %, respectively, depending on the specific reaction conditions. Optimal conditions were observed at neutral pH in water, whereas weak basic pH led to lower CE. Our findings thus offer a recommendation for optimizing the DMTMM-mediated amidation of sodium alginate, emphasizing the importance of pH values during the reaction.

Ultra-Pressurized Deposition of Hydrophobic Chitosan Surface Coating on Wood for Fungal Resistance.

Fungi (Neolentinus lepideus, Nl, and Trametes versicolor, Tv) impart wood rot, leading to economic and environmental issues. To overcome this issue, toxic chemicals are commonly employed for wood preservation, impacting the environment and human health. Surface coatings based on antimicrobial chitosan (CS) of high molar mass (145 × 105 Da) were tested as wood preservation agents using an innovative strategy involving ultra-pressurizing CS solutions to deposit organic coatings on wood samples. Before coating deposition, the antifungal activity of CS in diluted acetic acid (AcOOH) solutions was evaluated against the rot fungi models Neolentinus lepideus (Nl) and Trametes versicolor (Tv). CS effectively inhibited fungal growth, particularly in solutions with concentrations equal to or higher than 0.125 mg/mL. Wood samples (Eucalyptus sp. and Pinus sp.) were then coated with CS under ultra-pressurization at 70 bar. The polymeric coating deposition on wood was confirmed through X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) images, and water contact angle measurements. Infrared spectroscopy (FTIR) spectra of the uncoated and coated samples suggested that CS does not penetrate the bulk of the wood samples due to its high molar mass but penetrates in the surface pores, leading to its impregnation in wood samples. Coated and uncoated wood samples were exposed to fungi (Tv and Nl) for 12 weeks. In vivo testing revealed that Tv and Nl fungi did not grow on wood samples coated with CS, whereas the fungi proliferated on uncoated samples. CS of high molar mass has film-forming properties, leading to a thin hydrophobic film on the wood surface (water contact angle of 118°). This effect is mainly attributed to the high molar mass of CS and the hydrogen bonding interactions established between CS chains and cellulose. This hydrophobic film prevents water interaction, resulting in a stable coating with insignificant leaching of CS after the stability test. The CS coating can offer a sustainable strategy to prevent wood degradation, overcoming the disadvantages of toxic chemicals often used as wood preservative agents.

The Influence of Oat β-Glucans of Different Molar Mass on the Properties of Gluten-Free Bread.

The influence of β-glucans on the properties of gluten-free dough and bread is still not fully explained, with the literature suggesting both positive and negative effects. The aim of this study was to investigate the effect of the molar mass of oat β-glucans on the properties of gluten-free bread. Gluten-free breads were baked under standardized conditions from a model gluten-free mix without and with a 1% or 2% share of oat β-glucans of a low molar mass of 24,540 g/mol, a medium molar mass of 85,940 g/mol and a high molar mass of 1,714,770 g/mol. The share of β-glucans affected the increase in water addition to the baking mix and dough yield proportionally to the molar mass and amount of β-glucans. The β-glucans of the highest molar mass, particularly at a 2% share, were most effective in increasing bread volume, reducing hardness and increasing the moisture content of the bread crumb on the day of baking, as well as reducing the increase in hardness and maintaining a high moisture content of the bread crumb after 1 day of storage, compared to bread without added β-glucans.

Development of Two Novel Dibenzosilole-Based Conjugated Polymers with Thieno[3,4-c]pyrrole-4,6-dione for Use in Polymer Solar Cells

