| Reactive emulsifier has many excellent advantages, and it has been widely used in numerous fields of science, with broad prospects. But there are fewer researches of the reactive emulsifiers at home. In recent years, the paper industry has obtained many business opportunities, at the same time, higher requirements on paper enterprises have been set of. Surface sizing agent is particularly important for improving the performance of paper in the various paper additives. Because the surface sizing agents in the domestic market still have some defects, this thesis carried out a series of work about the emulsifier types, modified monomer and polymerization process.Firstly, a novel reactive emulsifier of sodium maleic hemihexadecylester propylsulfonate(SMHP) was synthesized via catalysis action of solid catalyst S2O82-/ZrO2-SiO2 taking maleic anhydride, sixteen alcohol and 1,3- Sulfonic acid ester as the raw materials. Nuclear magnetic resonance spectroscopy was used to characterize the molecular structure of the reactive emulsifier, and the comparison of emulsifying ability among the prepared emulsifier(SMHP), the traditional emulsifier sodium dodecyl sulfate(SDS) and another reactive emulsifier ammonium sulfate allyloxy nonyphenoxy poly(ethyleneoxy)(10)ether(DNS-86) was tested by emulsification experiment test. The critical micelle concentration(CMC) could be obtained by surface tension test. The results showed that the solid acid catalyst S2O82-/ZrO2-SiO2 has the best catalytic effect with fewer impurity in the target product,and its proper content is 0.6wt%. The prepared reactive emulsifier SMHP can effectively lower the surface tension of water, the CMC of SMHP is about 0.2 g·L-1and its emulsifying ability is much better than that of DNS-86 and SDS. This three kind of emulsifiers were applied to styrene-acrylic emulsion polymerization,respectively. The optimum content of reactive emulsifier SMHP is 4.5wt% and the particle size decreased with the increasing content of SMHP. Under the same condition of emulsifier content, the latex particles prepared by SMHP system have the largest particle size. The ion stability of emulsion prepared by SMHP is similar to thatof the emulsion prepared by DNS-86, but it is much higher than that of the emulsion prepared by SDS. The thermal gravimetric analysis showed that the type of emulsifier had little effect on the thermal stability of the emulsion film. The raw paper was sized by such surface sizing agent containing SMHP with sizing starch, its sizing degree can be greatly improved.Then, the effect of modified monomer on the properties of the surface sizing agent was studied. The methacrylate hexafluoride(HFMA) was introduced into the styrene-acrylic emulsion, which taking DNS-86 as the reactive emulsifier. A series of core-shell structure styrene-acrylic emulsions that only the shell-phase contain fluorine were synthesized through changing the content of DNS-86 and HFMA by semi-continuous seeded emulsion polymerization, respectively. The results showed that the optimum content of DNS-86 is 5.2wt% of monomers and the optimum content of HFMA is 18wt%. With the increasing content of fluorinated monomer, the water absorption of the emulsion film decreased gradually and the water contact angle(CA) became larger correspondingly, meanwhile, the positive CA of emulsion film is larger than that of the negative one. But the monomer conversion and viscosity(stable at 40 mPa·s) of the emulsion are not affected by the fluorinated monomer content.Nuclear magnetic resonance spectroscopy showed that the majority of monomers(St,BA and HFMA) has been involved in the emulsion polymerization. TEM image showed that latex particles with obvious core-shell structure were successfully prepared, and the compatibility of core-phase and shell-phase is good. TGA showed that the fluorine-containing emulsion film has a better thermostability than emulsion film without fluorine. At last, the base paper was sized by the mixture of surface sizing agent and sizing starch. SEM images showed that the fluorinated surface sizing agent has formed a layer of continuous film on the paper surface, which had a better film-forming ability. The sizing degree of paper can be up to 65 seconds, which significantly improve the water resistance of paper.In this thesis, the effect of polymerization process on the emulsion properties was also discussed. A new type of styrene-acrylic emulsion with novel reverse core-shell structure was successfully prepared through changing the feeding sequenceof the soft and hard monomers by semi-continuous seeded emulsion polymerization.At the same time, under the condition of controlling the total content of emulsifier, the effect of the emulsifier ratio on the emulsion properties was studied by changing the mass ratio of reactive emulsifier DNS-86 and non-ionic emulsifier Triton X-100. The results showed that the raise of mass ratio of DNS-86 could enhance the solid content of emulsion, the monomer conversion and the water absorption of emulsion film to some extent. The optimum mass ratio of two kind of emulsifiers was 1:1. Under the same condition, emulsions with reverse core-shell structure have higher solid content and monomer conversion than that with traditional core-shell structure. TEM images showed that the traditional core-shell structure was prepared by taking St as core-phase monomer and BA as shell-phase monomer, the island type of reverse core-shell structure was prepared by taking St as shell-phase monomer and BA as core-phase monomer, contrarily. Compared to the emulsion with traditional core-shell structure, emulsion with reverse core-shell particles exhibited better hydrophobic property, film-forming property and thermostability, and the emulsion film is relatively smooth, with a lower water absorption.In this thesis, a series of SAE surface sizing agent with high performance was prepared through the study of emulsifier, modified monomer and polymerization process. The use of solid acid catalyst S2O82-/ZrO2-SiO2 could avoid the corrosion of reactor in industrial production, and simplify the technological process. The prepared reactive emulsifier could solve the desorption problem occurred in the film-forming process of surface sizing to prevent environmental pollution. At the same time, it also enhance the stability of transportation, storage and electrolytes. The introduction of modified monomer could improve the waterproof performance of the surface sizing agent, which has great significance for the production of high performance paper in the paper industry. |
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