Mechanical and thermal properties of rigid polyurethane foams derived from sodium lignosulfonate mixed with diethylene‐, triethylene‐ and polyethylene glycols

Abstract

Sodium salt of lignosulfonic acid (LS), which was obtained as by‐product of cooking process in sulfite pulping, was solved in diethylene, triethylene or polyethylene glycol. Three series of polyurethane foams (LSPU) were synthesized by varying the LS content from 0 to 33 wt%. Apparent density (ρ) of LSPU foams ranged from 0.08 to 0.18 g cm−3 and was affected by both LS content and oxyethylene chain length. Glass transition temperatures increased with increasing amount of LS and with decreasing oxyethylene chain length. Thermal gravimetry analysis indicated that the LS component decomposes first and that the thermal stability increases with decreasing oxyethylene chain length. Compression strength and compression modulus increased linearly with increasing apparent density. It is concluded that LS is successfully utilized as a hard segment of rigid PU foams, whose thermal and mechanical properties can be tuned by changing the amount of LS and the length of soft oxyethylene chains.

Characterization of Thermal and Mechanical Properties of Lignosulfonate- and Hydrolyzed Lignosulfonate-based Polyurethane Foams

“…In general, the results were in agreement with the data found for biopolyol-based PUR (Hakim et al 2011). However, Hatakeyama et al (2003) found that Tg increased with increasing lignosulfonate content. Outstanding results were found for the reference PPG-based (REF) and HZ2 (PPG/HZ = 0.7/0.3 w/w) foams exhibiting Tg = 100 °C.…”

“…From the statistical analysis it was found that an increasing content of HZ lignin resulted in an increased 1 st degradation temperature. The major decomposition starts at approximately 280 °C, which corresponds to the dissociation of urethane linkages formed from phenolic hydroxyls (Hatakeyama et al 2003). The effect of PPG, glycerol, and HZ on T50% was the opposite.…”

“…Polyurethane foams prepared from liquefied, bamboo-based polyols were investigated by Xie et al (2014). A series of lignin-and lignosulfonate-based foams were successfully prepared and characterized (Hatakeyama et al 2003;Hakateyama and Hakateyama 2010). The authors showed that kraft lignin, sodium lignosulfonates, and hydroysis lignin exhibited good solubility in glycols and some types of lignin and that they could be used in PUR foams without pretreatment.…”

Formation of Ligno-Polyols: Fact or Fiction

“…A number of studies have suggested that the performance of lignin and PU products may be improved by the addition of other polyols, such as polyethylene glycol (PEG), polypropylene glycol (PPG) (Saraf et al 1985;Mörck et al 1988), and other chain lengths of polyether polyols, during the copolymerization process (Hatakeyama et al 2003). The addition of PEG and PPG affected the flexibility and rigidity of the PU.…”

Chemistry of lignin-based materials

“…Lignin-based PU synthesis requires catalysts and additives as shown in Scheme 2. Typical additives are poly(ethylene glycol) (PEG), 34,98,99 poly(caprolactone) 100 and diethylene glycol. 101 The additives are used to prevent brittleness of the PU by adding soft segments in the PU network structure.…”