Carosio Federico, Alongi Jenny, Paravidino Chiara, Frache Alberto
Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Alessandria Campus, Viale Teresa Michel 5, 15121 Alessandria, Italy.
Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
Materials (Basel). 2017 Jun 27;10(7):709. doi: 10.3390/ma10070709.
This work deals with the use of hydrotalcite nanoparticle post-diffusion in layer by layer (LbL) coatings with the aim of improving their flame retardant action on cotton. The selected LbL components, which encompass polydiallyldimethylammonium chloride and deoxyribonucleic acid, aim at the deposition of an intumescent coating. Infrared spectra pointed out a super-linear growth of the investigated assembly, indicating the ability to deposit thick coatings while maintaining a relatively low deposition number. A post-diffusion process, performed by exposing the LbL-treated fabrics to two different concentrations of hydrotalcite water suspensions (0.1 or 1 wt %), was carried out to improve the fireproofing efficiency of these coatings. Coatings treated with the lowest concentration suspension partially swelled as a consequence of their structural rearrangements while the use of the highest concentration led to nanoparticle aggregates. Horizontal flame spread tests were used for assessing the achieved flame retardant properties. The post-diffusion performed at the lowest hydrotalcite concentration lowers the minimum number of Bi-Layers required for obtaining cotton self-extinguishment while samples treated with the highest concentration showed detrimental effects on the performances of treated fabrics. This behavior is ascribed to the effects of hydrotalcite particles on the intumescence of LbL coatings, as evidenced by the morphological analyses of post-combustion residues.
这项工作涉及水滑石纳米颗粒在逐层（LbL）涂层中的后扩散应用，目的是提高其对棉织物的阻燃作用。选定的LbL组分包括聚二烯丙基二甲基氯化铵和脱氧核糖核酸，旨在沉积一种膨胀型涂层。红外光谱表明所研究的组装体呈超线性生长，这表明在保持相对较低沉积次数的同时能够沉积厚涂层。通过将经LbL处理的织物暴露于两种不同浓度的水滑石水悬浮液（0.1或1 wt%）中进行后扩散过程，以提高这些涂层的防火效率。用最低浓度悬浮液处理的涂层由于其结构重排而部分膨胀，而使用最高浓度则导致纳米颗粒聚集。采用水平火焰蔓延试验来评估所获得的阻燃性能。在最低水滑石浓度下进行的后扩散降低了使棉织物自熄所需的最小双层数，而用最高浓度处理的样品对处理后织物的性能产生了不利影响。这种行为归因于水滑石颗粒对LbL涂层膨胀的影响，燃烧后残留物的形态分析证明了这一点。
