Study On Preparation And Properties Of Nylon Fabric With Silver Deposition By Chemical Method

Silver metals are widely used in the surface treatment of materials because of its excellent properties such as electrical conductivity,antibacterial properties,ductility and self-catalytic activity.Nylon fabric is well known for having good mechanical properties.Silver metalized nylon fabric retains the original flexible style,but also has the function of metallic silver.Therefore,polyamide silver metallized fabrics are widely applied in smart textiles,antistatic materials,electromagnetic shielding materials,anti-reconnaissance camouflage materials,antibacterial materials,conductive materials and other fields.This paper first studies the pretreatment of nylon fiber on the stannous ion adsorption.The effect of acid treatment on the surface morphology of nylon fibers were explored.In addition,the crystallinity of fibers was also studied by varying the heat setting temperature,time and tension.The effects of fiber heat setting,silicone treatment,hydrochloric acid surface roughening,adsorption time and temperature,stannous chloride concentration on the adsorption of stannous ions on the nylon fabric surface were investigated.Secondly,the effect of the pretreatment of nylon fabric on the chemical silver plating was studied.The tannous chloride concentration,sensitization time and temperature,washing time and temperature on the weight gain rate and surface resistance of nylon silver plated fabrics were investigated.Finally,electroless plating was used to fabricate electroless silver plating fabric.Na₄EDTA,as auxiliary complexing agent,along with ammonia,as main complexing agent,were used on electroless silver plating process.By controlling the experimental variables,such as varying the chemical concentration of silver nitrate,glucose,and Na₄EDTA,reaction time and temperature,pH and other parameters in the process of chemical silver plating,the effects of silver plating process on the weight gain,surface resistance,surface morphology,coating adhesion and electromagnetic shielding and other properties are studied.The main conclusions are as follows:The surface of the nylon fabric treated with hydrochloric acid treatment has shown better roughening effects.The crystallinity of the fibers treated with lower setting temperature,shorter setting time and lower fixed tension,are suitable to the adsorption of stannous ion.At the same time,it was found that the hydrophilicity of the fiber also affected the stannous ion adsorption.The hydrophilic silicone treatment could increase the stannous ion adsorption capacity.With the increase of adsorption temperature,the adsorption capacity of stannous ions first increased and then decreased.The stannous chloride concentration and the increase of the adsorption time also lead to the increase of the adsorption amount,and reach the adsorption equilibrium after a certain period of time.In the sensitization process,with the increase of stannous chloride concentration,sensitization time and temperature;the weight gain rate and conductivity of the fabric were found to be increased and then decreased.Higher concentration of hydrochloric acid will lead to excessive fiber roughening and would weaken the fiber mechanical properties.In the process of washing,when the washing time is shorter or the temperature is lower,the conductivity of the fabric is deteriorated and vice-versa.In the process of electroless silver plating,with the increase of the concentration of silver nitrate,the weight gain rate of the fabric increased,the surface resistance decreased and the electromagnetic shielding performance was improved.However,with increase in the size of silver particles,the surface roughness increased,while as the adhesion force of the coating decreased.With the increase of bath pH and reaction temperature,the weight gain of nylon silver-plated fabric first increased and then decreased while as the surface resistance first decreased and then increased.With the increase of glucose concentration and silver plating time,the weight gain of nylon silver-plated fabric rises rapidly and becomes stable after some time,where as the surface resistance drops rapidly.Na₄EDTA almost have no effect on the texture of silver coating.With the increase of Na₄EDTA concentration,the deposition rate of silver was lowered while the stability of plating solution was improved.The weight gain of nylon-silver plated fabric decreased.The surface resistance first decreased and then increased,the grain size decreased,and the binding ability of fabric coating increased.The optimal sensitization conditions are as follows:stannous chloride concentration is 9 g/L,hydrochloric acid concentration is 20 m L/L,sensitization temperature is 20?,sensitization time is 25 min,washing time is 20 min,washing temperature is 15?.The optimal silver plating process conditions are as follows:the concentration of silver nitrate is 10 g/L,the concentration of glucose is 17 g/L,the pH is 11.0,the concentration of Na₄EDTA is 0.15 g/L,the reaction time is about 25-30 min,reaction temperature is 45?.In these process parameters,the nylon fabric obtained by electroless silver plating has the best conductivity,the silver coating is found to be uniform and compact.The silver nano-particles attached on the fiber surface have better crystallinity,higher purity and higher binding force.The fabric surface resistivity obtained by such treatment can reach 0.34?/cm.