Preparation And Application Of Porous Hydrophobic PDMS By Template Ablation Method

Polydimethylsiloxane(PDMS),also known as dimethyl silicone oil,is a hydrophobic silicone material.It has been applied in the pharmaceutical,daily chemicals,food,construction and other fields.It has hundreds of derivatives,polysiloxanes which have been commonly used include: polydimethylsiloxane,cyclomethicone,aminosiloxanes,polymethylphenylsiloxanes,polyether polysiloxane copolymers.Polydimethylsiloxane chemical state is dimethyl silicone oil at common temperature,colorless or light yellow liquid,tasteless,high transparency,with heat resistance,cold resistance,viscosity changes with temperature,water resistance,surface tension is small,with thermal conductivity,light transmission for the light transmission rate of 100%.PDMS material is non-toxic and tasteless,with physiological inertia and good chemical stability.Electrical insulation weather resistance and hydrophobicity is good,and has a high shear resistance,it can be used in-50 ℃ ~ 200 ℃ for a long term.It has excellent physical properties and can be used for insulation,damping,shock absorption,defoaming,lubrication and polishing.It is widely used for insulation lubrication,shockproof,anti-dust,dielectric liquid and heat carrier.As well as for defoaming,release agent,paint and chemical additives.At present,the treatment scheme for oil and water separation includes : combustion in situ,microbial degradation and chemical elimination and so on.These methods require long time and are easy to cause secondary pollution.In recent years,some new adsorbent materials such as activated carbon,organic clay and resin,because of its large amount of adsorption,is also used for organic adsorption recovery.But these materials exist oil selectivity is not high(that is,while absorbing water absorption),oil recovery Low,can not be reused and the high cost of separation.Superhydrophobic porous materials can overcome the problem of high water absorption of the material itself,thus exhibiting high selectivity for the absorption of organic matter.Based on the superhydrophobic lipophilic properties,good chemical stability and low surface energy of PDMS materials,PDMS was prepared into porous materials using sugar granules as template.The main work of this paper is as follows:(1)Preparation and characterization of porous polydimethylsiloxane materials.Diluting the PDMS prepolymer with xylene,reducing the viscosity of the prepolymer,improving the flowability,preventing the generation of bubbles,avoiding vacuum operation,taking glucose and sucrose particles as templates,adding sugar particles after curing,removing the sugar particles and removing excess particles after curing Xylene to obtain a porous material.The material has acid and alkali resistance to high temperature and good hydrophilicity,in addition,porous materials with interoperability pore structure,porosity up to 30%.(2)A porous lipophilic hydrophobic material was prepared by oil-water separation experiment using PDMS’s low surface energy,hydrophilic oleophobic and capillary pore size of porous materials.The effects of the ratio of sucrose and glucose on the porosity of porous materials,the effect of the porosity of the material on the oil absorption capacity of the material,and the mechanism of the change of the absorption capacity of the materials were studied.At the same time,the magnetic nano-iron particles were prepared without affecting the oil absorption performance,So that the material with magnetic,in the case of an external magnetic field to facilitate the recovery of materials.Using the sucrose and glucose as templates,two kinds of sugar particles with different particle size were mixed in different proportions to study the change of the porosity of the material.It was found that the porosity of the material increased from 8% to 30% with the increase of sucrose and glucose ratio,And then down to 17%.The absorption principle includes similar compatibility and surface adsorption,the highest absorption rate of carbon tetrachloride material,the lowest absorption rate of methanol,respectively 29.4g / g and 4.2g / g.(3)DDT in water samples of porous PDMS oil absorbing materials.Based on the ability of adsorption of organic matter under static conditions,the porous PDMS oilabsorbing material was used as solid-phase extraction material to extract DDT in aqueous solution.Through the investigation of the factors such as solvent type,stirring time and ion concentration,an efficient and rapid enrichment system was established.The enrichment times of n-hexane,toluene and chloroform were 55.8,11.7 and 22.4 respectively,and the highest recoveries were 98.32.The efficient and rapid enrichment of trace DDT in water samples was realized.(4)Study on the porosity of porous PDMS material and its light transmission performance.PDMS material itself is a colorless transparent material,with good light transmission performance,when the material into a porous material,the light inside the material constantly refraction,resulting in decreased light transmission performance,with the material compression,the material back to the original colorless and transparent State,light transmission performance with the material volume of the compression slowly restored to its original state.The organic solution is added to the porous PDMS material so that the volume of the material expands.At the same time,due to the addition of the organic solution,the silicon oxygen bond inside the PDMS is easier to open and the material is more compressible.When the compression volume is the same,the light transmission performance of the material is improved,And more easily compressed.