Two novel types of amine-terminated siloxane chain extenders bearing bulky trimethylsiloxy (TMS) side groups (EAA-trisTMS and EAA-diTMS) were successfully synthesized via the addition reaction of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane with 3-aminopropyltris(trimethylsiloxy)silane or 3-aminopropyldi(trimethylsiloxy)methylsilane. Subsequently, these chain extenders were incorporated into polyurethane (PU) backbones to prepare a series of TMS-modified polyurethane films. The chemical structure, thermal stability, mechanical properties, surface morphology, and dielectric properties of the resulting copolymers were systematically investigated. The results demonstrate that the introduction of bulky TMS side chains significantly enhances the thermal stability of the PU matrix. The modified polyurethanes exhibit a distinct microphase-separated morphology. The flexible, bulky organosilicon side chains act as internal plasticizers, resulting in a remarkable increase in elongation at break. Surface analysis reveals that the umbrella-like TMS groups preferentially migrate to the air/polymer interface, forming a dense hydrophobic layer. The water contact angle increases significantly to above 100 °, and surface saturation is achieved at approximately 10 wt% loading. Moreover, the incorporation of non-polar organosilicon segments effectively reduces the dielectric constant of the material. This work presents a new strategy for designing high-performance polyurethane materials with excellent hydrophobicity, thermal stability, and low dielectric properties.

This study systematically investigates the dual-role modification of addition-curable silicone rubber using tetra-armed star-shaped polysiloxanes (Q-type polymer) as both crosslink density enhancers and silica surface modifiers. First, dimethylvinylsiloxy-terminated Q-type polymers (Q-m-Vi, DP = 20-60) were synthesized to optimize the network structure. At a vinyl silicone oil (PDMS-Vi)-to-Q-40-Vi mass ratio of 4:1, Si-H/Si-Vi molar ratio of 1.3:1, and 30 wt% fumed silica loading, the Q-40-Vi modified silicone rubber achieved a balanced high performance with a tensile strength of 2.73 MPa (63 % improvement over the blank) and elongation at break of 283.5 %, along with a 15 % increase in 800 degrees C residual mass. This combination of strength and elasticity is critical for high-performance seals and damping materials. Mechanical properties testing confirmed that moderate DP (n = 40) enabled uniform crosslinking while avoiding spatial hindrance from excessive chain length. Second, methoxy-terminated Q-type modifiers (Q-m-OMe) were employed for silica surface treatment. At 4 wt% loading (relative to silica), Q-50-OMe maximized interfacial reinforcement, yielding a silicone rubber with an exceptional tear strength of 23.77 kN/m and 74.09 % residual mass at 800 degrees C, representing superior thermal stability. FT-IR, SEM, and wetting tests verified covalent Si-O-Si bonding and reduced silica agglomeration. DMA and DSC analyses further revealed that Q-type modifiers suppressed chain mobility with a crystallization peak shifted to-84.4 degrees C, and significantly enhanced the storage modulus, collectively contributing to a highperformance silicone rubber system.

To elucidate the structure-property relationships governing low-dielectric-constant (low-k) polyimide (PI) materials, this study focuses on molecular design and synthesis, preparing a series of alpha, omega-bis(aminopropyldimethylsiloxane)-terminated poly(dimethylsiloxane-co-methyltrifluoropropylsiloxane) (PFMS) flexible segments. By adjusting the fluorine content and molecular weight, these oligomers were copolymerized into a PMDA/ODA-type PI backbone, yielding fluorosilicone-modified PI (PI-PFMS) films. The influence of PFMS structural parameters on microphase-separated morphology and on the resulting thermal, mechanical, and dielectric behavior was systematically investigated. The results demonstrate that incorporating PFMS induces microphase separation, resulting in a characteristic "sea-island" morphology. A pronounced synergistic effect is observed between the siloxane segments and the fluorine atoms: the electronegative fluorine atoms reduce the electronic polarizability, while the flexible Si-O-Si linkages augment the free volume. Consequently, the dielectric constant of the modified PI is systematically tuned, decreasing from 3.5 for pristine PI to 2.24 at 10 MHz. Notably, this work highlights the intrinsic trade-off in material design-namely, that a reduction in dielectric constant is inevitably accompanied by changes in tensile strength and optical transmittance, attributable to thermodynamic incompatibility and phase separation. This study offers fresh insights into the synergistic optimization mechanism of fluorine/silicon comodification and provides a new pathway for the design of advanced polyimide dielectrics.

