Fiber reinforced silicon-containing arylacetylene resin composites

Synthesis and Characterization of Block Copolymers of Poly(silylene diethynylbenzen) and Poly(silylene dipropargyl aryl ether)

Poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl propane) copolymer (ABA-A), poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl ether) copolymer (ABA-O), and a contrast poly(silylene diethynylbenzene) with equivalent polymerization degree were synthesized through Grignard reactions. The structures and properties of the copolymers were investigated via hydrogen nuclear magnetic resonance, Fourier transform infrared spectroscopy, Haake torque rheometer, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis and mechanical tests. The results show that the block copolymers possess comprehensive properties, especially good processability and good mechanical properties. The processing windows of these copolymers are wider than 58 °C. The flexural strength of the cured ABA-A copolymer reaches as high as 40.2 MPa. The degradation temperatures at 5% weight loss (T_d5) of the cured copolymers in nitrogen are all above 560 °C.

Enhanced Magnetic Properties of FeSiAl Soft Magnetic Composites Prepared by Utilizing PSA as Resin Insulating Layer

Thermosetting organic resins are widely applied as insulating coatings for soft magnetic powder cores (SMPCs) because of their high electrical resistivity. However, their poor thermal stability and thermal decomposition lead to a decrease in electrical resistivity, thus limiting the annealing temperature of SMPCs. The large amount of internal stress generated by soft magnetic composites during pressing must be mitigated at high temperatures; therefore, it is especially important to find organic resins with excellent thermal stabilities. In this study, we prepared SMPCs using poly-silicon-containing arylacetylene resin, an organic resin resistant to high temperatures, as an insulating layer. With 2 wt % PSA as an insulating layer and annealed at 700 °C for 1 h, the FeSiAl SMPCs achieved the best magnetic properties, including the lowest core loss of 184 mW/cm³ (measured at 0.1 T and 50 kHz) and highest permeability of 96.

A Novel Zirconium Modified Arylacetylene Resin: Preparation, Thermal Properties and Ceramifiable Mechanism

With the rapid development of thermal protection systems for the aerospace industry and power electronics, polyarylacetylene (PAA) resin plays an important role because of its good mechanical properties, high glass transition temperature (T_g), low water absorption, high char yield (Y_c), and the fact that there is no byproduct released in the curing process. In order to further improve the thermal property of PAA based FRP for the thermal protection field, the introduction of a zirconium element into arylacetylene is promising. In this paper, zirconium modified arylacetylene (ZAA) resin was prepared by two-step synthesis. The FTIR analysis characterized its molecular structure and confirmed the products. The viscosity of ZAA was about 6.5 Pa·s when the temperature was above 120 °C. The DSC analysis showed that the ZAA had a low curing temperature, and its apparent activation energy was 103.86 kJ/mol in the Kissinger method and 106.46 kJ/mol in the Ozawa method. The dielectric constant at 1 MHz of poly(zirconium modified arylacetylene) (PZAA) was 3.4. The TG analysis showed that the temperatures of a weight loss of 5% (T_d5) and char yield (Y_c) at 800 °C of PZAA were 407.5 °C and 61.4%, respectively. The XRD results showed the presence of SiO₂ and ZrO₂ in the PZAA residue after ablation. The XRF results showed that the contents of SiO₂ and ZrO₂ in PZAA residual after ablation were, respectively, 15.3% and 12.4%. The SEM showed that the surface of PZAA after ablation had been covered with a dense and rigid ceramic phase composed of ZrO₂ and SiO₂. Therefore, the introduction of Zr into arylacetylene greatly improved the densification of the surface after ablation, and improved the heat resistant property.

Synthesis and properties of poly(dimethylsilylene-ethynylene-phenoxyphenoxyphenylene-ethynylene)

A novel resin, poly(dimethylsilylene-ethynylene-phenoxyphenoxyphenylene-ethynylene), was synthesized from 1,4-bis( p-ethynylphenoxy)benzene and dimethyldichlorosilane through Grignard reaction. The structures of the monomer and the resin were characterized by elemental analysis, Fourier transform infrared, proton nuclear magnetic resonance, electron ionization-mass spectrometry and gel permeation chromatography. The thermal behaviour of the resin was examined by differential scanning calorimetry. The cured resin exhibits excellent dielectric property, high glass transition temperature, good mechanical properties and high thermal stability. The flexural strength and impact strength of the cured resin were 55.0 MPa and 10.5 KJ m−2, respectively. The degradation temperature at 5% weight loss of the cured resin arrived at 549°C in nitrogen.

Preparation and properties of silicon-containing arylacetylene resin/benzoxazines blends

A series of aniline-based bifunctional benzoxazines (BZs) were synthesized using solventless or solvent method via the Mannich condensation reactions. The chemical structures of these BZs were confirmed using Fourier-transform infrared and proton-nuclear magnetic resonance spectroscopies. The polymer blends were prepared by mixing silicon-containing arylacetylene (poly(dimethylsilyleneethynylenephenyleneethynylene) (PSA)) resin with BZ in weight ratios at 110°C until a homogeneous viscosity liquid was obtained. The resultant blends were characterized by solubility tests, rheological analyses, differential scanning calorimetry, dynamic mechanical analyses and thermogravimetric analyses. The good solubility and low melt viscosity of the blends indicated excellent processability. The curing reactions resulted in the formation of interpenetrating polymer networks. The cured blends exhibited high glass transition temperatures (T gs) and thermal stabilities. The compressive strength and flexural strength of the blend casts improved when compared with pristine PSA.