Synthesis Of Vegetable Oil-based Triamine And Its Feasibility In Polyurea Production

In order to reduce the environmental pollution caused by non-biodegradable food packaging materials, more researches have been focused on preparing biodegradable polymeric materials derived from bio-resources. This study has established a methodology to synthesize a novel triamine from triolein via intermediates triol, trialdehyde and tribenzylamine. The structures of triol, trialdehyde, tribenzylamine and triamine were characterized by 1H NMR, 13 C NMR FT-IR and LC-MS. Triol was synthesized from rapeseed oil and tung oil. It proved that the developed methodology of synthesizing triamine can be applied to vegetable oils. A preliminary study of synthesizing polyurea from triamine and hexamethylene diisocyanate was also conducted, and its thermal properties were evaluated. In addition, the feasibility of triol as an alternative of glycerol used in food packaging was studied. The main contents and results of this thesis research are described as follows:1. Synthesis and characterization of vegetable oil-based triamineAfter ozone oxidation and sodium borohydride reduction, triolein was transformed into triol. The triol was isolated with a yield of 62.8%, and its structure was characterized by 1H NMR, 13 C NMR FT-IR and LC-MS. The reaction conditions were optimized.Triol was oxidized to trialdehyde by 2-Iodoxybenzoic acid(IBX). The trialdehyde was isolated with a yield of 30.3% and its structure was characterized by 1H NMR, 13 C NMR FT-IR and LC-MS. The reaction conditions were optimized.Trialdehyde was reacted with benzylamine to obtain tribenzylamine in reduction of sodium borohydride. The tribenzylamine was isolated with a yield of 71.4%, and its structure was characterized by 1H NMR, 13 C NMR FT-IR and LC-MS. The reaction conditions were optimized.Tribenzylamine was transformed into triamine when hydrocracked by reacting with hydrogen with palladium on c arbon. The triamine was isolated with a yield of 74.6%, and its structure was characterized by 1H NMR, 13 C NMR FT-IR and LC-MS. The reaction conditions were optimized.The fatty acid composition of rapeseed oil and tung oil was determined by gas chromatography to analyze the feasibility to synthesize triol with the developed methodology. Triol was then successfully prepared from rapeseed oil and tung oil with the yield of 42.6% and 52.2%, respectively. Considering the technical route to synthesize triamine from triol established in this study, triamine can be prepared from rapeseed oil and tung oil.2. Synthesis of polyurea from triaminePolyurea was synthesized via hexamethylene diisocyanate and triamine. When the molar ratio of hexamethylene diisocyanate and triamine was 0.8, polyurea elastomer can be effectively synthesized without gelation, and it was colorless and transparent.The results showed that the weight-average molecular weight(Mw) of polyurea was only 21,175 g/mol, and its thermal stability was good, while the melting point of polyurea was 374℃. Therefore, the synthesis conditions of polyurea via triamine need to be optimized, while the structural identification and property characterization of polyurea need further study.3. Usage of vegetable oil-based triol in packagingThe triol synthesized in this study was added to chitosan/poly(vinyl alcohol)/nano TiO2 solutions and made into composite packaging films by casting. The physical, mechanical and barrier properties of the film were investigated.The incorporated triol showed evident intermolecular effect with other molecules in the film, and influenced the microstructure, mechanical and barrier properties of the composite film. The results proved that triol as a new plasticizer used in packaging materials may be feasible, and the property can be improved through further optimizing the structure and the formula of the composite film.