Pub Date : 2025-02-17DOI: 10.1021/acs.macromol.4c02727
Jinlei Huo, Yulian Yang, Yang Hu, Rongrong Hu, Ben Zhong Tang
Polydithiocarbamates are a group of promising functional polymer materials with unique structures, dynamic reversible properties, and photosensitivity, but the efficient, convenient, and diversified syntheses of poly(N-substituted)dithiocarbamates remain challenging. In this work, room temperature transition-metal-free multicomponent tandem polymerization (MCTP) of CS2, secondary diamines, and 1,4-di(bromomethyl)benzene was reported to construct five poly(N-substituted)dithiocarbamates with high molecular weights (Mws) of up to 60800 g/mol and high yields of up to 91% using commercially available simple monomers under mild and convenient conditions, achieving high atom economy and about 60 g-scale synthesis. Most importantly, polymers with discontinuous Mws could be obtained in one pot, depending on the amine structures and polymerization time, and the solution underwent automatic stratification during the polymerization with a low-Mw portion in the upper layer and a high-Mw portion in the bottom layer. These poly(N-substituted)dithiocarbamates generally possessed good solubility, high thermal stability and could be photodegraded efficiently upon UV irradiation to produce terephthalaldehyde. The MCTP has provided a simple and robust synthetic approach for polydithiocarbamates, and the self-stratification has been suggested as a facile method for molecular weight control of step-growth polymerizations, which could accelerate the development of polymerization methodology and sulfur-containing polymer materials.
{"title":"Polydithiocarbamates with Discontinuous Mws Synthesized via Multicomponent Tandem Polymerizations of CS2, Secondary Diamines, and Dibromide","authors":"Jinlei Huo, Yulian Yang, Yang Hu, Rongrong Hu, Ben Zhong Tang","doi":"10.1021/acs.macromol.4c02727","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02727","url":null,"abstract":"Polydithiocarbamates are a group of promising functional polymer materials with unique structures, dynamic reversible properties, and photosensitivity, but the efficient, convenient, and diversified syntheses of poly(<i>N</i>-substituted)dithiocarbamates remain challenging. In this work, room temperature transition-metal-free multicomponent tandem polymerization (MCTP) of CS<sub>2</sub>, secondary diamines, and 1,4-di(bromomethyl)benzene was reported to construct five poly(<i>N</i>-substituted)dithiocarbamates with high molecular weights (<i>M</i><sub>w</sub>s) of up to 60800 g/mol and high yields of up to 91% using commercially available simple monomers under mild and convenient conditions, achieving high atom economy and about 60 g-scale synthesis. Most importantly, polymers with discontinuous <i>M</i><sub>w</sub>s could be obtained in one pot, depending on the amine structures and polymerization time, and the solution underwent automatic stratification during the polymerization with a low-<i>M</i><sub>w</sub> portion in the upper layer and a high-<i>M</i><sub>w</sub> portion in the bottom layer. These poly(<i>N</i>-substituted)dithiocarbamates generally possessed good solubility, high thermal stability and could be photodegraded efficiently upon UV irradiation to produce terephthalaldehyde. The MCTP has provided a simple and robust synthetic approach for polydithiocarbamates, and the self-stratification has been suggested as a facile method for molecular weight control of step-growth polymerizations, which could accelerate the development of polymerization methodology and sulfur-containing polymer materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"85 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1021/acs.macromol.4c03028
Jianghui Li, Yingying Zhang, Yang Li, Chengjian Zhang, Xinghong Zhang
Developing chemically depolymerizable polymers (CDPs) that can revert back to monomers is of great significance for realizing a circular polymer economy. Poly(thiocarbonate)s, sulfur analogs of polycarbonates, are a rather under-investigated group of sulfur-enriched polymers with high potential as CDPs. Here, we report a recyclable poly(monothiocarbonate) obtained via organocatalytic ring-opening polymerization of a six-membered cyclic monothiocarbonate. The resulting polymer exhibited a melting point up to 127 °C and a Young’s modulus of 305 MPa with a tensile stress of 23.2 MPa at 8.8% strain, while the analogue polycarbonate derived from trimethylene carbonate is amorphous with a low modulus (<100 MPa) under ambient temperature. Moreover, a successful copolymerization of 1,3-oxathian-2-one and 5,5-dimethyl-1,3-oxathian-2-one provided an access to precise tunability of thermomechanical performance of the poly(monothiocarbonate)s.
