Self-Blowing Non-isocyanate Polyurethane Foams from Cyclic Carbonate Linseed Oil

Abstract

Non-isocyanate polyurethane (NIPU) foams prepared from renewable resources have attracted much attention as benign alternatives to polyurethane (PU) foams due to their advantages for sustainable development and green production. However, the current synthesis of the NIPU foams mainly relies on external foaming agents. In this study, bio-based NIPU foams were developed by a simple selffoaming method composed of two simultaneous processes: Salkylation of multifunctional thiol compounds and carbonated linseed oil (CLSO) and ring-opening reaction between diamines and CLSO. The effects of curing conditions, thiol functionality, and the types of diamines on the chemical structure, morphology, and properties of the NIPU foams were systematically investigated. The cell diameter of the resulting NIPU foams could be tuned in the range 0.17−1.34 mm, and the compression strength could be tailored in the range 6.7−21.0 kPa. The solvent-free strategy for the synthesis of selfblowing plant oil-based NIPU foams offers a new and simple route for constructing next-generation NIPU foams that are environmentally friendly and have performance advantages.

Significant anisotropic deformation and optical shifts in stretched cholesteric liquid crystal elastomers

“…The main-chain type CLCE specimens under study are expected to contain finite amounts of such dangling portions due to imperfections in the network structure and a side reaction between a thiol and the carbonate group of the chiral molecules. 37 While the WAXS tests capture the entire mesogen orientation including dangling portions, the dangling chains do not contribute to stress-induced distortion of the helical structure, as they are elastically inactive. Davidson et al 35 employed almost the same value of r = 8.5 in this model to explain the opto-mechanical response for a twisted nematic elastomer with an almost similar structure to the CLCEs in this study.…”