Study On The Preparation And Thermal Insulation Performance Of Electroless Silver-Plated Polyamide Fabric

Ag is widely used in the surface treatment of various materials because of its excellent infrared reflection,ductility,and autocatalytic activity.Polyamide fabric has good mechanical properties.Electroless silver plating on polyamide fabric can not only maintain the original softness of the fabric but also possess the high infrared reflection characteristic of metal Ag.In order to make full use of the high infrared reflectance of Ag,the paper proposes to prepare the silver-coated nylon fabric with excellent heat insulation performance by electroless silver plating.Using thin polyamide fabric as a substrate,Ag in AgNO₃ was deposited on the surface of the polyamide fabric in the form of nanoparticles by the electroless silver plating method.Different deposition conditions were explored:The effects of HCl concentration,SnCl₂ concentration,sensitization time,sensitization temperature,washing times,silver nitrate concentration,reducing solution concentration,plating solution pH value,plating time,and plating temperature on the surface morphology,far infrared reflectance,and weight gain rate of the deposited layer of silver-coated nylon fabric were determined by the combination of far infrared reflectance and surface morphology.Optimized silver deposition conditions were obtained.Under optimized conditions,the effect of AgNO₃ concentration on the deposition layer of silver-coated nylon fabric was further discussed.SEM,AFM,and XRD were used to characterize the surface morphology,crystal structure,and surface roughness of the silvered fabric.Polyamide silver fabric was tested by FTIR 8–14μm band infrared reflectance,and the thermal infrared radiation properties of silver-coated nylon fabric were tested by an infrared thermal imager.The thermal insulation performance and wearability of silver-plated nylon fabric were tested.The main results are as follows:（1）The surface of HCl-treated polyamide fabric has uniform grooves,HCl has a good etching effect on the surface of the fabric,and HCl is selected for coarsening acidic solutions.When the concentration of HCl was different,the far-infrared reflectance of the silver-plated nylon fabric increased with the increase in the concentration of hydrochloric acid.When the concentration of HCl was 15 m L/L,the far-infrared reflectance of the fabric was about 53%.With the increase in SnCl₂ concentration,the far-infrared reflectance of silver-plated nylon fabric increases.When the concentration of SnCl₂ is 20 g/L,the far-infrared reflectance of the fabric reaches 65%.The far-infrared reflectance of silver-plated nylon fabric prepared with different sensitization times increases with the passage of time.With the increase of sensitization temperatures and washing times,the far infrared reflectance of silver-coated fabrics first increases and then decreases.（2）The far-infrared reflectance of the silver-plated fabric increases with the increase in AgNO₃ concentration.When the AgNO₃ concentration is 7 g/L,the far-infrared reflectance of the fabric is about 75%.The far infrared reflectance of silver-plated nylon fabric increases with the increase in reducing solution concentration.The far infrared reflectance of silver-plated fabric increases first and then decreases with the increase in pH value.When the pH value is 10,the far infrared reflectance of the fabric is about 50%.The far infrared reflectance of silver-plated fabric increases with the plating temperature and decreases when the plating temperature is too high.The deposition of Ag nanoparticles was mainly concentrated in the first 40 min,and the longer the reaction time was,the higher the far-infrared reflectance of the silver-coated fabric was.（3）Under optimized conditions,the far infrared reflectance and weight gain rate of the nylon-plated silver fabric prepared with different AgNO₃ concentrations increase with the increase of AgNO₃ concentration in the range of 1–9 g/L,and the highest far infrared reflectance is about 75%.Compared with the original fabric,the CLO value of the fabric after electroless silver plating can be increased to 2.2 times as much as that of the original fabric,and the corresponding thermal insulation is better.When co-placed with the composite floc,the CLO value of the composite floc increases by about 30%.When the AgNO₃ concentration is 5-7 g/L,the CLO value of the composite floc increases by about 30%.The far-infrared reflectance of silver-coated nylon fabric and the heat insulation performance of composite floc are in the best range.The permeability and moisture permeability,softness,and friction resistance of electroless silver-plated fabrics prepared with different AgNO₃ concentrations decreased with the increase in AgNO₃ concentration.The minimum permeability was above 40 mm/s,the minimum moisture permeability was above 87 g·m^-2·h^-1,and the bending length was less than 3.66 cm.The weight loss rate is less than 1.7%after 3000 frictions,which indicates that electroless silver plating does not affect the wear performance of the fabric.Basically,silver-plated fabric has good air permeability,moisture permeability,softness,and wear resistance.（4）To sum up,the optimal deposition conditions for the thermal insulation performance of the silver-plated fabric with polyamide are as follows:The concentration of HCl is 15 mL/L;the concentration of SnCl₂ is 20 g/L;Sensitization time:10 min;sensitization temperature:30℃;washing times:3 times;AgNO₃ concentration:7 g/L;reducing solution concentration:6 g/L;pH is 10;the plating temperature was 55℃;The plating time is 55 minutes.