The Preparation Of Electroless Plating Electromagnetic Shielding Fabrics Using Catalyst Immobilized On PAMAM

With the rapid development of our community, the use of electronic products andcommunication instruments become more and more popular in people,s lives, and variouselectronic devices generate different levels of electromagnetic radiation which not onlycaused interference between electronic products, but also polluted the human livingenvironment and endangered human health. Therefore, many countries have enacted strictelectromagnetic radiation protection standards and regulations.Due to the good conductivity and special structure, conductive fabrics coated withcopper or nickel can be utilized for shielding electromagnetic radiation and interference.In the traditional preparation process of electroless copper or nickel plating,sensitization and activation are important but hard to operate, in addition, the electrolesscopper plating using sodium hypophosphite as reducing agent is difficult to achieve. All ofthese because palladium, a kind of precious metal, is not enough to catalyseoxidation-reduction reaction.In this paper, PAMAM dendrimers polymers are proposed as good chelating agent.They can load palladium ions quantitatively, because its specialties are to design themolecular size，shape and functional group at the molecular level and high loadingcapability with many amino and imino.In this study, PAMAM has been synthesized and the molecular structures of theproduction have been characterized by means of infrared spectrum（IR） and nuclearmagnetic resonance（NMR）. PAMAM-Pd is prepared, and then the influence of [Pd²⁺]/[PAMAM], pH value and different generations on adsorption efficiency isinvestigated. Besides,the maximum adsorption capacity of PAMAM on palladium ions canbe obtained by UV spectra.In this paper, a new activation method which is based on the researches of a series ofPAMAM absorption capacity on palladium ions is proposed. Firstly, the objective of thisstudy is to prepare PAMAM-Pd complexes, and then be finished to polyester fabric. Thankto the high loading capability and film-forming properties of PAMAM, the fabric surfacehas a catalytic ability of PAMAM-Pd film. This activation method has more advantages,such as no etching and sensitization pretreatment process, low amount of metallicpalladium and uniform metal layer. The optimum process of electroless copper platingbased on PAMAM-Pd activation method is obtained though orthogonal and single-factorexperiment. Influences of bath composition and condition on coating composition,morphology, resistance are also studied.The results show that conductive fabrics with low surface resistance and highshielding effectiveness can be produced by the following processes: PAMAM-Pdactivation, electroless copper plating and reduction. The technology is friendly toenvironment, easy to operate and control, low production cost, and the fabrics preparedhave strong resistance to risk, which can be applied commercially. What’smore, theconductive fabrics have excellent conductivity and wearability.