Silicon-containing Epoxy Resins Research Articles

Simulation analysis of cryogenic mechanical properties of carbon fiber reinforced silicon-containing epoxy resin composite

The use of carbon fiber-reinforced resin matrix composites instead of metals to manufacture cryogenic propellant tanks for spacecrafts is a development trend in the world aerospace industry. Cryogenic mechanical properties of the composites should be investigated in detail due to that the ultra-low temperature environment may cause micro cracks in the composites, leading to propellant leakage. In the present study, cryogenic tensile properties of a carbon fiber reinforced silicon-containing epoxy resin aomposite are investigated using experimental and numerical simulation methods. A silicon-containing epoxy resin with excellent cryogenic mechanical properties is developed by introducing a synthesized organic silicon polymer epoxidized polysiloxane and Nano-SiO2 into bisphenol F type epoxy resin. The tensile strength and modulus of the silicon-containing epoxy resin at −180 °C are 202.63 MPa and 7.81 GPa, which are 16.71% and 3.03% higher than those of bisphenol F type epoxy resin. The tensile strength of the silicon-containing epoxy resin at −180 °C is increased by 107.7% compared to that at room temperature, and the modulus at −180 °C is nearly twice that at room temperature. The carbon fiber reinforced silicon-containing epoxy resin composite is prepared by vacuum injection molding. The finite element model for the representative volume element of the composite unidirectional plate is established. The random sequence expansion method is used to randomly distribute the carbon fibers and simulate the thermal residual stress, the elastic performance, and the damage of the composite at cryogenic environments. Through comparison, it is found that the simulation results are in good agreement with the experimental results. The simulation reliability for cryogenic mechanical properties of carbon fiber reinforced resin matrix composites is verified. It is expected to provide a reference for the analysis and evaluation of cryogenic mechanical properties of composite tanks.

Fabrication of bio-based amphiphilic hydrogel coating with excellent antifouling and mechanical properties

Antifouling coatings are crucial to protect marine facilities and aquacultures from the damage of microorganisms for long-term serves. However, it is still a challenge to fabricate coating with excellent antifouling performance and superior mechanical stability. Here, we report a bio-based amphiphilic hydrogel coating with excellent antifouling and mechanical properties. The coating was achieved by the in-situ formation of hydrophobic and hydrophilic interpenetrating polymer network (IPN). The hydrophobic part from a synthesized silicon-containing epoxy resin contributes to superior mechanical properties including high tensile strength and excellent adhesion of 5B. While the hydrophilic hydrogel part from the cross-linking of a hydrophilic polymer with AgNPs gives excellent antifouling properties, resist to proteins, bacteria, algae, and other marine organisms. The antifouling performance of the coating was evaluated by the attachment of proteins (BSA-FITC), bacteria (Escherichia coli and Bacillus subtilis), and Algae (Navicula torguatum and Phaeodactylum tricornutum). The results show that the bio-based amphiphilic hydrogel coating (e.g. SA-1-5) endows surface with excellent resistance to the fouling of proteins, bacteria and microorganisms. The overall antifouling and mechanical properties of the amphiphilic coating was also evaluated by field test in East China Sea from June 3rd 2020 to July 17th 2020 that the bio-based amphiphilic hydrogel coating was intact and almost no marine organisms attached. This work provides a new strategy for the fabrication of bio-based and high-performance antifouling coatings.

Synthesis of a novel silicon-containing epoxy resin and its effect on flame retardancy, thermal, and mechanical properties of thermosetting resins

A novel high-performance epoxy resin diphenyldi (9,9-Di-(4-(2,3-epoxypropoxy) phenyl)-4,5-diazafluorenoxysilane) (DEPFS) containing the diazafluorene and silicon group was synthesized by the nucleophilic substitution for the first time and added to bisphenol A epoxy resin (E-51) to form a thermoset blend. We observed that the incorporation of DEPFS remarkably enhanced the flame retardancy and thermal properties of E-51. The cured E-51-30% DEPFS thermoset exhibited a glass transition temperature of 187 °C and a limiting oxygen index of 30.1%, much higher than 153 °C and 22.6% for those of pristine E-51 thermoset, respectively. In addition, the incorporation of DEPFS has dual enhancement effects on the toughness and tensile strength of E-51. This study provides an effective means to prepare a high-performance epoxy resins and proposes flame retardancy and simultaneous reinforcing and toughening mechanism. It was found that the DEPFS with diverse performance has allowed an increasing number of versatile industrial application such as microelectronics, electronics, aerospace and so on.

