Macromolecules最新文献_第10页

Modulating Polyethylene Mimics with Degradability via Synthesis and Modeling

IF 5.5 1区化学

Macromolecules Pub Date : 2025-02-14 DOI: 10.1021/acs.macromol.5c00039

Xiaomeng Li, Amir Suhail, Nagarjuna A. Mahadas, Mengxue Zhang, Zhitao Hu, Morgan Stefik, Olga Kuksenok, Chuanbing Tang

{"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}

引用次数: 0

The Work of Mechanical Degradation in Elongating Polymer Melts

IF 5.1 1区化学

Macromolecules Pub Date : 2025-02-13 DOI: 10.1021/acs.macromol.4c0206310.1021/acs.macromol.4c02063

Nattavipa Chongvimansin, and , Thomas C. O’Connor*,

{"title":"The Work of Mechanical Degradation in Elongating Polymer Melts","authors":"Nattavipa Chongvimansin,  and , Thomas C. O’Connor*, ","doi":"10.1021/acs.macromol.4c0206310.1021/acs.macromol.4c02063","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02063https://doi.org/10.1021/acs.macromol.4c02063","url":null,"abstract":"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.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 4","pages":"1787–1794 1787–1794"},"PeriodicalIF":5.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.macromol.4c02063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Work of Mechanical Degradation in Elongating Polymer Melts

IF 5.5 1区化学

Macromolecules Pub Date : 2025-02-13 DOI: 10.1021/acs.macromol.4c02063

Nattavipa Chongvimansin, Thomas C. O’Connor

{"title":"The Work of Mechanical Degradation in Elongating Polymer Melts","authors":"Nattavipa Chongvimansin, Thomas C. O’Connor","doi":"10.1021/acs.macromol.4c02063","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02063","url":null,"abstract":"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.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"13 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417994","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}

引用次数: 0

Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations

IF 5.5 1区化学

Macromolecules Pub Date : 2025-02-13 DOI: 10.1021/acs.macromol.4c02181

Joonhyeok Park, Ruth M. Muthoka, Yongjin Lee

{"title":"Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations","authors":"Joonhyeok Park, Ruth M. Muthoka, Yongjin Lee","doi":"10.1021/acs.macromol.4c02181","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02181","url":null,"abstract":"We perform a systematic computational study for designing high-temperature resistant Oligo-polyimides (Oligo-PIs). Their properties can be significantly enhanced by substituting the diamine component. Oligo-PI Type A– end-capped with 4-Phenylethynyl anhydride (4-PEPA) groups and comprising of 11 repeat units of 1,3-Bis(4-aminophenoxy)benzene (TPE-R) and 10 repeat units of 3,4′-Biphthalic Anhydride (a-BPDA)) was chosen for modification. We selected 4-PEPA and a-BPDA due to their efficacy in forming thermally stable Oligo-PIs. Here, we developed a molecular modification approach to substitute the Oligo-PI Type A TPE-R segment with various commercially available polyimide (PI) monomers. This method, integrated with high-fidelity molecular dynamics simulations, allowed us to quantitatively predict the glass transition temperature (Tg) and identify 27 Oligo-PI candidates demonstrating structural integrity above 823 K, the conventional turbine inlet gas temperature. Posteriori structural analysis revealed important structural attributes such as side group, symmetry and configuration, chain–chain interactions, and molecular symmetry, which are crucial to their high Tg. This strategy demonstrates a promising method for the tailored design of high-temperature resistant materials, paving the way for advancements in gas turbine materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"63 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401348","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}

引用次数: 0

Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations

IF 5.1 1区化学

Macromolecules Pub Date : 2025-02-13 DOI: 10.1021/acs.macromol.4c0218110.1021/acs.macromol.4c02181

