Key Engineering Materials Vol. 852

Abstract: The diglyceryl phthalate epoxy resin contains a benzene ring in its molecular structure, and its molecular weight is small. In addition to the generality of epoxy resins, it also has the advantages of low viscosity, moderate reactivity, high adhesion, good compatibility, excellent electrical insulation and ultra-low temperature, and good weather resistance. It has good adhesion with carbon fiber, and it is suitable to make carbon fiber composite material. Based on this background, this article mainly focuses on the seat art design, and uses the wrapping method to analyze the preparation of the carbon fiber composite resin matrix. The optimal reaction conditions are determined by changing the reaction during the preparation of the thermoplastic resin matrix. / PA = 1.9, esterification time 120min, cyclization time 70min, reaction temperature 110 °C, amount of promoter water 6g, concentration of cyclizing agent sodium hydroxide solution 30%. The resin synthesized in this case is a light-yellow transparent liquid with an epoxy value of 0.51 (mol / 100g).

Abstract: Femtosecond laser micromachining is a hot topic in the field of micromachining. Femtosecond laser processing of biomacromolecular micro devices has a promising application prospect. The research content of this paper is femtosecond laser micromachining of biomacromolecule materials, aiming at exploring the mechanism of femtosecond laser micromachining. In this paper, the principle of the interaction between laser and polymer materials is briefly expounded, and the photophysical processes such as transition, energy conversion, energy transfer and electron transfer are explained from the molecular orbital, and the mechanism is classified as photothermal and photochemical action, which is manifested as accelerating material's relaxation transformation process and degradation process. The interaction between polymer materials and laser starts from molecules absorbing the energy of photons to complete the transition from ground state to excited state. Different modes of excitation state inactivation correspond to the conversion of light energy into light energy, heat energy or chemical energy. On the one hand, the thermal action leads to the viscoelastic transformation of the material, and the material deforms or flows under the thermoelastic action; on the other hand, the thermal action accelerates the degradation reaction of the polymer material. The carbonyl group on the molecular chain of PMMA and PLA is more likely to reach the excited state, and the chemical properties of the carbonyl excited state determine that the photochemical processes of PMMA and PLA concentrate on the carbonyl group.

Abstract: Partially stabilized zirconia (PSZ) materials were fabricated using 4 wt% CaO, 3 wt% MgO, and 5.4 wt% Y₂O₃ as stabilizing agents together with monoclinic zirconia powder. The physical properties, phase compositions, and microstructures of the Ca-PSZ, Mg-PSZ, and Y-PSZ samples were investigated by X-ray diffraction, scanning electron microscopy, and energy spectrum analysis. A crucible method was used to explore the relationship between the stabilizing agent and erosion resistance to alkaline steel slag. The results revealed that the zirconia materials stabilized by different stabilizing agents showed obvious differences in their bulk densities, apparent porosities, microstructures, and erosion resistances to alkaline steel slag. The structure of Y-PSZ showed highest density, containing a small number of uniformly distributed pores. In terms of Mg-PSZ, the intergranular bonding in its structure was observed to not be close, and the sample contained some cracks, but no pores. A large number of intragranular pores and a small number of overall pores was observed in Ca-PSZ, resulting in this material having the lowest bulk density. The pores and cracks provide the path to penetrate and diffuse for alkaline steel slag, which weakens the corrosion resistance of PSZ materials. The phase composition of the affected layers in all of the samples after corrosion was almost completely transformed from monoclinic phase to cubic phase, and the phase transition of both the original and transition layers was not obvious due to the formation of a slag film. Y-PSZ did not react with components of the steel slag such as SiO₂ and Al₂O₃, showing the best corrosion resistance to alkaline steel slag.

Abstract: In view of the particularity of marine foam sandwich composite structure, this paper establishes an equivalent parameter conversion system based on the classical sandwich structure design idea, and forms an equivalent simulation method to determine the initial stiffness, initial failure load and ultimate failure load of the structure. The simulation discriminant method makes the SHELL91 shell unit available for the marine foam sandwich composite structure. The bending test of the basic structure of marine foam sandwich composite beams and plates is described in detail. The equivalent simulation method is verified. The initial stiffness, initial failure load and ultimate failure load of the equivalent simulation are in good agreement with the experimental results. The paper finds through the finite element numerical simulation that the research results are consistent with the reality and have strong practicability and popularization. The paper preliminarily believes that this method can be applied to the simulation calculation of large foam sandwich composite ships and marine structures. The calculation amount is greatly reduced based on ensuring the accuracy, and the calculation work such as strength criterion and stiffness check of the overall structure has Strongly convincing.