{"title":"Organocatalytic Ring-Opening (Co)polymerization of Six-Membered Monothiocarbonates for the Synthesis of Recyclable Poly(monothiocarbonate)s","authors":"Jianghui Li, Yingying Zhang, Yang Li, Chengjian Zhang, Xinghong Zhang","doi":"10.1021/acs.macromol.4c03028","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03028","url":null,"abstract":"Developing chemically depolymerizable polymers (CDPs) that can revert back to monomers is of great significance for realizing a circular polymer economy. Poly(thiocarbonate)s, sulfur analogs of polycarbonates, are a rather under-investigated group of sulfur-enriched polymers with high potential as CDPs. Here, we report a recyclable poly(monothiocarbonate) obtained via organocatalytic ring-opening polymerization of a six-membered cyclic monothiocarbonate. The resulting polymer exhibited a melting point up to 127 °C and a Young’s modulus of 305 MPa with a tensile stress of 23.2 MPa at 8.8% strain, while the analogue polycarbonate derived from trimethylene carbonate is amorphous with a low modulus (<100 MPa) under ambient temperature. Moreover, a successful copolymerization of 1,3-oxathian-2-one and 5,5-dimethyl-1,3-oxathian-2-one provided an access to precise tunability of thermomechanical performance of the poly(monothiocarbonate)s.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"51 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1021/acs.macromol.4c02412
Lucas P. Kreuzer, Marie Betker, Marcell Wolf, Bart-Jan Niebuur, Jacques Ollivier, L. Daniel Söderberg, Stephan V. Roth
The water dynamics in a nanocomposite film that consists of the electrically conductive poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and cellulose nanofibrils (CNFs) have been investigated during three cycles of exposure to low and high relative humidity (RH = 5% and 85%, respectively) using quasi-elastic neutron scattering (QENS). The obtained dynamical structure factors are transformed into the imaginary part of the dynamic susceptibility to better differentiate between the individual relaxation processes. In a humid environment, two different water species are present inside the films: fast-moving bulk water and slow-moving hydration water. During the first cycle, a large amount of hydration water enhances the polymer chain mobility, eventually leading to irreversible structural rearrangements within the film. In the subsequent cycles, we observed a release of all bulk water and portions of hydration water upon drying, along with an uptake of both water species in a humid environment. The relaxation times of hydration water diffusion as a function of momentum transfer can be described by a jump-diffusion model. The obtained jump lengths, residence times, and diffusion coefficients of hydration water suggest a change in the hydration layer upon drying: water molecules around hydrophobic groups are released from the film, while the hydrogen bonds between water and hydrophilic groups are sufficiently strong to keep these molecules inside the films, even in a dry state. The QENS results can be correlated to the structural and conductive properties. In the dry state, the low hydration water content and the absence of bulk water allow for improved wetting of the CNFs by PEDOT:PSS, which eventually increases the electrical conductivity of the films.
