Search

The winding tension of the dry-wound forming process is uniform, the process is easy to control and the structure and performance of the prepared vehicle-mounted hydrogen composite pressure vessels are stable. Since the vehicle-mounted hydrogen pressure vessels must be subjected to rigorous fire experiments, the flame-retardant epoxy prepreg yarn technology is currently monopolized by foreign countries. The development of flame-retardant prepreg yarn with good processing properties is of great significance to the promotion and application of hydrogen pressure vessels. Here, a flame-retardant additive hexaphenoxy cyclotriphosphazene (HPCTP) was synthesized and dissolved in epoxy resin of prepreg yarn named P/N-EP. Then, the flame-retardant prepreg yarn was made by the solution impregnation method. Curing behavior, thermal analysis combustion behavior and mechanical properties of P/N-EP and tensile properties of flame-retardant prepreg yarn were investigated. Experimental results showed that the LOI value reached 36.4% at 10 phr and reached the V-0 level of the UL-94 test. The results about thermal stability of the P-N/EP resin system showed that with the increase of P-N content, T5% (temperature at 5% weight loss) and CY600 (carbon residue rate) both increased. The microstructure of carbon residue after UL-94 test was studied by electron microscope and laser Raman spectrometer. The results showed that with the increase of P-N content, the carbon layer structure became denser and the ID/IG decreased significantly, to achieve the flame-retardant effect by the condensed phase mechanism. [ABSTRACT FROM AUTHOR]

Large tow carbon fiber (LTCF) has excellent performance and low cost. However, there are still many difficulties in the application of LTCFs, among which the problem of interfacial penetration is mainly solved. Building interfaces with sizing structures of fiber composites is an effective approach to achieve high performance. In this article, a water-based epoxy sizing agent suitable for LTCF fiber thermoset composites was studied. A comparison of the five LTCFs in this study shows that the wettability and contact angle of the sized LTCFs are significantly improved. In addition, the interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) increased from 52.3 to 71.0 MPa (35%) and 36.4 to 54.6 MPa (50%), respectively. Compared with other imported LTCFs, domestic large-size LTCFs have a wide variety and a large number of surface functional groups, thereby improving their wettability and covalent bonding with the resin matrix. This work has reference significance for the practical application and industrial production of LTCFRP. [ABSTRACT FROM AUTHOR]