Polymers
·
2023
·Vol. 15
·期 12
·2623
·
IF 5
Jiadong Wang,Min Wang,Chenxin Xu,Yang Han,Xuan Qin,Liqun Zhang
The development of damping and tire materials has led to a growing need to customize the dynamic viscoelasticity of polymers. In the case of polyurethane (PU), which possesses a designable molecular structure, the desired dynamic viscoelasticity can be achieved by carefully selecting flexible soft segments and employing chain extenders with diverse chemical structures. This process involves fine-tuning the molecular structure and optimizing the degree of micro-phase separation. It is worth noting that the temperature at which the loss peak occurs increases as the soft segment structure becomes more rigid. By incorporating soft segments with varying degrees of flexibility, the loss peak temperature can be adjusted within a broad range, from −50 °C to 14 °C. Furthermore, when the molecular structure of the chain extender becomes more regular, it enhances interaction between the soft and hard segments, leading to a higher degree of micro-phase separation. This phenomenon is evident from the increased percentage of hydrogen-bonding carbonyl, a lower loss peak temperature, and a higher modulus. By modifying the molecular weight of the chain extender, we can achieve precise control over the loss peak temperature, allowing us to regulate it within the range of −1 °C and 13 °C. To summarize, our research presents a novel approach for tailoring the dynamic viscoelasticity of PU materials and thus offers a new avenue for further exploration in this field.Keywords:micro-phase separation;polyurethane;dynamic viscoelasticity;diols
研究领域:
材料科学
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高分子化学
·
机械工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2018
·Vol. 59
·期 4
·724-729
·
IF 1.551
Xiaoxia Jian,Yufang Song,Weiliang Zhou,Leqin Xiao
The correlation of diisocyanate structure with hydrogen bonding and microphase separation and further their influence on mechanical property was investigated in high soft segment (about 90 wt%) energetic poly(bis-azidomethyl oxetane/tetrahydrofuran) polyurethane binder. The hydrogen bonding analysis from Fourier transform infrared spectroscopy demonstrated that the limited intersegmental hydrogen bonding can occur in the hard domain, and small-angle X-ray scattering results also showed that the absence of high-order peaks in synthesized high soft segment polyurethanes. However, coplanar and symmetric diisocyanate and its inner benzene ring are favorable to ordered arrangement of hard segment, and further mircophase seperation enhance the tensile strength. POLYM. ENG. SCI., 59:724–729, 2019. © 2018 Society of Plastics Engineers
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1522
·
IF 3.164
Ming Zhang,Mingqing Chen,Zhongbin Ni
We synthesized PPG-terminated tetra-carbamates as a new toughening additive for epoxy thermosets through facile addition reaction of hexamethylene diisocyanate (HDI) with poly(tetra-methylene glycols) (PTMG) and poly(propylene glycols) (PPG). The effects of prepared tetra-carbamates on the rheological behavior of neat epoxy resin were studied along with the various cured properties of their modified epoxy systems. Four carbamate groups (–NHCOO–) endow the prepared additives not only with good intramolecular interactions, but also with optimal intermolecular interactions with epoxy polymers. This results in the suitable miscibility of the additives with the epoxy matrix for the formation of the typical biphasic structure of microparticles dispersed in the epoxy matrix via polymerization-induced microphase separation. The impact strength and critical stress concentration factor (KIC) of cured modified epoxy systems with the additives are significantly higher than those of unmodified epoxy systems, without sacrificing the processability (Tg) and flexural strength. The toughening mechanism is understood as a synergism combination among the phase separation mechanism, the in situ homogeneous toughening mechanism, and the particle cavitation mechanism.Keywords:tetra-carbamates;epoxy polymer;toughening;microphase separation;particle
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2019
·
IF 7.467
Qian Yang,Xue Lang Gao,Hong Yue Wu,Yuan Yuan Cai,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Herein, a novel strategy to improve the performance of anion exchange membranes (AEMs) is adopted to build a crosslinked structure by tethering the rigid poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) backbone and the flexible poly(4-vinylphenol) (PVP) backbone using an oscillational chain. The incompatibility between the PPO and PVP backbones makes them self-aggregated resulting in occurrence of distinct microphase separation and development of ion transport channels in the AEMs to facilitate the transport of hydroxide ion. The microphase separation of the as-prepared AEMs has been revealed by transmission electron microscopy (TEM) and DI multimode atomic force microscopy (AFM). The existence of the hydrophilic PVP chain also ensures sufficient water uptake to enhance the conductivity of the AEMs. A maximum ionic conductivity of 134 mS cm −1 is achieved at 80 °C by the PPO-c-PVP-40% (40% is the molar content of PVP chains) membrane. A maximum power density of 173 mW cm −2 at 80 °C is obtained by a H 2 /O 2 single cell using the PPO-c-PVP-40% membrane electrode assembly . The PPO-c-PVP-40% membrane also exhibits robust alkaline stability (retains about 90% ionic conductivity after 480 h alkaline stability test) and excellent mechanical property. Those render the AEMs a potential membrane electrode material for fuel cell applications .
