Preparation Of Self-assembled Molecular Film Silver-coated Yarn And Its Application In Electric Heating Fabric

In recent years,the amount of greenhouse gases in the atmosphere has repeatedly set new records,with annual growth rates higher than the 2011-2020 average,and this trend will continue in the coming years.The rise of global temperature has directly led to more extreme cold waves in winter.In this situation,electrical heating fabric has attracted a lot of attention in the field of low temperature protection due to its advantages of clean environmental protection,high thermal efficiency and adjustable temperature.Silver-plated yarn(SPY)is widely used in electrical heating fabric because its good electrical conductivity,flexibility and antibacterial properties.In this paper,SPY was used as conductive material to prepare electrical heating fabric based on silver-plated yarn(SPYEHF)with excellent thermal performance through embroidery process.Firstly,the surface of polyamide yarn(PA)was modified by dopamine or tannic acid to improve the effect of electroless silver plating,so as to prepare silver-plated polyamide yarn(PASPY).Through the test and analysis of its surface morphology,resistance stability,electrothermal performance and mechanical properties,the relatively optimal preparation process of PASPY was obtained.At 25 ℃,the PA was treated with 4 g/L dopamine solution for 120 min before electroless silver plating,and the PASPY resistivity was 11.678 Ω ·10 cm.After 120 h of electrical aging,the resistance change rate was 104.53%,and the heating temperature of single PASPY reached 24.677 ℃ in steady state.When exposed to the air directly,SPY will corrode and thus affect the stability of resistance.The thiol self-assembled molecular film can be prepared on the yarn surface by soaking it in thiol solution for a certain period of time to form protection.This paper discusses the effect of thiol solution concentration and thiol treatment time on yarn anticorrosion and compares the changes of yarn properties before and after thiol treatment.When the PASPY was treated with 100 mmol/L thiol solution for 90 min at25 ℃,the corrosion inhibition rate was up to 89.29%.Although thiol treatment increased the yarn resistivity to 16.302 Ω·10 cm,the resistance stability and electrothermal performance of SAM-PASPY were improved.After 120 h electrical aging,the resistance change rate of PASPY was 13.41%,and the steady state heating temperature of single yarn was 24.982 ℃.SPYEHF was made by combining SPY with substrate fabric through embroidery process.The influence of yarn spacing and circuit design on electrothermal performance was analyzed and discussed,and the power consumed by SPYEHF to reach the target heating temperature under different low temperature environment was tested.The results show that the heating temperature of SPYEHF prepared by the relatively optimal process can reach 50.184 ℃ and has good thermal uniformity under the voltage of 4 V.When the ambient temperature was-15 ℃,its heating temperature reached 40 ℃ only consumed 6.202 W power.Finally,the optimized SPYEHF was used to produce electric heating gloves,and "five fingers + back of hand" heating was realized through yarn circuit design.The gloves had stable heating and controllable temperature,which can provide effective low temperature protection for human body,indicating that SPYEHF had a good development prospect in the field of low temperature protection.