Abstract: This topic is based on the research and development of inorganic silver-loaded antibacterial materials with good antibacterial activity, and the preparation of silver-loaded calcium carbonate inorganic nano-antibacterial agents by redox reaction. At the same time, the mixed rare earth oxide was added to the ceramic glaze containing silver nano antibacterial agent, and the nano antibacterial building sanitary ceramics were prepared by firing at 1180 °C in an oxidizing atmosphere. This experiment investigated the effect of adding mixed rare earth oxides on the quality and properties of glaze. Experiments show that the new glaze has stronger antibacterial effect than the nano antibacterial glaze without mixed rare earth oxide, and the glaze quality is good. After adding 0.5 wt% of mixed rare earth oxide, the whiteness, abrasion resistance, hardness and thermal shock resistance of the glaze were significantly improved.This topic is based on the research and development of inorganic silver-loaded antibacterial materials with good antibacterial activity, and the preparation of silver-loaded calcium carbonate inorganic nano-antibacterial agents by redox reaction. At the same time, the mixed rare earth oxide was added to the ceramic glaze containing silver nano antibacterial agent, and the nano antibacterial building sanitary ceramics were prepared by firing at 1180 °C in an oxidizing atmosphere. This experiment investigated the effect of adding mixed rare earth oxides on the quality and properties of glaze. Experiments show that the new glaze has stronger antibacterial effect than the nano antibacterial glaze without mixed rare earth oxide, and the glaze quality is good. After adding 0.5 wt% of mixed rare earth oxide, the whiteness, abrasion resistance, hardness and thermal shock resistance of the glaze were significantly improved.

Abstract: Early-age cracks in shaft concrete has become a serious problem in 1000m-plus deep mine due to the high internal temperature and thermal stresses. For the purpose of improve the cracking resistance of concrete, we report a novel experimental design by Temperature Stress Test Machine (TSTM) to study the influence of three fibers including basalt fiber, polyvinyl alcohol fiber and steel fiber on early-age cracking resistance of shaft wall mass concrete. Results of the experimental research indicated that (1) Three fibers can restrain expansion and shrinkage deformation finitely, and the shrinkage resistance effect of different fibers was steel fiber>polyvinyl alcohol fiber>basalt fiber; (2) Three fibers can finitely reduce the tensile stress increasing speed which was basalt fiber>polyvinyl alcohol fiber>steel fiber during; (3) The main function of fibers is restrain crack expansion and brittle failure rather than reduce cracking potential, and the rank of function is steel fiber>basalt fiber>polyvinyl alcohol fiber.

Abstract: The insulation wall provides suitable heat for winter production of solar greenhouse. A thermal insulation mortar containing paraffin/expanded perlite composite phase change material based on desulfurized gypsum was studied as an inner insulation mortar to improve heat preservation and storage/exothermic capacities in solar greenhouse walls. Results showed that the ideal mass ratio of paraffin and expanded perlite was 60:40. The phase change temperature of the paraffin/expanded perlite composite particles was 25.3 °C, and the latent heat was 122.3 kJ/kg. The ideal mass ratio of this composite phase change material and desulfurized gypsum was 1:3. The ideal mixing amounts of dispersible polymer powder, redispersible latex powder, citric acid, hydroxypropyl methyl cellulose ether, and polypropylene fiber were 2%, 0.15%, 0.5%, and 0.5% of desulfurized gypsum content, respectively. The prepared composite phase change thermal insulation mortar had a dry density of 363 kg/m³, a compressive strength of 0.73 MPa, a softening coefficient of 0.65, a coefficient of thermal conductivity of 0.076 W/m·K^-1, a heat capacity of 1.35×10³ J/kg·°C^-1, a heat storage coefficient of 11.65 W/m²·K^-1, a phase change temperature of 25.6 °C, and a phase change latent heat of 89.8 kJ/kg. The phase change temperature and the phase change latent heat were suitable for solar greenhouse production.

Abstract: After the paper uses a unique domestic natural rubber Eucommia to establish a chemical link between the asphalt and the solubility of the powder, analyzed the structure of the double bond vulcanization gutta percha and the solubility of the powder, gutta percha and asphalt amino group of the reaction maleic anhydride, and so gutta appreciate and a chemical link. Analysis then grafted with maleic anhydride mix and low temperature, water stability and mechanical properties, aging resistance. The results found, gutta vulcanized rubber powder can be promoted, but enhance mixing; material properties are not obvious. Maleic anhydride grafted gutta percha is established after the reaction network vulcanized rubber powder and asphalt, so that performance significantly. : Less than 2% when the dosage was added gutta percha grafted SBS modified asphalt to improve its high temperature and aging resistance, without reducing the low-temperature performance, and 1.5% ash graft gutta SBS modified to be most significant .

Abstract: In casting temperature Laquan silica sol crust process suitable for the production of surface roughness is small, precision high accuracy in size, and has become the mainstream technology has been widely used. Silicon sol casting with high dimensional accuracy, good surface quality and other advantages, is a widely used less advanced technology without cutting, using silica sol casting method can save a lot of machine equipment and processing time, but also greatly saves metal materials. Hard fiber sisal has high tensile strength, resistance to seawater immersion, friction resistance, flexibility and other characteristics, can be used for fishing, sailing, mining, transportation rope, canvas, waterproof cloth and other raw materials. The most commonly used binder in investment casting is silica gel solution (abbreviated as silica sol), such as ethyl silicate hydrolysate, water glass and silica sol.

Abstract: The paper introduces the research background, current status and performance of architectural membrane materials, analyzes the superiority of PVC and PTFE performance, discusses the aging and standards of architectural membrane materials, and conducts new rheological destruction of architectural membrane materials. The aging and relaxation characteristics described by the constitutive equations, and the viscos-elastoplastic rheological failure of architectural membranes for constitutive experiments. At the end of the thesis, the aging performance degradation of architectural membrane materials is discussed, and the aging of architectural membrane materials and the significance of membrane performance degradation are explored in depth.