High-Strength and Low-Cost Biobased Polyurethane Foam Composites Enhanced by Poplar Wood Powder Liquefaction

Abstract

An environmentally friendly liquefaction of wood powder was prepared by atmospheric pressure liquefaction technology to replace the non-renewable petroleum polyols in the preparation of polyurethane foam composites. The liquefaction time varied from 0 min to 140 min. The composition of liquefied products and the effects of liquefaction time on the morphology, apparent density and mechanical properties of polyurethane foam composites were investigated. The results showed that the optimal process time for the preparation of wood powder liquefaction products, which could replace traditional petroleum polyols, was 110 min. At this time, polyether polyols are the main liquefaction products, with an average molecular weight in Mn reaching 237 and average molecular weight in Mw reaching 246. The functional group of the liquefied product consisted mainly of hydroxyl, with the highest content of 1042 mg KOH/g and the lowest acid number of 1.6 mg KOH/g. In addition, the surface of the polyurethane foam based on poplar wood is dominated by closed cell foam; thus its foam has good heat insulation and heat preservation properties. At 110 min liquefaction time, the apparent density of polyurethane foam is 0.164 g/cm3 and the compression strength is 850 kPa, which is higher than that of traditional polyurethane foam (768 kPa), which is without wood powder modification. Replacing petroleum polyol with renewable wood powder liquefaction products to prepare biomass-based polyurethane foam composite materials, researching complex chemical changes in different liquefaction stages, and finding the best liquefaction conditions are of great significance to optimize the performance of polyurethane, address the shortage of resources and reduce environmental pollution.

Lignocellulose Biomass Liquefaction: Process and Applications Development as Polyurethane Foams

“…As expected, the liquefaction reaction time has an influence on the mechanical properties of the resulting foams through the molecular weight of the obtained polyols. Recently, an intense variation of the polyol molecular weights with the liquefaction reaction time was observed [ 95 ]. The molecular weights of the polyols are dependent on the reaction parameters (time) ( Table 4 ).…”

Polysiloxane-Based Polyurethanes with High Strength and Recyclability

“…Conventional polyurethane raw materials, such as polyether and polyester polyols, are petroleum-dependent products, which considerably limit their sustainable development [ 33 , 34 , 35 , 36 ]. The Earth’s crust contains over 90 elements, with O and Si accounting for approximately 49% and 26% of the total abundance of these elements, respectively [ 37 ].…”

Elaboration of Thermally Performing Polyurethane Foams, Based on Biopolyols, with Thermal Insulating Applications

“…This was directly related to the use of a polyol derived from the liquefaction of lignocellulosic biomass, which presented a higher hydroxyl index than the one from the industrial polyol. In fact, authors contributing to the literature have already reported that higher values of the hydroxyl index usually lead to an incremented density of the polyurethane foams [ 77 , 78 ]. This is because a high hydroxyl number provides a higher degree of crosslinking of the PUF [ 79 ].…”