Study On Pickering Paraffin Emulsions Stabilized By Nano-SiO₂ And GMS/PEG

Paraffin emulsion is generally used in industry and other fields. But paraffin emulsions stabilized solely by emulsifier have a lot of problems remained to be solved. This article focused on fixing those issues, using nanoparticles along with compound non-ionic emulsifiers to stabilize pickering paraffin emulsions.Chapter 2 is mainly about preparing pickering paraffin emulsions stabilized by nano-silica along with non-ionic emulsifiers. First, using sol-gel method, we prepared nano-silica whose general particle size was 20 nm. Then, we found out the most suitable HLB value for preparing paraffin emulsion. The test results showed that when we added 0.25wt% silica to the system, we could lower the dosage of emulsifiers from 8wt% to 4wt%. And when the reaction temperature is 85 ℃, the content of water is 50wt%, the content of the laponite is 0.15wt%and the primer location of silica is water, we could prepare paraffin emulsion whose solid content is 50wt%, general particle size is 180 nm, viscosity is 19 Pa-s(indoor temperature), centrifuge stability is 97.1v%, and it could be finely stored for two months.Chapter 3 is mainly about modifying the Pickering emulsions. First, we used KH-550 to modify the silica to make it more hydrophobic. We prepared silica whose contact angle is 90 °～100°. Using the modified silica, we prepared pickering emulsions. Results showed that when the dosage of the modified silica is 4.5%, we could lower the dosage of the emulsifier from 4wt% to 1.5wt%, and when the primer location of the silica is water, the content of NaCl is 6wt%-8wt%, we could prepare paraffin emulsions whose general particle size is 100-300 nm, and its stability is 99.7v% which it can be finely stored for six months at room temperature. Besides, by adding acrylate emulsion to the paraffin emulsions, we could improve the film-forming ability of paraffin emulsion, and we found that the best ratio of the two emulsions is Vacylate emuision:Vparaffinemuisions=1:9, and its rate of water adsorption of the film is 7.2%.Chapter 4 is mainly about using modified UF resin/paraffin micro-capsules which were prepared by microencapsulation technology with melamine modified urea-formaldehyde resin as capsule wall and anionic and non-ionic paraffin emulsion as capsule core. The results showed that when the material of capsule core is anionic paraffin emulsion prepared by stearic acid and ammonia, the mass ratio of the capsule core and wall is 1:6, we can prepare the micro-capsules whose coating rate is 52.41%, average particle size is 20 μm, wall thickness is 500 nm. The micro-capsule’s enthalpy is 166 J/g, has great effect on phase change energy storage.This thesis prepared pickering paraffin emulsions with high-solid content, evenly particle size, great stability. Successfully, it realized the appeal to lower the dosage of the emulsifiers. Making use of the excellent film-forming property of the acrylate emulsions, we prepared the mixed emulsion with remarkable water-repellence and film-forming property.