POLYMER DEGRADATION AND STABILITY
·
2020
·
IF 4.032
Yaoyuan Xu,Jun Long,Runze Zhang,Yunzhe Du,Shengjie Guan,Yuying Wang,Lingyun Huang,Hongwei Wei,Li Liu,Yudong Huang
Silicone resins, due to its excellent high thermal stability, are widely applied in high-temperature environment. However, it is still a problem that the initial decomposition temperature of silicone resins is relatively low, which limits their wider applications. In this paper, three kinds of polyhedral oligomeric silsesquioxane (POSS) (aminopropyl, mercaptopropyl and chloropropyl) were synthesized and analyzed by FTIR, NMR and MS for structure characterization and purity analysis. Significant improvement of thermal stability was achieved by incorporating POSS into silicone resins. Three different POSS were used to modify silicone resins, and the effects of different POSS on thermal stability of silicone resins were studied. The results indicated that the thermal stability of octa-aminopropyl POSS modified silicone resins improved most significantly, with the decomposition temperature increased by nearly 45 °C compared with pure silicone resins. Moreover, the thermal decomposition mechanism of silicone resins with different POSS was studied, and chemical simulation indicated the thermal stability of silicone resins greatly improved by forming hydrogen bond between POSS and silicone resins. And the results showed one distinctive mode of increasing thermal stability, forming hydrogen bond to block resin chains' movements.
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
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Nan Yang,Guoshuai Cai,Yange Wan,Ruoyu Zhang,Jiancun Li,Jingfang Zhang,Haijun Zhang,Hongli Liu,Xiaolei Yu,Mingchao Wang
In order to improve the burn-through resistance and environmental friendliness of epoxy resin-based flame-retardant coatings, high-performance coatings were developed by modifying them with silicone resin and B 4 C. By incorporating B 4 C and silicone resin, the coating's thermal stability was significantly enhanced. By participating in a series of chemical reactions when the coating was exposed to fire, they promoted spontaneous ceramicized and vitrified modification, increased the mass of char residue, improved the surface compactness, optimized the foam structure, and improved the specific surface area of char residue. Compared to blank sample E10S0 and others, E85S15B3 coating co-modified with silicone resin and B 4 C showed the best performance. The backside temperature of E85S15B3 was only 164.34 °C after a 2 h combustion test. The peak heat release rate (PHRR), total heat release rate (THR), total smoke production (TSP), peak smoke production rate (PSPR), peak CO release rate (PCOPR), and peak CO 2 release rate (PCO 2 PR) of E85S15B3 were all significantly improved, with a decrease of 20.38 %, 40.06 %, 37.67 %, 49.21 %, 64.71 %, 0.03 % compared with that of E10S0 sample. The LOI value was 34.6 %, which was 48.24 % better than that of E10S0. Moreover, the compressive, tensile, and bending strengths of E85S15B3 were measured at 85.6 MPa, 25.6 MPa, and 45.3 MPa, respectively, marking a 22.1 % increase, 11.23 % increase, and 23.19 % increase over those of E10S0. The mechanism of flame-retardant includes cooling insulation, non-flammable gas-phase dilution flame retardancy, condensed phase physical insulation, reinforced-phase flame retardancy, and free radicals capturing to block combustion.
