The limited availability of fossil resource is causing the urgent need to get renewable chemicals. Solvent liquefaction can convert rice husk into bio‐based chemicals. Rice husk was liquefied in polyhydric alcohol catalyzed by sulfuric acid under atmospheric pressure. The viscosity, residue content, and weight average molecular weight (Mw) of liquefied rice husk were 3089 cps, 23.6% and 4100, respectively. Prolonging the liquefaction time decreased the residue content and increased the average molecular weight. Polyurethane (PU) foams were successfully prepared from the liquefied rice husk with different molar ratios of NCO to OH (NCO/OH). The mechanical properties of PU foams showed that the compressive strength in the vertical direction is higher than that in the horizontal direction. With Increase of the NCO/OH molar ratio from 1.0 to 2.0, compressive strength in the vertical direction of PU foams increased from 70.6 to 114.7 kPa at 10% strain. Thermal analysis results showed that thermal stability of liquefied rice husk‐based PU resins was better than that of fossil‐ and liquefied wood‐ based PU resins. Increasing the NCO/OH molar ratio and inorganic residue of rice husk can help to increase thermal stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45910.

Bambusa dolichoclada Hayata (long-shoot bamboo) was liquefied in phenol with H 2 SO 4 as a catalyst. The phenol-liquefied bamboo was then used as a raw material to prepare spherical phenol-formaldehyde (PF) resin beads by a suspension polymerization in a two-step process. The influence of the stirring speed (300, 350 and 400 rpm), the stabilizer dosage (3%, 4% and 5%) and the total molar ratio of formaldehyde to free phenol (F/P) (3.0/1, 3.5/1 and 4.0/1) on the properties of spherical PF beads was investigated. The results show that the yield, diameter and dimensional distribution of prepared PF beads were influenced by reaction conditions. The diameter of beads decreased as the stabilizer dosage increased. It had a more uniform dimensional distribution when stirred with a speed of 400 rpm. Differential scanning calorimetry analysis shows that PF beads obtained were not completely cured and the post-curing reaction took place at temperatures exceeded 1508C. As revealed by thermal gravimetric analysis, the char yield was over 60% after heating to 8008C.

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Waterborne polyurethane resins (WPUs) were prepared from polytetramethylene ether glycol (PTMG) and PTMG/polyhydric alcohol liquefied lignin (LL) with isophorone diisocyanate (IPDI), and ethylenediamine (EDA) and 1,4-butanediol (1,4-BD) were used as chain extenders. The effects of LL and the kind of chain extender on the properties of the WPU suspensions and dried films were studied. WPU suspensions prepared with PTMG/LL as the polyol had higher viscosity and larger average particle dimension than those with PTMG alone. WPU films prepared with EDA as the chain extender had higher tensile strength with less tensile deformation. LL can enhance the stiffness of WPU films, but the breaking deformation decreases. Dynamic mechanical analyzer (DMA) results showed that the main effect of LL was reduced thermal activity of the soft segment. Thermogravimetric analyzer (TGA) results showed WPU films prepared with EDA as the chain extender had better heat-resistance than those with 1,4-BD.