Preparation And Properties Of Attapulgite/Nylon 66 Nanocomposites

Attapulgite (AT) is a typical natural silicate mineral with a unique layer chain structure, containing Mg, Al, Si,O, H et al. It appears fibrous crystal, the diameter of a single rod is below 100 nm and the length is near 1μm, the aspect ratio is larger than 10. With the characteristics of nanocomposite and the stiffness of short-fiber reinforced materials, AT/polymer nanocomposites have aroused growing interests in nanocomposite research. Nylon 66 is one of the most widely used engineering plastics. Nylon 66 nanocomposites have been highly attention in the field of research and application, because of the high strength and dimensional stability, excellent thermal performance and so on.In order to improve the mechanical and thermal properties of nylon 66, the AT/nylon 66 nanocomposites have prepared by masterbatch technology. The mechanical and thermal properties, rheological behavior, and crystallization kinetics have been investigated. The main contributions are as follows:(1) AT was organically modified by silane coupling agent (KH550). Nylon 66 masterbatch with high AT content was prepared by in situ polymerization. The results showed that when the amount of KH550 was up to 10%, the graft ratio of KH550 on the surface of AT reached the maximum. FT-IR results showed that the combination of nylon 66 molecules and AT was not a simplly physical adsorption in the masterbatch, but a chemical link. DSC and TGA results showed that the melting temperature of the sample was 244.3℃ and the decomposition temperature of that was 417.3℃. The amount of AT in nylon 66 masterbatch reached more than 30%.(2) The preparation of AT/nylon66 nanocomposites was carried out by blending the masterbatch and nylon 66 melt. SEM observations showed that the modified AT dispersed well had a good compatibility with nylon 66 and dispersed well in nylon 66 matrix. TGA results showed that the thermal decomposition temperature of the samples increased 9-21℃ by addition of AT. POM observation revealed that addition of AT caused the nylon 66 lossed spherulitic growth ability. DMA results showed that the glass transition temperature of the sample increased about 10% by addition of AT.(3) AT/nylon 66 nanocomposites and pure nylon 66 were analyzed by DSC under different cooling rates. The non-isothermal crystallization kinetics of AT/nylon 66 nanocomposites and pure nylon66 were described by Jeziorny equation, Ozawa equation, Mo equation and Kissinger equation, respectively. The results showed that the crystallization temperature of the nanocomposites increased 6-8℃ by addition of AT, and the crystallization rate increased.