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Liu Y, Harth E. Distorted Sandwich α‐Diimine Pd
II
Catalyst: Linear Polyethylene and Synthesis of Ethylene/Acrylate Elastomers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yu‐Sheng Liu
- Center of Excellence in Polymer Chemistry Department of Chemistry University of Houston 3585 Cullen Blvd Houston TX 77204 USA
| | - Eva Harth
- Center of Excellence in Polymer Chemistry Department of Chemistry University of Houston 3585 Cullen Blvd Houston TX 77204 USA
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Liquid-Crystal Ordering and Microphase Separation in the Lamellar Phase of Rod-Coil-Rod Triblock Copolymers. Molecular Theory and Computer Simulations. Polymers (Basel) 2021; 13:polym13193392. [PMID: 34641206 PMCID: PMC8512297 DOI: 10.3390/polym13193392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 12/28/2022] Open
Abstract
A molecular model of the orientationally ordered lamellar phase exhibited by asymmetric rod-coil-rod triblock copolymers has been developed using the density-functional approach and generalizing the molecular-statistical theory of rod-coil diblock copolymers. An approximate expression for the free energy of the lamellar phase has been obtained in terms of the direct correlation functions of the system, the Flory-Huggins parameter and the Maier-Saupe orientational interaction potential between rods. A detailed derivation of several rod-rod and rod-coil density-density correlation functions required to evaluate the free energy is presented. The orientational and translational order parameters of rod and coil segments depending on the temperature and triblock asymmetry have been calculated numerically by direct minimization of the free energy. Different structure and ordering of the lamellar phase at high and low values of the triblock asymmetry is revealed and analyzed in detail. Asymmetric rod-coil-rod triblock copolymers have been simulated using the method of dissipative particle dynamics in the broad range of the Flory-Huggins parameter and for several values of the triblock asymmetry. It has been found that the lamellar phase appears to be the most stable one at strong segregation. The density distribution of the coil segments and the segments of the two different rods have been determined for different values of the segregation strength. The simulations confirm the existence of a weakly ordered lamellar phase predicted by the density-functional theory, in which the short rods separate from the long ones and are characterized by weak positional ordering.
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Harth E, Liu YS. Distorted Sandwich a-Diimine Pd(II) Catalyst: Linear Polyethylene and Synthesis of Ethylene/Acrylate Elastomers. Angew Chem Int Ed Engl 2021; 60:24107-24115. [PMID: 34403566 DOI: 10.1002/anie.202107039] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/29/2021] [Indexed: 11/09/2022]
Abstract
The introduction of m-xylyl substituents to α-diimine Pd(II) catalyst promotes living ethylene polymerization at room temperature and low pressure to yield high molecular weight polyethylene (PE) with low branching (<17/1000C). m-Xylyl groups provide a highly effective blockage to the axial sites of the catalytic center and form a distorted sandwich geometry. The shielding prevents chain-transfer and easy accessibility of polar monomers, leading to a living polymerization. Conducting a light irradiation as part of the one-step metal-organic insertion light initiated radical (MILRad) process leads to diblock copolymers of ethylene and acrylates. Incorporation of different acrylate block sequences can significantly modify the mechanical and chemical properties of block copolymers which can be modulated to be a hard plastic, elastomer, or semi-amorphous polymer.
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Affiliation(s)
- Eva Harth
- University of Houston, Chemistry, 406 STL Building, United States, 77004, Houston, UNITED STATES
| | - Yu-Sheng Liu
- University of Houston System, Chemistry, UNITED STATES
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Nam C, Lee WB, Kim Y. Self-assembly of rod-coil diblock copolymer-nanoparticle composites in thin films: dissipative particle dynamics. SOFT MATTER 2021; 17:2384-2391. [PMID: 33480958 DOI: 10.1039/d0sm02149k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, the assembled structures of rod-coil diblock copolymer and nanoparticle blends were studied via dissipative particle dynamics (DPD). Thin films were composed of soft confinement DPD fluid beads and the fluctuating film structure was maintained during the simulation process. Analysis of the position of nanoparticles was done in the smectic lamellar phase of the rod-coil polymer matrix, and density distributions of rods, coils, and nanoparticles were obtained as functions of the size of the nanoparticle and the DPD repulsion constant between the rod and the nanoparticle. The distribution of nanoparticles was explained by using the concept of translational entropy of nanoparticles, stretching energy of the polymer chain, relative repulsion enthalpy of nanoparticles to rods or coils, and the effect of the liquid crystalline rod.
