Phenyl Silicone Resin Research Articles

Study on interface adhesion between EP/IFR/HBPSi epoxy intumescent coating and steel substrate

Interface adhesion is a key factor to systematically understand heat transfer process from intumescent coating to underlying steel substrate. In this paper, epoxy intumescent coating EP/IFR/HBPSi was prepared by adding ammonium polyphosphate (APP), melamine (MEL) and a new organosilicone flame retardant phenyl silicone resin (HBPSi) to epoxy resin (EP). The temperature function was obtained by fitting the interval distance between the intumescent coating and the steel substrate measured from 23 °C to 715 °C with muffle furnace, which showed that the interface adhesion was greatly affected by the heating conditions. At the same time, the effects of incident heat flux, chemical formulation, thicknesses of epoxy intumescent coating, the composition, thickness and surface roughness of steel substrate on interface adhesion were investigated by SEM, energy spectrum analyzer, and temperature distribution measurement and so on. The results indicate that all of these factors have influence on interface adhesion. This work helps to further understand thermal protection mechanism of the intumescent coating for steel structure buildings.

Study of Microwave-Active Composite Materials to Improve the Polyethylene Rotomolding Process

The present paper reports on the formulation and characterization of composite coating materials susceptible to microwave (MW) heating to investigate their application in making the rotomolding process (RM) more energy efficient. SiC, Fe2SiO4, Fe2O3, TiO2 and BaTiO3 and a methyl phenyl silicone resin (MPS) were employed for their formulations. Experimental results showed that the coatings with a ratio of 2:1 w/w of inorganic/MPS are the most MW-susceptible materials. To test the coatings in working mimicking conditions, they were applied to molds, and polyethylene samples were manufactured by MW-assisted laboratory uni-axial RM and then characterized by calorimetry, infrared spectroscopy and tensile tests. The results obtained suggest that the coatings developed can be successfully applied to convert molds employed for classical RM process to MW-assisted RM processes.

Progress in the Preparation and Application of Arylsilane

Abstract: Arylsilanes are the basic raw material for the synthesis of advanced silicone new materials such as phenylsilicone resin, phenylsilicone oil and phenyl silicone rubber, etc. The silicone polymers containing aryl groups were applied widely in the fields including electronics, and aerospace. In the past decades, arylsilanes have been widely used in organic synthesis, such as Hiyama coupling, C-N bond formation, synthesis of biaryl, polyketone polymer, and so on. Therefore, synthetic research on arylsilanes has also received wide attention. In this paper, the research progress of the synthesis and applications of arylsilanes in the past decades has been reviewed.

Improved Mechanical Amplification of Monolithic PZT and PZT Composite via Optimized Honeycomb Macrostructures.

Honeycomb-based, modular composites with a relative density of 0.3948 and a slenderness ratio Lges/t of 6.48 were fabricated on PZT building blocks connected with a PZT-filled phenyl silicone resin. The macro- and micro-structure, phase composition, and the interface between the two materials were analyzed by SEM and image analysis techniques. The mechanical in-plane strain response was determined with uniaxial compression tests and the transversal piezoelectric strain response was determined by applying an electric field. These deformations were analyzed by a 2D digital image correlation analysis to calculate the mechanical strain amplification of monolithic and composite PZT lattice structures. Compared to bulk PZT, the piezoelectric strain amplification in the Y-direction |aypiezo| was higher by a factor of 69 for the composite and by a factor of 12 for the monolithic cellular PZT lattice, when it was assumed that the ratio of the deformation of the bulk material to bulk material was 1. The mechanical amplification of the composite lattices increased up to 73 and that of the cellular PZT lattices decreased to 12. Special focus was given to the fracture behavior and the interface of the PZT/PZT-filled phenyl silicone resin interface.

The preparation of rigid hybrid silicone resins by combining carbon nanomaterial loading nanoparticles

AbstractA series of carbon nanotubes and graphene loading nanoparticles (Mo, Ru, and Pt) were synthesized by the ethylene glycol reduction, in addition, the nanomaterials went through the silanization process by (3‐aminopropyl)triethoxysilane in order to obtain the perfect consistency and dispersibility. The characterization results were then exhibited by X‐ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy tests. Furthermore, the nanomaterials modified silicone resins were obtained by combining methyl phenyl silicone resins, nanocarbon material and HOOBt. The differential scanning calorimetry, sol–gel time and thermogravimetric analysis tests showed the preferable improvement of heat‐resistant quality. Then the silicone resin matrix composites were manufactured by molding process and went through a thermal decomposition process. The ILSS, bending strength and modulus results showed that the hybrid modified silicone resin composites had the leading trend (361.4 MPa, 190.3 MPa, 13.5 GPa, etc.) at all temperature stages. This experimental scheme of carbon nanomaterial loading nanoparticles and hybrid modified silicone resins would have a competitive advantage in exotic material field.