The donor-acceptor (D-A) strategy has proven to be one of the most effective methods for tuning the band gaps, absorption characteristics, and optoelectronic properties in conjugated polymers. Two novel D-A conjugated polymers, PDBSTPD-1T and PDBSTPD-2T, were synthesized using dibenzosilole (DBS) and thieno[3,4-c]pyrrole-4,6-dione (TPD) as the building blocks. These polymers were linked through either a single thiophene or two thiophene rings as π-bridges and were copolymerized using a Suzuki coupling reaction. The effect of the incorporation of the different π-bridges on the electrical/optical properties of the prepared copolymers was also investigated. The synthesized polymers, PDBSTPD-1T and PDBSTPD-2T, were soluble in organic solvents and demonstrated high molar mass along with excellent thermal stability. The conjugation of the electron-accepting TPD unit with the electron-donating DBS unit produced relatively deep HOMO levels, which were fine-tuned to be −5.44 and −5.36 eV via the addition of the different π-bridges. PDBSTPD-1T and PDBSTPD-2T displayed absorption wavelengths between 350 and 650 nm with high Eg opt of 2.01 and 1.97 eV, respectively. X-ray diffraction analysis presented several diffraction peaks, and the π-π stacking distances of PDBSTPD-1T and PDBSTPD-2T were 3.45 and 3.65°A, respectively.

Ultrasonic Control of Protein Splicing by Split Inteins.

Utilizing ultrasound as an external stimulus to remotely modulate the activity of proteins is an important aspect of sonopharmacology and establishes the basis for the emerging field of sonogenetics. Here, we describe an ultrasound-responsive protein splicing system that enables spatiotemporal control of split-intein-mediated protein ligation. The system utilizes engineered split inteins that are caged and can be activated by thrombin released from a high molar mass DNA-based carrier under focused ultrasound sonication. This approach represents a general method for controlling the functions of proteins of interest by ultrasound, as demonstrated here by the controlled synthesis of the superfolder green fluorescence protein (GFP) and calcitonin. Furthermore, calcitonin receptor-mediated signal transduction in cells was triggered by this system in vitro without harming cell viability. By expanding the sonogenetic toolbox with protein splicing technologies, this study provides a possible pathway to deploy ultrasound for remotely controlling a variety of protein functions in deep tissue in the future.

Lipase-catalyzed synthesis of poly(ω-pentadecalactone-co-globalide) in supercritical carbon dioxide

This work investigates the enzymatic ring-opening polymerization of poly(ω-pentadecalactone-co-globalide) using supercritical carbon dioxide as a solvent. Copolymerizations were carried out in a high-pressure variable-volume view cell to evaluate the influence of CO2:monomers mass ratios and the use of chloroform as a cosolvent. Also, Novozym® 435 and Lipura® Flex were compared as catalysts. The highest molar mass obtained with the use of a cosolvent (Mn = 24,380 g mol−1) was achieved in the 1:2:1 (CO2:monomers:chloroform) condition, reflecting the combined effect of the cosolvent and a higher concentration of the monomers, while reactions without it showed better results for molar mass (Mn up to 27,902 g mol−1). Dispersity was higher when a cosolvent was used (Dispersity up to 7.51) than reactions with supercritical carbon dioxide only (Dispersity up to 5.36). Monomer conversions above 97 % and reaction yields from 55.77 wt% up to 79.61 wt% were achieved for copolymerizations with and without a cosolvent, using Novozym® 435 as catalyst. Lipura® Flex produced copolymers with high molar mass (Mn up to 21,605 g mol−1), reaction yields up to 73 wt%, and monomer conversions from 82 % to 96 %.

Monothiolactide, a New Monomer for the Synthesis of Recyclable, Alternating Ester-Thioester Polymers.

Aliphatic polyesters and polythioesters are very interesting alternatives for current fossil-based and degradation-resistant plastics, due to their high (bio)degradability and (chemical) recyclability potential. Two important examples include polylactide (PLD), currently leading the synthetic bioplastics market, and its sulfur analog polythiolactide (PTLD). Both polymers can be made by ring-opening polymerization (ROP) of their corresponding (thio)dilactones, lactide (LD) and thiolactide (TLD) respectively. In this work, the benefits of esters and thioesters were combined in one material by the successful catalytic synthesis and ROP of monothiolactide (MTL), an unprecedented monomer containing half a LD and half a TLD structural unit. MTL can be obtained by a simple direct condensation of biobased lactic acid and thiolactic acid aided by Brønsted acid catalysis. The novel, but simple monomer showed to be easily polymerized with triethylamine to materials containing alternating lactic and thiolactic ester units with a very high molar mass. The lower stability of MTL (vs. TLD) resulted in improved ROP thermodynamics, while also fast and controllable polymerization kinetics were observed. The new polymers feature a good chemical recycling and hydrolytic degradation potential with important improvements compared to PTLD and PLD. Finally, a successful co-polymerization with commercial LD was shown, paving the way towards industrialization.