Comparative study on flame retardancy and thermal degradation of phosphorus- and silicon-containing epoxy resin composites

Epoxy composites containing phosphorus and/or silicon were prepared using polyphenylmethoxysilicone (PPMS) and microencapsulated ammonium polyphosphate (MFAPP) as modifiers. Siliconized epoxy copolymer (EPMS) was obtained via the polycondensation of PPMS and diglycidyl ethers of bisphenol A (DGEBA) type epoxy resin. Then MFAPP was added into EPMS or DGEBA based hybrids respectively to improve their flame retardancy further. Thermal and flame retardant properties of EPMS/MFAPP and DGEBA/MFAPP composites were evaluated by Limited Oxygen index (LOI), UL-94 test and thermogravimetric analysis (TGA). The higher LOI value and UL-94 rating confirmed that MFAPP was an effective flame retardant in DGEBA compared with EPMS. A remarkable synergistic effect of phosphorus and silicon on flame retardation of EPMS/MFAPP was not observed. The reason was that the flame retardancy of epoxy composites containing phosphorus was based on solid phase. FTIR spectra of the char residue showed that when MFAPP was added, without sufficient O-H groups in EPMS/MFAPP, an effective insulative layer which protects underlying materials can’t form during combustion.

The Synthesis of Silicon-Containing Epoxy Resin and its Application in Environmentally-Friendship Epoxy Molding Compound for IC Packaging

Silicon-containing epoxy resin (CNE-Si) was synthesized from diphenylsilandiol (DPSD) and ortho-cresol novolac epoxy resin using SnCl2 as catalyst. The chemical structure of CNE-Si prepared in this paper was characterized by 1H-NMR and FTIR. The thermal stability was analyzed by TGA. The result showed that the –Si- group enhanced the thermal stability of the epoxy resin. The curing kinetics of the system was studied by non-isothermal DSC. The kinetic parameters of the curing reaction including the activation energy were calculated using Kissinger and Ozawa method. The results showed that the system containing CNE-Si has lower curing temperature and more quick curing speed compared to CNE, which can be used for manufacturing the quick-curing EMCs or afterward-curing-free EMCs.

Synthesis and properties of two novel silicon‐containing cycloaliphatic epoxy resins for electronic packaging application

AbstractIn this paper, two silicon‐containing cycloaliphatic olefins were synthesized through the nucleophilic substitution reactions of cyclohex‐3‐enyl‐1‐methanol with di‐ or tri‐chlorosilane compounds. Then, after epoxidation, two new cycloaliphatic epoxy resins with different epoxy groups were successfully prepared. Their chemical structures were confirmed by 29Si NMR, 1H NMR, and Fourier‐transform infrared spectra (FTIR). The properties of cured products, including viscoelasticity, glass transition temperature (Tg), coefficient of thermal expansion, thermal stability and water absorption, were investigated. Compared to the difunctional epoxy resin, the trifunctional one exhibited a remarkably increased cross‐linking density from 0.82 to 4.08 × 10−3 mol/cm3 and Tg from 157 to 228°C. More importantly, prior to curing, they had viscosities of only 240–290 mPa sec at 25°C, which were much lower than that of ERL‐4221 (409 mPa sec), providing the possibility of easy processing. The high glass transition temperatures, good thermal stabilities, and mechanical properties as well as excellent flowability endow the silicon‐containing epoxy resins with promising potential in microelectronic packaging application. Copyright © 2011 John Wiley & Sons, Ltd.

Synthesis and thermal properties of silicon-containing epoxy resin used for UV-curable flame-retardant coatings

A novel silicon-containing trifunctional cycloaliphatic epoxide resin tri(3,4-epoxycyclohexylmethyloxy) phenyl silane (TEMPS) was synthesized and characterized by FTIR, 1H NMR, 13C NMR, and 29Si NMR spectroscopic analysis. A series of flame-retardant formulations by blending TEMPS with a commercial epoxide resin DGEBA (EP828) in different ratios were prepared, and exposed to a medium pressure lamp to form the cured films in the presence of diaryliodonium hexafluorophosphate salt as a cationic photoinitiator. The thermal degradation behaviors of the cured films were evaluated by thermogravimetric analysis. The char yields under nitrogen and air atmospheres increased along with the TEMPS content. The limiting oxygen index (LOI) value increased from 22 for EP828 to 30 for TEMPS80, demonstrating the improved flame retardancy. The data from the dynamic mechanical thermal analysis showed that TEMPS had good miscibility with EP828. The Ts and Tg both decreased from 93 and 138 to 78 and 118 °C, respectively. The crosslinking density (νe) increased along with the TEMPS content. The mechanical property measurements indicated that the addition of TEMPS led to a decrease in the tensile strength and an increase in the elongation-at-break.