{"title":"Impact of Humidity on Water Dynamics and Electrical Conductivity in PEDOT:PSS/Cellulose Nanofibril Nanocomposite Films: Insights from Quasi-Elastic Neutron Scattering","authors":"Lucas P. Kreuzer, Marie Betker, Marcell Wolf, Bart-Jan Niebuur, Jacques Ollivier, L. Daniel Söderberg, Stephan V. Roth","doi":"10.1021/acs.macromol.4c02412","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02412","url":null,"abstract":"The water dynamics in a nanocomposite film that consists of the electrically conductive poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and cellulose nanofibrils (CNFs) have been investigated during three cycles of exposure to low and high relative humidity (RH = 5% and 85%, respectively) using quasi-elastic neutron scattering (QENS). The obtained dynamical structure factors are transformed into the imaginary part of the dynamic susceptibility to better differentiate between the individual relaxation processes. In a humid environment, two different water species are present inside the films: fast-moving bulk water and slow-moving hydration water. During the first cycle, a large amount of hydration water enhances the polymer chain mobility, eventually leading to irreversible structural rearrangements within the film. In the subsequent cycles, we observed a release of all bulk water and portions of hydration water upon drying, along with an uptake of both water species in a humid environment. The relaxation times of hydration water diffusion as a function of momentum transfer can be described by a jump-diffusion model. The obtained jump lengths, residence times, and diffusion coefficients of hydration water suggest a change in the hydration layer upon drying: water molecules around hydrophobic groups are released from the film, while the hydrogen bonds between water and hydrophilic groups are sufficiently strong to keep these molecules inside the films, even in a dry state. The QENS results can be correlated to the structural and conductive properties. In the dry state, the low hydration water content and the absence of bulk water allow for improved wetting of the CNFs by PEDOT:PSS, which eventually increases the electrical conductivity of the films.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"35 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1021/acs.macromol.4c03067
Diego Ciardi, Ianis Retailleau, François Tournilhac
Precipitation of bivalent metal carboxylates is a well-known issue in detergency, resulting in decreased efficiency and unwanted accumulation of lime soap on laundry. We demonstrate that the same phenomenon occurs in formulations of metal-catalyzed epoxy-acid vitrimers. When, for instance, a Zn(II) salt and glutaric acid are allowed to be in contact with each other in the same reaction feedstock, precipitation takes place, resulting in phase separation of zinc glutarate and a glutarate-poor polymer network, showing no vitrimer properties. We present a strategy to overcome this issue based on step addition at a single end of the dicarboxylic acid monomer prior to contacting with zinc. In this case, formation of crystalline zinc soap is completely avoided, and the network shows thermostimulated stress relaxation. This strategy is particularly appealing for the synthesis of polyhydroxyester networks showing high-glass-transition temperature and fast relaxation.
{"title":"The Soap Opera of Metal Catalysis in Epoxy-Acid Vitrimers","authors":"Diego Ciardi, Ianis Retailleau, François Tournilhac","doi":"10.1021/acs.macromol.4c03067","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03067","url":null,"abstract":"Precipitation of bivalent metal carboxylates is a well-known issue in detergency, resulting in decreased efficiency and unwanted accumulation of lime soap on laundry. We demonstrate that the same phenomenon occurs in formulations of metal-catalyzed epoxy-acid vitrimers. When, for instance, a Zn(II) salt and glutaric acid are allowed to be in contact with each other in the same reaction feedstock, precipitation takes place, resulting in phase separation of zinc glutarate and a glutarate-poor polymer network, showing no vitrimer properties. We present a strategy to overcome this issue based on step addition at a single end of the dicarboxylic acid monomer prior to contacting with zinc. In this case, formation of crystalline zinc soap is completely avoided, and the network shows thermostimulated stress relaxation. This strategy is particularly appealing for the synthesis of polyhydroxyester networks showing high-glass-transition temperature and fast relaxation.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"13 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1021/acs.macromol.4c02582
Nicholas E. Jackson, Brett M. Savoie
The phrase “polymer theory” is typically associated with classical predictions of structural, thermodynamic, or mechanical properties in which chemical structure is treated nonspecifically. This is because historically, modeling chemically specific polymer phenomena or predicting their properties required prohibitively costly computational methods. However, recent methodological developments have made previously inaccessible polymer reactivity predictions now potentially addressable with a combination of data-driven and physics-based computational approaches. This perspective highlights ten such problems, showcases related previous successes, and speculates on what the near future holds as working solutions to polymer reactivity prediction become available.
