Synthesis Of Melamine Modified Amide Gelator And Its Gelation Behavior

Low-molecular-mass organogelators (LMOGs) are a kind of organic compounds which could limit the flowability of solvents and gelate these solvents at low concentration. Melamine derivatives have been widely used in the assembly of supramolecular materials due to their unique properties. Hence, it has important scientific significance and applied value to prepare supramolecular organogelators with melamine derivatives. In this thesis, a novel amide gelator with melamine moieties (AMOG) was designed and synthesized, and the gelation behavior of AMOG in various organic solvents was investigated. Hansen solubility parameters (HSPs) were introduced to reveal the solvent effect on gelation behavior of AMOG. Polymer was used to tune the gelation behavior. The details are summarized as follows:1. A novel amide gelator AMOG with melamine moieties was synthesized from melamine derivative and dicarboxylic acid with amino group by using HOBt and EDC as coupling agents. AMOG was found forming gel in various common organic solvents through gelation experiment and showed strong gel-forming ability. Sol-gel transition temperature raises with the increasing of gelator concentration. Solvent type showed significant influence on macro and micro morphology of gel, which exhibited evident solvent effect.2. HSPs were introduced to reveal the solvent effect on gelation behavior. The macro and micro morphology were tightly related to hydrogen bond parameter 8h. 1.0MPa1/2<?h<4.1MPa1/2 for organic solvents is the favorable domain for transparent gels formation, opaque gels occur in the range of 4.1 MPa1/2<8h<8.0MPa1/2 and solution/precipitation remain if 8h is larger than 8.0MPa1/2. Most of the solvents that could form gels cluster in a certain region in Hansen space. Sol-gel transition temperature was related to parameter 8d and ?P.3. Polystyrene (PS) and poly vinyl acetate (PVAC) were mixed into current gel system and four new gel systems were produced, namely PS-AMOG/toluene, PS-AMOG/xylene, PVAC-AMOG/toluene and PVAC-AMOG/xylene. The investigation on these four gel systems showed the polymer added significantly influenced gelation forming time and sol-gel transition temperature. The gelation time of above four systems decreased at first and then increased with the increase of polymer concentration. The sol-gel transition temperature increased at first and then decreased in system PS-AMOG/toluene and PS-AMOG/xylene, while remained same in system PVAC-AMOG/toluene and PVAC-AMOG/xylene.These results above showed that gelator with amide-melamine structure is favorable for gel formation and the gelation behavior exhibit evident solvent effect. The application of Hansen solubility parameters is an effective method to analysis and predict gelation behavior and lay experimental foundation for further exploration in this field. Gelation behavior can also be tuned by adding polymer into current gel system, which provides scientific basis for the preparation of gel-polymer hybrid system.