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Shanthi, P. Michael SL, et al. Journal of colloid and interface science 350.1 (2010): 39-43.
Nativeness, high affinity for bone, good biocompatibility and nanometer size are the characteristics of nano HAp that make it an excellent candidate for bone-promoting drug delivery systems (ODDS). However, size limitation and porosity generation are challenges in the preparation of such systems. In this paper, porous nanohydroxyapatite was successfully prepared using the cationic surfactant cetrimide as a template.
Synthesis of HAp Using Cetrimide as template
HAP was prepared using 0.1 M Ca(NO3)2 4H2O and 0.06 M (NH4)2HPO4 aqueous solution as precursors. Using cationic surfactant cetrimide as template, the conductivity of surfactant solution at different concentrations was measured by conductivity meter to determine the micelle formation concentration CMC. According to the plotted concentration (M)-conductivity graph (Sμ), the critical micelle concentration at room temperature (~30 °C) was calculated to be 0.00388 M. Therefore, 4 mM cetrimide and 50 mL of PO43- ion solution were added. At room temperature and pressure, 50 ml of Ca2+ solution was added to the PO43- solution at a rate of 1 drop/15 s with moderate stirring. The pH value was maintained at 11.3-11.5 throughout the experiment.
The preparation was carried out according to the procedure shown in the right figure. The dried samples were then calcined at different temperatures such as 350, 550 and 750 °C for 8 h, which were called HAP-350 °C, HAP550 °C and HAP-750 °C, respectively.
Ali, A. H., Mohanad Yakdhan Saleh, and Khalid Ahmed Owaid. Iran. J. Catal 13 (2023): 73-83.
Some polythioesters, such as polythioethylene terephthalate, are among the most widely produced polymers due to their good tolerance. Cutting-edge performance and other excellent properties, such as low cost, enable them to be widely used to provide films, fibers and bone cements. Therefore, we developed a new route and method to efficiently and cleanly synthesize polythioester polymers with different main chain structures using cetrimide as a green and environmentally friendly phase transfer catalyst.
Synthesis of Five Polythioester Polymers (A-E) Catalyzed by Cetrimide Ionic Liquid Phase Transfer
By using chloroform-water interfacial system as interfacial polycondensation reaction system and cetrimide as phase transfer catalyst, diacyl chloride derivatives and 5,5'-methylenebis(1,3,4-oxadiazole-2-thiol) were synthesized by interfacial polycondensation method.
1. In a round-bottom flask, a mixture of 0.01 mol sodium hydroxide and 0.005 mol synthetic 5,5'-methylenebis(1,3,4-oxadiazole-2-thiol) was added, and 10 mg of cetrimide (phase transfer catalyst) was dissolved in 5 mL water.
2. 0.005 mol of diacyl chloride monomers were dissolved in 20 mL chloroform and quickly added to the aqueous phase, and stirred with a stirrer at room temperature for 5 min to obtain an organic phase.
3. Then, 20 mL of acetone was added. The polymer was separated by filtration and washed with acetone and distilled water to remove unreacted starting materials and secondary products such as sodium chloride. The product was dried in an oven at 60 °C for 1 h.
Grunlan, J. C., et al. Biomacromolecules 6.2 (2005): 1149-1153.
Recently, various functional thin films have been developed using the "layer-by-layer" (LbL) assembly of polyelectrolytes and other charged species. Here, polyelectrolyte multilayers were prepared using silver nitrate and/or cetrimide as antimicrobial agents.
Materials
Polyethyleneimine (PEI) is a polycation with a molecular weight (Mw) of 25000 g/mol, while poly(acrylic acid) (PAA) is a polyanion with a molecular weight of 100000 g/mol. Polyethylene terephthalate (PET) films with a thickness of 175 µm were used as substrates for thin film deposition. The PET films were always rinsed with water and methanol before deposition to remove impurities. Aqueous solutions containing 0.1 wt% PEI were prepared by rolling for 24 h and then adding 1 M HNO3 to reduce the pH to 7. Solutions containing 0.3 wt% PAA were prepared in the same manner and then the pH was adjusted to 5 using 1 M NaOH. 20 mM silver nitrate was always added to the PEI solution before starting the self-assembly procedure to avoid extensive silver reduction due to ambient UV exposure. The PEI solutions containing cetrimide were prepared 24 hours before deposition to allow complete dissolution. The pH of the silver-containing solutions and cetrimide-containing solutions were not adjusted prior to use.
Thin Film Deposition
In some cases, the PET films were corona treated at a frequency of 3 kHz and an output of 1.7 kW before deposition to enhance their negative surface charge. The initial bilayer of each film was deposited by immersing the PET substrate in each ionic solution for 5 minutes, starting with the cationic solution. Subsequent bilayers were deposited with one-minute immersions. After each immersion, the substrate was rinsed with deionized water for 30 seconds and dried with nitrogen for 30 seconds. After deposition of 16 bilayers, the films were dried in an oven at 70 °C for 15 minutes to remove residual water.
