POLYURETHANES BASED ON MODIFIED HEMP OIL

Abstract

Polyurethane materials of different composition and structure were prepared using diisocyanates of different nature, native and functionalized vegetable oils. Hydroxylated derivatives of hemp oil, namely lineoyl diethanolamide (LDEA), whose structure was confirmed by IR spectroscopic studies, were obtained by amidation of hemp oil with diethanolamine. LDEA is used as an isocyanate extender of functionalized castor oil with the formation of film-forming materials (content of components of naturally renewable origin up to 70%). A decrease in the strength characteristics of synthesized polyurethanes from 31 to 18.8 MPa and an increase in their elasticity is due to the presence of the fatty acid fragment in LDEA. The content of LDEA (internal plasticizer) can be a factor in regulating the level of strength-elastic properties, and its presence in the composition of polyurethane contributes to increased resistance in an acidic environment. Analogues of the specified material were prepared using diethanolamine as an extender. Aggregatively stable (more than 12 months) film-forming aqueous polyurethane dispersions containing LDEA (10 and 20 wt.% in the composition of oligomeric diols) were prepared. The size of their dispersed phase is 460–328 nm, which decreases with increasing LDEA content. The breaking strength indicators of film materials obtained based on IPU increase with the increase of LDEA content from 4.76 MPa to 5.86 MPa, respectively, and the relative elongation decreases from 469 to 430% with the content of LDEA 6.8 and 13.5 wt.%, respectively. Since the weight loss in alkaline and acidic environments decreases with increasing content of lineoyl diethanolamide in the dispersion, its presence in the composition of anionic polyurethanes is a factor in increasing their stability in aggressive environments.