Dissertation
NOVEL VEGETABLE OIL-BASED EPOXY RESIN SYSTEMS: SYNTHESIS, PROPERTIES AND POTENTIAL APPLICATIONS
Doctor of Philosophy (PhD), Washington State University
01/2018
Handle:
https://hdl.handle.net/2376/111238
Abstract
In contrast to the conventional epoxidized vegetable oil (VO), a new type of VO-based epoxy monomers built on the structures of polyunsaturated fatty acids (FA) with multiterminal epoxy groups was successfully prepared, which has a shorter average distance between the functional groups and more reactive terminal epoxy groups. The FA were first converted to polycarboxylic acids and subsequently into polyglycidyl esters. Consequently, the resulting cured epoxy materials demonstrated significantly improved mechanical and thermal properties. After the synthesis method was confirmed using methyl linoleate (model compound), the same procedure was applied to prepare the hempseed oil-based curing agent (HO-polyacid) and epoxy monomer (HO-EP). Because the HO-polyacid is a flexible compound, the rigid maleopimaric acid (MPA) was used as a cocuring agent in curing a commercial bisphenol A epoxy. By varying the cocuring agent ratio, the properties of resulting epoxy materials were adjusted greatly. In addition, the properties of the cured HO-EP materials were also adjusted greatly by curing with different curing agents.
Using flexible HO-EP paired with stiff MPA and flexible HO-polyacid paired with rigid MPA-derived epoxy (MPA-EP), two fully bio-based epoxy vitrimers were prepared. The mechanical properties of the HO-EP/MPA and MPA-EP/HO-polyacid vitrimers increased with increase in the MPA or MPA-EP content. For the HO-EP/MPA system, the vitrimer with a molar ratio of 2/1 showed better stress relaxation and self-healing properties, while the vitrimer with a molar ratio of 1.5/1 exhibited a greater shape memory property than others. In contrast, the stress relaxation and self-healing properties of the MPA-EP/HO-polyacid vitrimer with a 1/1 molar ratio were better, and the shape memory property of the one with a 2/1 molar ratio was better than others.
To modify a commercial asphalt binder, a waste cooking oil-derived polyepoxy (WCO-EP) was synthesized using the same method, and then cured with a kraft lignin-based polycarboxylic acid (KL-COOH). A liquid NMA was applied as a cocuring agent to improve the processability. The mechanical and thermal properties of the cured WCO-EP materials increased with increase in the ratio of KL-COOH/NMA. Moreover, the epoxy asphalts exhibited great improvement in high-temperature rutting resistance without compromising their low-temperature cracking resistance.
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Details
- Title
- NOVEL VEGETABLE OIL-BASED EPOXY RESIN SYSTEMS: SYNTHESIS, PROPERTIES AND POTENTIAL APPLICATIONS
- Creators
- Ran Li
- Contributors
- Jinwen Zhang (Advisor)Yuehe Lin (Committee Member)Junna Xin (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Materials Science and Engineering Program
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 156
- Identifiers
- 99900581710701842
- Language
- English
- Resource Type
- Dissertation