Jiarong Niu

A series of flame-retardant waterborne polyurethane (AWPU-X) compounds with core–shell structures were synthesized by encapsulating hexaphenoxycyclophosphazene (HPCTP) with WPU. AWPU-X, melamine (MA), and AO₁₀D₃-WPU (a flame-retardant WPU self-made in the lab) were synergistically used to prepare flame-retardant microfiber synthetic leather by a two-step method, and the relevant properties of AWPU-X and the microfiber synthetic leather were characterized. The results showed that AWPU-X formed a core–shell structure and had good emulsion stability and film thermal properties. The limiting oxygen index (LOI) value of AWPU-11 reached 27.5% when the HPCTP addition was 11% by mass. The mechanical properties of the flame-retardant microfiber synthetic leather were improved, while the hand-feel of the leather was not affected. When the mass ratio of AWPU-11/MA/AO₁₀D₃-WPU was 60 : 20 : 20, the flame retardancy of the microfiber synthetic leather was the best, with the LOI value of 27.6%, no after-flame, and a damage length of only 0.5 cm in the vertical flame test. At the same time, the peak heat release rate (PHRR) and total heat release (THR) in the cone calorimeter test were reduced by 42% and 30%, respectively. Although the introduction of flame-retardant components decreased the thermal performance of the microfiber synthetic leather, the thermal decomposition residual carbon rate was significantly improved. Based on the results of SEM-EDS, TG-IR, and Raman tests, it was speculated that the flame retardancy of the microfiber synthetic leather was primarily attributed to the joint action of the flame-retardant components in both the gas and condensed phases.

Oxidized sucrose is a non-formaldehyde crosslinking agent with many applications in polymer crosslinking and modification, such as in the preparation of starch films and protein films. However, research on the structure of oxidized sucrose is lacking. In this paper, oxidized sucrose was synthesized through selective oxidation of sodium periodate. By LC-MS, FTIR, TGA, NMR, and HRMS analyses, it was shown that oxidized sucrose existed in the form of a hydrate, and the tetraaldehyde oxidized sucrose could isomerize into the form of two six-membered hemiacetal rings. The structure of oxidized sucrose was also verified by theoretical calculations. Furthermore, the diffusional properties of oxidized sucrose were investigated by the rolling-film method. Finally, it was found that oxidized sucrose used as a crosslinking agent could effectively improve the wrinkle recovery performance of cotton fabrics.

TPU-coated polyester fabric was used as the substrate of a flexible temperature sensor and Ag nanoparticles were deposited on its surface as the temperature sensing layer by the magnetron sputtering method. The effects of sputtering powers and heat treatment on properties of the sensing layers, such as the temperature coefficient of resistance (TCR), linearity, hysteresis, drift, reliability, and bending resistance, were mainly studied. The results showed that the TCR (0.00234 °C⁻¹) was the highest when sputtering power was 90 W and sputtering pressure was 0.8 Pa. The crystallinity of Ag particles would improve, as the TCR was improved to 0.00262 °C⁻¹ under heat treatment condition at 160°. The Ag layer obtained excellent linearity, lower hysteresis and drift value, as well as good reliability and bending resistance when the sputtering power was 90 W. The flexible temperature sensor based on the coated polyester fabric improved the softness and comfortableness of sensor, which can be further applied in intelligent wearable products.