In vitro release and antioxidative potential of Pequi oil-based biopolymers (Caryocar brasiliense Cambess)

Polyurethane derived from castor oil monoacylglyceride (Ricinus communis) for bone defects reconstruction: characterization and in vivo testing

“…We have obtained the MAG and polyurethane as described by Cunha and coworkers [14], Moura Neto and coworkers [15], and Nascimento and coworkers [16].…”

“…The reaction lasted for 5 h and occurred in the absence of solvent, following a stoichiometric ratio of 1: 4 (MAG: HDI). The ratios used here have been chosen based on our previous studies [14][15][16], in which a broader review was possible.…”

“…The FTIR spectra of MAG and polyurethane samples were obtained in a Thermo Fisher SCIENTIFIC NICOLET iS5 spectrophotometer with a purge pump and wavelength between 400 and 4000 cm −1 , 128 accumulated scans, 4 cm −1 resolution, in ATR, in Transmittance module. The method has been used to verify the curing reaction of polyurethane and free isocyanate functional groups (NCO) after the response [14][15][16][17]. The TG/DTG curves were obtained simultaneously in the SD Instruments Q 600, from TA Instruments, using a heating rate of 10°C/min, between 25°C and 600°C, in N2 atmosphere, with a sample mass of 10 mg [14].…”

“…Two peaks observed in DTG coincide with the mass loss present in TG between 175°C to 225°C and 225°C and 275°C. A gradual mass loss above the latter is related to the decomposition of long polyurethane chains [15,16].…”

“…The fact that the bonds cause an orderly arrangement of atoms or molecules with regular repetition in space can explain this semi-crystallinity. The molecular chains are densely packed in an ordered and parallel configuration, which justifies that the addition of HDI to castor oil leads to the formation of urethane groups through bonds between HDI and hydroxyls (-OH) [16][17][18]20].…”