RENEWABLE ENERGY
·
2021
·
IF 8.001
Changzhong Chen,Rong Chen,Tangyuan Zhao,Linge Wang
To reveal the influence of organic polymer supports on the properties of shape stabilized phase change materials (ssPCMs), a linear polyurea (LP) and crosslinked polyurea (CP) were synthesized for stabilizing polyethylene glycol (PEG) for thermal energy storage . Though the surface area of LP are about 25 times of that of CP, the shape stability of CP for melt PEG is better than that of LP. Due to the crosslinked network, CP has much stronger interactions with PEG, which could promote the adsorption capacity of PEG. The highest PEG loading capability of LP and CP without liquid leakage above melting point is 70 wt% and 80 wt% respectively, and the corresponding melting enthalpy is 95.42 J/g and 107.60 J/g respectively. However, the heat storage efficiency of PEG/LP ssPCMs is higher than that of PEG/CP ssPCMs with the same PEG content, which caused by the weak restrictions of free movement of PEG chains from LP. Both types of ssPCMs exhibit good reusability from thermal cycle test and good thermal stability from thermal analysis, and the thermal conductivity of ssPCMs can effectively enhance after adding some carbon materials. The study supplied an inspiration to select proper polymer matrix for ssPCMs.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2025
·
IF 4
Zhou Xiao-Xia,Yin Yi-Ting,Zhang Xiao-Yi,Li Shu-Sheng,Jiang Xu-Bao,Zhu Xiao-Li,Kong Xiang-Zheng
Fluorescent polyurea-carbon dots (PU-CD) were successfully achieved through a co-pyrolysis technique, combining polyurea (PU) with carboxyl-containing carbon dots (PCD) at a temperature of 220 °C. The PU was fabricated via a simple precipitation polymerization process using toluene diisocyanate in a water/acetone binary solvent system. PCD was generated by thermal treatment of poly(ethylene glycol) (PEG) at the same elevated temperature. To elucidate the structural characteristics of PU-CD, as well as its precursor components PU and PCD, a comprehensive suite of analytical techniques was employed, including transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS). These analyses confirmed the formation of amide bonds resulting from the reaction between the terminal amines of PU and the carboxyl groups of PCD. An in-depth comparison of the fluorescence properties of PU-CD revealed marked enhancements in fluorescence intensity when contrasted with PU, PEG, and the individual PCD. The research explored the impact of various factors such as concentration, pH in aqueous solutions, and solvent type on the fluorescence emission of these materials, providing valuable insights into their emission mechanisms. It was particularly noteworthy that both PCD and PU-CD exhibited a confined-domain crosslink-enhanced emission effect. Utilizing the aqueous dispersion of PU-CD as a fluorescent probe, the detection of doxycycline (DOX), a long-acting, broad-spectrum, semi-synthetic tetracycline antibiotic, was achieved with a detection limit of 2.9×10 −7 mol/L. This study introduces a simple, green, and cost-effective fluorescent probe for the detection of DOX, which has significant potential for application in the realms of analytical chemistry and food safety monitoring in the future.
