Lignin-Based Polyurethanes from the Blocked Isocyanate Approach: Synthesis and Characterization.

ABSTRACT: Lignin, the world's second most abundant biopolymer, has been investigated as a precursor of polyurethanes due to its high availability and large amount of hydroxyls present in its structure. Lignin-based polyurethanes (LPUs) are usually synthesized from the reaction between lignin, previously modified or not, and diisocyanates. In the present work, LPUs were prepared, for the first time, using the blocked isocyanate approach. For that, unmodified and hydroxypropylated Kraft lignins were reacted with 4,4'-methylene diphenyl diisocyanate in the presence of diisopropylamine (blocking agent). Castor oil was employed as a second polyol. The chemical modification was confirmed by ³¹P nuclear magnetic resonance (³¹P NMR) analysis, and the structure of both lignins was eluci

SUBMITTER: Antonino LD 

PROVIDER: S-EPMC10398858 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature