Non-Isocyanate Polyurethane (NIPU) based on Rubber Seed Oil Synthesized via Low-Pressured Carbonization Reaction

Abstract

Epoxidised rubber seed oil (ERSO) was successfully synthesized into non-isocyanate polyurethane via carboxylation method whereas peroxoformic acid was formed by in-situ reaction for epoxidation. The effects of temperature and ratio of hydrogen peroxide and formic acid to rubber seed oil carboxylation were studied. The optimum temperature for the epoxidation reaction was found at 50 °C to avoid ring opening reaction of epoxy whilst the optimum ratio of hydrogen peroxide and formic acid is equal molar of double bond: formic acid at 1:2 and 1:1, respectively. At a lower concentration of hydrogen peroxide and formic acid, the oxirane ring was stable due to the lower hydrolysis (oxirane cleavage) of an epoxide. The effect of using low content of formic acid tends to minimize unwanted epoxide ring opening to occur and make the epoxidation rate increased with increasing of oxirane number. Fourier transform infrared (FTIR) spectral displayed the presence of an epoxy functional group at 822 cm-1 and the disappearance of double bond peak at 3011 cm-1 corresponding to epoxidised oil and carbonyl group confirmed the epoxidation reaction had taken place. 1H-NMR was used to confirm the formation of carboxylate functionality after the reaction of epoxy at δ 4.83 and 4.61 ppm. In conclusion, ERSO has great potential to be used as a precursor in producing environmentally friendly non-isocyanate polyurethane.

pH‐responsive polyurethane‐acrylate from palm olein and sunflower oil: Sustainable synthesis, enhanced lovastatin solubility, and potential drug carrier for targeted delivery

“…As shown in Scheme 1a,b, the cyclic carbonates produced from oleic acid‐based acyl chains, the product would be a di‐urethane compound, while for the cyclic carbonated produced from linoleic acid‐based acyl chains, the product would be in polymerized form. In all the reported works of NIPU reaction, linseed oil, 70 soybean oil, 37 sunflower oil, 71 rubber seed oil, 72 and jojoba oil 73 have been used in the production. The NIPUs produced were primarily aimed at applications in elastomeric materials, 37 coatings, 71 and composites 73 .…”

“…Appearance of peaks at 1703, 1697, 1533, and 1247 cm À1 , were attributed to the urethane groups, N H deformation of the urethane group, and C N bending of the urethane group, respectively, 28,36 which indicated the successful formation of urethane linkages. In addition, peak formation was also observed at 3336 cm À1 which corresponded to O H or N H stretching, 72 indicating the formation of the O H group within the backbone of the PU after ring opened by BDA. When the amount of BDA was in excess (molar ratio of NIPU: BDA = 1:1.6), a peak was observed at 1654 cm À1 corresponding to C O carbonyl amide peak, resulting from the undesired aminolysis side reactions of the ester groups (Figure 1b).…”

Innovations in applications and prospects of non‐isocyanate polyurethane bioplastics

“…The synthesis of NIPUs at room temperature has been reported in the literature and revealed that the reaction is extremely sluggish while raising the temperature significantly increases the reactivity. [ 72 ] Both the number of hydrogen bonds and viscosity increase during polymerization. Because of this, a rise in temperature will resolve the problem and increase reaction rates.…”