Study On Preparation And Ultraviolet Resistance Of Polypropylene Spunbonded Needle-punched Geotextiles

Polypropylene（PP）spunbonded needle-punched geotextiles have the advantages of high modulus and elongation,acid and alkali resistance,freeze-thaw resistance,light weight,low cost,etc.They have a vital application value in high-cold frozen soil,alkaline soil,high temperature and high humidity environment.However,PP is prone to ultraviolet aging degradation during application,which greatly reduces the service life and engineering quality of products.Therefore,it is of significant to study and improve the ultraviolet resistance of PP spunbonded needle-punched geotextiles.In this paper,the PP spunbond needle-punched geotextiles with ultraviolet resistance were prepared by raw material blending modification technology and finishing technology.This paper studied the effect of anti-aging masterbatch on the ultraviolet resistance of PP spunbond needle-punched geotextiles,the stability of water-based polyurethane（WPU）&titanium dioxide（TiO₂）composite emulsion,the effect of WPU&TiO₂ composite emulsion finishing on ultraviolet resistance of PP geotextiles,the effect of the combination of anti-aging masterbatch and WPU&TiO₂ composite emulsion finishing on the ultraviolet resistance of PP spunbond needle-punched geotextiles.The following are mainly accomplishments:（1）PP spunbonded needle-punched geotextiles were prepared from PP slices and different anti-aging masterbatch,then the ultraviolet aging test was carried out.The effects of different types of anti-aging masterbatch on the ultraviolet resistance of PP spunbonded needle-punched geotextiles were investigated by fourier transform infrared spectroscopy（FTIR）and tensile tests.Studies have shown that pure PP spunbond needle-punched geotextiles have poor ultraviolet resistance,and were prone to aging degradation under ultraviolet irradiation.The ultraviolet resistance of PP spunbonded needle geotextiles can be improved by adding anti-aging masterbatch containing hindered amine light stabilizer（HALS）or benzophenone light stabilizer.HALS and benzophenone light stabilizers can play a synergistic role to achieve better ultraviolet resistance.Adding anti-aging masterbatch does not affect the pore size distribution of PP spunbonded needle geotextiles,but it will have a certain effect on its tensile properties.（2）WPU&TiO₂ composite emulsion with better stability were prepared from nano-TiO₂ and WPU.The effects of mixing mode,dispersion mode,dispersion time,solvent and other factors on the stability of WPU&TiO₂ composite emulsion were studied by ultraviolet-visible spectrophotometer and sedimentation process recording and recording method.Studies have shown that the optimal configuration process of WPU&TiO₂ composite emulsion is:first dissolve nano-TiO₂ in 15wt%ethanol aqueous solution,then mix the nano-TiO₂ dispersion with WPU emulsion,and then disperse ultrasonically for 60 min.（3）PP spunbonded needle-punched geotextiles with uniform surface loading TiO₂ particles were prepared by WPU&TiO₂ composite emulsion.The effect of WPU&TiO₂ composite emulsion finishing on ultraviolet resistance of PP geotextiles was investigated by ultraviolet resistance test.Studies have shown that WPU&TiO₂ composite emulsion can improve the ultraviolet resistance of PP geotextile,but its effect is worse than that of anti-aging masterbatch.PP geotextiles’ductility and pore size distribution were basically unchanged,the breaking strength was increased by about 10%after finishing with WPU&TiO₂ composite emulsion.PP spunbonded needle-punched geotextiles with excellent ultraviolet resistance were prepared by combining anti-aging masterbatch modification and WPU&TiO₂ composite emulsion finishing.After 10 days of ultraviolet irradiation,the retention rate of longitudinal and transverse breaking strength can reach more than 99%,and the retention rate of longitudinal and transverse breaking elongation can reach more than 94%.