研究领域:
材料科学
·
能源化学
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产品关联
DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Zhixiang Yan,Huiting Yang,Shuo Zheng,Zhiyong Tan
High-performance dielectric materials have gained widespread attention, due to their great potential for various applications, such as flexible electronics and capacitive sensors. In this study, sulfamide (SA) and sulfanilamide (SAN), containing sulfonyl groups, were introduced into polyurethane (PU) as chain extenders. The polyurethane with the best performance was end-capped with 3-methylsulfonyl-1-propanol (3-MSP) to investigate the effects of the SAN/SA molar ratio and the capping agent on the microstructure, dielectric properties, and mechanical performance of the PU. The experimental results indicated that, at a frequency of 102 Hz, the polyurethane material with an SAN/SA molar ratio of 2:1 (sample PU-N2S1) exhibited the highest dielectric constant (15.65), representing a 144% increase, compared to sample PU-N0S0. Meanwhile, sample PU-N2S1 showed the highest degree of microphase separation. At a frequency of 1.26 × 105 Hz, its dielectric loss was 0.055. Notably, 3-MSP had a relatively large dipole moment (μ = 6.93 D). However, its incorporation into polyurethane significantly reduced the dielectric constant. The results demonstrated that the dielectric constant and dielectric loss of polyurethane were not only dependent on its dipole moment but were also closely related to its microstructure, including microphase separation and intermolecular interaction.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOID AND POLYMER SCIENCE
·
2025
·
IF 2.3
Yan Zhixiang,Yang Peiqi,Yang Huiting,Zheng Shuo,Tan Zhiyong
With the development of flexible electronics and smart devices, the performance of high-dielectric polyurethane materials is more demanding, and an in-depth understanding of the relationship between their structure and dielectric properties is crucial for material design. In this work, a series of polyurethane materials with different hard segment content were synthesized, using poly(tetramethylene ether)glycol (PTMG) and poly(carbonate diol) (PCDL) as the soft segments, and 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) as the hard segments. The effects of hard segment content on the microphase separation, mechanical properties, and dielectric properties of the polyurethane were systematically investigated. The results revealed that with increasing hard segment content, the degree of microphase separation, tensile strength, and dielectric constant of the polyurethane all increased. Among them, the sample with a hard segment content of 55% (PU-55%) exhibited the best overall performance and exhibited the most pronounced microphase separation, with a dielectric constant of 10.50 at 10 2 Hz and a tensile strength of 18.33 MPa. In addition, it was found that N,N-dimethylformamide (DMF) produces dipole–dipole interactions with precursor molecules (MDI, PTMG, and PCDL) during the synthesis process, thereby modulating the polarity of the reaction environment. This work provides meaningful guidance for structure modulation and performance optimization of polyurethane materials. Graphical abstract
研究领域:
高分子材料科学
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介电材料
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弹性体性能研究
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产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2025
·Vol. 32
·期 2
·1-11
·
IF 2.8
Yan Zhixiang,Liu Chenyao,Zheng Shuo,Tan Zhiyong