研究领域:
材料科学
·
防火材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 32
·47834
·
IF 2.188
Jianjun Chen,Zien Fu,Hengchao Huang,Zhonghua Chen,Xingrong Zeng
A facile route was introduced to prepare homogeneous silicone resin doped with titanium hybrid with high refractive index (RI). Specifically, the hybrids were obtained from the transesterification of hydroxyl-phenyl-vinyl silicone resin and titanium isopropoxide under anhydrous conditions. The structures of hybrid silicone and their corresponding intermediates (hydroxyl-phenyl-vinyl silicone) were characterized by nuclear magnetic resonance spectroscopy ( 1 H NMR, 29 Si NMR) as well as Fourier transform infrared spectroscopy (FTIR). The hybrids had a transmittance of more than 88% ranging from 450 nm to 800 nm, a high RI of 1.585, and a lower water vapor permeability of 3.58 g /m 2 .24h. Results from FTIR showed intensity of Ti-O-Si bond in hybrid decrease with extended the storage time, but the properties of cured hybrids including optical, mechanical, and gas permeability were not influenced. Compared to chips encapsulated with pure silicone, the luminous efficiency of the chips encapsulated with hybrids was improved from 138.6 lm/W to 156.4 lm/W. The thermal shock and hygrothermal aging test also demonstrated the hybrids had a wide range application in light-emitting diode (LED) packaging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47834.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 7
·1142
·
IF 3.164
Jianye Ji,Xin Ge,Xiaoyan Pang,Ruoling Liu,Shuyi Wen,Jiaqi Sun,Weijie Liang,Jianfang Ge,Xunjun Chen
Methoxyl-capped MQ silicone resin (MMQ) was first synthesized by the hydrosilylation of vinyl-containing MQ silicone resin and trimethoxysilane and then used in condensed room-temperature vulcanized (RTV) silicone rubber as a self-reinforced cross-linker. Results show that modified silicone rubber exhibits good light transmission. Compared with unmodified silicone rubber, the hardness, tensile strength and elongation of MMQ at the break are increased by 26.4 A, 2.68 MPa and 65.1%, respectively. In addition, the characteristic temperature of 10% mass loss is delayed from 353.5 °C to 477.1 °C, the temperature at maximum degradation rate is also delayed from 408.9 °C to 528.4 °C and the residual mass left at 800 °C is increased from 1.2% to 27.7%. These improved properties are assigned to the synergistic effect of the rigid structure of MMQ, the formation of a dense cross-linking structure in polymers and the uniform distribution of MMQ cross-linking agent in RTV silicone rubber.Keywords:cross-linker;MQ silicone resin;hydrosilylation;silicone rubber;modified
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Coatings
·
2019
·Vol. 9
·期 10
·605
·
IF 2.33
Jianye Ji,Xin Ge,Weijie Liang,Xiaoyan Pang,Ruoling Liu,Shuyi Wen,Jiaqi Sun,Xunjun Chen,Jianfang Ge
To overcome the inherent limitation that the preparation of high molecular weight MQ copolymers (Mw ≥ 30,000 g/mol) via the hydrolysis and condensation of solicate salts generally results in an intractable gel, vinylphenyl-containing MQ silicone resin with a high molecular weight was designed and synthesized through the hydrosilylation reaction of vinyl-containing MQ silicone resin and linear poly(diphenylsiloxane) with two terminal Si–H bonds. The weight average molecular weight of these modified copolymers reported here is at least 30,000 dal·mol−1. These polymers have favorable thermal stability and a higher refractive index than that of the base resin due to the formation of novel regular macromolecular structures and the introduction of phenyl groups. These inorganic/organic hybrid materials could be used as a potential component for temperature-resistance electronics adhesive, heat-resistant coatings and high-performance liquid silicone rubber. Moreover, the proposed process also provides a possibility to choose higher molecular weight MQ silicones according to application requirements.Keywords:MQ silicone resin;modified;hydrosilylation;high molecular weight
研究领域:
材料科学
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有机化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2020
·Vol. 12
·期 10
·2284
·
IF 3.426
Rui Huang,Jinshui Yao,Qiuhong Mu,Dan Peng,Hui Zhao,Zhizhou Yang
Silicone resin is a high-temperature resistant material with excellent performance. The improvement of its thermal stability has always been the pursuit of researchers. In this paper, a sequence of silicone resins containing trifluorovinyl ether groups were prepared by the co-hydrolysis-polycondensation of methyl alkoxysilane monomers and {4-[trifluorovinyl(oxygen)]phenyl}methyldiethoxysilane. The structures of the silicone resins were characterized by FT-IR and1H NMR. The curing process of them was studied by DSC and FT-IR spectra, and results showed that the curing of the resins included the condensation of the Si-OH groups and the [2 + 2] cyclodimerization reaction of the TFVE groups, which converted to perfluorocyclobutane structure after curing. The thermal stability and thermal degradation behavior of them was studied by TGA and FT-IR spectra. Compared with the pure methyl silicone resin, silicone resins containing TFVE groups showed better thermal stability under both N2and air atmosphere. Their hydrophobic properties were characterized by contact angle test. Results showed that PFCB structure also improved the hydrophobicity of the silicone resin.Keywords:silicone resin;trifluorovinyl ether group;thermal stability;degradation
