Study On The Construction Of Polydimethylsiloxane Sponge And Its Application In Oil-water Separation

In recent years,with the continuous development of oil extraction,production,processing,and transportation,oil spills have occurred frequently.which have seriously polluted the ocean and river environment.Therefore,the research of highly efficient and reusable oil-absorbing materials has become a hot topic in the field of oil-water separation.Polydimethylsiloxane（PDMS）is a hydrophobic silicone material,which has good hydrophobicity,chemical stability and flexibility.Therefore,PDMS has shown great application prospects in the field of oil-water separation.In this thesis,a solvent template and a template-free construction method are designed,three materials are selected to prepare PDMS sponge.The mechanical properties and oil-water separation properties of the sponge were explored to investigate the preparation methods of new recyclable oil-water separation materials.The main research contents of this topic are as follows:（1）Ethyl cellulose（EC）was used as a supporting structure,and epichlorohydrin（ECH）was used as a cross-linking agent to cross-link with amino-terminated polydimethylsiloxane（PDMS）.Finally,silica（SiO₂）was attached to the surface of the sample,and after freeze-drying treatment,a three-dimensional porous structure sponge（PECS）with excellent hydrophobic properties was successfully prepared.The structural characterization of PECS sponge shows that under the support of ethyl cellulose,PECS sponge has a uniform three-dimensional network structure.The water contact angle reaches143.4°.The adsorption experiment verified that the PECS sponge has excellent oil-water separation effect,and the maximum adsorption capacity for chloroform is 3536.25 wt%.This part of the experimental results shows that ethyl cellulose can play a role as a supporting structure in the polydimethylsiloxane sponge.（2）Under mild conditions,graphene oxide（GO）was used as a support structure to crosslink with amino-terminated polydimethylsiloxane（PDMS）through dehydration condensation.The gas generated in the material preparation process was used as a porogen,and a self-foaming three-dimensional porous structure sponge（GO-PDMS）with excellent elasticity was successfully prepared.The structural characterization of GO-PDMS sponge shows that GO-PDMS sponge has excellent mechanical properties.After 20cycles of compression,no significant deformation occurs.The adsorption experiment verified that GO-PDMS sponge is highly recyclable.After 30 times of cycles of petroleum ether,96.30%of the adsorption capacity is still retained.The experimental results of this part show that the addition of graphene oxide can support the polydimethylsiloxane network and form a porous structure inside the polydimethylsiloxane,which also enhances the elasticity of the sponge.（3）Carboxylated multi-walled carbon nanotubes（CNT）was used as support structures and are cross-linked with amino-terminated polydimethylsiloxane（PDMS）.The gas generated in the material preparation process was used as a porogen,and a three-dimensional porous sponge（PCNT）with excellent elasticity was successfully prepared.Structural characterization shows that the PCNT sponge has excellent elasticity,no obvious deformation after 10 cycles of compression.The adsorption experiment verified that the PCNT sponge still retains 99.47%of its adsorption capacity after 30 cycles of adsorption of petroleum ether.The experimental results of this part show that the carboxylated multi-walled carbon nanotubes play a supporting role of"reinforcing steel"inside the PDMS sponge,which improve the elasticity and tensile properties of the sponge.