Tunable thermal and flame response of phosphonated oligoallylamines layer by layer assemblies on cotton.

In the present paper we have demonstrated how the change of the layer by layer deposition parameters can influence the final properties of cotton fabrics in terms of coating morphology, thermal stability and flammability. To this aim, novel synthetized oligoallylamines and phosphonated oligoallylamines have been assembled on the surface of cotton exploiting different molecular weights and pH conditions. Low molecular weights have yielded an incomplete "island growth" coating while high molecular weight resulted in a homogeneous coating which thickness was controlled by the adopted pH. Both low and high molecular weight assemblies induced a reduction of the cellulose decomposition temperatures that was, conversely, delayed by coatings assembled at pH=10. All assemblies were able to improve cotton flammability by suppressing the afterglow phenomenon; the best results in terms of flame spread and final residue have been achieved by high molecular weight assemblies.

Intrinsic intumescent-like flame retardant properties of DNA-treated cotton fabrics.

In the present work, the effect of different DNA add-ons (namely, 5, 10 and 19 wt.%) has been thoroughly investigated as far as the flammability and the resistance to an irradiating heat flux of 35 or 50 kW/m(2) are considered. The results have shown that 10 wt.% is the minimum amount that allows reaching the self-extinguishment of cotton when a methane flame is applied. Furthermore, only 19 wt.% is able to confer resistance to the fabric towards an irradiating heat flux of 35 kW/m(2): indeed, the specimens tested under the cone calorimetry do not burn. Measurements of temperature runs as a function of time have clearly indicated that cotton, instead of burning, pyrolyses: indeed, because of the protective role exerted by DNA molecules, the deposited coatings have turned out to absorb heat, form char and induce its formation on the fabric, and finally to release inert gases.

Thermal stability and flame resistance of cotton fabrics treated with whey proteins.

It is well described in the literature that whey proteins are able to form coatings, which exhibit high mechanical and oxygen barrier properties, notwithstanding a great water vapour adsorption. These peculiarities have been exploited for applying a novel protein-based finishing treatment to cotton and for assessing the protein effect on the thermal and thermo-oxidative stability and on the flame retardant properties of the cellulosic fabric. Indeed, the deposited whey protein coatings have turned out to significantly affect the thermal degradation of cotton in inert and oxidative atmosphere, and to somehow modify its combustion when a flame has been applied. Furthermore, the influence of the secondary and tertiary structure of these proteins on the morphology of the deposited coating, and thus on the thermal and flame retardant properties of the treated fabrics, has been evaluated by performing a denaturation thermal treatment before the protein application.