Preparation Of Halloysite Nanotubes-Benzotriazole Composites And Application On VCI Paper

Incorporating nanoparticles with inorganics or organics for preparing hybrids ornanocomposites is an important direction in the development of materials science.Halloysite nanotubes (HNTs) is a viable and inexpensive nanoscale container with a hollowtubular structure, which has high aspect ratio, specific surface area, excellent chemical andthermal stability. HNTs’ special lumen can be used for loading small molecules andmonomer. The nanocomposites have controlled release properties under certain conditions.Benzotriazole(BTA), a kind of often used volatile corrosion inhibitor(VCI), is loadedinto the inner volume of HNTs by vacuum method. And the BTA-HNTs composites arefabricated using the layer-by-layer (LbL) self-assembly technique by positively chargedpoly allylamine hydrochloride(PAH) and negatively charged poly styrene sulfonate(PSS),which absorb on the surface of HNTs and form polyelectrolyte multilayer. Then BTA-HNTscomposites are coated on unbeached kraft paper with starch and carboxy styrene-butadienelatex to prepare VCI paper. This paper studies the influence of polyelectrolyte multilayerand pH value on the controlled release of BTA-HNTs composites and the corrosioninhibiting effect of VCI paper on each metal such as copper, aluminum and iron. Here arethe experiments’ results in detail.1. The influence of loading methods, drying method, alcohol to water ratio and BTAconcentration in mixed solution are studied. It shows that the optimal conditions areintermittent loading4times, each time include2cycles (1h); heated-air drying;10%alcoholand90%water in mixed solution(wt%, the same below); BTA concentration3%. The BTAquantity loaded into HNTs is5%.2. This paper studied the Zeta potential and the release in different pH of BTA-HNTscomposites after encapsulation. Results show that PAH and PSS form polyelectrolytemultilayer structure on the surface of BTA-HNTs composites. In neutral (pH=6.5) NaClaqueous solution (0.5mol/L), BTA-HNTs composites release less BTA with the increase ofpolyelectrolyte layers. BTA-HNTs composites after encapsulating four layers nearly releaseno BTA in the present article. In acidic, neutral, and alkaline NaCl aqueous solutions(0.5mol/L), BTA concentration released from BTA-HNTs composites is pH=10.0> pH=2.9> pH=6.5. The result shows that nanocontainers release more encapsulated BTA when thecorrosion process is started under certain environment.3. This paper studied the anti-corrosion performance of VCI paper and the influence ofthe proportion of starch and latex on surface intensity of paper. The result is that thecorrosion inhibiting ratio of VCI paper increases with the increase of coating weight. Thecorrosion inhibiting effect is best when coating weight is38g/m2. When starch: latex is5:10,surface intensity improves significantly, which can meet the requirements of VCI paper.4. The analysis on corrosion inhibiting ratio of three kinds of VCI paper is studied.Theprepared VCI paper has excellent corrosion inhibiting effect on copper and aluminum,whereas the effect on iron is not so significant. Effect of prepared VCI paper has reachedthe level of some commercially available products or even better,but there still exist a gapwhen compared with metal multifunctional universal VCI paper..The research indicates that the BTA-HNTs composites which were encapsulated by PAHand PSS attain controlled release properties. The BTA-HNTs composites were used aspigment and the prepared VCI paper after coating has good corrosion inhibiting effect oncopper and aluminum.