Non‐isothermal DSC curing kinetics study of silicone‐modified epoxy/ABS/GO nanocomposite

AbstractIn this study, non‐isothermal curing kinetics of the prepared samples was studied using differential scanning calorimetry (DSC) to evaluate the effect of methyl phenyl silicone resin (MPS), acrylonitrile butadiene styrene (ABS), and graphene oxide (GO) on the cure reaction of epoxy resin. Chemical and microscopic structure of prepared nanocomposites was investigated using Fourier‐transform infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM), respectively. Izod impact strength of modified epoxy resin with 5 phr MPS, 2 phr ABS, and 0.1 phr GO was about 53% higher than pure epoxy resin. Evaluation of activation energy (Ea) by Kissinger, Ozawa, FWO and Friedman methods showed that the presence of GO facilitates the curing reaction by reducing Ea about 30% which is due to the catalytic effect of hydroxyl groups presented on the surface of GO for epoxy ring opening. According to Friedman's plots, curing reaction remained autocatalytic for all of samples. The presence of GO increased the autocatalytic term of the reaction (n) from 0.26 to 0.32. Non‐isothermal DSC diagrams obtained from experimental data fitted well with data obtained from theoretical relations.

Preparation and Characterization of a Thermal Barrier Heat-Resistant Silicone Coating

In this study, a heat resistant coating with thermal barrier property was designed. Two types of silicone resin (based on methoxy methyl polysiloxane and methyl phenyl silicone resin) were used as thermal resistant binders, and the black iron oxide pigment and glass micro hollow sphere (MHS) additive were utilized to formulate the heat resistant/thermal barrier coatings. Coatings were applied to the steel substrates, and general properties of the coatings such as film formation, curing, and adhesion were then studied. The thermal stability of the coatings was evaluated by thermogravimetric analysis up to 450 °C. The thermal conductivity coefficient of the coatings was measured by temperature modulated differential scanning colorimeter (TMDSC). Investigation of the properties of all coatings showed that the silicone coating with the 7% of hollow microsphere had higher thermal stability (Tmaximum weight loss= 538 °C) and better barrier properties (Thermal conductivity= 0.29 W/mK (compared with other coatings.

Trifluoromethanesulfonic acid-assisted one-pot catalytic synthesis of phenyl silicone resins

A facial one-pot method for the preparation of phenyl silicone resins is introduced. Vinyl end-capped phenyl silicone resin (i) and phenyl hydrosilicone resin (ii) were successfully prepared by selecting trifluoromethanesulfonic acid (TfOH) as the catalyst. The structures and the thermo-optical performances of the resulting resins were investigated by IR, NMR, GPC, TGA and UV–Vis, respectively. The results show that the yield, the transparency and the refractive index for resin (i) are 95%, 90.4% and 1.5253, respectively, and for resin (ii) are 94%, 92.8% and 1.5201, respectively. The properties of the cake obtained by hydrosilylation of resin (i) and (ii) in the ratio of 1:1 for LED chip encapsulation were studied, and the packaging effect was examined preliminarily.

Synthesis of Epoxy-Modified Methyl Phenyl Silicone Resins for LED Encapsulation

The epoxy-modified silicones have the advantages of both epoxy and organic silicon. In this paper, a series of epoxy-modified methyl phenyl silicone resins were synthesized through the hydrosilylation reaction between 1, 2-epoxy-4-vinylcyclohexane and methyl phenyl silicone resins. The effects of catalyst dosage, reaction time and temperature on the products were further discussed to determine optimal reaction conditions. Then, the as-prepared epoxy-modified silicone resins were cured with methylhexahydrophthalic anhydride. The curing kinetics was investigated through differential scanning calorimetry (DSC). The curing conditions were determined as follows: 1-h curing at 80 °C for and subsequent 1-h curing at 110 °C. The as-prepared products exhibited high light transmittance (~ 90% at 450 nm), strong bonding, suitable hardness and sound waterproof performance. In addition, the introduction of methylphenylsiloxane chain significantly improved the heat resistance and UV resistance of cured products. The epoxy-modified silicone resins are ideal LED packaging materials.