Effect of the molar mass of chitosan and film casting solvents on the properties of chitosan films loaded with Mentha spicata essential oil for potential application as wound dressing

Chitosan based films endowed with antibacterial features have witnessed remarkable progress as potential wound dressings. The current study aimed at appraising the effects of the molar mass of chitosan (MM) and the film casting acids on the properties of unplasticized chitosan films and plasticized MSO-embedded chitosan films in order to provide best suited film formulation as a potential candidate for wound dressing application. The prepared films were functionally characterized in terms of their qualitative assessment, thickness, density, swelling behavior, water vapor barrier, mechanical and antibacterial properties. Overall, all chitosan films displayed thickness lower than the human dermis even though thicker and denser films were produced with lactic acid. Assessment of the swelling behavior revealed that only high molar mass (HMM) chitosan films may be regarded as absorbent dressings. Moreover, unplasticized HMM lactate (HMM-LA) films furnished lower stiffness and higher percent strain break as compared to acetate films, due to the plasticizing effect of the remaining lactic acid as alluded by the FTIR analysis. Meanwhile, they provided suitable level of moisture and indicated substantial antibacterial activity against S. aureus and E. coli, the most commonly opportunistic bacteria found in infected skin wound. Plasticized chitosan films doped with MSO were significantly thicker and more permeable to water compared to unplasticized films. Furthermore, MSO significantly potentiate the antibacterial effect of chitosan-based films. Therefore, plasticized HMM-LA/MSO chitosan film flashing good swelling behavior, adequate WVTR and WVP, suitable mechanical properties and antibacterial performances substantiated to be a promising antibacterial dressing material for moderately exuding wounds.

Fractionation and Characterization of Commercial Low Acyl Gellan Gum

AbstractCommercial low acyl gellan (LAG) is purified by the fractional dissolution method. An aqueous solution of purified commercial LAG exhibits polyelectrolyte character due to its high molar mass and carboxylic groups in glucuronic acid fragments. The empirical Fuoss equation determines the intrinsic viscosity of purified LAG in salt‐less water. Fractionation of commercial LAG is carried out by ultrasound treatment. LAG fractions are characterized by 1H NMR and FTIR spectroscopy. The intrinsic viscosities of ultrasonically treated LAG samples are measured in 0.025 m of tetramethylammonium chloride (TMACl). The molecular weights of LAG fractions are determined by the Mark–Kuhn–Houwink equation.

Organo-Mediated Ring-Opening Polymerization of Ethylene Brassylate from Cellulose Nanofibrils in Reactive Extrusion.

Ethylene brassylate is a renewable macrolactone from castor oil that can be polymerized via ring-opening polymerization (ROP) to obtain a fully biosourced biodegradable polyester. ROP mediated by organometallic catalysts leads to high molar mass poly(ethylene brassylate) (PEB). However, the use of metal-free organocatalysis has several advantages, such as the reduction of toxic and expensive metals. In this work, a novel cellulose nanofibril (CNF)/PEB nanocomposite fabrication process by organocatalysis and reactive extrusion (REx) is disclosed. Here, ROP was carried out via solvent-free REx in the presence of CNFs using organic 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst. Neat or lactate-esterified CNFs (LACNF) were used as initiators to investigate the effect of surface topochemistry on the in situ polymerization and the properties of the nanocomposites. A molar mass of 9 kDa was achieved in the presence of both unmodified and LACNFs with high monomer conversion (>98%) after 30 min reaction in a microcompounder at 130 °C. Tensile analysis showed that both nanofibril types reinforce the matrix and increase its elasticity due to the efficient dispersion obtained through the grafting from polymerization achieved during the REx. Mechanical recycling of the neat polymer and the nanocomposites was proven as a circular solution for the materials' end-of-life and showed that lactate moieties induced some degradation.