Preparation, thermal properties and flame retardancy of phosphorus- and silicon-containing epoxy resins

Phosphorus- and silicon-containing epoxy resins were prepared from (2,5-dihydroxyphenyl)diphenyl phosphine oxide (Gly-HPO), diglycidyloxy methylphenyl silane (DGMPS) and 1,4-bis(glycidyloxydimethyl silyl)-benzene (BGDMSB) as epoxy monomers and diaminodiphenylmethane (DDM), bis(3-aminophenyl)methyl phosphine oxide (BAMPO) and bis(4-aminophenoxy)dimethyl silane (APDS) as curing agents. Epoxy resins with different phosphorus and silicon content were obtained. Their thermal, dynamic mechanical and flame retardant properties were evaluated. The high LOI values confirmed that epoxy resins containing hetero-atoms are effective flame retardants, but a synergistic efficiency of phosphorus and silicon on flame retardation was not observed.

Synthesis and characterization of a novel silicon-containing epoxy resin

A novel silicon-containing epoxy resin, the diglycidylether of bisphenol A-silicon (DGEBA-Si), was synthesized and characterized. The properties of the DGEBA-Si epoxy resin cured with 4,4-diaminodiphenyl methane (DDM), including its cure behavior, glass transition temperature, thermal stability, and mechanical strength were investigated. The char yield of the DGEBA-Si/DDM system was higher than that of a commercial DGEBA/DDM system, indicating that the DGEBA-Si epoxy resin showed good flame-retardance. The cured DGEBA-Si/DDM specimens possessed lower glass transition temperatures and higher mechanical properties than DGEBA/DDM specimens. These features were attributed to the introduction of siloxane groups into the main chain of the epoxy resin, which resulted in the improved flexibility of the cured DGEBA-Si/DDM system.

Thermal stability of epoxy resins containing flame retardant components: an evaluation with thermogravimetric analysis

The thermal properties of epoxy resins containing flame retardants based on silicon, phosphorus, and melamine, were investigated with thermogravimetric analysis (TGA). The weight loss behaviour (including the weight loss temperatures, weight loss rates, and the activation energy for each weight loss stage) and the thermal stability (including the initial decomposition temperature and integral procedure decomposition temperature) were characterized. Phosphorus groups lowered the epoxy resins' initial decomposition temperature, and silicon and melamine groups did not. The integral procedure decomposition temperatures of the epoxy resins were significantly increased with simultaneous incorporation of phosphorus and silicon, owing to the formation of highly anti-oxidant and thermally stable char. Incorporating melamine groups into the silicon-containing epoxy resins did not seriously alter the resins' thermal stability and degradation characteristics.

Chemical modification of dicyclopentadiene-based epoxy resins to improve compatibility and thermal properties

A series of siloxane-containing epoxy resins was obtained by curing dicyclopentadiene-containing epoxy DG with the silicon-containing curing agents TS, DS, and AS. Curing behavior was studied using DSC, and the activation energies of the DG curing reaction with curing agents TA, DS, and AS were found to be 59, 80, and 157 KJ/mol. Meanwhile, the curing reaction of DG with diamines was found to be a first-order reaction using Arrhenius plots. In addition, thermal stability and the weight loss behavior of the cured polymers were studied via TGA. The silicon-containing resins displayed higher weight loss temperatures and higher char yields than the silicon-free resin. The activation energies of degradation ranged from 108 to 206 KJ/mol. The morphology of the cured pieces were investigated using SEM. The DG/TS and DG/DS are more compatible between the epoxy and the curing agents than DG/AS. The limited oxygen index (LOI) values of 31 to 34 for the DG-based resin confirmed the effectiveness of silicon-containing epoxy resins as flame retardants.

Synthesis, characterization, thermal and flame-retardant properties of silicon-based epoxy resins

A new silicon-containing oxirane triglycidyl phenyl silane oxide (TGPSO) and its corresponding silicon-containing epoxy resins are synthesized and characterized. The activation energies of TGPSO curing reaction with various curing agents, including 4,4-diaminodiphenylmethane, 4,4-diaminodiphenylsulfone, and dicyanodiaminde, are found to be 180, 196.5, and 154 kJ/mol. The curing reaction of TGPSO with diamines is determined to be a first-order reaction through means of Arrhenius plots. The introduction of the silicon-containing group results in higher curing reactivity. This silicon-containing resin possesses higher char yield as well as higher limiting oxygen index (LOI = 35) than the commercial epoxy resins, confirming the usefulness of these silicon-containing epoxy resins as flame retardants. Char yields and LOI measurements demonstrate that incorporating silicon into epoxy resins is able to improve their flame retardancy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1231–1238, 1999