Lignins for phenol replacement in novolac‐type phenolic formulations, part I: Lignophenolic resins synthesis and characterization

Abstract

Several lignin (L)-based novolac-type phenolic prepolymers with two phenol (P) substitution degrees have been synthesized using three L from different origin (kraft pine L, soda/anthraquinone (AQ) flax L, and sulfonated kraft softwood L). These lignophenolic (LPF) resins have been characterized by means of free P and formaldehyde (F) analysis, viscosity, chemical structure (FTIR), and thermal behavior (DSC). Temperature at which curing reaction begins (DSC), hardening time at several curing temperatures (rheology) and volumetric changes (PVT) have also been determined for the curing process with 10 wt % hexamethylenetetraamine (HMTA). All the results have been compared to those obtained for a commercial novolac. Depending on the L type employed a homogeneous material with lower curing onset temperature and gelation time than reference PF can be obtained even at high P substitution level (45 wt %).

Thermal properties of lignin in copolymers, blends, and composites: a review

“…111 For example, 25% and 45% of the phenol used in an original PF sample was substituted with three different types of lignins (pine KL, soda anthraquinone flax lignin and sulphonated SKL). 111 For example, 25% and 45% of the phenol used in an original PF sample was substituted with three different types of lignins (pine KL, soda anthraquinone flax lignin and sulphonated SKL).…”

Lignin utilization options and methods

“…In synthesis of phenol-formaldehyde resins, 20, 30, 40, and 50% phenol can be replaced by lignins; the latter were used for phenol replacement in novolac-type phenolic formulations [54,55]. Lignin acts as nucleating agent able for accelerating nonisothermal crystallization of poly(ethylene glycol terephthalate): The higher the lignin content, the lower the glass transition temperature and the melting temperature of the polymer; thereby, the processing of composite materials is facilitated [56].…”

Chemical Elucidation of Structurally Diverse Willow Lignins

“…However, more and more researchers are considering other applications for conversion of lignin to energy; for example, lignin has been considered as a replacement for phenol in phenolformaldehyde resins (Tejado et al 2007(Tejado et al , 2008, vanillin production (Araújo et al 2010;Pinto et al 2010), synthetic tanning agents production (Suparno et al 2005), a biosorbent for heavy metals (Yun et al 2008;Hengky et al 2009), and dyes (Suteu et al 2009;Saad et al 2012). FitzPatrick et al (2010) pointed out that biomass has a complex composition, similar to petroleum, and its primary fractionation can yield a wide range of products.…”