The Research On Structure And Properties Of Polypropylene Asymmetric Solid-liquid Separation Membrane In Harsh Conditions

Recently years, the polypropylene asymmetric solid-liquid separation membrane hasgradually replaced the concrete release agent used in civil engineering, which is widely used inmajor road works and water conservancy projects. It is able to avoid trachoma, cellular, pock andother defects on the surface of concrete effectively. And it can also improve the strength andquality of concrete appearance, and extend the service life of concrete structures maximumly.However, at the process of use and storage, the membrane is prone to aging or corrosion underthe condition of light, heat, acid and alkali, which may make its appearance and filtrationperformance deteriorate, affecting the quality of the concrete and construction schedule. To solvetheseproblems, this paper based on the storage and use environment of the polypropylenemembrane uses artificial accelerated aging and corrosion method to process it, to explore the lawof membrane’s aging and corrosion preliminary through studying the appearance morphology,physical, mechanical properties and filtration performance of membrane.In the first place, the membrane was treated by ultraviolet irradiation at differenttemperatures. The results showed that the C=O stretching vibration was found in polypropylenemembrane surface which was handled at45degrees celsius for1day,indicating that themembrane surface began to be oxidized; the separation membrane’s rupture strength,respectively, declined2.28%and5.81%after they, respectively, treated at45degrees celsius for6day and at60degrees celsius for4day, and then they all had lost value in use, further themembrane surface’s hydrophilic disappeared and the water conductivity decreased rapidly,indicating that temperature can accelerate photo-aging of the separation membrane. Thepolypropylene separation membrane was treated at a temperature of60degrees celsius and foundthat it had a good thermal stability; after30days treatment, the surface of separation membranewas without cracks, and remained stable permeability, the separation membrane’s rupturestrength declined23.50%, the melting point and decomposition temperature only, respectively,decreased1.86degrees celsius and10.96degrees celsius.The polypropylene separationmembrane did not own acid and alkali resistance well after acid and alkali corrosion experiments. The wettability of the separation membrane surface disappeared, after it was respectively treatedby0.005mol/L HCl and0.005mol/L NaOH for1day, and to continue to increase the processingtime, the thickness, contact angle and permeability increased gradually, but the rupture strength,hydraulic conductivity and average pore diameter all reduced gradually.As a result, the polypropylene separation membrane had excellent heat resistance, but thelight and acid resistance were poor, which could provide a theoretical basis for its appropriatestorage environment, at the same time, it could also reduce the cost of storage and use, and wasconducive to the further promotion of polypropylene membranes, therefore it had a certainpractical significance.