研究领域:
分析化学
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材料科学
·
纳米技术
·
传感器
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Jinlong Fan,Jie Zhang
Polymer blending has been an important method to create materials with specific properties that have synergistic effects. However, there are few reports on the mechanism of synergistic effects. It is well known that it is quite difficult to obtain ideal blends composed of nonpolar organosilicon polymers and polar polymers. In this paper, thermoplastic polyurea elastomer blends with a co-continuous microphase structure consisting of polysiloxane–polyurea (PDMS-PUA), polyether amine–polyurea (PEA-PUA), and compatibilizer PDMS-PUA-grafted PEA-PUA (PDMS-PUA-g-PEA-PUA) were prepared for the first time. For the first time, introduction of polysiloxane does not sacrifice mechanical properties of thermoplastic polyurea elastomers. For example, the tensile strength of the elastomer blend with 30 wt % PDMS-PUA content reached 25.7 MPa, which is higher than those of PEA-PUA and PDMS-PUA. The blends also show typical outstanding characters such as exceptional heat and water resistance. The mechanism of the synergistic effect on mechanical properties is revealed based on in-depth studies on mutual interphase interaction. In situ variable temperature infrared spectroscopic analysis (VTIR) shows that compatibilization facilitates the construction of a denser hydrogen bonding network at the blend interface, which is thought to play a key role in the co-continuous microphase structure. Microscopic morphological characterization shows that PDMS-PUA and PEA-PUA phases are deformed and oriented together during the stretching process, thus jointly resisting external forces. Moreover, the blends show an exceptional self-healing ability due to their strong and reversible hydrogen bonding network.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Fang Wu,Junfeng Li,Heng Quan,Jiang Han,Xiaoxuan Liu,Xiaokun Zhang,Jinglei Yang,Yong Xiang
Polyurea/poly(urea–formaldehyde)/Al 2 O 3 hybrid microcapsules with a dense Al 2 O 3 nano-layer containing 4,4′-methylenebis cyclohexyl isocyanate (HMDI) have been successfully fabricated via combaning Atomic layer deposition (ALD) process and interfacial/in-situ polymerization process. This dense Al 2 O 3 nano-layer can be controllable deposited in the form of a single atom film through continuous self-limiting reactions of Al(CH 3 ) 3 and H 2 O on the surface of the PU/PUF microcapsules at a temperature range of 120–180 °C. The formed hybrid microcapsules showed a monodispersed diameter of ~60 µm with a controlled and nano-sized Al 2 O 3 shell. Moreover, the deposited Al 2 O 3 nano-shell significantly increased the thermal stability and mechanical property of hybrid microcapsules, which could maintain their integrity under harsh conditions. In addition, by embedding hybrid microcapsules into an epoxy matrix, an excellent anticorrosion performance in scratched coatings via self-healing functionality was obtained. Therefore, the formed hybrid microcapsules with enhanced thermal stability and mechanical property via ALD process could promote their practical application in self-healing composites.
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
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Ting Li,Zhining Xie,Jun Xu,Yunxuan Weng,Bao-Hua Guo
In this work, diamine chain extenders containing disulfide bonds are reacted with triisocyanates to yield dynamic chemical cross-links based on exchangeable disulfide bonds. The polyurea system with dynamic bonding shows drastic decline of storage modulus and very short relaxation times above 150 °C so that this polymer exhibits typical dynamic properties, e.g. self-healing, recycling and hysteresis loop recovery. The introduction of disulfide bonds dominates the thermal stimulated dynamic properties, since the control samples without disulfide bonds have longer relaxation times even at high temperatures. Interestingly, presence of disulfide bonds leads to the decline of hydrogen bonding strength which can result in their easier dissociation and subsequently easier topological network rearrangement. In addition, almost complete reversibility of the hydrogen bonding is observed from temperature-dependent Fourier Transform Infrared Spectroscopy, which reveals the important influence of hydrogen bonding on dynamic properties. Thus, Hydrogen bonding dissociation is an indirect reason of dynamic properties, while exchange reaction of disulfide bonds is the primary cause. The results may deepen our understanding of the role of hydrogen bonding in the dynamic materials. In addition, the available commercial raw component, operational feasibility and simplicity constitute a great advantage of the so-prepared dynamic polyurea system, i.e. an effective step to implementation of industrial applications and recycle the nonbiodegradable crosslinked polyureas.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2019
