The Preparation And Properties Of PU/Zeolite Organic-inorganic Composite Materials

Polyurethane(PU) elastomer has been widely applied because of its fine comprehensive properties. But its heat resistance properties and solvent resistance properties don't very well, which limit its application in a certain. In order to widen the realm of application, mechanical properties, heat resistance properties and solvent resistance properties of PU/zeolite, PU/montmorillonite (PU/MMT) composite materials are discussed in this paper.The theory hypothesis of "pore restriction" is first proposed in this paper. During polymerization, one end of linear molecule inserts the channels of zeolite to form hard end through chemical bond or supermolecule acting force, the other end forms soft end through condensing or polymerizing with other monomer molecule. On the basis of the theory hypothesis, a kind of novel pattern of organic-inorganic composite materials-PU/zeolite composite materials-has been designed.Zeolite is a kind of silicate materials and it has shape selectivity. Microporous zeolites are chosen in this paper. It has high selectivity in adsorpting water , polar molecule or polarizable molecule on account of the existing of mighty coulomb field and polar interaction in the internal of crystal cave of zeolite, the high electric field gradient and the uneven surface caused by the exposure of exchangable cation of equilibrium framework negative charge in framework structures. By reasons of its mildly polarity and its kinetic radius which less than pore-opening size of the chosen zeolites, oligopolyols will wiggle into the channels of the zeolite when adding zeolite to oligopolyols. The existing of zeolite in PU made the crosslinking density improved. Thus mechanical properties, heat resistance properties and solvent resistance properties of PU are greatly enhanced.Crystal forms of composite materials, surfacial reactivity and adsorption assemble properties of zeolite are discussed in this paper by means of XRD, FTIR and TG etc. The test results of XRD prove that MMT can be exfoliated into nanocomposites in PU/MMT, while zeolite keep its original crystal structure in PU/zeolite. The spectras of FTIR prove that TDI can graft on the surface of the zeolite. Perforating mechanism is further illustrated by TGA.The modifying effects on PU of different fillers such as zeolite, MMT etc are discussed in this paper. The test results show that the properties of PU are almost all best when using "one step "processing, NCO/OH equaling 1.1, the content of fillers being 5%. Compare to pure PU, the elongation percentage at break, tear resistance, tensile strength, solvent resistance of PU modified with zeolite can be improved about 70%,80%,100%,40% respectively. All properties of PU/zeolite, PU/MMT are superior to PU modified with ordinaryfillers. Mechanical properties and heat resistance properties of PU/zeolite are correspond to those of PU/MMT, but the solvent resistance properties of the former are preferable.The special mechanism of PU which modified with zeolite is studied in this paper. There may be not only a new way to modifying PU, but also a new thought of modifying polymer.