| Paraffin emulsion as a waterproof agent is generally used in the wood-based panel industry. Compared with solid paraffin, people do not need to melt or dissolve when use paraffin emulsion, and it has anti-acid-base and other excellent performance, besides, it has a safe, efficient and economical advantages. Two types of paraffin emulsion (Non-ionic paraffin emulsion and Anionic paraffin emulsion) were prepared in this thesis and the stability and rheological properties of different types of paraffin emulsion were researched, too.Non-ionic paraffin emulsion was prepared with Phase Inversion Emulsification (PIE) method in Chapter2. The types of emulsifier were selected with Hydrophilic-Lipophilic Balance (HLB) method. And the effect of different emulsifier types to emulsion performance from the structure of the emulsifier was discussed. The results show that, with the composite emulsifier consisting of glycerol monostearate and polyoxyethylene (100) stearate and the HLB value is13.0, the emulsion with better performance can be obtained. The emulsifier dosage was determined at5%. The orthogonal experiment results showed that optimum conditions were, emulsifying time20minutes, emulsifying temperature85℃, stirring rate5000rad/min and emulsifying water was added by three times. The paraffin emulsion was prepared under this condition, with solid content is51.6%, emulsion particle size distribution range is0.3-5.Oμm, viscosity is15s, centrifuged stability is99.8%. Malvern rheometer was used to study the rheological properties of the emulsion, the paraffin emulsion usually show a non-Newtonian fluid, specifically a pseudoplastic behavior, with the nature of shear-thinning, with the addition of the solids content of the emulsion, the non-Newtonian index m tends to gradually decreases. The results of dynamic strain sweep show that emulsion demonstrated resilience with the strain less than0.02%, and emulsion demonstrated viscous with the strain more than0.02%.Anionic paraffin emulsion was prepared with saponification method in Chapter 3. Selecting stearic acid as emulsifier, ammonia as saponifier, the saponification rate on the properties of emulsion was studied. The results show that, with the saponification rate1.2:1, the emulsion with better performance can be obtained, the emulsifier dosage was determined at4.5%. The relationships between the emulsion conductivity and the phase behaviors were studied with the conductivity method. The orthogonal experiment results showed that optimum conditions were, emulsifying time20minutes, emulsifying temperature85℃, stirring rate8000rad/min and emulsifying water was added by three times. The solid content of the paraffin emulsion is48.9%, and the distribution range of the emulsion particle size is3.5-11.Oμm, And the viscosity of the paraffin emulsion is17s with centrifuged stability is89.5%. The appropriate stabilizer was added to improve the stability of the emulsion, when PVA1799used in conjunction with lithium magnesium silicate, the centrifuged stability of the emulsion increased to98.8%, Foam has a significant negative impact on the performance of the emulsion, the methods for eliminating foam during emulsion preparation process was researched, add silicone defoamer with0.5%mass fraction before discharge the material can play a better anti-foaming effect, the foam can be completely removed from the emulsion after cooling using a vacuum degassing. Malvern rheometer was used to study the rheological properties of the emulsion, the paraffin emulsion usually show a non-Newtonian fluid, specifically a pseudoplastic behavior, with the nature of shear-thinning, with the addition of the solids content of the emulsion, the non-Newtonian index m tends to gradually decreases. The results of dynamic strain sweep show that emulsion demonstrated resilience with the strain less than0.02%, and emulsion demonstrated viscous with the strain more than0.02%.Preparation of petroleum resin emulsion and its performance were discussed in Chapter4. An O/W type C-5petroleum resin emulsion was prepared with paraffin wax as viscosity regulator and blend of nonionic emulsifier. Effect of HLB value and concentration of emulsifier on stability, droplet size, viscosity and surface tension of the petroleum resin emulsion were examined. The results showed that when the paraffin added with30%percentage composition, the C-5petroleum resin melt viscosity decreased obviously and the material in the low temperature mixing uniformly. The suitable HLB value is about10.75and emulsifier concentration is16%. The orthogonal experiment results showed that optimum conditions were, emulsifying temperature98℃, emulsifying time20minutes, stirring rate5000rpm and emulsifying water quantity1/3. The O/W type C-5petroleum resin emulsion which solid content is40.0%was prepared under this condition; it showed excellent stability, small droplet size and low viscosity. |
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