Lignin-derived bio-based flame retardants toward high-performance sustainable polymeric materials

Multifunctional lignin-based nanocomposites and nanohybrids

At present, nanotechnology is a priority in research in several nations due to its massive capability and financial impact. However, due to the uncertainties and abnormalities in shape, size, and chemical compositions, the existence of certain nanomaterials may lead to dangerous effects on the human health and environment. The present review includes the different advanced applications of nanomaterials in textiles industries, as well as their associated environmental and health risks. The four main textile industry fields using nanomaterials, nanofinishing, nanocoatings, nanofibers, and nanocomposites, are analyzed. Different functional textiles with nanomaterials are also briefly reviewed. Most textile materials are in direct and prolonged contact with our skin. Hence, the influence of carcinogenic and toxic substances that are available in textiles must be comprehensively examined. Proper recognition of the conceivable benefits and accidental hazards of nanomaterials to our surroundings is significant for pursuing its development in the forthcoming years. The conclusions of the current paper are anticipated to increase awareness on the possible influence of nanomaterial-containing textile wastes and the significance of better regulations in regards to the ultimate disposal of these wastes.

https://www.mdpi.com/1996-1944/13/22/5134/pdf

Sustainable Use of Nanomaterials in Textiles and Their Environmental Impact.

Scientific researches have been focused on finding halogen-free solutions as effective as halogenated ones owing to environmental and health problems in recent years. This fact is the main driving force for upcoming academic works in the flame retardancy field. Boron compounds, are high potential flame retardant additive in polymer based materials owing to their low toxicity, molecular diversity, and various ways of flame retardant action. They have been used solely or as an adjuvant in combination with mineral fillers, intumescent systems, phosphorus, halogen, nitrogen, silicone and carbon containing additives. This review provides a comprehensive description of the flame retardant effect of boron compounds with general flame retardant mechanisms in natural polymers, biocomposite applications, thermoplastics, elastomers, and thermosets as well as the synergistic effect studies with other flame retardant additives. This review covers the related studies until the end of 2020. Remarkable future research opportunities and some challenges are also suggested.

Flame retardant effect of boron compounds in polymeric materials

Novel and eco-friendly flame-retardant cotton fabrics with lignosulfonate and chitosan through LbL: Flame retardancy, smoke suppression and flame-retardant mechanism

Sodium lignin sulfonate (SLS) has been explored as a fire retardant finishing agent on cotton fabric. 30% [w/v] SLS treated cotton fabric has registered LOI value of 28.5 with minimum char length of 4 cm (self-extinguishment) whereas control cotton fabric was found to burn out with flame and afterglow within 1 min. Thermo-gravimetry of the treated cotton fabric showed 35% mass retention at 500 °C while only 8% char mass was left for the control cotton fabric at the said temperature. Volatile species liberated during burning were analyzed by GC–MS technique which demonstrated the restriction of flammable gas formation from the SLS treated fabric. Char mass left after burning also has been characterized in terms of its morphology, elemental analysis, etc. Moreover, it has also been proven that SLS treatment imparts a natural attractive yellow color, UV protective property to the treated fabric without altering physical strength of the fabric which can be considered as an added advantage over flame retardant effect.

Sodium lignin sulfonate: a bio-macromolecule for making fire retardant cotton fabric

In the present context, synthesized zinc borate was demonstrated as a thermal resistant agent by applying it by in-situ method on the cotton fabric wherein zinc borate was synthesized from zinc nitrate and borax. Particle formation and its morphology were confirmed by particle size analyzer, and scanning electron microscopy analysis, respectively. It has been observed that zinc borate-cotton registered the high oxygen index value of 30% against 18% oxygen index of the control cotton fabric. Furthermore, zinc borate treated cotton fabric showed a black colour char and a char length of 25 mm. The extent of heat generated from the treated cotton fabric was also found to be 75% less compared to the untreated cotton fabric. A thermo-oxidative decomposition experiment was performed by thermo-gravimetry analyzer and reported in detail. It was found that the treated fabric recorded more than 40% weight retention at a higher temperature. The surface morphology of the charred mass was also examined to fortify the dehydration mechanism of the treated sample.

Exploration of flame retardant efficacy of cellulosic fabric using in-situ synthesized zinc borate particles

Textiles play an important role in our everyday life, from apparel to home furnishings to industrial usages. A major worry is that it is a potential fuel to ignite, create fire hazards, and thus jeopardize life. Thus a series of fire-retardant chemicals have been conceived, developed, and commercialized. Although satisfactory fire retardancy has been obtained by incorporating them into textiles using several approaches, challenges remain as either the composition is not free from toxicity or it loses the fabric’s inherent physical properties such as flexibility, strength, and feel. As a consequence, this has become an area of interest and stimulates researchers to search for new alternatives where less add-ons to textiles would create fire-retardant functionality without greatly affecting the fabric’s basic qualities. In this respect, nanoparticles could potentially be an important substitute. Hence, this chapter is intended to discuss the various options of fire retardants in nanoparticulate form to make textiles fire retardant. Promising research outcomes in this area and future challenges to commercialize this novel approach are also revealed.

Akshay Shukla

Papers

Sodium lignin sulfonate: a bio-macromolecule for making fire retardant cotton fabric

Exploration of flame retardant efficacy of cellulosic fabric using in-situ synthesized zinc borate particles

Nanoparticles: a potential alternative to classical fire retardants for textile substrates