Journal of Physical Chemistry C
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2025
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IF 3.2
Panpan Yang,Yifei Wu,Kunxin Wang,Xiaole Zheng,Junxi Wan,Kun Wu,Jun Shi,Peiwei Hong,Li Yang
Polymers with high thermal conductivity are crucial for addressing the heat dissipation challenges associated with high-performance compact electronic devices. In this work, a series of high thermal conductivity polyesters (PEnx) were synthesized. Their molecular structure is regulated by introducing flexible chains with segments containing n methylene units between 2 and 8. The thermal diffusivity and thermal conductivity of a series of polyesters were studied in relation to their structure. As a result, the thermal diffusivity of polyesters rose from 0.173 to 0.334 mm2 s–1. PEn6 exhibits a thermal conductivity of 0.578 ± 0.0021 W/(m·K), which is 180% higher than PEn2 and three times higher than conventional thermoplastics. The enhanced thermal conductivity can be attributed to the regular molecular structure, which augments heat transfer by mitigating phonon scattering. Thus, it is possible to enhance both the heat absorption and thermal conductivity of the polymer by adjusting the number of methylene groups in the polyester. Meanwhile, the main diffraction peaks of all of the polyesters were around 20°, indicating their semicrystalline nature. Furthermore, PEn6 has excellent thermal stability with a T5% of 396.2 °C, Tmax of 431.1 °C, and residual carbon content of 6.47% at 800 °C.
研究领域:
材料科学
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热物理学
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DOI
高影响因子
IRANIAN POLYMER JOURNAL
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2023
·Vol. 33
·期 1
·93-103
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IF 3.1
Wan Liying,Yan Meiling,Wang Jianhong,Liu Xianglong,Huang Juntong,Yang Hao,Kong Xinming
This study reports the innovative preparation of triple-shape-memory epoxy resin (EP-DA) through thermal programming. Flexible poly(propylene glycol) diglycidyl ether (PEGDE) segments and reversible Diels–Alder (DA) dynamic covalent bonds were introduced into epoxy resin through molecular structural design, controlling glass transition temperature ( T g ) and DA reaction temperature, respectively, which then was used as the two reversible switches of EP-DA. FTIR results verified that PEGDE and DA bond were successfully brought in EP-DA network. DSC and TG tests were used to demonstrate the three stages of EP-DA thermal behavior: T g , DA thermal reversible reaction temperature and thermal degradation temperature. Bending-recovery test verified the dual-shape-memory, and DMA test verified the excellent triple-shape-memory of EP-DA. The general elastic deformation, high elastic deformation and flow deformation of EP-DA molecular segments revealed its shape-memory mechanism. Furthermore, when PEGDE content increased, T g , crosslinking density of EP-DA, fixity ratio and strength decreased, toughness increased, and recovery rate as well as recovery speed were promoted. The thermal reversibility of DA bonds in EP-DA also endues it with retrievability and self-reconstruction. Graphical abstract
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
ACS Applied Polymer Materials
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2024
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IF 4.4
Yiyuan Sun,Zenghui Yang,Liming Tao,Qihua Wang,Xinrui Zhang,Yaoming Zhang,Tingmei Wang
It remains a challenge to balance the trade-off between toughness, stiffness, and shape memory properties in shape memory epoxy resins (SMEP). In this study, we employed molecular engineering to synthesize stiff–flexible SMEP, by reacting furan-containing epoxy monomers 2,5-bis[(2-epoxymethoxy)methyl]furan (BOF), derived from biomass, with amines containing imine-amine (IA) and 4,4′-dithiodiphenylamine (4-DTDA). The results indicate that the sacrificial hydrogen bonding and the necessary flexible segments confer BOF/4-DTDA/IA (BDI) with a toughness of up to 13.9 MJ/m3 and a stiffness of 3.5 GPa. Furthermore, the introduction of hyperbranched epoxy resin (HER) yields BOF/4-DTDA/IA/HER (BDIH), which maintains a stiffness exceeding 2 GPa while retaining a toughness of 11.2 MJ/m3. Additionally, BDIH exhibits enhanced tensile strength with an increasing strain rate, which we rationalize based on the loss modulus and scanning electron microscopy morphology analyses. The collaborative motion of the rigid–flexible chain segments and the hydrogen bonding contributes to BDI’s excellent shape memory performance (shape fixation ratio (Rf = 99.00%) and shape recovery ratio (Rr = 99.15%). The physical barrier effect and flexibility of the HER further enhance the shape memory properties. In conclusion, the mechanical features and shape memory performance of BDI and BDIH demonstrate the significant potential for applications in smart molds, smart devices, and other advanced technologies.
