Lignin-based foams as insulation materials: a review

Abstract

The bulk use of renewable polymers is currently largely limited to cellulose and, less significantly, hemicelluloses. Technical lignins are only applied in novel materials to a rather limited extent, although bulk lignin utilization is a worldwide research object. Native lignins, which belong to the second or third most abundant biopolymers of terrestrial plants, are mostly used in the form of technical lignins from wood pulping processes; they are employed in low-performance sectors or simply burnt for the generation of energy. Technical lignins are available in huge quantities and have a large application potential, mainly in areas where their aromatic nature is of relevance. This review presents the state of the art of foamed lignin-based polymers (lignofoams) as high-performance insulation materials. In the focus of this presentation are the fundamental foaming principles and influential agents that have an improvement potential concerning the matrix interactions between technical lignins (including lignosulfonates) and a copolymer in foam composites. The different approaches for foam preparation are critically compared. In general, the reviewed papers disclose that the lignin part in foams should be less than 37%. There are significant difficulties to improve the properties of lignofoams, and thus intensive research is needed to find better formulations and new technologies.

Microalgae Chlorella vulgaris and kraft lignin stabilized cellulosic wet foams for camouflage

“…27,28 Lignin has been used in composite foams for insulating purposes with both fossil and bio-based raw materials, but the structural complexity of lignin hampers its use. 29,30 To provide the color needed for stealth, there are a plethora of natural dyes, however, many dyes suffer from poor stability, limiting their applicability. 31 In the boreal forest, the most important colors are green and brown.…”

Synthesis of Colloidal Silver Using Lignosulfonates

“…Их выпуск как коммерческого продукта не превышает 2 % от общего количества получаемых при химической переработке растительной биомассы технических лигнинов. Лигносульфонаты используют в качестве диспергаторов и добавок для бетона, пылеподавляющих средств, флокулянтов, добавок в свинцово-кислотных аккумуляторных батареях, компонентов композитов и ионообменных смол, в медицине и косметологии [11].…”

Characterization and structural properties of bamboo fibre solid foams

“…More recently, progress has been made on developing structurally competitive biopolymer foams from several types of organic materials. These involve the usage of vegetable oils (Tu et al 2008), and wood byproducts such as lignin (Mimin et al 2016;Tondi et al 2016;Stevens et al 2010) and tannin (Szczurek et al 2014;Tondi and Pizzi 2009;Merle et al 2016).…”