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
PubMed
高影响因子
Polymers
·
2018
·Vol. 10
·期 9
·979
·
IF 2.935
Chunfang Zhu,Haitao Yang,Hongbo Liang,Zhengyue Wang,Jun Dong,Lei Xiong,Jianping Zhou,Junjun Ke,Xi Xu,Weixian Xi
Low surface energy materials have attracted much attention due to their properties and various applications. In this work, we synthesized and characterized a series of ultraviolet (UV)-curable fluorinated siloxane polymers with various fluorinated acrylates—hexafluorobutyl acrylate, dodecafluoroheptyl acrylate, and trifluorooctyl methacrylate—grafted onto a hydrogen-containing poly(dimethylsiloxane) backbone. The structures of the fluorinated siloxane polymers were measured and confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. Then the polymers were used as surface modifiers of UV-curable commercial polyurethane (DR-U356) at different concentrations (1, 2, 3, 4, 5, and 10 wt %). Among three formulations of these fluorinated siloxane polymers modified with DR-U356, hydrophobic states (91°, 92°, and 98°) were obtained at low concentrations (1 wt %). The DR-U356 resin is only in the hydrophilic state at 59.41°. The fluorine and siloxane element contents were investigated by X-ray photoelectron spectroscopy and the results indicated that the fluorinated and siloxane elements were liable to migrate to the surface of resins. The results of the friction recovering assays showed that the recorded contact angles of the series of fluorinated siloxane resins were higher than the original values after the friction-annealing progressing.Keywords:ultraviolet (UV) curable coatings;low surface energy materials;fluorinated siloxane resin
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2020
·
IF 4.469
Xiaoqiang Zheng,Ai-min Pang,Yu Wang,Wei Wang,Yongping Bai
Novel UV-curable methacrylate functionalized fluorosilicone resin (MAFSR) and sulfhydryl functionalized fluorosilicone resin (SFSR) were synthesized respectively. The molecular structure, UV curing process, thermal properties and surface properties were studied. Further application as protective coatings in the field of printed circuit board (PCB) was explored. Results show that the MAFSR with more than 30 wt % SFSR possess a high carbon-carbon double bonds conversion above 95 % after 15 s UV exposure. Besides, the surface energy of the coatings is as low as 11.5 mN/m, showing excellent hydrophobicity . The XPS results further reveal that the migration and orientation of the fluorine groups to the surface is an intrinsic reason for low surface energy. In addition, the coatings also demonstrate excellent heat resistance and solvent resistance . This study shows that UV-curable fluorosilicone resins are presumably promising special protective coatings for PCB.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2015
·
IF 2.587
Jian-Chao Liu,Miao-Jun Xu,Tao Lai,Bin Li
Ammonium polyphosphate (APP), which is an important component of intumescent flame retardant (IFR), has been modified with (3-aminopropyl) triethoxysilane (KH550) and silicon resin to enhance its hydrophobic properties. The structure and properties of the modified ammonium polyphosphate (MAPP) were well-characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), and water contact angle (CA). The water CA of MAPP was as high as 148°, which demonstrated that MAPP possessed excellent hydrophobic properties. MAPP and APP were mixed with triazine, which is a char-foaming agent (CFA), and polypropylene (PP) to prepare PP/MAPP/CFA and PP/APP/CFA composites, respectively. The fire retardancy and thermal degradation behavior of PP/MAPP/CFA and PP/APP/CFA composites were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetry, and thermogravimetric analysis. The surface and fracture morphologies were evaluated by SEM. The mechanical properties was analyzed by tensile, flexural, and izod impact tests. The results demonstrated that the MAPP imparted excellent flame retardancy of PP/MAPP/CFA systems, along with a higher LOI value, UL-94 rating, and lower heat release rate and total heat released values. The modification enhanced the interfacial adhesion, mechanical stability, and thermal stability of PP/MAPP/CFA composites. Moreover, PP/MAPP/CFA composites with the thickness of 1.6 mm can still pass the UL-94 V-0 rating after treatment with water for 168 h at 70 °C, meanwhile the weight loss rate was decreased from 2.31% for PP/APP/CFA composites to 0.85%, indicating excellent water resistance. This investigation shows a promising formulation for water-resistant intumescent flame-retardant PP composites with extraordinary properties.
