Study On The Surface Modification Of Ppta Fibers

In this paper, progresses and developments of PPTA fiber were reviewed, the properties of it were introduced, and the surface modifications, applications and composites of it were reviewed. On the basic of these, the surface modification of PPTA fibers was studied.Firstly, PPTA fibers were treated with H₃PO₄ solution. Fourier Transform Spectrum (FTIR) was employed to character the change of the fiber; scanning electromicrograph (SEM), contact angle test were employed to research the changes of the surface properties of the fibers. And single fiber strength experiment was used to show the strength loss because of the treatments. All the results showed that H₃PO₄ solution could improve the surface properties of PPTA fibers efficiently with little strength loss. The orthogonal design was used to find the best technical condition. It showed that the best treated condition was to treat the PPTA fibers with 5% H₃PO₄ solution at 55℃for 1 h.Secondly, PPTA fibers that treated with H₃PO₄ solution at 55℃for 1 h was treated with LaCl₃ solution further. It showed that the rare earth treatment did no harm to the fiber strength while the wettability of fiber was improved. The SEM photo of the fracture surface of PPTA/epoxy composites showed that the surface of untreated fibers was smooth, and little epoxy resin was adhered to the surface. However, for the PPTA fiber treated with rare earth solution, a large amount of epoxy adhered to its surface and formed a thick layer. This fact meant that rare earth treatment improve PPTA fiber surface properties effectively. IFSS experiment was employed to study the relationship between the concentration of the rare earth solution and the surface prosperities. It showed the best technical condition was to treat the PPTA fibers with 0.9% rare earth solution.Additionally, PPTA-pulp was used as reinforcement in phenol formaldehyde resin friction slice. PPTA-Pulp showed great advantage over asbestos especially at high temperature. The friction property of PPTA pulp treated by H₃PO₄ or H₃PO₄/rare earth solution was better than the untreated one. The impact strength of the composite was measured. It showed that the impact strength of treated one was better than the untreated one.