Study On Preparation And Its Applications Of Conducting Polyaniline/Polyurethane Foam

Polyurethane foam, commonly abbreviated as PUF, is one of polymers consisting of a chain of organic units joined by urethane (carbamate) links. It can be used as an ideal packaging material because of its good oil resistance, toughness, abrasion resistance and aging resistance. But polyurethane is a kind of insulation material essentially and there are defects due to poor antistatic properties. Polyaniline (PAn) is currently considered as one of the most promising conductive polymers. And polyaniline is becoming a research hotspot in the field of functional polymer materials because of its adjustable conductivity, rich redox states, easy preparation and good environmental stability.In this thesis, conducting polyaniline/polyurethane foam composite was prepared by in-situ chemical oxidative growth of polyaniline on the surface of polyurethane foam carrier. The volume electrical resistivity of composites can be controlled in a certain range in order to improve their antistatic properties effectively. Furthermore, a multi-component composite Ag/PAn/PUF can be directly obtained by using redox polyaniline loaded on polyurethane foam during the process of adsorptive reduction of silver ion. The influence of different preparation conditions on the volume electrical resistivity of the composite was investigated. And the application of as-prepared polyaniline/polyurethane composite was studied in the recovery of silver ion.The main research results were as follows:(1) The conducting foam can be prepared by in-situ chemical oxidative growth of polyaniline on the carrier of polyurethane foam (PUF). The variation of volume electrical resistivity of composite was measured. The stability of volume electrical resistivity of as-prepared composite was also studied. The results show that the aniline monomer concentration, the kind and its concentrations of medium acid, the molar ratio of monomer to oxidant have important influences on volume electrical resistivity of the composite. And the volume resistivity of the conducting polyurethane foam can be controlled in the range of 103-108Ω·cm by changing the in-situ growth conditions of polyaniline on PUF. And the composite doped by macro-molecule acid has been found to show better electrical conductivity and environmental stability than small molecule acids.(2) The reaction of silver ions reduced by PAn/PUF composite was conducted by using in-situ reduction method. The application of the resulting composite was studied in the recovery of silver ion. The reaction mechanism of reduction of silver ions by PAn/PUF composite was speculated and verified. The kinetic curves of reduction of Ag+ ion by the PAn/PUF composite were analyzed. The results show that PAn/PUF composite had a good effect for recovering silver ion. Silver recovery in this process amounted to 99.0% under certain conditions and its mean activation energy was about 30.22 kJ-mol-1. The factors which contained the AgNO3 concentration, temperature, vibration conditions, the preparation conditions of PAn/PUF composite could affect the effect of reduction of silver ions by PAn/PUF composite.(3) Ag/PAn/PUF composites have been obtained by in-situ reduction complex method. The structure, morphology, crystalline forms and thermal stability of products were characterized by FT-IR, SEM, XRD and TGA techniques. The anti-bacterial performance of the Ag/PAn/PUF composites was studied. And the results show that the preparation conditions have a certain influence on morphology of Ag/PAn/PUF composites. And the structure and crystalline forms of Ag/PAn/PUF composites are different from PAn/PUF composites. The thermal stability of Ag/PAn/PUF composite was improved and it also had excellent anti-bacterial properties.In a word, conducting foam composite could be prepared by using in-situ chemical oxidative growth of polyaniline on the carrier of polyurethane foam. The method showed two advantages:controllable volume resistivity of the composite and good performance in adsorbing and recovering silver ion. It will have great promising applications in the manufacture of excellent anti-static and anti-bacterial packaging materials and functional conducting polymer/metal nano-composite materials.