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
PROGRESS IN ORGANIC COATINGS
·
2023
·
IF 6.6
Jialong Zhu,Jieyuan Zheng,Yang Hu,Jiao Wei,Yuanchuan Ma,Haolan Gou,Hong Fan
The demand for high-transparent functional coatings with glass-like hardness, polymer-like flexibility, and anti-smudge properties has increased significantly, especially for foldable touchscreens. However, it is challenging to achieve all the required properties in a coating because the realization of these properties may conflict with each other. In this study, we present a facile method for preparing a special organic-inorganic hybrid coating by utilizing epoxy MTQ silicone resins and amine-terminated hyperbranched polysiloxane (HPSi). The chemical structure of the MTQ resin was fine-tuned to obtain the optimal M/T/Q ratio, and a novel HPSi with rich crosslinking sites and excellent flexibility was prepared as the curing agent. The resulting hybrid network imparted the coating with exceptional hardness (pencil hardness, 7–9H) and excellent flexibility (<2 mm bend diameter). In addition, by modifying the MTQ resin with fluorosilane, the surface energy of the coating was reduced to 14.8 ± 0.4 mJ/m 2 and its anti-smudge and self-cleaning properties were improved without sacrificing the transparency of the coating (99.4 % at 550 nm). Notablely, even after 1000 cycles of steel wool abrasion, these coatings still maintain their outstanding performance. This study provides a promising strategy for the development of hard, flexible, and anti-smudge coatings suitable for foldable displays and other related fields.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Xibing Zhan,Huijuan Liu,Junying Zhang
In this study, vinyl-terminated polysiloxane (abbreviated VISR) and allyl-terminated polysiloxane (abbreviated ALSR) were synthesized and characterized. The curing behaviors and viscoelastic and thermal properties of VISR/PHSR and ALSR/PHSR were comparatively investigated. DSC and in situ FT-IR spectroscopy can be adopted to study the influence of molecular structures on reactivity. The results prove that ALSR/PHSR shows higher reactivity including a higher reaction rate constant and cure degree than VISR/PHSR. Moreover, it is found that the Šesták-Berggren equation can adequately depict the cure kinetic model of silicone resin in hydrosilylation comparing the calculated results with experimental data. Additionally, DMA exhibits that the glass transition temperature and cross-linking density of ALSR/PHSR are much lower than those of VISR/PHSR, TGA data reveal that they have similar thermal stability as well as high char yield, and the decomposition energy ranges from 100 to 270 kJ/mol with increment of degree of mass conversion (αd) (αd = 0.15–0.85).
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
Silicon
·
2020
·Vol. 12
·期 12
·3005-3013
·
IF 1.499
Pan Zhaoqun,Zeng Kelin,Huang Bingsheng,Zhu Liqiang
The oligosiloxane resins were synthesized through hydrolytic sol-gel reaction and remained many hydroxyl groups, which did great harm to the curing process and resulted in poor performance of the cured products. In previous works, epoxy-modified silicone resins were synthesized by dealcoholization, a reaction between 3-glycidoxypropylmethyldimethoxysilane and terminal hydroxyl groups in phenyl silicone resins. Although this method eliminated the hydroxyl groups, it caused a large loss of vinyl groups inevitably and a poor stability of cured products. In this study, methyltrimethoxysilane (MTMS) was used to eliminate hydroxyl groups containing in vinyl methyl phenyl silicone resins, which were synthesized through hydrolytic sol-gel reaction. Most of residual hydroxyl groups were deleted effectively and the great loss of vinyl groups were avoided in the dealcoholization reaction. Then, the methyl phenyl silicone materials were fabricated by hydrosilylation reaction between the synthesized vinyl methyl phenyl silicone resins and hydrogen-containing ones. The cured silicone materials showed excellent optical performance (~ 89.1% at 450 nm) and good adhesion performance. In addition, due to less vinyl loss in the vinyl methyl phenyl silicone resins, the cured methyl phenyl silicone materials exhibited higher cross-linking density, better thermal resistance (5% mass loss at 435 °C) and better mechanical properties (50 shore D) compared with the epoxy-modified phenyl silicone materials. The lumen depreciation (working 168 h at 50 mA) and reflow soldering tests further demonstrated the methyl phenyl silicone materials possessed good thermal stability. These results indicated that the methyl phenyl silicone materials could be used as a LED encapsulant with a good performance.
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
危险品化学品经营许可证（带存储）