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Affiliation(s)
- Chongyong Nam
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
| | - YongJoo Kim
- School of Advanced Materials Engineering, Kookmin University, 77 Jeongneung-ro, Seongbuk-gu, Seoul, 02707, Republic of Korea.
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Melting temperature versus crystallinity: new way for identification and analysis of multiple endotherms of poly(ethylene terephthalate). JOURNAL OF POLYMER RESEARCH 2020. [DOI: 10.1007/s10965-020-02327-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AbstractPoly(ethylene terephthalate) (PET) materials with different molecular weights were isothermally crystallized from melt by systematically varying the temperature and duration of the treatment performed in the differential scanning calorimeter (DSC). Multiple endotherm peaks were observed on the subsequent heating thermograms that were separated from each other on the basis of their melting temperature versus crystallization temperature and melting temperature versus crystallinity function. By this new approach five sub-peak sets were identified and then comprehensively characterised. Wide-Angle X-Ray Diffraction (WAXD) analyses revealed that the identified sub-peak sets do not differ in crystalline forms. By analysing the crystallinity and the melting temperature of the sub-peak sets as a function of crystallization time, crystallization temperature and intrinsic viscosity, it was concluded that below the crystallization temperature of 460 K the sub-peak sets that were formed during primary or secondary crystallization transform partially or completely to a third sub-peak set during the heating run of the measurement, while above this temperature, the sub-peak set formed during primary crystallization gradually transforms to a more stable structure, with higher melting temperature. These formations and transformations are described with mathematically defined parameters as well.
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Li Q, Zhu YL, Zhang X, Xu K, Wang J, Li Z, Bao Y. Self-Assembly of Single-Polymer-Tethered Nanoparticle Amphiphiles upon Varying Tail Length. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:nano10112108. [PMID: 33114093 PMCID: PMC7690793 DOI: 10.3390/nano10112108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
We systematically investigated the roles of tail length on the self-assembly of shape amphiphiles composed of a hydrophobic polymer chain (tail) and a hydrophilic nanoparticle in selective solvent using Brownian dynamics simulations. The shape amphiphiles exhibited a variety of self-assembled aggregate morphologies which can be tuned by changing tail length (n) in combination with amphiphile concentration (φ) and system temperature (T*). Specifically, at high φ with T*=1.4, the morphology varied following the sequence "spheres → cylinders → vesicles" upon increasing n, agreeing well with experimental observations. At low φ with T*=1.4 or at high φ with T*=1.2, the morphology sequence becomes "spheres or spheres and cylinders mixture → cylinders → vesicles → spheres" upon increasing n, which has not been found experimentally. Two morphological phase diagrams depending on n and φ were constructed for T*=1.4 and 1.2, respectively. The rich phase behaviors on varying tail length could provide the feasible routes to fabricate target aggregate morphologies in various applications, especially for the vesicles with tunable thickness of membranes that are crucial in drug and gene delivery.
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Affiliation(s)
- Qingxiao Li
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
| | - You-Liang Zhu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Xinhui Zhang
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
| | - Kaidong Xu
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
| | - Jina Wang
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
| | - Zhixin Li
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
| | - Yun Bao
- School of Material and Chemical Engineering, Henan University of Urban Construction, Pingdingshan 467036, China; (X.Z.); (K.X.); (J.W.); (Z.L.); (Y.B.)
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Comparing the sorption kinetics of poly-tetrafluoroethylene processed either by extrusion or spark plasma sintering. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fodor JS, DesLauriers PJ, Lamborn MJ, Hamim SU. Further investigation of the relationship between polymer structure and HDPE post yield properties. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lv Y, Wang L, Wu F, Gong S, Wei J, Lin S. Self-assembly and stimuli-responsive behaviours of side-chain liquid crystalline copolymers: a dissipative particle dynamics simulation approach. Phys Chem Chem Phys 2019; 21:7645-7653. [DOI: 10.1039/c9cp00400a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Side-chain liquid crystalline copolymers are able to self-assemble into various aggregates in selective solvents, in particular, deformed structures.
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Affiliation(s)
- Yisheng Lv
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
| | - Fangsheng Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
| | - Shuting Gong
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
| | - Jie Wei
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials
- State Key Laboratory of Bioreactor Engineering
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
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Liu F, Tang P, Zhang H, Yang Y. Archimedean Tiling Patterns Self-Assembled from X-Shaped Rod–Coil Copolymers with Hydrogen Bonds. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Faqiang Liu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Ping Tang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Hongdong Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yuliang Yang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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