With the growing demand for miniaturized and flexible electronic devices, exploring polymer-based materials with high dielectric properties will play a crucial role in high-energy–density capacitors. In this study, a polyurethane material (PU-S x ) with excellent tensile and dielectric properties was prepared by introducing the aromatic disulfide 2,2'-Diaminodiphenyl disulphide (DTDA). The effect of DTDA content on the dielectric and mechanical properties of PU-S x was investigated. In the frequency range of 10 2 Hz to 10 6 Hz, PU-S x exhibits a high dielectric constant (> 8.29) and low dielectric loss (< 0.014). With the increase in DTDA content, PU-S x did not form a conductive network, resulting in a conductivity of only 5.35 × 10 –10 S·m at a frequency of 10 –1 Hz. The presence of two benzene rings and disulfide bonds (S–S) in DTDA significantly enhanced the tensile strength and elongation at break of PU-S x . The results indicate that, although the disulfide bonds in DTDA are inherently nonpolar, their strong interaction with the hard segments enhances the aggregation tendency of these hard segments, thereby promoting microphase separation to some extent, which leads to an increase in the dielectric constant.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 77
·49074-49082
·
IF 3.108
Yizhou Huang,Yazhou Tian,Yuanyuan Li,Xiaocun Tan,Qing Li,Jue Cheng,Junying Zhang
A series of epoxy systems with tunable rigid-flexibility were prepared by the curing reaction of bisphenol F diglycidyl (DGEBF), a single-ended amine with alkyl chains (n-butyl, octyl, dodecyl), 4,4′-diaminodiphenylmethane (DDM) and 4,4′-diaminodicyclohexylmethane (H-DDM). By means of adjusting the composition of the curing agent (the molar ratio between H-DDM and DDM), nano- and submicron-sized phase separations were observed by atomic force microscopy (AFM). And diffraction peaks were not observed in the wide angle X-ray scattering (WAXS) characterization which revealed that there was no crystallization in the modified epoxy resin. Besides, the result of nanoIR characterization proved that the aggregation of aliphatic chains led to the microphase separation structure, which can remarkably improve the mechanical properties of epoxy resins. The effects of side chains on the mechanical and thermal properties of epoxy networks were investigated. Especially, the EC8-5′ (the molar ratio between H-DDM and DDM was 45/55, the mass ratio of the n-octyl amine to DGEBF was 5 : 100) sample exhibited splendid mechanical properties with an attractive tensile strength of 88.4 MPa, an elongation at break of 6.6% and a tensile modulus of 3.5 GPa.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Hangtian Zhang,Fang Zhang,Yixian Wu
Thermoplastic polyurethane (TPU) elastomers based on polyoxytetramethylene glycol (PTMG) with 2000 g·mol–1 as soft segments (SSs) and isocyanates as well as their reaction with butanediol as hard segments (HSs) were synthesized. The three-dimensional supramolecular networks were constructed in TPU by the formation of physical HSs-rich domains via microphase separation, hydrogen bonding, and microcrystallization, which are dominated by the chemical structure of HSs. The robust stretchable TPU with an excellent tensile strength of 32 MPa and elongation of 1378% at break could be successfully prepared, and no crystallization happened to keep the elasticity even at a low temperature (−90 °C) when the steric semisymmetric bis(4-isocyanatocyclohexyl)methane (HMDI) was introduced into HSs-rich domains. The crystallinity and ordered hydrogen bonding content decreased in HSs-rich domains with increases in steric hindrance and asymmetry of diisocyanates. A new approach was developed to construct the high-performance TPUs by introducing long PTMG SSs for the flexibility and elasticity and steric semisymmetric HMDI hard segments.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 15
·11835-11844
·
IF 4.6
Yanru Chen,Ke Yang,Hanhai Dong,Hongyu Niu,Quanguo Wang,Qingli Cheng