·Vol. 37
·期 12
·1257-1266
·
IF 2.804
Li Ting,Zheng Tian-Ze,Guo Zhao-Xia,Xu Jun,Guo Bao-Hua
A well-defined quadruple hydrogen bonding strategy involving dimerization of 2-ureido-4[1 H ]-pyrimidone (UPy) units is innovatively designed to prepare polyureas with high overall mechanical properties. Three polyureas containing different amounts of UPy units were synthesized by replacing a portion of isophorone diisocyanate (IPDI) with a UPy-derived diisocyanate. The formation of quadruple hydrogen bonds in hard segments via UPy dimers was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the polyureas were evaluated by uniaxial tensile testing. Compared to the polyurea without UPy units, remarkable improvements in Young’s modulus, tensile strength, and toughness were simultaneously achieved when UPy units were incorporated. The mechanism behind the strong strengthening effect rooted in the stronger intermolecular forces among hard segments brought by the quadruple hydrogen bonds, which were stronger than the inherent bidentate and monodentate hydrogen bonds among urea groups, and the slower soft segmental dynamics reaveled by both increased T g and relaxation time of the soft segments. The mechanism behind the strong toughening effect was ascribed to more effective energy dissipation brought by the quadruple hydrogen bonds that served as stronger sacrificial bonds upon deformation. This work may offer new insight into the design of polyurea elastomers with comprehensively improved mechanical properties.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 2
·326
·
IF 3.057
Yanxuan Ma,Yingrui Zhang,Jiatong Liu,Yi Sun,Yajie Ge,Xiaoning Yan,Jian Wu
Polyurea microcapsules with Ethylenediamine (EDA) as the core material were synthesized. A set of characterization methods, including optical and scanning electron microscopy (OM and SEM), the Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were used to confirm the microcapsule morphology and chemical structures. The influence of emulsifier content and stirring rate on size and morphology of the microcapsules was investigated, and the self-healing performance of EDA-Polyurea microcapsule/epoxy coatings was evaluated by electrochemical impedance spectroscopy (EIS) measurements. The results showed that the microcapsules obtained had good spherical shape with a mean diameter of 0.54–0.70 μm. Compared with pure core material, the microcapsule showed excellent thermostability, and the content of core materials was up to 56.00 wt%. The epoxy coating with 5.0 wt% EDA-Polyurea microcapsules achieved average corrosion resistance efficiencies of 90.00%, significantly enhancing the capability of the scratched coating to resist external corrosion.Keywords:ethylenediamine;polyurea;microcapsules;self-healing;anti-corrosion
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
COMPOSITES COMMUNICATIONS
·
2025
·
IF 7.7
Qinyong Liu,Jingfan Zhang,Ximei Wen,Baozhu Wang,Jun Sun,Hongfei Li,Xiaoyu Gu,Sheng Zhang
This research outlines a strategy to improve both the flame retardancy and water resistance of polyurea (PUA) while largely preserving its mechanical integrity. Aluminum hypophosphite (AHP) was coated by triphenyl phosphate (TPP), and the resultant TPP@AHP exhibited improved compatibility and hydrophobicity. Additionally, ZIF-8@MXene, a nanohybrid material combining a metal-organic framework with MXene (Ti 3 C 2 T x ) sheets, served as both a reinforcing filler and a synergistic flame retardant. The use of 17 wt% TPP@AHP and 1 wt% ZIF-8@MXene in PUA enabled the composite to achieve a UL-94 V-0 rating and to maintain a limiting oxygen index (LOI) of 26.9% even after 7 days of water immersion. Cone calorimetry tests demonstrated that this formulation significantly reduced the peak heat release rate by 70.9%, total heat release by 30.8%, and smoke production by 32.1%. This work provided a feasible solution for preparing PUA composites with durable flame retardancy and qualified mechanical properties.