With the miniaturization and high integration of modern electronic devices, thermal interface materials (TIMs) with high thermal conductivity and long-term reliability are urgently required. This study proposes a molecular engineering strategy employing star-shaped polysiloxane derivatives to address the critical trade-off between thermal performance, processability, and reliability in silicone-based TIMs. Vinyl-terminated star-shaped polymers (Q-m-Vi) are introduced into the poly(dimethylsiloxane) (PDMS) matrix to modulate the cross-link network topology. Optimizing the degree of polymerization (DP = 40) and the dosage of Q-m-Vi facilitates the formation of a uniform, dense threedimensional network. This architecture effectively immobilizes free silicone chains, significantly suppressing the "oil bleeding" phenomenon while maintaining matrix compliance to ensure low contact thermal resistance. Concurrently, alkoxy-terminated star-shaped polymers (Q-m-OMe) are utilized for surface treatment of AlN/Al2O3 hybrid fillers. Q-m-OMe forms robust covalent bonds (Si-O-Al) and a dense organic coating on filler surfaces, drastically enhancing interfacial compatibility. Molecular dynamics simulations confirm that Q-m-OMe constructs an effective phonon bridge via low-frequency resonance and high-frequency extension, minimizing interfacial phonon scattering. By further optimizing the filler formulation (78 vol % loading with a 6:3:3 volume ratio of 120 mu m AlN: 10 mu m Al2O3: 1 mu m AlN), the fabricated thermal pad achieves an excellent thermal conductivity of 3.67 W center dot m(-1)center dot K-1 and a low thermal resistance of 8.29 K center dot cm(2)center dot W-1. This work demonstrates a dual-functional modification approach using tailored star-shaped polymers, offering a promising pathway to the development of next-generation high-performance TIMs.

To address the poor hydrophobicity, insufficient dielectric performance, and limited thermal stability of traditional polyurethane acrylates (PUA) in electronic packaging applications, alpha-trimethylsilylmethyl-omega-dihydroxyalkyl-terminated polymethyltrifluoropropylsiloxane oligomers (TMPME-PMTFPS, MNMR = 2038-5004 g center dot mol-1) with varying molecular weights (or degrees of polymerization) were synthesized via molecular design. These oligomers feature a flexible side-chain unit integrating both fluorine and silicon atoms. Using this segment as a functional unit, it was chemically grafted onto acrylate-terminated polyurethane. Subsequently, a series of fluorine-silicon synergistically modified polyurethane acrylate (FSi-PUA) films was successfully prepared using an efficient and environmentally friendly ultraviolet (UV) curing technology. The effects of the molecular weight and content of TMPME-PMTFPS on the comprehensive properties of the modified films (FSi-PUA) were systematically investigated. It was found that the fluorine-silicon segments spontaneously migrated and enriched at the film surface during curing, significantly enhancing the surface properties. Adding 10 wt% of TMPME-PMTFPS3 (MNMR = 5004 g center dot mol-1) substantially increased the water contact angle from 74.5 degrees to 114.6 degrees, while simultaneously significantly reducing the water absorption yield. Adding 10 wt% of TMPME-PMTFPS1 (MNMR = 2038 g center dot mol-1) raised the soft segment decomposition temperature to 416.20 degrees C, which is 34.2 degrees C higher than that of the unmodified FPUA-0. Dielectric performance tests revealed that at 14.2 GHz, the dielectric constant of the modified film could be as low as 2.77, representing a 1.77% reduction compared to the unmodified FPUA-0 material. In contrast, the film's transparency was maintained. This study combines a "fluorine-silicon integrated" side-chain design with UV curing technology, providing an effective strategy for preparing advanced electronic packaging materials with excellent hydrophobicity, a low dielectric constant, good heat resistance, and tunable mechanical properties.

