The Preparation And Properties Of Poly (ethylene Terephthalate) Nanocomposites And Fibers Modified By Attapulgite

Poly(ethylene terephthalate)(PET)is a polymer material which has been found wild applications to fields of fibers and non-fibers. On the other hand,the disadvantages such as low rate of crystallization and long period of moulding cycle limit its application as an engineering plastic.Historically,its property can be improved by many kinds of ways.However,Attapulgite(AT)is resolved as a randomly oriented network of densely packed rods with the diameter of a single rod being less than 100nm.Recently,nano-attapulgite has been applied to the modification of polymers,to reduce the cost of polymer materials and to enhance the mechanical properties of polymers.In this work,PET/AT nanocomposites and fibers were prepared.The work is summarized as following:Preparation and properties of PET/AT nanocomposites:It is always difficult to let nano-particles dispersed well in polymers.In my research,PET/AT nanocomposites have been prepared by in-situ polymerization and ultrasonic method was applied in the dispersion of attapulgite.According to the observation of transmission electron microscopy(TEM),attapulgite could be well dispersed in the PET matrix in a nanometer scale.The thermal properties and the crystallization behavior were investigated by TGA,DSC and POM. The TGA curves indicated that the addition of AT improved the thermal ability of nanocomposites.Through the non-isothermal analyses,it is also suggested that AT plays as a nucleating agent in PET and a proper amount of attapulgite can increases the temperature of crystallization and the rate of crystallization.The ARES-RFS rheometer was used to study the rheological behavior of samples.The result showed that as compared with pure PET,PET/AT nanocomposites had much higher complex viscosity,the storage modulus and the loss modulus due to the interaction between AT and PET.Preparation and properties of PET/AT fibers:The resins were dried under vacuum until the water percent was less than 20ppm.The fibers of pure PET and PET/AT nanocomposites were prepared by melt spinning.According to the result of XRD experiment,it can be concluded that the PET/AT nano-particle composites exhibited smaller crystallization size but almost unchanged structure of crystalloid.The result of DMA indicated that the existence of AT had an influence on dynamic mechanical properties of the nanocomposites.The analysis of birefringence experiments and mechanical properties showed that the addition of AT enhanced the orientation,the strength at break and the modulus of nanocomposites which indicated that the mechnical properties of fibers could be improved by proper content of AT.