Preparation and characterization of hydrophobically-modified sodium alginate derivatives as carriers for fucoxanthin

Micelles are nano-architectured structures capable of encapsulating hydrophobic substances in aqueous solutions, thereby improving their stability, solubility, and bioavailability to control the release of bioactive compounds. In this study, the sodium alginate backbone was modified via a hydrophobic modification scheme where octyl chains were covalently attached to the alginate chains via esterification reactions. Fourier-transformed infrared spectrometry (FTIR), 1H nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) were used to characterize the structure of the sodium alginate derivatives of varying molar mass (ALG-C8). Fluorescence spectroscopy, surface tension measurements, and dynamic light scattering (DLS) were employed to assess the self-assembly performance of ALG-C8. The three methods produced consistent results, indicating that self-assembly decreased with higher molar mass. The self-assembled ALG-C8 micelles were utilized to encapsulate fucoxanthin. The loading capacity (LC) and encapsulation efficiency (EE) were determined using UV–Vis spectrophotometry. The molar mass of ALG-C8 has a key influence on fucoxanthin loading and release behavior. The ALG-C8 molecules with the lowest molar mass produced micelles with the smallest hydration diameter, resulting in the highest LC and EE. Furthermore, the release of fucoxanthin is significantly influenced by the pH and ionic strength of the medium. ALG-C8 micellar-like aggregates exhibit resistance to low pH and high ionic strength environments, releasing encapsulated material at the target site under alkaline conditions. Therefore, synthesized ALG-C8 is a potential candidate for preparing pH-responsive self-assembled micellar-like aggregates, enabling targeted delivery and gradual release of hydrophobic functional food components.

Nitriles as Functionalization and Coupling Agents for Polyolefins Obtained by Coordinative Chain Transfer Polymerization.

Coordinative chain transfer polymerization (CCTP) of ethylene and its copolymerization with 1,3-butadiene is conducted in toluene at 80 °C using a combination of {(Me2Si(C13H8)2)Nd(μ-BH4)[(μ-BH4)Li(THF)]}2 (1) metal complex and various organomagnesium compounds used as chain transfer agents including n-butyl-n-octyl-magnesium (BOMAG), n-butyl-mesityl-magnesium (n-BuMgMes), n-butyl-magnesium chloride (n-BuMgCl), n-pentyl-magnesium bromide (n-C5H11MgBr), pentanediyl-1,5-di(magnesium bromide) (PDMB) and isobutyl-magnesium chloride (i-BuMgCl). Kinetics and performance in terms of control of the (co)polymerization are comparatively discussed particularly considering the presence of ether and the nature of the organomagnesium compounds employed. Taking advantage of the well-known reactivity between nitrile and molecular organomagnesium compounds, the functionalization of the chains is further carried out by deactivation of the polymerization medium with benzonitrile or methoxybenzonitrile compounds leading to ketone ω-functionalized chains. The success of the functionalizations is extended to coupling strategies using dinitrile reagents and to the functionalization of high molar mass ethylene butadiene rubber (EBR).

Ionic liquid pretreatment of lignocellulose for complete hemicellulose removal to produce high-purity cellulose mixed esters

Strategic valorization of agricultural waste can serve as waste management and promote sustainable biorefineries. Sugarcane bagasse is a readily available lignocellulosic biomass and can be converted into valuable cellulose-based thermoplastics. However, the cellulose purity significantly influences the material properties of the resulting thermoplastics, potentially limiting their applications. Therefore, conventional production necessitates harsh pretreatment of lignocellulose to isolate high-purity cellulose, followed by chemical modification. Here, we demonstrate a facile and green pretreatment method for complete removal of hemicellulose by incubating bagasse in a mixed system of an ionic liquid, 1-ethyl-3-methylimidazolium acetate (EmimOAc), and dimethyl sulfoxide (DMSO) at 140 °C, followed by precipitation in water, achieving >99 % hemicellulose removal. The pretreated bagasse, containing 71 % cellulose and 28 % lignin, underwent homogeneous transesterification with vinyl decanoate and isopropenyl acetate, using EmimOAc as both the solvent and catalyst, assisted by a co-solvent of DMSO. The polysaccharide derivative in the resulting acylated bagasse was separated from the lignin derivative by precipitation in methanol. The obtained polysaccharide derivative with high cellulose purity displayed a high weight-average molar mass of 1.5×106 g mol−1 and a polydispersity of 4. It also exhibited superior thermal stability (thermal degradation temperature, Td−5 %: 359 °C; glass transition temperature, Tg: 144 °C) compared to pulp-derived cellulose acetate decanoate (Td−5 %: 349 °C; Tg: 129 °C).