Polycarbonate (PC) is widely used in applications that require optical transparency and fire safety; however, conventional flame retardants often compromise its mechanical properties and clarity. In this study, a series of hyperbranched polyborosiloxanes (PBS) with varying boron-to-silicon ratios was synthesized via a one-step dehydration condensation reaction. The effects of PBS on the flame-retardant performance, mechanical properties, optical transparency, and hydrophobicity of PC were systematically investigated. Results demonstrated that PBS-C, with the highest boron content, significantly improved the flame retardancy of PC. At a loading of 6 wt%, the PC/PBS-C6 composite achieved a UL-94V-0 rating and a high limiting oxygen index (LOI) of 40.3. Cone calorimetry tests revealed reductions in peak heat release rate (PHRR) and total heat release (THR) by 35.9% and 15.7%, respectively. Moreover, the composite exhibited enhanced mechanical properties, with flexural strength and impact strength increasing by 28.8% and 21.9%, respectively. The incorporation of PBS also improved the hydrophobicity (water contact angle up to 108.86 degrees) while maintaining high optical transmittance (>83%). This work presents a promising strategy for developing high-performance PC composites with balanced flame retardancy, mechanical strength, and transparency.

The development of high-performance thermal interface materials (TIMs) is crucial for addressing the escalating thermal management challenges in modern electronics. While incorporating high-thermal-conductivity fillers is a common strategy, enhancing the intrinsic thermal properties of the polymer matrix remains a significant challenge. This study presents a novel approach by synthesizing cerium-ion-bridged polydimethylsiloxane (PDMS) fluids (VC and HC, terminated with dimethylvinylsiloxy and dimethylsiloxy groups, respectively) via an anionically catalyzed non-equilibrium polymerization of cyclic siloxane (D3) using CeCl3 as a bridging agent. These fluids were comprehensively characterized by GPC, FT-IR, and NMR techniques, confirming the successful incorporation of Ce and the tailored polymer structures. Subsequently, a series of thermally conductive silicone gels was prepared by employing VC-1 as the matrix and the HC series as crosslinkers, with 70 vol

This study systematically investigated the synthesis, thermophysical properties, and electronic characteristics of three novel trimethylsiloxy (TMS)-functionalized amino silane coupling agents: 3-aminopropyltris(trimethylsiloxy)silane (AP-trisTMS), 3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]-1-disiloxanyl]-1-propanamine (AP-diTMS), and 1,1,1,3,5,5,5-heptamethyl-3-N-2-(aminoethyl)-3-aminopropyltrisiloxane (AEAP-diTMS). By precise design of the molecules through partial replacement of alkoxy groups with TMS, the hydrogen bonding ability, hydrophobicity, and thermal stability of these compounds were adjusted. Based on experimental results such as density, viscosity, and vapor pressure, combined with density functional theory calculations of electronic properties (the analysis of electrostatic potential energy of molecular surfaces, frontier molecular orbitals, simplified density gradient functional analysis, and localized orbital locator scatter plots), the molecular characteristics are comprehensively discussed. This research not only deepens our understanding of these compounds but also highlights their potential as high-performance materials.