研究领域:
材料科学
·
防火材料
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Zhangcheng Gao,Lianfang Feng,Xueping Gu,Jintang Duan,Mingzhe Jiang,Cailiang Zhang
The combination of aromatic and aliphatic structures can endow polyurea with distinct performance advantages. A one-step feeding method is used to synthesize linear hybrid aliphatic/aromatic copolyureas by varying the ratio of m -phenylenediamine (MPD) and polyoxypropylenediamine (D2000) reacting with 4,4′-diphenylmethane diisocyanate (MDI). Real-time Fourier-transform infrared spectrometer monitoring reveals that D2000 exhibits higher reactivity than MPD. Consequently, in the MDI/MPD/D2000 system, D2000 initially reacts with MDI to form an isocyanate-terminated prepolymer, which subsequently reacts with MPD. Compared with the two-step feeding method, this approach successfully eliminates biuret formation and enhances tensile strength. Additionally, decreasing the molar ratio of D2000 to MPD ( λ m ) reduces the size and degree of microphase separation in the polyurea by increasing the ordered hydrogen bonding and benzene conjugation, leading to an increase in tensile strength. Specifically, as λ m decreases from 70 mol% to 30 mol%, the degree of microphase separation decreases from 0.47 to 0.2, causing the tensile strength to rise from 28 to 48 MPa. Further reducing λ m to 30 mol% decreases the degree of microphase separation to 0.16, resulting in an increase in tensile strength to 78 MPa.
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
CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 10
·1150-1156
·
IF 2.016
Qiu Wei-Guang,Zhang Fei-Long,Jiang Xu-Bao,Kong Xiang-Zheng
Polyureas (PU) are well known as a class of high impact engineering materials, and widely used also in emerging advanced applications. As a general observation, most of them are only soluble in a very limited number of highly protonic solvents, which makes their chemical structure analysis a great challenge. Besides the presence of abundant hydrogen bonding, the poor solubility of PU in common organic solvents is often ascribed to the formation of biuret crosslinking in their molecular chains. To clarify the presence of biuret groups in PU has been of great interest. To this end, two samples, based on hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI) respectively, were synthesized by precipitation polymerization of each of these diisocyanates in water-acetone at 30 °C. Their chemical structures were analyzed by high resolution magic angle spinning (HR-MAS) NMR, and through comparison of their NMR spectra with those of specially prepared biuret-containing polyurea oligomers, it was concluded that biuret group was absent in all the PU prepared at 30 °C. In addition, this NMR analysis was also applied to a PU obtained by copolymerization of TDI with ethylene diamine (EDA) and water at 65 °C in EDA aqueous solution. It was confirmed that biuret unit was also absent in this PU and that EDA was more active than water towards TDI. The presence of EDA was crucial to the formation of uniform PU microspheres. This study provides therefore a reliable method for the analysis of PU chemical structure.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Shangzhong Zhang,Lifeng Yan
Direct conversion of CO2 to polymers, such as polyurea, is an effective approach for CO2 capture and utilization. However, traditional methods involving CO2 and diamine polymerization require high pressures and temperatures (>5 MPa, ∼180 °C) and result in low molecular weight polyurea. A method has been developed to synthesize polyurea directly from CO2 at mild temperature and pressure (0.1–0.5 MPa, 15–90 °C) in a one-step reaction using organic superbases as both catalysts and dehydrants with the formation of DBU-H2O. This process allows for fast polymerization (10–30 min) and yields high molecular weight polyurea (>106 g/mol). The tensile strength of the as-prepared polyurea film reaches 13.5 MPa, which indicates excellent mechanical properties.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2017
·Vol. 25
·期 12
·1153-1157
·
IF 1.405
Li Yanyan,Yin Mingying,Yan Ying,Wang Ce,Liu Xincai,Chao Danming
Electrochromic materials have attracted much attention due to their potential in intelligent applications. We report here the preparation of a crosslinked electrochromic polyurea containing oligoanilines and silicon groups (PUOSi), which shows good thermostability and interesting spectral properties. The crosslinked network structure (c-PUOSi) could be accomplished easily by virtue of hydrolysis reaction. The reversible electrochemical activity and improved electrochromic behavior have been disclosed through multiple electrochemical techniques coupled with UV-Vis spectroscopy. The stability of c-PUOSi film in the electrochemical switching measurements has been effectively enhanced through the crosslinking reaction of triethoxysilane end groups, whilst the resulting densified electroactive film shows low response speed during the electrochemical process. Our demonstrated system presents a deep understanding of structure-function relationship, which is a vital implication for the fabrication and application of the electrochromic devices.
研究领域:
材料科学
·
电化学
✓ 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）