Development and characterisation of flame-retardant fibres from isotactic polypropylene melt-compounded with melamine-formaldehyde microcapsules

Thermo‐physical properties of polypropylene fibers containing a microencapsulated flame retardant

“…The Young's modulus of the fibers containing microcapsules presents no significant difference with the modulus of iPP fiber for the lower DR, while they are between those of the iPP and iPP‐Ca for a DR of 3; for the higher DR, the Young's modulus of iPP‐Ca‐µm is similar to that of iPP and higher than that of iPP‐Ca‐µmpt. This difference between the two kinds of fibers containing microcapsules can be due to the small amount of β‐phase detected in the sample and may explain the lower modulus . On the other hand, the multifilament loaded with microcapsules displays a higher Young's modulus than iPP‐Ca, and this is probably due to the greater stiffness of the melamine microcapsules compared to the coupling agent.…”

“…The microencapsulation process of the FR formulation, PU‐118, with an amino resin was established from the results of our previous studies to form microcapsules in four consecutive steps, i.e. dispersion step; etherification reaction decreasing the water solubility of amino‐resin in the continuous phase; pre‐polymer separation and deposition of the oligomers at the interface to create the primary shell of the microcapsules and in the last step the crosslinked polymeric shell is obtained by either ether or methylene linkages formation.…”

“…The degree of dispersion of the particles in the iPP matrix, as well as their surface characteristics, morphologies and degree of aggregation influence their spinnability and therefore the mechanical properties of the resulting fibers. In a previous study, we denoted that the spinnability of iPP loaded with microcapsules containing an inorganic FR was restricted to a maximum DR of 3. During the spinning process, breaks of individual filament and/or breakage of all the filaments were observed due to poor adhesion between them and polymer matrix leading to the formation of voids in the matrix.…”

“…Furthermore, they observed that the increase of density and elongation at break, as well as the decrease of polypropylene fibers were correlated to an increase of loading in microcapsules, without influencing the malting temperature of the fibers. Salaün et al also investigated the incorporation of FR microcapsules into polypropylene fibers without coupling agent or lubricant. They observed that the formulation and composition of the microcapsules had an influence on the mechanical and thermal properties of the filaments obtained.…”

Development of a Halogen Free Flame Retardant Masterbatch for Polypropylene Fibers

“…The lowest melting peak is ascribed to the melting of the β-phase (150 °C), and may be due to the presence of additives in the raw PP, whereas the highest temperature relates to the melting of the α-phase. The absence of this β-phase in the four other samples may result to the beta to alpha phase transition which can occur during the thermal treatment and spinning process [26,27]. The effect of the additives formulation on the relative crystallinity is shown in Table 4.…”