Silicone polyurea typically exhibits inferior mechanical properties due to the microphase separation between the siloxane and polyurea segments. To address this issue, we propose a method to enhance the mechanical properties through interfacial reactions. The mechanical properties and microphase separation of silicone polyurea we synthesized were studied. And poly(isobutene-alt-maleic anhydride) (PBAM) and γ-aminopropyl triethoxysilane (KH550) which are capable of interfacial reactions were respectively introduced into polyurea and siloxane segments to reduce the degree of microphase separation and enhance the mechanical properties of silicone polyurea. The mechanism behind the improvement was elucidated through experimental results. FT-IR spectra confirmed that the maleic anhydride groups in PBAM and the amino groups in KH550 undergo rapid reactions. Additionally, it was observed that the rapid interaction of PBAM and KH550 at the interface made interfacial tension decrease fast through the pendant-drop method. Stability analysis and light microscope observations revealed that PBAM and KH550 can stabilize the two-phase interface, forming stable droplets within the mixture. Scanning electron microscopy (SEM) observations indicated a reduction in the degree of microphase separation in the silicone polyurea. Consequently, the introduction of PBAM and KH550 decreases interfacial tension and the dispersion size of the silicone phase within the carbon phase, thereby reducing the degree of microphase separation and enhancing the mechanical properties of the silicone polyurea.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Hairui Wang,Yongxu Li,Hongyu Zhang,Xiurui Lang,Xiaolei Wang,Lan Cao,Chengzhong Zong
Thermoplastic polyurethane (TPU) with shape memory characteristics exhibits excellent comprehensive performance and structural design flexibility, wherein the composition and structure of the soft segment play a crucial role. We synthesized four linear-structured polyurethanes (PUs) using 4,4′-methylene diphenyl diisocyanate (MDI), polytetramethylene ether glycol (PTMG), and 1,4-butanediol (BDO) in identical molar ratios and systematically investigated the impact of soft segment molecular weight on hydrogen bonding, thermal properties, microphase separation, and mechanical performance of TPU. The results show that an increase in soft segment molecular weight leads to a reduction in hydrogen bonding, microphase separation, and modulus, while the tensile strength initially increases and then decreases. PU650 exhibits the highest hydrogen bonding index of 5.17 and the maximum microphase separation. Additionally, all TPU materials exhibit low-temperature multiple shape memory behavior and excellent recyclability. This work provides valuable insights into the structural design and performance optimization of recyclable PU materials. Graphical
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Shan Jiang,Tianyi Han,Tongshuai Tian,Chuanqing Yang,Li Liu
Compared with isocyanate-based polyurethanes (PUs), poly(hydroxyurethane)s (PHUs) are more likely to form phase mixing structure, inducing poor elastic properties. To avoid this, stronger interaction between hard segments is required. Herein, carbon dioxide-based poly(hydroxyurethane-urea)s (PHUUs) with different hard segment contents were prepared through polyaddition reaction using 5-membered dicyclic carbonate (BADC) as hard segment, poly(propylene glycol) bis(2-aminopropyl ether) (D2000) as soft segment, and amino-terminal polyurea oligomer (HMDA*) chain extender, and several PHUs were prepared by using hexamethylenediamine (HMDA) chain extender or without using chain extender as controls. The interaction between hard segments were strengthened with the introduce of chain extender. Compared with PHUs, PHUUs with HMDA* chain extender were more inclined to form significant microphase separation. For PHUUs, the hard segment T g appeared at around 60°C when hard segment content reached 40 wt%, and the interdomain spacings were in the range of around 14–23 nm with 40–50 wt% hard segment content. In addition, PHUUs exhibited better solvents resistance and mechanical properties than PHUs with the same hard segment content. PHUUs with certain hard segment content showed good elastic recovery, with a residual strain less than 2% after 10 cycles, which comparable with conventional isocyanate-based PUs.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）