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Your search keyword '"Wei, Yunzhao"' showing total 12 results
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12 results on '"Wei, Yunzhao"'

7. Synthesis and characterization of divinylbenzene-based cyanate resin and its quartz fiber-reinforced composite

Author

Dongliang Shen, Zhao Yuyu, Kuang Hong, Wu Jianwei, Fu Gang, Wang Guan, and Wei Yunzhao

Subjects
Moisture absorption, Quartz fiber, Materials science, Polymers and Plastics, Organic Chemistry, Composite number, 02 engineering and technology, Dielectric, 010402 general chemistry, 021001 nanoscience & nanotechnology, Cyanate, Divinylbenzene, 01 natural sciences, 0104 chemical sciences, Characterization (materials science), chemistry.chemical_compound, chemistry, Cyanate ester, Materials Chemistry, Composite material, 0210 nano-technology
Abstract

Cyanate ester (CE) resins are important polymeric materials with excellent dielectric properties, low moisture absorption, and good heat resistance, which have shown great superiority for use in electronic and aerospace industries. In this article, a novel CE resin was designed and synthesized from divinylbenzene. The proposed structures were characterized with Fourier transform infrared spectroscopy, gel permeation chromatography, and mass spectrometry. The chemical reaction activity, heat resistance, dielectric properties, and water adsorption of the synthesized CE derived from divinylbenzene (DVBCy) were examined and compared with the traditional bisphenol A and bisphenol M (4,4′-[1,3-phenylenebis(1-methyl-ethylidene)]bisphenol)-based CE. The DVBCy resin exhibits a glass transition temperature ( T g) of 162.7°C, a dielectric constant of 2.61, a dielectric loss tangent angle of 0.0035 at about 10 GHz, and a lower water absorption of 0.77%. Compared with the bisphenol M type CE, DVBCy resin provides slightly superior dielectric properties, higher mechanical properties, more favorable process technology for prepreg construction, and lower costing. The DVBCy blend resin modified with bisphenol A-based CE and core–shell particles possesses suitable rheological properties, and the corresponding quartz fiber-reinforced composite exhibits excellent mechanical as well as dielectric properties.

Published
2020
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9. Effects of a composite flame retardant system on the flame retardancy and mechanical performance of epoxy resin adhesive.

Author

Li, Sheng, Wang, Xiaohui, Chen, Tianran, Xu, Miaojun, Liu, Lubin, Gao, Suliang, Wei, Yunzhao, and Li, Bin

Subjects
FIREPROOFING, FIREPROOFING agents, RESIN adhesives, EPOXY resins, MELAMINE, SHEAR strength, FIRE prevention
Abstract

A flame‐retarded epoxy resin (ER) adhesive with strong flame retardancy and adhesion performance was prepared. The coated ammonium polyphosphate (MFAPP), melamine (MEL), and organic montmorillonite (OMMT) were mixed to prepare a composite flame retardant. It was subsequently blended with a toughened ER thoroughly and then the mixture was cured with polyamide. The resultant ER adhesive thermosets achieved UL‐94 V‐0 rating during vertical burning test, and the limiting oxygen index value was as high as 31.6%. The shear strength of the ER adhesive was 27.9 MPa when 25 wt% MFAPP/MEL/OMMT was introduced. Compared with the pure adhesive, the flame retardant epoxy adhesive maintained outstanding adhesion performance because of the good compatibility between the composite flame retardant additives and the toughened ER adhesive. Cone calorimetry tests indicated that the release of heat and smoke were obviously declined with the incorporation of the composite flame retardant system in comparison to pure ER adhesive thermoset. The investigation of flame retardant mechanism revealed that the composite MFAPP/MEL/OMMT flame retardant system stimulated the generation of highly expanded, integral, and strong char layer and the formed char layer exerted superior insulation effect during combusiton. The present work provided an alternative approach to prepare flame retardant ER adhesive with the similar excellent adhesive performance. [ABSTRACT FROM AUTHOR]

Published
2022
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