JOURNAL OF SOLID STATE CHEMISTRY
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2023
·
IF 3.3
Shibin Wu,Keru Song,Jianwen Wang,Siyu Huang,Fengyue Shi,Guangdong Zhao
ZrB 2 –SiC ceramics were successfully prepared via sol–gel method using phenyltrichlorosilane, borane dimethyl sulfide , and zirconium tetrachloride in stoichiometric amounts as the raw materials. The macromolecular network structure formed after the sol–gel process was investigated via Fourier transform infrared (FT–IR) spectroscopy. The phase evolution of the ZrB 2 –SiC ceramics were analyzed by FT–IR spectroscopy, X–ray diffraction, and transmission electron microscopy , whereas morphological and elemental analyses were performed using scanning electron microscopy. In particular, the change in phase composition was monitored after the pyrolysis from 1400 to 1500 °C, and the heat treatment of BZ6 precursor at 1500 °C enabled one to produce the ZrB 2 –SiC ceramic with a homogeneous crystal phase distribution. Therefore, the controllable microstructure adjustment of the ceramic phase composition could be achieved and a new way was paved for the structural and functional applications of ultra–high–temperature ceramics (UHTCs) series.
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高影响因子
POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Wei Tang,Lijun Qian,Silvia González Prolongo,De-Yi Wang
In this work, small amounts of piperazine/phenyl-silicon charring skeleton NSi-n (n=1, 2, 3) with varied aggregation degrees were respectively inserted into a hydrogen-bonded macromolecule fabricated with melamine and cyanuric acid, to prepare a series of nitrogen/silicon-based macromolecules MNSi-n (n=1, 2, 3), which achieved the efficient charring flame retardant effect of MNSi-n/ammonium polyphosphate (APP) in polypropylene (PP). Due to the formation of compact barrier char layers with rich phosphorus and silicon contents, (MNSi-n/APP)/PP performed higher limited oxygen index, glow-wire flammable index and UL 94 V-0 level, and also exhibited lower heat release rate. Comparatively, the melamine cyanurate macromolecule without NSi-n skeleton with APP only formed ineffective char layers and weaker flame retardancy. More importantly, the higher aggregation degree of piperazine and phenyl-silicon groups in MNSi-n apparently led to higher intumescent flame retardant efficiency. The high aggregation degree of NSi-n structure strengthened the full interaction between macromolecules MNSi-n and APP, thus forming compact char layers and increasing flame retardancy. It disclosed an effective way to enhance charring flame retardancy by small changes in molecular structure.
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高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2022
·Vol. 33
·期 2
·328-336
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IF 3.518
Gao Feifei,Wu Feiyang,Zhang Xianyang,Jiang Bowen,Li Qizhong
In this paper, zirconium-based MOF (Zr-MOFs) materials, namely UIO-66, UIO-66-NH 2 , GMA-UIO-66 and NB-UIO-66, were selected as fillers to enhance the mechanical properties of polydicyclopentadiene (PDCPD) nanocomposites, and Zr-MOFs/PDCPD nanocomposites were prepared by in situ polymerization. The functional groups and morphology of Zr-MOFs were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM). The mechanical properties of Zr-MOFs/PDCPD composites were studied by tensile toughness, notched impact strength and bending strength test. Furthermore, the optimum Zr-MOFs loading was determined. The results show that when the mass fraction of NB-UIO-66 is 0.4%, the composites’ tensile toughness, flexural strength, impact strength and heat distortion temperature (HDT) are simultaneously increased by 47.3%, 37.5%, 119.4%, and 59.2% respectively, compared with the pure PDCPD, which synergistically enhances the mechanical properties. Graphical Abstract
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高影响因子
POLYMER INTERNATIONAL
·
2014
·Vol. 63
·期 10
·1875-1880
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IF 2.247
Chunfang Li,Zhupeng Zhang,Jinrong Wu,Dongxiang Li,Wanguo Hou
Dendritic amphiphiles as novel building blocks are very important for self-assembling in the supramolecular chemistry area. In this work, a carbosilane dendrimer with hexamethylene as the branching unit (G1) was first synthesized as a hydrophobic core and then linked with poly(ethylene glycol) (PEG) units as the periphery by a hydrosilylation reaction to prepare an amphiphilic dendrimer (G1-PEG) with a yield of 27%. The aggregation behavior of G1-PEG in water was studied with surface tension, dynamic light scattering and transmission electron microscopy methods. The surface tension data showed that the critical aggregation concentration of such dendrimers in water is approximately 0.75 g L −1 . The results of dynamic light scattering and transmission electron microscopy indicated that the aggregate size of G1-PEG dendrimers in water is related to the concentration. Small micelles of about 10 nm were found at high concentration, large vesicles of about 100 nm were observed at low concentration, and a mixture of micelles and vesicles was found at middle concentrations. The encapsulation of G1-PEG to a fluorescence probe verified the existence of a hydrophobic microenvironment in the aggregates at high concentrations of the amphiphilic dendrimer. © 2014 Society of Chemical Industry
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高影响因子
Materials Today Communications
·
2025
·
IF 4.5
Fei Wu,Fengqing Chen,Zhenghong Guo,Hangtian Hu,Lina Liu
With the swift advancement of green sustainability, efficient bio-based flame retardant is imperative to be created for epoxy resin (EP) especially in construction materials. This article designed a bio-based flame retardant (EUSP) which contains epoxy groups through the synthesis between epoxidation of eugenol and Phenyl trichlorosilane. The obtained flame retardant was applied for conventional E51 EP. The resultant EP composites achieved the V-0 rating in accordance with UL-94 standards and demonstrated a high limiting oxygen index (LOI) value of 30.2 % when 30 wt% EUSP was introduced. Compared to pristine E51 EP, the peak heat release rate (PHRR) and the peak smoke release rate (PSPR) were reduced by 38 % and 35.2 %, respectively. The flame-retardant effect of EUSP is achieved through the condensed phase flame retardant of silicon element. The silicon oxygen bond in EUSP reacts at the initial stage of combustion to form silicon dioxide. After the formation of silicon dioxide, a layer of silicon dioxide is formed outside under the promotion of combustible gas, which can reduce the internal exchange of external heat and epoxy resin and prevent the release of combustible gas inside the sample. Under the protection of the silicon dioxide layer, a compact and complete carbon layer is formed inside, which can further absorb the external heat, stabilize the internal temperature of the epoxy resin and protect the matrix. In comparison to the pristine E51 EP, the incorporation of 30 wt% EUSP resulted in an increase in both tensile strength and flexural strength, with values rising from 55.16 MPa and 90.69 MPa to 85.05 MPa and 146.83 MPa, respectively, representing a rise of 54.1 % and 67.3 %. This study provides a simple pathway for the preparation of bio-based flame retardants aimed at enhancing both the flame retardancy and mechanical properties of epoxy resin (EP).
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高影响因子
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