Sol–Gel Flame Retardant and/or Antimicrobial Finishings for Cellulosic Textiles

Cotton and cellulosic textiles easily burn when exposed to a flame or a heat source: this detrimental effect significantly limits the possible applications of these materials, especially where flame retardant fibers and fabrics are specifically required. As a consequence, one of the possible solutions may exploit surface engineering methods that aim at creating fully inorganic or hybrid organic-inorganic protective coatings on the fiber/fabric surface. This way, it is possible to reduce and limit the heat and mass transfer phenomena that take place during the fire stages: in fact, according to its structure and composition, the obtained coating is able to form a fully ceramic or a hybrid organic–inorganic protective layer on the underlying textile, hence providing this latter with the required flame retardant features. One of the most effective approaches utilizes the sol–gel technique, which is a very well consolidated approach for the fabrication of ceramics, but has started to be exploited also in the textile field because of its advantageous characteristics: among them, it is easily applicable to even irregular substrates as fibers and fabrics, it can be carried out using the already existing industrial finishing lines (such as impregnation/exhaustion units) and it is very efficient in providing the treated substrates with flame retardant features. Besides, it is possible to tailor the sol–gel derived coatings in order to provide the treated fibers/fabrics with more than a single functionality: in particular, the scientific literature reports on the use of sol–gel formulations that exhibit antimicrobial properties, too. Furthermore, the sol–gel method usually provides good washing fastness to the treated textiles, hence widening their possible applications. This chapter is aimed at summarizing the recent advances on the use of sol–gel treatments as efficient flame retardant and also antimicrobial systems; in particular, some recent examples are discussed, highlighting the further potential developments of this textile finishing technique and its current limitations.