A series of alpha, omega-dimethylglycidoxypropyl-terminated PDMS oligomer (PDMS-GE) oligomers with different polymerization degrees were synthesized and used to modify the bisphenol-A diglycidyl ether E51 (DGEBA) / 4,4-diaminodiphenylmethane (DDM) epoxy resin, resulting in epoxy resins with high hydrophobicity, low dielectric constant, good impact toughness, low combustion heat release rate, and low total heat release. The combustion heat release rate and total heat release of the material decreased with the increase in the loadings of PDMS-GE. Relative to pure epoxy resin, the composite E51/D30-10, which using DGEBA as the matrix, PDMS-GE with a degree of polymerization of 30 as the modifier in an amount of 10 phr relative to the mass sum of DGEBA, PDMS-GE and DDM, exhibited the best comprehensive performance with a water contact angle of 102.42 degrees, a dielectric strength of 6.49 kV/mm, a dielectric constant of 2.93 at 14.2 GHz, the peak rate of heat release (PRHR) and total heat release (THR) are of 378.3 kW/m2 and 134.4 MJ/m2, respectively. These comprehensive performances underscore the potential of PDMS-GE oligomers in significantly improving epoxy resin properties. When the loadings of PDMS-GE oligomers are less than 5 wt%, PDMS-GE with a lower degree of polymerization can improve the toughness of epoxy resins. The impact strength of the composite E51/D24-5, which uses DGEBA as the matrix, PDMS-GE with a degree of polymerization of 24 as the modifier in an amount of 5 phr relative to the mass sum of DGEBA, PDMS-GE, and DDM, reaches 98.1 kJ/m2, which is about 28.9 % higher than that of pure epoxy resin. The results also indicated that the degree of polymerization of PDMS-GE oligomers has less influence on the dielectric properties and mechanical properties of composite materials.

Several single- and double-dihydroxyalkylamino groups terminated polysiloxanes with different molecular weights were prepared by a four-step synthesis method using diethanolamine, allyl bromide, and hydrogen-containing silicone oil. The emulsified dihydroxyalkylamino group-modified polysiloxane lotion was used as a softener in fabric finishing. Compared to fabric treated with the commercial amino silicone oil softener, fabric treated with them can improve the hydrophilicity from hydrophobic to hydrophilic, and the tertiary amine structure can resist yellowing defects of the amino silicone oil with the whiteness difference value in line with the normal yellowing value change range. It will not affect the color brightness of the fabric. Fabric treated with such modified polydimethylsiloxane will increase softness rating greater than 4.0. Meanwhile, its improved anti-static ability was indicated by fabric resistance lowered from 10 13 to 10 12 Ω, and fracture strength was enhanced from 211.2 N to more than 400 N.

Various types of polyethylene (PE) and their maleic anhydride grafts (MAPE) were incorporated into PA66 to enhance its tribological properties. The effects of PE modulus and interfacial compatibility on the friction and wear properties of PA66/PE blends were investigated. The results demonstrate that the coefficient of friction (COF) and volume wear rate (omega) of PA66/PE blends were significantly reduced with the inclusion of PE. Notably, as the flexibility of the PE chains increased (indicated by a reduction in the flexural elastic modulus), both COF and omega further decreased. The optimal blend exhibited a COF of 0.22 and a omega of 6.68 x 10(-6) mm(3)/(N.m), representing reductions of 56.8% and 82.0%, respectively, compared to neat PA66. Moreover, the introduction of maleic anhydride groups improved interfacial compatibility, resulting in the PA66/MAPE blends with superior wear resistance and mechanical properties.

To develop flame-retardant epoxy resin (EP) with high strength and toughness, a series of glycidyl ether-terminated polydimethylsiloxanes (PDMS-GEs) with varying branching degrees were synthesized. These PDMS-GEs, along with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), were utilized to modify a diglycidyl ether of bisphenol A/diaminodiphenylmethane (DGEBA/DDM) epoxy system. This approach successfully yielded hydrophobic, low-dielectric EP composites exhibiting excellent integrated mechanical and flame-retardant properties. Characterization of mechanical and thermal properties revealed that both the branching degree of PDMS-GE and the incorporation of DOPO positively impacted the material's strength and toughness. The EP composite (EP/H-GE/DOPO) co-modified with hyper-branched PDMS-GE (H-GE), and DOPO demonstrated optimal mechanical performance. Compared to neat EP, this composite exhibited increases of 11.3 % in tensile strength, 21.1 % in flexural strength, and 32.5 % in impact strength. Furthermore, the EP/H-GE/DOPO composite established an effective P/N/Si synergistic flame-retardant system. It achieved a UL-94 V-0 rating and possessed a high limiting oxygen index (LOI) of 37.5. Compared to neat EP, cone calorimetry tests (CCT) indicated significant fire safety improvements with a char residue increased by 142.9 %, the peak heat release rate (PHRR) and total heat release (THR) decreased by 38.2 % and 30.3 %, respectively. Additionally, the total yields of CO and CO2 were reduced by 35.3 %.