{"title":"Ten Problems in Polymer Reactivity Prediction","authors":"Nicholas E. Jackson, Brett M. Savoie","doi":"10.1021/acs.macromol.4c02582","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02582","url":null,"abstract":"The phrase “polymer theory” is typically associated with classical predictions of structural, thermodynamic, or mechanical properties in which chemical structure is treated nonspecifically. This is because historically, modeling chemically specific polymer phenomena or predicting their properties required prohibitively costly computational methods. However, recent methodological developments have made previously inaccessible polymer reactivity predictions now potentially addressable with a combination of data-driven and physics-based computational approaches. This perspective highlights ten such problems, showcases related previous successes, and speculates on what the near future holds as working solutions to polymer reactivity prediction become available.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"15 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-16DOI: 10.1021/acs.macromol.4c03178
Ravi Teja Ananthu, Yingjun An, Yusaku Tajima, Hironori Taguchi, Takako Kikuchi, Tomohiro Kubo, Hiroyasu Masunaga, Sono Sasaki, Atsushi Takahara, Kotaro Satoh
Poly(butylene succinate) (PBS) is a promising biodegradable and sustainable thermoplastic, but its poor degradability in marine environments is a cause for concern. In this study, we aimed to mitigate this issue by developing novel PBS derivatives with labile acetal linkages periodically distributed along the polymer backbone. An efficient protection–deprotection synthesis yielded monodisperse dihydroxy oligo(butylene succinate)s (OBS) with precisely controlled molecular weights, which were consequently employed as the telechelic macromonomers to be polymerized with divinyl ethers in a step-growth fashion. The obtained poly(OBS-acetal)s had high-molecular-weight (Mn > 100,000 Da) and showed PBS-like semicrystalline properties due to the presence of well-defined crystallizable OBS segments joined together by labile spacers. Selective cleavage of the backbone acetal linkages under acidic conditions enabled rapid depolymerization into simpler oligomers with better degradability. Therefore, this general strategy could be utilized to improve the degradability of the polymers while retaining their physical properties.
{"title":"Polyaddition of Discrete Oligo(butylene succinate)s with Divinyl Ethers for Periodic and Selectively Cleavable Main-Chain Acetal Linkages","authors":"Ravi Teja Ananthu, Yingjun An, Yusaku Tajima, Hironori Taguchi, Takako Kikuchi, Tomohiro Kubo, Hiroyasu Masunaga, Sono Sasaki, Atsushi Takahara, Kotaro Satoh","doi":"10.1021/acs.macromol.4c03178","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03178","url":null,"abstract":"Poly(butylene succinate) (PBS) is a promising biodegradable and sustainable thermoplastic, but its poor degradability in marine environments is a cause for concern. In this study, we aimed to mitigate this issue by developing novel PBS derivatives with labile acetal linkages periodically distributed along the polymer backbone. An efficient protection–deprotection synthesis yielded monodisperse dihydroxy oligo(butylene succinate)s (OBS) with precisely controlled molecular weights, which were consequently employed as the telechelic macromonomers to be polymerized with divinyl ethers in a step-growth fashion. The obtained poly(OBS-acetal)s had high-molecular-weight (<i>M</i><sub>n</sub> > 100,000 Da) and showed PBS-like semicrystalline properties due to the presence of well-defined crystallizable OBS segments joined together by labile spacers. Selective cleavage of the backbone acetal linkages under acidic conditions enabled rapid depolymerization into simpler oligomers with better degradability. Therefore, this general strategy could be utilized to improve the degradability of the polymers while retaining their physical properties.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"13 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1021/acs.macromol.4c03108
Johannes Reeb, Yibo Shen, Patrick Theato, Yosuke Akae
A new photodegradable AB-type monomer (3-nitro,4-hydroxylmethyl benzoylazide) was developed for the synthesis of polyurethanes featuring a photodegradability, which could be finely controlled through copolymerization. Because of the o-nitrobenzyl alcohol framework on the monomer, the resulting polymer was decomposed by UV irradiation at 365 nm. Moreover, since the introduction of a nitro group on the AB-type monomer framework reduced the reactivity of the alcohol group and increased that of the isocyanate group, copolymerization with other monomers induced a certain preference of diad patterns, which would affect the photodegradability of polyurethanes. The results suggested the AB-type monomer protocol enables the synthesis of more precisely designed polyurethane structures than the conventional synthesis, i.e., by a polyaddition between diol and di-isocyanate.