Joonhyeok Park, Ruth M. Muthoka and Yongjin Lee*,

{"title":"Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations","authors":"Joonhyeok Park, Ruth M. Muthoka and Yongjin Lee*, ","doi":"10.1021/acs.macromol.4c0218110.1021/acs.macromol.4c02181","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02181https://doi.org/10.1021/acs.macromol.4c02181","url":null,"abstract":"We perform a systematic computational study for designing high-temperature resistant Oligo-polyimides (Oligo-PIs). Their properties can be significantly enhanced by substituting the diamine component. Oligo-PI Type A– end-capped with 4-Phenylethynyl anhydride (4-PEPA) groups and comprising of 11 repeat units of 1,3-Bis(4-aminophenoxy)benzene (TPE-R) and 10 repeat units of 3,4′-Biphthalic Anhydride (a-BPDA)) was chosen for modification. We selected 4-PEPA and a-BPDA due to their efficacy in forming thermally stable Oligo-PIs. Here, we developed a molecular modification approach to substitute the Oligo-PI Type A TPE-R segment with various commercially available polyimide (PI) monomers. This method, integrated with high-fidelity molecular dynamics simulations, allowed us to quantitatively predict the glass transition temperature (Tg) and identify 27 Oligo-PI candidates demonstrating structural integrity above 823 K, the conventional turbine inlet gas temperature. Posteriori structural analysis revealed important structural attributes such as side group, symmetry and configuration, chain–chain interactions, and molecular symmetry, which are crucial to their high Tg. This strategy demonstrates a promising method for the tailored design of high-temperature resistant materials, paving the way for advancements in gas turbine materials.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 4","pages":"2145–2156 2145–2156"},"PeriodicalIF":5.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478042","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}

引用次数: 0

Hexagonal and Orthorhombic Crystal Formations in Ethylene Glycol-Based Long-Spaced Aliphatic Polyesters Driven by Layer Packing of Proximate Ester Groups

IF 5.1 1区化学

Macromolecules Pub Date : 2025-02-12 DOI: 10.1021/acs.macromol.4c0295610.1021/acs.macromol.4c02956

Mengru Ding, Lingling Ni, Ying Zheng, Bao Wang, Chengtao Yu, Guorong Shan, Yongzhong Bao, Junfeng Liu* and Pengju Pan*,

{"title":"Hexagonal and Orthorhombic Crystal Formations in Ethylene Glycol-Based Long-Spaced Aliphatic Polyesters Driven by Layer Packing of Proximate Ester Groups","authors":"Mengru Ding, Lingling Ni, Ying Zheng, Bao Wang, Chengtao Yu, Guorong Shan, Yongzhong Bao, Junfeng Liu* and Pengju Pan*, ","doi":"10.1021/acs.macromol.4c0295610.1021/acs.macromol.4c02956","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c02956https://doi.org/10.1021/acs.macromol.4c02956","url":null,"abstract":"Long-spaced aliphatic polyesters are typical sustainable polyethylene (PE)-like polymers. However, the presence of a low amount of ester groups can exert a profound effect on the crystalline structure of such PE-like polymers. Herein, we synthesized a series of long-spaced aliphatic polyesters bearing two proximate ester groups from ethylene glycol (EG) and n-methylene diacids (n = 9–18) and investigated their polymorphic crystallization and phase transitions. We find that the EG-based polyesters exhibit unique crystal polymorphism and phase transition behaviors. They can form a metastable hexagonal phase (form II) with nontilted, extended chain conformations at low temperatures or during rapid cooling but adopt the thermally stable orthorhombic phase (form I) with tilted chain packing at high temperatures or under slow cooling. Form I demonstrates a more densely packed chain structure and displays distinct mechanical properties compared to form II. The metastable hexagonal phase can transform into an orthorhombic phase during heating through a melt-recrystallization mechanism. This study advances the current understanding of the multiphase crystallization of PE-like long-spaced polyesters.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 4","pages":"2005–2013 2005–2013"},"PeriodicalIF":5.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478281","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}

引用次数: 0

Synergizing Visible Light-Mediated Cationic and Radical PET RAFT Through Electron-Rich Dithiobenzoates

IF 5.1 1区化学

Macromolecules Pub Date : 2025-02-12 DOI: 10.1021/acs.macromol.4c0306010.1021/acs.macromol.4c03060