Isomer‐Dependent Melting Behavior of Low Molar Mass Azobenzene Derivatives: Observation of a Higher Melting Z‐Isomer

AbstractAzobenzene compounds are putative solar thermal fuels (STF) due to the excellent photostability and structural control of isomerization rates. Azobenzenes, in which both Z‐ and E‐isomers are liquid at room temperature, are promising candidates for STF flow technology. A literature survey of melting points led to the synthesis and isomer separation of ortho‐ and meta‐monosubstituted azobenzenes with fluoro, methyl, ethyl, trifluoromethyl and methoxy substituents and several dimethyl substituted azobenzenes. Four of the compounds are liquid azobenzenes with higher specific energy than literature work with higher molar mass, liquid compounds. Eight of the compounds unexpectedly displayed a higher melting point for the Z‐isomer which is rarely observed. Intermolecular close contacts in the crystal lattice of the Z‐isomer are the main factor responsible for the higher melting temperatures.

In Vivo Polymer Mechanochemistry with Polynucleotides.

Polymer mechanochemistry utilizes mechanical force to activate latent functionalities in macromolecules and widely relies on ultrasonication techniques. Fundamental constraints of frequency and power intensity have prohibited the application of the polymer mechanochemistry principles in a biomedical context up to now, although medical ultrasound is a clinically established modality. Here, a universal polynucleotide framework is presented that allows the binding and release of therapeutic oligonucleotides, both DNA- and RNA-based, as cargo by biocompatible medical imaging ultrasound. It is shown that the high molar mass, colloidal assembly, and a distinct mechanochemical mechanism enable the force-induced release of cargo and subsequent activation of biological function in vitro and in vivo. Thereby, this work introduces a platform for the exploration of biological questions and therapeutics development steered by mechanical force.

Thermally Stable and Chemically Recyclable Poly(ketal-ester)s Regulated by Floor Temperature.

Chemical recycling to monomers (CRM) offers a promising closed-loop approach to transition from current linear plastic economy toward a more sustainable circular paradigm. Typically, this approach has focused on modulating the ceiling temperature (Tc) of monomers. Despite considerable advancements, polymers with low Tc often face challenges such as inadequate thermal stability, exemplified by poly(γ-butyrolactone) (PGBL) with a decomposition temperature of ∼200 °C. In contrast, floor temperature (Tf)-regulated polymers, particularly those synthesized via the ring-opening polymerization (ROP) of macrolactones, inherently exhibit enhanced thermodynamic stability as the temperature increases. However, the development of those Tf regulated chemically recyclable polymers remains relatively underexplored. In this context, by judicious design and efficient synthesis of a biobased macrocyclic diester monomer (HOD), we developed a type of Tf -regulated closed-loop chemically recyclable poly(ketal-ester) (PHOD). First, the entropy-driven ROP of HOD generated high-molar mass PHOD with exceptional thermal stability with a Td,5% reaching up to 353 °C. Notably, it maintains a high Td,5% of 345 °C even without removing the polymerization catalyst. This contrasts markedly with PGBL, which spontaneously depolymerizes back to the monomer above its Tc in the presence of catalyst. Second, PHOD displays outstanding closed-loop chemical recyclability at room temperature within just 1 min with tBuOK. Finally, copolymerization of pentadecanolide (PDL) with HOD generated high-performance copolymers (PHOD-co-PPDL) with tunable mechanical properties and chemical recyclability of both components.