The Crosslinking of Epoxidated Jatropha Oil with Diamines

In 2010, 130 million tonnes of epoxy resins were produced worldwide, most of them were made of petroleum based chemicals. In this research epoxidated Jatropha oil (EJO) is investigated as a renewable monomer for epoxy chemistry, and crosslinked with hexamethylenediamine (HMD), triethylenetetramina (TETA) and para-xylenediamine (pXD). First, Jatropha oil was successfully epoxidated with performic acid, in situ formed from formic acid and peroxide in toluene with a yield of >92%. Tin(II) methyl hexanoate was tested as a catalyst in 5 and 10wt% for the reaction of bisphenol A diglycidylether with HMD and the reaction was followed by DSC. The 5wt% of catalyst had no influence on the reaction. The 10wt% of catalyst decreased the reaction temperature from 150°C to 70°C and increased the reaction speed. The crosslink reaction with HMD, TETA and pXD was performed at 150°C (based on DSC) without a catalyst in different mol ratios and characterized with FT-IR and 1H-NMR spectroscopies. Beside aminolysis of the epoxy group, amidation of the ester group took place. When increasing the amount of amine, a rubbery solid could be formed with TETA and pXD. The tin based catalyst was also tested for the crosslinking of EJO and HMD, in which it increased the speed of the amide formation. Therefore, the catalyst was not investigated further. From the TETA 1:1.65 and the pXD 1:3.3 mol ratio a series of test specimens were pressed and tested by tensile stretching. The tensile stretching results showed that EJO with TETA resulted in a very flexible rubbery material, while the pXD crosslinked with EJO network was much more rigid and showed necking with large deformation before breaking. All final test specimens had a Tg below RT, with a slightly higher Tg for the TETA material. The mechanical properties were determined above the Tg of the material, leaving it in a rubbery state, the values will be different when measured below the Tg. Although only three diamines were tested in this research, the results indicate that the properties of the final network correlate with the structure of the diamine used for the crosslinking. Additionally, more amines should be investigated to further determine the structure-properties correlation for the final network after crosslinking with EJ-oil.