High Modulus, Strength, and Toughness Polyurethane Elastomer Based on Unmodified Lignin

Abstract

Lignin-based polyurethane elastomers (LPUe) with high stiffness, strength, and toughness were facilely prepared by direct cross-linking of unfunctionized lignin as hard segments and poly­(propylene glycol) tolylene 2,4-diisocyanate terminated (PPGTDI) as soft domains. The effects of lignin molecular weight (3600 and 600 g mol–1) and weight fraction (5–40 wt %) on the thermal and mechanical properties of LPUe were studied. With an increase in lignin content, LPUe exhibited improved thermal stability, and the glass transition temperature (T g) also increased, especially for LPUe derived from lignin with low lignin molecular weight of 600 g mol–1 (600-LPUe). Furthermore, LPUe also exhibits excellent mechanical properties. For 600-LPUe with 40 wt % of lignin, the Young’s modulus, tensile strength, and strain at break reach 176.4 MPa, 33.0 MPa, and 1394%, respectively, which could be attributed to better dispersion of low molecular weight lignin in elastomers as evident from DSC, SEM, and TEM studies. Our results demonstrate the potential application of unmodified lignin in developing biobased high-performance PU materials. This is in contrast to many current studies of LPUe systems that need lignin modification to prepare PU materials.

Investigation on Effects of Chain Extenders and Cross-linking Agents of Polyurethane Elastomers Using Independent Building Vibration Isolation Sensor

“…(3,4) Polyurethanes are a class of versatile macromolecules with extraordinary and versatile performances, including excellent elasticity, flexibility, a wide range of hardness, high tearing capacity, good abrasion resistance, and processability. (5)(6)(7)(8) There is high interest in their applications as coatings, (9,10) adhesives, (11,12) air filters, (13,14) protective textiles, (15,16) and sensors. (17,18) Polyurethane elastomers (PUEs) have a special microphase separation structure, which has shown excellent performance (19) and has attracted the interest of researchers for use in damping and vibration isolation.…”

Sustainable rubbers and rubber additives

“…used amino acid (such as serine, aspartic acid, and glutamic acid) derived biorenewable diol chain extenders for the synthesis of thermoplastic polyester‐urethane elastomers. Unmodified lignin based polyurethane elastomers with high stiffness, strength, and toughness were prepared by Li et al . Carvone, a component of the oils extracted from caraway seed Carum carvi and spearmint Mentha spicata , is converted to a seven‐membered lactone: carvomenthide.…”

Fabrication of thermo-sensitive lignocellulose hydrogels with switchable hydrophilicity and hydrophobicity through an SIPN strategy

“…22,23 In addition, the numerous functional groups of lignin, such as phenolic and aliphatic hydroxyl, methoxyl and carbonyl groups, endow it with sufficient reactivity with various compounds. Different studies have shown that incorporation of lignin in PVA hydrogels, 24 epoxy resins 25 and polyurethane products 26 can effectively improve their mechanical properties and increase their renewable content. In addition, as a complex network of different phenylpropane units, lignin provides necessary hydrophobicity to plant cell walls.…”