Study on the synthesis and thermal stability of silicone resins reinforced by Si-O-Ph cross-linking.

A novel silicone resin (SR-OH) containing phenolic hydroxyl (Ph–OH) groups was designed and synthesized via co-hydrolysis/condensation and catalytic hydrogenation. During the curing process, the cross-linking degree of the resin was further increased by the Si–O–Ph bonds formed by the reaction of the Ph–OH and terminal Si–OH groups. Thermogravimetric analysis (TGA) showed that the cured resin product exhibited excellent thermal and thermo-oxidative stability, which was much higher than that of a typical methyl phenyl silicone resin (SR-Ph). The temperature at which 5% weight loss occurs (Td5) was up to 606 °C (nitrogen) and 542 °C (air), and its char yield at 800 °C was 91.1% and 85.3% in nitrogen and air, respectively. The significant improvement in thermal stability was mainly attributed to the formation of Si–O–Ph bonds which not only increases the cross-linking degree of the resin but also significantly prevents degradation by the ‘back-biting’ and oxidative cleavage.

Synthesis of Hydrogen-Containing Methyl Phenyl Silicone Resins with a High Refractive Index for LED Encapsulation

Addition-curing is the most common method for preparing high-performance silicone materials for light-emitting diode (LED) encapsulation. The structure and the hydrogen content of the hydrogen-containing cross-linking agents used in addition reactions have a significant influence on the performance of the cured products. In this study, a series of hydrogen-containing methyl phenyl silicone resins with different hydrogen content were synthesized through hydrolysis condensation. Subsequently, the high-refractive-index hydrogen-containing silicone resins reacted with vinyl methyl phenyl silicone resins to obtain methyl phenyl silicone materials. The cured products showed high light transmittance (> 89% at 450 nm), appropriate hardness and good thermal stability. The tests of reflow soldering (265°C ± 5°C for 10 cycles) and lumen depreciation (50 mA for 165 h) further demonstrated that the prepared silicone materials possessed high thermal resistance and stability. In addition, increasing the hydrogen content enhanced the cross-link density, thereby improving the thermal stability of the silicone materials. The prepared hydrogen-containing methyl phenyl silicone resins can thus serve as a cross-linker for addition-curing in high-power LED encapsulation.

A New Dealcoholization Method in the Synthesis of Vinyl Methyl Phenyl Silicone Resins for LED Encapsulation

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.

Thermal and water absorption properties of cyanate ester resins modified by fluoride‐containing and silicone‐containing components

In order to enhance the moisture resistance of cyanate ester resins, modifiers containing silicon or fluorine moieties were introduced. The curing behaviors of the obtained resins, as well as thermal, water absorption, and dielectric properties of all cured polymers, were investigated in detail. Results show that properties of fillers in polymer have great influence on the thermal property and of polymer. In all cases, modifier exhibited percolation threshold at 5 wt%. Compared with pristine cyanate ester resins (CE), when the methyl phenyl silicone resin B filler was added, the cured polymer exhibited water absorption as low as 0.39% and excellent thermal oxygen stability at 300°C. The introduction of silicon H improved thermal oxidative stability at 400°C without significant compromise in processability or mechanical properties.

Synthesis of High Refractive Index Epoxy Modified Methyl Phenyl Silicone Resin and Amine Phenyl Silicone Resin for LEDs Packaging

A series of epoxy modified methyl phenyl silicone resins with different epoxy values were prepared by an approach of combination of hydrolytic sol-gel and non-hydrolytic sol-gel process. Then, in order to solve poor compatibility between epoxy modified silicone resins and commercial amine curing agents, amine phenyl silicone resin curing agent was synthesized by non-hydrolytic sol-gel method. The test results exhibited that the process of combination of hydrolytic sol-gel and non-hydrolytic sol-gel process had a significant effect on the elimination of hydroxyl groups. A lot of experiments and mechanism analysis exhibited that the activity and content of hydroxyl groups are two important factors for ring-opening of epoxy groups and gelation of product. So, epoxy groups can be stably and efficiently introduced in the terminal of product in the course of non-hydrolytic sol-gel process, which hugely avoided ring-opening of epoxy groups. Subsequently, epoxy modified silicone materials were obtained by thermal curing reaction between epoxy modified silicone resins with different epoxy values and amine phenyl silicone resin. And the curing reaction can be completed at 80 °C for 2 h. Transmittance of light, thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and reliability test were used to analyze performance of epoxy modified silicone materials. The results exhibited that prepared silicone materials had a high transmittance (>90%), strong adhesive strength, good thermal stability and mechanical performance. Therefore, epoxy modified silicone material can be applied in high-power LEDs packaging.

Synthesis of High-Refractive-Index Epoxy-Modified Vinyl Methyl Phenyl Silicone Resins for Encapsulation of LEDs

A series of high-refractive-index epoxy-modified vinyl methyl phenyl silicone resins with different content of vinyl groups have been synthesized by a combination of hydrolytic and nonhydrolytic sol–gel processes to improve their adhesion. The products were characterized by Fourier-transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy. The results showed that epoxy and vinyl groups were successfully introduced into the products while the content of hydroxyl groups was low. Then, epoxy-modified silicone materials were manufactured by addition reaction between the epoxy-modified vinyl methyl phenyl silicone resins and hydrogen-containing phenyl silicone resin. The epoxy-modified silicone materials were characterized by thermal aging (250°C for 2 h) experiments, light transmittance measurements, thermogravimetric analysis, red dye penetration tests, reflow soldering (270°C for 10 cycles), and lumen depreciation (50 mA for 165 h) tests. The results showed that the epoxy-modified silicone materials exhibited high transmittance (> 90%) and good thermal stability. The epoxy-modified silicone materials showed better resistance to high temperature and ultraviolet (UV) radiation than commercial epoxy resin (6103). The introduced epoxy groups greatly improved the adhesion of the silicone resin. The epoxy-modified silicone material prepared using epoxy-modified vinyl methyl phenyl silicone resin with higher content of vinyl groups showed better mechanical performance (50 Shore D). The epoxy-modified silicone material EVMPS-3′ is expected to be applicable in packaging of high-power light-emitting diodes (LEDs).

Synthesis and Properties of Phenyl Silicone Resin Reinforced Addition Type Liquid Phenyl Silicone Rubber

Phenyl silicone resin reinforced addition type liquid phenyl silicone rubber was prepared by vulcanization of vinyl end-capped polymethylphenylsiloxane (PVPS), phenyl MT resins and hydrogen end-capped polydiphenylsiloxane (PHPS) under Pt catalysis at 150°C for 4h. The effects of the proportion and the vinyl content of phenyl MT resins on the mechanical properties of cured products were investigated. The thermal stability was explored by thermogravimetric analysis. The changes of mechanical properties were also studied before and after irradiation. Phenyl silicone rubber with good performance was obtained when the phenyl MT resin content was 50~60 wt% and the vinyl content was at 5.5~6.6 wt%. The onset temperature of thermal degradation and the center temperature of thermal degradation were 443.7°C and 502°C, respectively. When the radiation dose increased from 0 to 300 KGy, the tensile strength decreased from 4.1MPa to 2.3MPa and the tearing strength decreased from 8.9MPa to 5.1MPa. When the radiation dose continues to increased from 300 to 900 KGy, the tensile strength increased from 2.3MPa to 6.4MPa and the tearing strength increased from 5.1MPa to 6.5MPa. During the process of radiation, the elongation at break had been kept down from 96% to 52%, and the hardness increased from 80A to 90A.

Curing mechanism, heat resistance, and anticorrosion properties of a furan/methyl phenyl silicone coating

