Isabelle Vroman

Microencapsulation of phosphate: application to flame retarded coated cotton

Polyurethane-phosphates combination is known to form a flame retardant (FR) intumescent system. The intumescent formulation could not be permanent because of the water solubility of the phosphate. This problem could be solved by the technique of microencapsulation. Di-ammonium hydrogen phosphate (DAHP) was microencapsulated with a polyurethane (PU) shell. Polyurethane for textile coating was loaded with neat or microencapsulated DAHP. We studied the thermal degradation behaviour of DAHP microcapsules, PU loaded formulations and cotton coated by these PU formulations. Improvement of the thermal stability for PU textile coating was observed with neat and microencapsulated DAHP. The flame retarding behaviour of these coated cotton fabrics was also valued with the cone calorimeter. This new concept of phosphate encapsulated by PU shell showed a significant FR effect.

Flame retardant formulations for cotton

This paper evaluates and compares the flame retardant behaviour of the following flame retardants cellulose fabric: Ignilys FDR [Feutrie S.A.], diguanidine hydrogen phosphate and 3-aminopropyltriethoxysilane. Furthermore the durability to laundering processes is tested. The thermal behaviour of FR-treated cellulosic fabric is studied through TGA analysis.

Flame Behavior of Cotton Coated with Polyurethane Containing Microencapsulated Flame Retardant Agent

Polyurethane-phosphates combination is known to form flame retardant (FR) intumescent system. But the intumescent formulation could not be permanent because of the water solubility of the phosphate. This problem could be solved by the technique of microencapsulation. Microcapsules of di-ammonium hydrogen phosphate (DAHP) with a polyurethane (PU) shell were synthesized. Chemical and physical structure of the DAHP microcapsules were characterized. Cotton fabrics were coated with polyurethane (PU) coating including neat DAHP or encapsulated DAHP. The flame retarding behavior of these coated cotton fabrics was valued with the cone calorimeter. This new concept of phosphate encapsulated by PU shell showed a significant FR effect.

Guanidine hydrogen phosphate-based flame-retardant formulations for cotton

Classical flame-retardant treatments for cellulosic materials are phosphorous-nitrogen-based compounds. In this work, cotton fabric is treated with different formulations based on diguanidine hydrogen phosphate (DGHP) or monoguanidine dihydrogen phosphate (MGHP), individually or in combination with a resin (melamine) or with 3-amino propylethoxysilane (APS). Flame behaviour of the treated cotton fabrics is evaluated using the electric burner test and the limiting oxygen index (LOI). Their thermal stability is then examined using thermal analysis. While all the formulations raise LOI higher than 30 vol.%, it was noticed that MGHP provides better flame-retardant properties than DGHP. The formulations can be classified into two groups: the first group, raising the LOI value between 30 and 40 vol.%, corresponds to the formulations of guanidine with or without melamine, and the second group, providing an LOI value between 60 and 70 vol.%, is formulations with APS. TG analysis reveals a significant difference in the thermal degradation of these two groups. While this degradation is initiated at lower temperatures for all padded fabrics compared to untreated cotton, the residual amounts of char is higher at 800 C for formulations with APS (i.e. the second group).

Incorporation of poly(dimethylsiloxane) into poly(tetramethylene oxide) based polyurethanes: The effect of synthesis conditions on polymer properties

Two procedures for incorporating low levels of poly(dimethylsiloxane) (PDMS) in polyurethane (PU) have been studied. The bulk synthesis of poly(siloxane-urethane) was performed in two steps: the first involves the formation of a prepolymer between isophorone diisocyanate (IPDI) and poly(tetramethylene oxide) (PTMO). In the second step 1,4-butanediol (BD) was added as the chain extender. A kinetic study followed by infrared spectroscopy showed the higher reactivity of PDMS compared to PTMO. Thus, two procedures for incorporating PDMS are described, depending on whether the poly(dimethylsiloxane) was introduced in the first or in the second step. Films were made from these formulations, and we studied their morphology. The products obtained from each procedure were characterized by size-exclusion chromatography (SEC), differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMTA) and uniaxial tensile testing, and showed significant differences. These poly(siloxane-urethane) polymers are intended to be used as hydrophobic coated formulations on polyester fabrics in a further study.

Curcumin-Loaded Nanocapsules: Formulation and Influence of the Nanoencapsulation Processes Variables on the Physico-Chemical Characteristics of the Particles

The aim of this work was to assess the influence of various formulation parameters on the incorporation of Curcumin into nanoparticles. For this purpose, the influence of the aqueous monomer (ethylene diamine, hexamethylene diamine, and 1,4-diaminobutane), as well as the effect of the stirring rate and the influence of the nanoencapsulation method on the encapsulation efficiency were investigated. It was found that variation in the amount of ingredients had profound effects on the curcuminoid loading capacity, the mean particle size, and size distribution. Furthermore, from the thermal results, it is concluded that the reactivity of diamine and the length of flexible methylene chain in diamine determine the thermal properties of resultant polymer wall membrane. The encapsulation yield depends not only on the encapsulation process but also on the chemical structure of the diamine. Whereas, the size and its distribution vary according to the process choice and the emulsification stirring rate.