Polydimethylsiloxane (PDMS) was modified via high-temperature thermal blending with K+, Ce3+, and Zr4+ ions to synthesize metal-incorporated polysiloxane fluids. Structural characterization by 29Si NMR, FT-IR, XPS, and TGA confirmed successful modification. Systematic investigations revealed that the type, content, and blending temperature of metals critically influenced thermal stability and conductivity. Notably, Ce3+-modified PDMS exhibited enhanced performance: incorporation of 2 wt% cerium stearate increased intrinsic thermal conductivity to 0.203 W/(m center dot K) (13.4 % higher than pure PDMS) while significantly reducing dielectric constants from 2.67 to 2.56 and the dielectric loss from 0.0060 to 0.0025 at 1 kHz. Further application studies demonstrated scalable thermal conductivity improvements in alumina-filled composites. Utilizing Ce3+-modified PDMS as a matrix and alpha-trimethylsilyloxy-omega-triethoxysilylethyl terminated PDMS as an alumina surface treatment agent (86 vol% loading), the resultant silicone paste achieved 6.84 W/(m center dot K), representing a 38.2-fold enhancement over pure PDMS. Analogous formulations with alpha-dimethylvinylsilyloxy-terminated PDMS as the surface treatment agent attained 6.62 W/(m center dot K) (a 37.0-fold improvement). Thermal dissipation experiments validated the superior performance of these composites, highlighting their potential for advanced thermal management applications.

The ring-opening polymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetraethylcyclotetrasiloxane with various capping agents such as 1,1,3,3-tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, or 1,1,3,3-tetramethyl-1,3-diethyldisiloxane was conducted under the catalysis of acidic linear phosphazene chloride to produce differently functionalized poly(methylethyl)siloxane fluids. Additionally, copolymers containing active Si-H bonds and methylethylsiloxane segments were prepared by copolymerizing 1,3,5,7-tetramethyl-1,3,5,7-tetraethylcyclotetrasiloxane with 1,3,5,7-tetramethylcyclotetrasiloxane. The effects of the capping agent, reaction time, deactivator dosage, and catalyst dosage on the reaction process were investigated. Optimal conditions included a catalyst concentration of 750 ppm and a deactivator dosage five times the catalyst dosage, yielding a lower polydispersity index (PDI = 1.46-1.55) and high production efficiency within 6 h. Silicone rubbers containing MeEtSiO segments were successfully synthesized via hydrosilylation reactions between polymers with active Si-H bonds and polysiloxanes with Si-CH-CH2 bonds. FT-IR analysis confirmed the successful hydrosilylation reaction, resulting in the formation of ethyl silicone rubber. Compared to pure methyl silicone rubber, the gel fractions and low-temperature performance of ethyl-containing silicone rubber were improved. At the same time, the tensile strength, elongation at break, tear strength, water contact angle, and Tg decreased with increasing ethyl content. The mechanism of linear phosphazene chloride-catalyzed ring-opening polymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetraethylcyclotetrasiloxane was also explored.

A series of T-shaped trialkoxysilylethyl-terminated polydimethylsiloxane oligomers with different terminal structures and different degrees of polymerization have been synthesized by a series of reactions and functioned as the surface treatment agent for Alumina particles. The influence of the structure, degree of polymerization, the treatment method of the prepared oligomers, the mass ratio of alumina particles with different particle sizes, the viscosity of the matrix, the ratio between the modifier and the matrix, and the volume fraction of the mixed-size alumina particles on the fluidity and thermal conductivity of the silicone paste were investigated in detail. When a T-shaped trimethoxylsilylethyl-terminated polydimethylsiloxane with a degree of polymerization of 8 was used as the modifier for the mixed-size alumina particles consisting of 70 mu m, 3 mu m and 0.5 mu m blended in a mass ratio of 9: 4: 2 and its dosage is 1/10 mass of the dimethyl silicone oil with a viscosity of 100 mPa.s, a silicone paste filled with 87 vol% hybrid alumina particles with a thermal conductivity of 6.95 W/(m center dot K) and good fluidity could be prepared. In the 30 W HB-LED heat dissipation application experiment, the results of thermal infrared imaging indicated that compared with the silicone paste filled with 83 vol% alumina with the same compositions while no modifier is used, the surface temperature on the HB-LED chip dropped from 118.2 degrees C to 79.0 degrees C. Moreover, the silicone paste with 87 vol% alumina had a higher cone penetration than that without the addition of any modifier. Based on the FT-IR, XPS, and 3D microscopy images of the modified alumina filler, the modification mechanism was briefly discussed.

The saturation temperatures of tetrakis(trimethylsiloxy)silane (TTMS), 3-ethenyl-1,1,1,5,5,5-hexamethyl-3-[(trimethylsilyl)oxy]trisiloxane (VTMS) and (gamma-chloropropyl)tri(trimethylsiloxy)silane (TClTMS) were measured over the pressure ranges (3.000 to 91.000) kPa. The density data and viscosity values of TTMS, VTMS, and TClTMS were obtained over the temperature ranges (298.15 to 328.15) K. The density values show a reasonable correlation that can be accurately described with a linear equation. The relationship between the viscosity of these compounds and temperature is strongly supported by the Ghatee, Litovitz, Andrade, and Vogel-TammannFulcher equations, demonstrating their reliability and predictive power. The saturated vapor pressure values were estimated using the Clarke-Glew and Antoine equations. The critical properties of pressure, temperature, and volume were calculated using the group contribution method, specifically the Nannoolal model. The acentric factor (omega) at a reduced vapor pressure was calculated by these critical parameters. The calculated ESP map, HOMO and LUMO energy display the electron density and potential energy. The thermodynamic properties of TTMS, VTMS, and TClTMS are crucial values for designing and operating industrial separation processes.

Hexamethylcyclotrisiloxane was polymerized by non-equilibrium anion living polymerization initiated by lithium dimethylsilanol, and bridged with methyltrifluoropropyldichlorosilane to prepare methyltrifluoropropylsiloxy-bridged alpha, omega-dimethylsiloxy-terminated polydimethylsiloxane (DTFP), and then methyltrifluoropropylsiloxy-bridged alpha, omega-dimethylacryloxybutylsiloxy-terminated polydimethylsiloxane (DAFP) was prepared through hydroxyl protection, hydrosilylation, deprotection of trimethylsiloxyl groups and condensation reaction with acrylic acid. DAFP was mixed with alpha, omega-bis[dimethyl-[3-[2,2-bis(acryloyloxy) butoxy]propyl]silyl]-terminated PDMS oligomer (DBABP), a crosslinking density modifier, at a mass ratio of 70: 30, and then 2 parts of a photoinitiator consisting of 2-hydroxy-2-methyl-1-phenyl-1-propanone and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide blended at a mass ratio of 1: 1 were added, and a cured film was prepared under UV light irradiation. The effects of initiator composition, UV irradiation time, and molecular weight of DAFP oligomers on the gelation yield, water absorption, water contact angle, thermal stability, and dielectric properties of the UV-cured products were investigated. These findings are significant as they contribute to the understanding of the synthesis and characteristics of new materials in the field of materials science and polymer chemistry. DAFP oligomers can be copolymerized with the DBABP oligomer within 25 s of UV irradiation. The sample (DAFP-2) with the best performance has a gelation yield of about 87 %, its T5% in nitrogen can reach 377.7 degrees C, its water absorption rate is as low as 0.85 %, and its surface water contact angle can reach 116 degrees. Under 2 GHz conditions, the dielectric constant of the UV-cured PDMS film containing 2.61 % F element is 2.71, which is 9.1 % lower than that of the pure PDMS. Meanwhile, its dielectric loss is also significantly reduced.

