Raw materials: Epoxy resin E-51 (epoxy value 0.51 eq/100g, industrial grade), curing agent methyltetrahydrophthalic anhydride (MTHPA, industrial grade), accelerator 2-ethyl-4-methylimidazole (EMI-2,4, analytical grade), continuous basalt fiber (diameter 13μm, tensile strength ≥3500MPa, modulus ≥90GPa), silane coupling agent KH-560 (analytical grade), anhydrous ethanol (analytical grade). Preliminary preparation: Basalt fibers were cut into 10cm short fibers, soaked in anhydrous ethanol for 30min to remove oil, dried in an 80℃ oven for 2h to remove moisture, and sealed for later use. Fiber surface modification: A single-factor variable experiment was used to optimize KH-560. The key parameters were coupling agent concentration (1%, 3%, 5%, 7% by volume), modification temperature (40℃, 60℃, 80℃), and modification time (1h, 2h, 3h). The implementation process was as follows: KH-560 ethanol solution was prepared according to the concentration and ultrasonically dispersed for 10min. The pretreated fibers were placed in the solution and stirred at 100r/min at the set temperature. After the reaction, the fibers were washed three times with anhydrous ethanol, dried in a 100℃ oven for 3h, and sealed for preservation. Characterization was performed using FT-IR to analyze functional groups, SEM to observe morphology, and a contact angle measuring instrument to test hydrophilicity/hydrophobicity. Composite material preparation: The mass ratio of epoxy resin to curing agent was 100:80, the amount of accelerator was 2% of the mass of epoxy resin, and the fiber content was 10wt%-25wt%. Orthogonal experiment L₁₆(4³) was used for process optimization. The influencing factors were fiber content (10wt%, 15wt%, 20wt%, 25wt%), curing temperature (60℃, 70℃, 80℃, 90℃), and curing time (2h, 3h, 4h, 5h). The evaluation indexes were tensile strength and impact strength. The preparation process was as follows: the materials were weighed according to the formula and mixed by stirring in a 60℃ oil bath for 30min to prepare the resin matrix. The modified fibers were added according to the content and mechanically stirred at 300r/min for 20min, followed by ultrasonic dispersion for 15min. The mixture was poured into a mold coated with mold release agent (150mm×100mm×4mm) and cured under 5MPa pressure in a hot press according to the set conditions. After cooling and demolding, the blank material was obtained. Tensile, impact, and bending specimens were processed according to the standards to remove burrs and defects. Performance testing: For mechanical properties, 5 specimens were tested in each group and the average value was taken. Tensile properties were tested according to GB/T1447-2005 using a universal testing machine. Impact properties were tested according to GB/T1451-2005 using a simple supported beam impact testing machine (impact energy 5J). Bending properties were tested according to GB/T1449-2005 using a bending testing machine. Microstructure analysis: SEM was used to observe fiber surface roughness and interface bonding. FT-IR was used to test the wave number from 4000-400cm⁻¹. TGA was used to test aging damage in a nitrogen atmosphere from 30-800℃. Aging resistance test: Treatment methods included thermal aging at 100℃ with time gradients of 0h, 200h, 400h, 600h, 800h, and 1000h, and hygrothermal aging at 85℃ and 85% relative humidity with the same time gradients.
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Table of Contents (TOC) based on the abstract:
Pressure engineering is a potent method for tailoring material properties, but the resulting changes are usually reversible. This study presents a unique exception in the 1D hybrid metal halide (C4H8N)2PbCl4, where self-trapped exciton (STE) emission displays unusual asymmetry and irreversibility during compression and decompression. This uncommon behavior arises from a pressure-activated chemical process within the crystal lattice. Although this process is inherently reversible, it initiates a permanent structural mutation in the inorganic [PbCl4]2− chains, leading to a persistent reshaping of the excitonic energy landscape.
By uncovering an unconventional mechanism that links exciton dynamics with lattice reconstruction and organic chemical reactivity, this research demonstrates that pressure engineering can go beyond simple lattice compression. It also offers a practical strategy for achieving irreversible optoelectronic modulation in hybrid materials.](/_next/image?url=https%3A%2F%2Fpub-8c0ddfa5c0454d40822bc9944fe6f303.r2.dev%2Fai-drawings%2FTVAa3VmfflgMgMB7hwJLJaCFGK8awU99%2F47769a4d-56f9-4d5d-a1de-b2eeddd2b0cc%2Fcfe88c6f-22bf-4a93-9ed0-e57f2f40cdee.png&w=3840&q=75)