The Chitosan Applied To Electroless Fabrics With Pd-free Activation And Research Of The Product Properties

Chitosan(CTS)was a kind of natural polymeric chelant,there were a lot of-OH and-NH2,which could absorb most of metal ions.CTS had many excellent properties and extensive applied values,among that,film formation property was one of notable properties.The CTS film,which had good adhesiveness and physical and mechanical properties,could be prepared easily.However,the semirigidity caused by intermolecular hydrogen bondings effected its Coordination ability with metal ions.To improve its usability,the article used glutaraldehyde(GA)to cross CTS,then generated crosslinked chitosan(CCTS).The crolesslinking could release-OH and-NH2,which bounded by hydrogen bondings,and improve the adsorbability of CTS film.Firstly,this papar make a systemic discussion on the technological conditions of polyamide(PA)fabric pretreated by CCTS(PA-CCTS).Then,we worked out the proper pretreatment conditions as follows:the concentration of CTS(CCTS)lOg/L,the concentration of GA(CGA)9g/L,the time of pretreatment(tTM)20min,the temperature of curing(TCR)140℃,the time of curing(tCR)50min。Secondly,adopting CCTS-Ag with activation and plating simultaneously,without sensitization on the PA-CCTS fabric.The best synthetical condition was decided by orthogonal and single-factor experiments as follows:the time of adsorbing Ag ions(tAP-Ag)40min,the concentration of AgNO3(CAgNO3)14g/L,the concentration of NaOH(CNaOH)6g/L,the concentration of NH4OH(CNH4OH)130mL/L,the concentration of glucose(CC6H12O6)2 g/L,the time of electroless Ag(tET-Ag)50min,the temperature of electroless Ag(TET-Ag)30℃,the bath ratio of electroless Ag was 1:250.The obtained fabrics,including electroless Ag on the PA fabric treated by CTS(PA-CTS-Ag),electroless Ag on the PA-CCTS fabric(PA-CCTS-Ag),electroless Ag on the PA-CCTS fabric with SnCl2 sensitization(PA-CCTS-Sn-Ag)and so on,were characterized by Field emission scanning eleetronmicroscopy(FE-SEM),Atomic force microscope(AFM),X-ray diffraction(XRD).Besides,the shielding effectiveness(SE),rubbing fastness and washing fastness properties were characterized.The result showed that CCTS increased the roughness of PA,then expanding its Adsorption area.During 300Hz～2.5GHz,the SE of PA-CCTS-Ag came to 99.9999%.The PA-CCTS-Ag coating inciuding granula on it was uniform.The grain size was 28.86nm,with(111)crystal plane preferred orientation obviously.After ten times firction,the surface square resistance changed from 40mΩ to72mΩ,change rate of PA-CCTS-Ag was 80%,After five times washing,the surface resistance change from 40mΩ to 78mΩ,change rate of PA-CCTS-Ag was 94%.Finally,using CCTS-Ni electroless plating Ni with Pd-free on PA-CCTS fabric(PA-CCTS-Ni).According to the effection of coating on square resistance and weight gain rate,we gained the proper activation process as follows:the time of adsorbing Ni ions(tAP-Ni)40min,the concentration of NiSO4(CNiSO4)0.25mol/L,the concentration of NaBH4(CNaBH4)10g/L,activation pH 10.5,the time of activation(tAT-Ni)40min.The proper electroless plating process as follows:the concentration of NiSO4(CNiSO4)20g/L,the concentration of NaH2PO2(CNaH2PO2)15g/L,the concentration of Na3C6H5O7(CNa3C6H5O7)20g/L,the concentration of NaH2PO2(CH3BO3)20g/L,the time of electroless Ni(tET-Ni)40min,the temperature of electroless Ag(TET_Ni)60℃,electroless plating pH 9.The obtained fabrics were characterized by FE-SEM,AFM and XRD.Besides,the SE,rubbing fastness and washing fastness properties were characterized.The result showed that the layer was an amorphous structure compactly.The SE of electroless Ni fabrics were more than 99.99%.Aftert a score of times firction,the surface square resistance change rate of electroless Ni on the condition of pH9 was 7.63%,and after five times washing,the surface Resistance change rate was 14.51%.