This study focuses on the synthesis and characterization of silicone-based composite materials. Four alpha-(nbutyldimethyl)-omega-(acryloxybutyldimethyl)-terminated polydimethylsiloxanes (BATP) with varying molecular weights were prepared through anionic living polymerization, hydrosilylation, hydroxyl protection/deprotection, and esterification reactions. These BATP oligomers were blended with either a tetrafunctional acryloxy polysiloxane (DBABP) or a difunctional fluorinated polysiloxane (DAFP). The mixtures were subsequently UVcured using a hybrid photoinitiator. The effects of UV curing time, blend composition, and structure on the structure and properties of the cured materials were investigated. Notably, all blends achieved cross-linking within 40 s of UV exposure. Composites prepared using BATP-3 oligomer with a number-average molecular weight of 3800 g/mol exhibited the highest gelation yield, approximately 70 %. Among the composites, the BATP-3@DAFP material demonstrated the lowest water absorption at 1.4 %, while the BATP-3@DBABP composite showed the highest water contact angle of 124.62 degrees, indicating excellent hydrophobicity. This research highlights the potential of these silicone composites for applications requiring tunable surface and interface properties.

A series of intrinsic flame-retardant epoxy resins were prepared by adding dual epoxy-functionalized polysiloxane (PDMS-GE) and DOPO to the epoxy resin (EP) of the DGEBA/DDM (60/20) system for curing reaction. The results showed that PDMS-GE and DOPO had excellent synergistic flame retardancy on EP, which was conducive to the formation of large-sized SiO2 particles and the formation of stable and dense char when the material burns. In this work, the LOI of the composite DGEBA/DDM/PDMS-GE/DOPO (60/20/5/5) reached 37.3, which was better than that of the material with only PDMS-GE or DOPO added and was 11.4 higher than that of neat EP. Compared with neat EP, the PHRR and THR of the CCT test were also reduced by 51.0 and 48.0%, respectively, and its UL-94 test reached the V-0 level. At the same time, the material also showed good hydrophobicity, and its water contact angle reached 102.63 degrees. Based on the good dielectric properties and molecular chain flexibility of the PDMS structure, the dielectric constant of the prepared composite material at 14.2 GHz was reduced to 2.63, and the impact strength was also improved by about 33% relative to neat EP.

Three kinds of trimethoxysilyl-functionalized siloxane oligomers with different structures were prepared through condensation and hydrosilylation reactions to increase the volume fraction of Al2O3 fillers in the polysiloxane matrix and improve their dispersibility. The surface modification effect of the oligomers with different structures on the Al2O3 particles and their influence on the thermal conductivity, thermal resistance, and cone penetration of the thermal interface materials filled with the modified Al2O3 particles were studied in detail. The thermal conductivity and cone penetration of the composite material prepared from the Al2O3 particles treated with the alpha-trimethylsilyloxyl-omega-trimethoxysilylethyl-terminated PDMS oligomers showed a decreasing trend with the increase of the degree of polymerization of the siloxane segment. The thermal conductivity and cone penetration of the thermal interface material filled with Al2O3 particles treated with the alpha, omega-bistrimethylsilyloxyl-terminated PDMS oligomers bridged by (MeO)3Si(CH2)2MeSiO segment and the methoxyl-functionalized tris(trimethylsilyloxyl-terminated polydimethylsiloxyl)silane oligomers showed a trend of first increasing and then decreasing with the increase of the length of the siloxane chain segment. The alpha, omega-bistrimethylsilyloxyl-terminated PDMS oligomers bridged by (MeO)3Si(CH2)2MeSiO segment showed the best modification effect on Al2O3 fillers when the degree of polymerization n = 9. It could be used to prepare a thermally conductive silicone paste with an Al2O3 particle filling volume fraction of 88.0 vol%, a thermal conductivity reached up to 9.119 W / (m center dot K), and a 1/4 cone penetration of about 55.0.