Studies On Preparation And Properties Of Inorganic-organic Composite Pigments With Improved Thermo And Photostability

The hydrotalcite-like materials (LDHs), being a kind of layered structureinorganic functional materials, are widely applied in the fields such asadsorption materials, catalysis materials, biological medicine carrier, plasticfunctional additives etc due to their highly tunable properties and unique anionexchange properties. Therefore, it is of great significance to study thepreparation and properties of functional materials based on LDHs.In this dissertation, a series of supramolecular inorganic-organiccomposite pigments were synthesized by intercalating several dye anions intothe interlayer space of ZnAl-LDHs through coprecipitation or anion-exchangemethod. Mg-Al-carbonate layered double hydroxides with high purity andcrystallinity was synthesized by an atom-economic reaction underhydrothermal conditions. The detail contents are shown below:1. Acid red57(AR57) and mordant yellow3(MY3) anion wereintercalated into ZnAl-LDHs to obtain inorganic-organic composite pigmentsZnAl-R57-LDHs and ZnAl-MY3-LDHs via co-precipitation and ion-exchangemethod respectively. XRD, FT-IR, TG-DTA and ICP results confirm the intercalation of the dye anions into the galleries of ZnAl-LDHs and there arestrong host-guest interactions between the host matrix layers and the guest dyeanions. The temperature for thermal oxidative decomposition of MY3andAR57anions are improved by intercalating into the interlayer galleries ofZnAL-LDHs. The thermo-and photo-stability of the dye anions are alsoenhanced through incorporating into the interlamellar room of ZnAl-LDHs.2. Acid red6(AR6) and acid blue25(AB25) anions were co-intercalatedinto ZnAl-LDHs to form a class of color-controllable supramolecularinorganic-organic composite pigments by co-precipitation method. XRD,FT-IR, TG-DTA and ICP data confirm the co-intercalation of the two dyeanions into the interlayer galleries of ZnAL-LDHs and there exist stronghost-guest interactions between the hydroxide layers and the dye anions. Thehybrid pigments display higher decomposition temperature than the prestinedyes as a result of the interaction between the dye anions and the host layers.Thermal aging and photo aging tests indicate that the composite pigmengshave better lightfastness and heat resistance than the dyes.3. MgAl-CO₃-LDHs was synthesized using Light MagnesiumCarbonate (LMC), Mg(OH)₂and Al(OH)₃as raw materials by atom-economicreactions under hydrothermal conditions. XRD, FT-IR, TG-DTA, ICP, SEMand TEM characterizations confirm that MgAl-CO₃-LDHs parpared by thismethod has high crystallinity and purity and the particle size ofMgAl-CO₃-LDHs is at the range of1-2μm. The major advantage of the method is that no by-product is produced, thus fltration and washingprocesses can be omitted, resulting in benefits to the environment and aconsiderable saving in water and energy resources.