研究领域:
材料科学
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分子工程学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2022
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IF 9.224
Wei-Qiang Du,Teng Fu,Xing-Liang Li,Yao Li,Cong Deng,Xiu-Li Wang,Yu-Zhong Wang
High-performance biobased polyesters with excellent thermal, mechanical, and gas barrier properties are in demand nowadays, while current design strategies have failed to endow polyesters with such integrated performances synchronously. Herein, we synthesize a series of furan-based copolyesters poly(butylene 4-hydroxy-N-(2-hydroxyethyl)2,5-furandicarboxylate) (PBAnF) containing an amide structure and flexible aliphatic segments in the main chains via condensed polymerization. The resultant copolyester PBA20F records balanced pre-eminent mechanical properties including tensile strength (78.0 MPa) and a large elongation at break (199%) while exhibiting a high glass transition temperature (54 °C) and a good enough gas barrier property. Such integrated excellent performances of copolyesters are ascribed to the combined effects of introduced intermolecular hydrogen bonds and flexible segments. Besides, PBAnFs still display high optical transparency in the visible region. This work provides an innovative design strategy to prepare a new class of advanced furan-based copolyesters with remarkable mechanical, thermal, and gas barrier properties, thus supplying a series of promising high-performance biobased copolyesters for potential packaging applications.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2018
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IF 3.741
Yanhua Yang,Hang Lu,Juqing Liu,Yingzhong Shen
An efficient and readily available novel carbazole-based aromatic diamine was synthesized and characterized. Two polyimides ( PI-a and PI-b ) were prepared via a two-step procedure using the new synthesized diamine reacting with low-cost and the commercialized pyromellitic dianhydride (PMDA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), respectively. PIs were characterized and exhibited highly organo-solubility and thermal stability. The Al/ PI-a /ITO device showed binary write-once read-many-times (WORM) behavior with an ON/OFF current ratio up to 10 9 and the threshold voltage as low as −0.21 V, whereas the Al/ PI-b /ITO device presented ternary WORM behavior with an ON2/ON1/OFF current ratio up to 10 5 :10 4 :1 and the switching voltage below −3 V. The memory switching mechanisms were further elucidated through molecular simulation based on the density functional theory (DFT) method. This provides an effective strategy to achieve a ternary memory device.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2025
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IF 6.3
Chi Zhang,Zixuan Lei,Yuhong Liu
Mechanical properties of thermosetting polymers are intricately linked to the heterogeneity of cross-linked network structures, particularly in balancing strength and toughness. To tackle this trade-off, this work presents how the cross-linking and heterogeneous network influence the viscoelastic and mechanical behaviors of polybenzoxazine (PBZ) resins via tuning cross-linked bonding modes and network topologies. A novel epoxy resin bearing Si-O-Si flexible groups (ES) with different pre-polymerization conversions was incorporated into PBZ cross-linking network. Utilizing imidazole as both a catalyst and curing agent, three network topologies of P(BZ-PESI X ) blends were fabricated via the specific curing cycles. Note that the ratio of thermal and catalytic curing units for three network topologies increased and then dropped as the PESI conversions increased from PESI 0 to PESI 100 . It was found that the chemical reactions involving functional groups, active sites and end groups from free, dangling, and unequal length chains can be significantly enhanced by thermal curing at high temperature ranges. This resulted in a decrease in heterogeneity of the cross-linked network. For cross-linked copolymer networks topology (P(BZ-PESI 40 )), the flexural strength, impact strength and K IC were 26.6 %, 36.7 % and 193.5 % higher than that of neat PBZI respectively. Meanwhile, a significant increase in cross-linking density and storage modulus was observed. It was confirmed that the strengthening and toughening mechanism of resins can be summarized as the synergistic effect of reduced network heterogeneity, plastic deformation effect of Si-O-Si flexible chain segments, and weakened hydrogen-bonding interactions. These insights offer practical and economic prospects for the development of versatile, high-performance thermosetting materials.
研究领域:
材料科学
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高分子化学
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机械工程
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化学工程
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纳米技术
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DOI
高影响因子
危险品化学品经营许可证（带存储）