Martin Orságh*, and , Ondrej Sedlacek*,

{"title":"Synergizing Visible Light-Mediated Cationic and Radical PET RAFT Through Electron-Rich Dithiobenzoates","authors":"Martin Orságh*,  and , Ondrej Sedlacek*, ","doi":"10.1021/acs.macromol.4c0306010.1021/acs.macromol.4c03060","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03060https://doi.org/10.1021/acs.macromol.4c03060","url":null,"abstract":"In this work, we developed a novel electron-rich dithiobenzoate chain transfer agent (CTA) with excellent control for both cationic and radical photoelectron/energy transfer-reversible addition–fragmentation chain transfer (PET RAFT) polymerizations. The 2,4-dimethoxydithiobenzoate-based CTA enables the optimized stabilization of chain transfer intermediates, outperforming trithiocarbonates in the control of cationic RAFT polymerizations and dithiocarbamates in radical RAFT polymerizations of more active monomers. The excellent control of cationic PET RAFT polymerization offered by this novel CTA was demonstrated by the blue-light-mediated synthesis of poly(isobutyl vinyl ether) of various chain lengths with sub-1.2 dispersities. Furthermore, to highlight its benefit over previously reported dithiocarbamate and trithiocarbonate CTAs, this new CTA was employed for the one-pot synthesis of poly(isobutyl vinyl ether)-block-poly(methyl acrylate) diblock copolymers. The prepared CTA-terminated poly(isobutyl vinyl ether) was chain-extended by methyl acrylate via red-light-mediated radical RAFT polymerization, which afforded a diblock copolymer with a dispersity of 1.26, which significantly surpassed the dispersities achieved with analogous trithiocarbonates. The radical polymerization step uses a zinc tetraphenylporphyrin photocatalyst to achieve complete wavelength orthogonality, with a tris(4-methoxyphenyl)pyrylium photocatalyst used for the cationic polymerization step. The optimized electron-rich dithiobenzoate can then be used as a universal agent in the synthesis of advanced copolymers involving radical-cationic RAFT crossover polymerization steps.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"58 4","pages":"2085–2093 2085–2093"},"PeriodicalIF":5.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.macromol.4c03060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

pH-Responsive Shape-Changing Molecular Bottlebrush Emulsifier

IF 5.5 1区化学

Macromolecules Pub Date : 2025-02-12 DOI: 10.1021/acs.macromol.4c03034

Bin Zhao, Michael T. Kelly, Sachini H. Dayarathne, Shichen Yu, Kingsley O. Ojima, Christopher Y. Li

{"title":"pH-Responsive Shape-Changing Molecular Bottlebrush Emulsifier","authors":"Bin Zhao, Michael T. Kelly, Sachini H. Dayarathne, Shichen Yu, Kingsley O. Ojima, Christopher Y. Li","doi":"10.1021/acs.macromol.4c03034","DOIUrl":"https://doi.org/10.1021/acs.macromol.4c03034","url":null,"abstract":"By utilizing the large size and the tunable amphiphilicity of shape-changing molecular bottlebrushes (MBBs), we show that MBBs with heterografted poly(ethylene oxide) (PEO) and poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEAEMA) side chains (MBB-OE) are an efficient and pH-responsive emulsifier, producing highly stable emulsions that can be disrupted by external stimuli. MBB-OE was wormlike in acidic solution and collapsed into a globular shape with increasing pH due to the insolubility of PDEAEMA in basic water. Upon vortexing, water-in-oil (w/o) emulsions were formed from the mixtures of toluene and a pH 9.5 buffer with mass ratios ≥0.8:1.0, even using only 0.0068% MBB-OE. Vortexing caused the globular brushes to unfold and adsorb at the interface, reconfiguring into a Janus wormlike structure with PEO and PDEAEMA extending into the aqueous and toluene phase, respectively. This is supported by the observations of the partitioning of PEO and PDEAEMA between the two phases and the interfacial wrinkling of emulsion droplets during solvent evaporation. The emulsions were readily disrupted by changing the pH to 4.0 and reformed by vortexing after increasing the pH to 9.5; the emulsion formation and breaking can be repeated multiple times. Interestingly, oil-in-water (o/w) emulsions were formed at the toluene-to-water mass ratio ≤0.6:1.0 and remained stable after the pH was changed to 4.0 by HCl, likely because H+ was unable to cross the interface. However, bubbling with CO2 disrupted the emulsions. This work demonstrates the potential of shape-changing MBBs as stimuli-responsive emulsifiers, opening up opportunities for designing advanced emulsifiers by leveraging the large size, unique characteristics, and responsiveness of MBBs.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"29 1","pages":""},"PeriodicalIF":5.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393539","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}

引用次数: 0

Polymers for Fiber Batteries

IF 5.1 1区化学

Macromolecules Pub Date : 2025-02-12 DOI: 10.1021/acs.macromol.4c0173810.1021/acs.macromol.4c01738

Chuanfa Li, Kun Zhang, Jiaxin Li, Qian Ye, Kailin Zhang, Bingjie Wang and Huisheng Peng*,

引用次数: 0

Polymers for Fiber Batteries

IF 5.5 1区化学

Macromolecules Pub Date : 2025-02-12 DOI: 10.1021/acs.macromol.4c01738

Chuanfa Li, Kun Zhang, Jiaxin Li, Qian Ye, Kailin Zhang, Bingjie Wang, Huisheng Peng

引用次数: 0