A coating composed by methyl phenyl silicone resin (PSi) and furan resin (FR) was prepared, and its curing mechanism, heat resistance, and anticorrosion properties were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, electrochemical test, and chemical resistance test. Aldol condensation reaction between FR and PSi occurred at below 200°C, and PSi underwent self‐multidehydrogenation at above 200°C. These curing reactions gave excellent thermal stability and anticorrosion properties. Compared with pure PSi, the blended containing lower than 20 wt% FR had better thermal properties, manifested as over 390°C of 5 wt% weight loss temperature and over 40% of char yield at 800°C. The adhesion property of cured blended system on the metal surface reached the first level which exceeded that of pure PSi coating (the third level). Furthermore, the corrosion resistances of coating in acid, alkali, and salt environments were all improved compared with those of monomeric polymer coating. The impedance of blended coating in 3.5% NaCl solution decreased with increasing FR content, which was 1.8 × 106 Ω cm2 when the FR content was 40%, being higher than that of pure PSi coating (7.12 × 105 Ω cm2). This was mainly due to the formation of a cross‐linked network structure based on Si―O―C bond and the enhanced adhesion of cured blended coating. In addition, the surface roughness of cured blended coating was below 2.0 μm, which may have a positive effect on drag reduction in real applications.

Direct synthesis of zirconium containing phenyl silicone resin for LED encapsulation

ABSTRACTZirconium containing phenyl silicone resin were synthesized through hydrolysis among zirconium n-propoxide (ZP), diphenyldimethoxysilane, and 3-(trimethoxysily)propyl methacrylate under acidic conditions. The results indicated that the resins have favorable thermal stability for practical usage, and the thermal weightless of all resins are less than 3% under 200°C.The refractive index of the materials is positively correlated with zirconium content, and tunable between 1.57 and 1.59, and light transmittance does not change significantly with the increase of zirconium element. In addition, the resins can be stably stored for more than 6 months without any effect on the application.

Direct grafting of octamaleamic acid-polyhedral oligomeric silsesquioxanes onto the surface of carbon fibers and the effects on the interfacial properties and anti-hydrothermal aging behaviors of silicone resin composites

The interface between carbon fibers (CFs) and matrix resin makes a critical contribution to bulk performance of composites. In order to enhance interfacial properties and anti-hydrothermal aging behaviors of methyl phenyl silicone resin (MPSR) composites, octamaleamic acid-polyhedral oligomeric silsesquioxanes (POSS-acid) were directly grafted onto CFs surface by chemical bonding for the first time. Surface chemical groups and morphologies of CFs before and after POSS-acid grafting were systematically characterized. Scanning electron microscopy and atomic force microscopy images showed a uniform distribution of POSS-acid on the fiber surface and the improved surface roughness. POSS-acid cages grafting could improve obviously the fiber polarity, wettability, and free energy by dynamic contact angle analysis testing. The interlaminar shear strength (ILSS) of MPSR composites reinforced with the POSS-acid-modified CFs (CF-POSS) was 45.01 ± 1.69 MPa, which increased by 52.73 % compared to that of MPSR composites reinforced with untreated CFs (29.47 ± 0.94 MPa). And, impact strength of CF-POSS composites (77.69 ± 2.83 kJ m−2) was increased by 32.89 % compared to that of untreated CF composites (58.46 ± 1.91 kJ m−2). Moreover, ILSS of CF-POSS composites after hydrothermal aging treatment was 40.89 ± 1.51 MPa with a decrease of just 9.15 % compared to that of untreated CF composites (20.52 ± 0.65 MPa) with an obvious decrease of 30.37 %. Meanwhile, POSS-acid functionalization did not decrease fiber tensile strength. Based on our design starting from simple chemistry and inexpensive materials, such hierarchical reinforcements with improved interfacial strength and anti-hydrothermal aging behaviors have great potential in advance polymer matrix composites.

Synthesis of phenyl silicone resin with epoxy and acrylate group and its adhesion enhancement for addition-cure silicone encapsulant with high refractive index

A novel phenyl silicone resin with epoxy and acrylate group (PSREA) was successfully synthesized via the non-hydrolytic sol-gel condensation reaction of 3-glycidoxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, and diphenylsilanediol, and was employed as the adhesion promoter for addition-cure silicone encapsulant (ASE) with high refractive index. The structure of PSREA was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, and 29Si nuclear magnetic resonance spectroscopy. The influence of PSREA on the properties of ASE was studied. It was found that PSREA could markedly enhance the adhesion strength of ASE to aluminum (Al) and poly(p-phenylene terephthamide) (PPA) substrate. When the content of PSREA was 1.5 phr, the shear strength of ASE was 4.43 and 2.27 MPa for Al and PPA substrate, which was about 71 and 266% higher than that of ASE without the adhesion promoter, respectively. In addition, PSREA had little effect on the mechanical properties, refractive index, and viscosity of ASE.