研究人员开发了一种新型光降解 AB 型单体（3-硝基、4-羟甲基苯甲酰肼），用于合成具有光降解性的聚氨酯，这种光降解性可以通过共聚来精细控制。由于单体上存在邻硝基苄醇框架，因此在 365 纳米波长的紫外线照射下，生成的聚合物会被分解。此外，由于在 AB 型单体框架上引入了硝基，降低了醇基的反应活性，提高了异氰酸酯基的反应活性，因此与其他单体共聚会诱发某种偏好的二元结构，从而影响聚氨酯的光降解性。研究结果表明，与传统的合成方法（即二元醇和二异氰酸酯之间的加成反应）相比，AB 型单体方案能够合成设计更精确的聚氨酯结构。
{"title":"Controllable Photo-degradability on Polyurethane from AB-Type Monomers","authors":"Johannes Reeb, Yibo Shen, Patrick Theato, Yosuke Akae","doi":"10.1021/acs.macromol.4c03108","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03108","url":null,"abstract":"A new photodegradable AB-type monomer (3-nitro,4-hydroxylmethyl benzoylazide) was developed for the synthesis of polyurethanes featuring a photodegradability, which could be finely controlled through copolymerization. Because of the <i>o</i>-nitrobenzyl alcohol framework on the monomer, the resulting polymer was decomposed by UV irradiation at 365 nm. Moreover, since the introduction of a nitro group on the AB-type monomer framework reduced the reactivity of the alcohol group and increased that of the isocyanate group, copolymerization with other monomers induced a certain preference of diad patterns, which would affect the photodegradability of polyurethanes. The results suggested the AB-type monomer protocol enables the synthesis of more precisely designed polyurethane structures than the conventional synthesis, i.e., by a polyaddition between diol and di-isocyanate.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"29 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1021/acs.macromol.4c02523
Annelore Podevyn, Joachim F. R. Van Guyse, Petra J. M. Bouten, Jan C. M. van Hest, Richard Hoogenboom
Poly(2-alkyl-2-oxazoline)s (PAOx) featuring methyl ester side chains have received increasing interest in recent years, as they readily undergo various post-polymerization modification reactions, such as amidation, thereby enabling straightforward structural diversification from a single reactive precursor. Furthermore, ester functional PAOx can be generated with various spacer lengths between the ester functional group and the polymer backbone, allowing straightforward tuning of the solution and thermal properties. In this work, we subjected different methyl ester-bearing PAOx to full amidation reactions with various primary and secondary amines to establish the structure–reactivity and structure–property relationships. Kinetic investigations of the 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-catalyzed amidation reactions revealed that the reactivity correlates with the nucleophilicity of the amines and inversely correlates with the spacer length between the polymer backbone and the ester functionality (PC2MestOx > PC3MestOx > PC4MestOx). These results highlight the importance of macromolecular parameters in the TBD-catalyzed amidation of polymers with pendant ester groups involving intramolecular activation. Finally, we explored the thermal solution and bulk properties of a 30-membered library of amidated polymer products to derive structure–property relationships, which can serve as guidelines for the design and synthesis of functional PAOx (bio)materials.
{"title":"Unraveling Structure–Reactivity and Structure–Property Relationships for the Amidation of Methyl Ester-Functionalized Poly(2-Oxazoline)s","authors":"Annelore Podevyn, Joachim F. R. Van Guyse, Petra J. M. Bouten, Jan C. M. van Hest, Richard Hoogenboom","doi":"10.1021/acs.macromol.4c02523","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02523","url":null,"abstract":"Poly(2-alkyl-2-oxazoline)s (PAOx) featuring methyl ester side chains have received increasing interest in recent years, as they readily undergo various post-polymerization modification reactions, such as amidation, thereby enabling straightforward structural diversification from a single reactive precursor. Furthermore, ester functional PAOx can be generated with various spacer lengths between the ester functional group and the polymer backbone, allowing straightforward tuning of the solution and thermal properties. In this work, we subjected different methyl ester-bearing PAOx to full amidation reactions with various primary and secondary amines to establish the structure–reactivity and structure–property relationships. Kinetic investigations of the 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-catalyzed amidation reactions revealed that the reactivity correlates with the nucleophilicity of the amines and inversely correlates with the spacer length between the polymer backbone and the ester functionality (PC<sub>2</sub>MestOx > PC<sub>3</sub>MestOx > PC<sub>4</sub>MestOx). These results highlight the importance of macromolecular parameters in the TBD-catalyzed amidation of polymers with pendant ester groups involving intramolecular activation. Finally, we explored the thermal solution and bulk properties of a 30-membered library of amidated polymer products to derive structure–property relationships, which can serve as guidelines for the design and synthesis of functional PAOx (bio)materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"21 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-14DOI: 10.1021/acs.macromol.5c00039
