Research On Preparation Of Super-hydrophobic PET By Atmospheric Plasma Polymerization Of Octamethylcyclotetrasiloxane

Atmospheric pressure dielectric barrier discharge(DBD)plasma is a completely dry-processing technology,which possesses various advantages,such as simplification of equipment,free of a high vacuum system,energy saving and emission reduction,together with being low temperature and so on.It shows great significance for a number of materials processing and modification applications.Conventional silicone finishing process cannot endow the fabric with superhydrophobicproperty.In this paper,under atmospheric pressure,take the air and a small amount of argon as working gas,octamethylcyclotetrasiloxane(D4)was applied as the monomer.The polyester polymer films were successful polymerized and deposited on the fabric surface by the use of DBD plasma.It endowed the fabrics with excellent and durable super-hydrophobic property.In addition,the optical emission spectrum(OES)system on-line diagnostic for plasma polymerization of D4 was performed.In this paper,based on atmospheric plasma,the following studies were conducted:1)Different parameters affecting on weight gain rates of the PET fabrics in reaction were analyzed by single factor method,including monomer content,plasma plate spacing,flow rate of argon gas,discharging voltage as well as the discharge processing time.The results showed that:effective control of discharge voltage access to stable and uniform glow plasma.With the amount of monomer content improving,weight gain rates of the polyester shows a corresponding increasing.Keeping the amount of monomer content as 80%(owf),based on the plasma plate spacing ranging from 2 to 3mm,argon gas flow rate ranging from 1.5 to 2.0 L/min,discharge voltage ranging from 98 to 103V,treatment time ranging from 100 to 150s,modified polyester could get a higher weight gain rate.2)The OES on-line diagnostic system for detecting the emission spectra of plasma polymerization of D4 was performed.It indicated that the O,N plasma spectra play a more significant role on plasma entire system spectra intensity.The relationship between the O,N plasma spectra intensity and processing conditions was analyzed.These become the important corroboration of the various plasma factors affecting the polymerization of D4.3)The impacts of weight gain rate on hydrophobic effect of treated fabric effect were investigated.The contact angle of the fabric experiments showed that the hydrophobic effect became more visible as the weight gain rate grew in a certain range.When the weight gain rate reach at a certain critical value(around 18%),the water contact angle of the modification fabric was up to 150°.Continue to increase weight gain rate of the PET has little effect on the property of hydrophobic.Be with super-hydrophobic properties,the water proofing characterization of modified polyester level to the highest standards by the tests.4)The wearabilities and thermal stability of the treated fabrics were evaluated.The test results showed that softness improved with the increasing of fabric weight gain rates.There are small change in whiteness,breaking strength and breaking elongation compared with the original fabrics.Permeability of the modified polyester fabrics decreased slightly,and the scope of reduce is still within the acceptable range.After repeated washing test,the modified fabrics showed a little amount of weight loss,at the same time,it basically remains the super-hydrophobic property.The TG analysis compared with the original and modified PET showed that the modified one still possess a good thermal stability.5)The surface morphology of the fabrics was tested by means of field emission scanning electron microscopy,it showed that the polymer film coating on the polyester fibers with the characteristics of successive,uniform and compact.The molecule structure of the original and modified fabrics were characterized by means of FT-IR,the spectra showed that the silicon-contained polymer has been introduced onto the treated one.The specific elements and their content were measured by EDS testing and XPS testing,the results showed that many Si are introduced onto the modified polyester surface.D4 molecules were occurred open-loop by bombardment of high-energy electron in plasma.Major in the fracture action of the Si-O bond.With the result of D4 broken down into small fragments involved activity free radicals.These small fragments reacted polymerization among each other,and eventually deposited on the fabric.