Xiaomeng Li, Amir Suhail, Nagarjuna A. Mahadas, Mengxue Zhang, Zhitao Hu, Morgan Stefik, Olga Kuksenok, Chuanbing Tang
Polyethylene (PE) is one of the most important and widely used commodity polymers in the world. It is also among the vital and notoriously nondegradable plastics. Recent efforts are revisiting different approaches to create new generations of PE mimics. We report a model system to explore mimics of functionalized high-density polyethylene (HDPE) and low-density polyethylene (LDPE) via ring-opening metathesis polymerization (ROMP) and thiol–ene click chemistry. By combining experimental and computational studies, we demonstrated that the properties of PE mimics are highly tunable by changing the ester-to-methylene ratio (E:M), with low E:M (e.g., 1:413) functional polymers having characteristics similar to those of HDPE. Controlling the branch-to-methylene ratio (B:M) from 1:159 to 1:22 provided a handle for mimicking the transformation from HDPE to LDPE characteristics. The PE mimics exhibit competitive mechanical properties, melting temperature, and high molecular weight comparable to PE while being accessible via an efficient synthetic route. Notably, the PE mimics can be degraded into oligomers and then recycled, demonstrating the potential for circularity and sustainability. This study provides valuable insights into predicting the properties of aliphatic long-chain functional polymers to mimic PE.
{"title":"Modulating Polyethylene Mimics with Degradability via Synthesis and Modeling","authors":"Xiaomeng Li, Amir Suhail, Nagarjuna A. Mahadas, Mengxue Zhang, Zhitao Hu, Morgan Stefik, Olga Kuksenok, Chuanbing Tang","doi":"10.1021/acs.macromol.5c00039","DOIUrl":"https://doi.org/10.1021/acs.macromol.5c00039","url":null,"abstract":"Polyethylene (PE) is one of the most important and widely used commodity polymers in the world. It is also among the vital and notoriously nondegradable plastics. Recent efforts are revisiting different approaches to create new generations of PE mimics. We report a model system to explore mimics of functionalized high-density polyethylene (HDPE) and low-density polyethylene (LDPE) via ring-opening metathesis polymerization (ROMP) and thiol–ene click chemistry. By combining experimental and computational studies, we demonstrated that the properties of PE mimics are highly tunable by changing the ester-to-methylene ratio (E:M), with low E:M (e.g., 1:413) functional polymers having characteristics similar to those of HDPE. Controlling the branch-to-methylene ratio (B:M) from 1:159 to 1:22 provided a handle for mimicking the transformation from HDPE to LDPE characteristics. The PE mimics exhibit competitive mechanical properties, melting temperature, and high molecular weight comparable to PE while being accessible via an efficient synthetic route. Notably, the PE mimics can be degraded into oligomers and then recycled, demonstrating the potential for circularity and sustainability. This study provides valuable insights into predicting the properties of aliphatic long-chain functional polymers to mimic PE.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"38 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1021/acs.macromol.4c02063
Nattavipa Chongvimansin, Thomas C. O’Connor
Molecular dynamics simulations are used to study the mechanical degradation of well-entangled polymer melts during uniaxial extensional flow. Simulations measure the transient rise in extensional stresses and relate them to the molecular alignment and scission of chain backbones. Intermolecular entanglements couple chain scission in space and time, making degradation sensitive to deformation history and strain rate in ways not displayed by dilute polymer solutions. The rate of chain scission is nonmonotonic and peaks at strains corresponding to the maximum extensibility of entanglement segments but prior to the full extension of chain backbones. We measure a specific work per scission event w* and decompose it into separate contributions associated with chain alignment, chemical bond breaking, and scission-induced plasticity. We find chain scission in melts requires activating plastic dissipation that is multiple orders of magnitude larger than the chemical work required to break a covalent backbone bond. Our findings underscore the critical need to consider bulk polymer mechanics and rheology in designing efficient mechanical degradation and mechanochemical processes.
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