Halogen-Free Flame Retardant Polypropylene Fibers with Modified Intumescent Flame Retardant: Preparation, Characterization, Properties and Mode of Action

Abstract

A novel intumescent flame retardant (IFR) agent designated as Dohor-6000A has been used to prepare halogen-free flame retardant polypropylene (PP) fibers via melting spinning. Before being blended with PP resin, a surface modification of Dohor-6000A was carried out to improve its compatibility with the PP matrix. The rheological behavior of flame retardant Dohor-6000A/PP resin, the structure, morphology, mechanical properties, flammability of the Dohor-6000A/PP fibers were studied in detail, as well as the action mode of flame retardant. X-ray diffraction (XRD) showed that the addition of Dohor-6000A did not damage the crystal as well as the orientation structure of PP matrix, which was helpful to the maintenance of mechanical properties. The presence of the IFR significantly improved the flame retardant performance and thermal stability of PP fibers. When the content of Dohor-6000A reached 25%, the fibers displayed a limiting oxygen index (LOI) value of 29.1% and good melt-drop resistance. Moreover, the peak heat release rate (PHRR) and total heat release (THR) from microscale combustion colorimetry (MCC) tests were decreased by 26.0% and 16.0% in comparison with the same conditions for pure PP fibers. In the condensed phase, the IFR promoted a carbonization process and promoted the formation of a glassy or stable foam protective layer on the surface of the polymer matrix. In addition, the IFR decomposed endothermically to release of non-combustible gases such as NH3 and CO2 which dilutes the combustible gases in the combustion zone.

Fire, thermal and mechanical properties of TPE composites with systems containing piperazine pyrophosphate (PAPP), melamine phosphate (MPP) and titanium dioxide (TiO2)

“…Neat TPE is a block copolymer with hard blocks and soft blocks as repeating units in the main chain. Relatively high plastic processing performances, good aging resistance, tensile strength and friction resistance were given to the material by the hard blocks; and the soft blocks make TPE more flexible and amorphous, showing excellent tensile strain, flexural properties and high resilience [1][2][3]. TPE combining the advantages of the flexibility of rubbers, the strength of plastics and the processability of thermoplastics, has been widely used in furniture, footwear, ideal cable sheathing layers, insulation materials, coatings, adhesives and elastomers.…”

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

“…It is also worth noting that a reduction in the mass fraction of PP in the composite has an impact on crystallinity. Therefore, the crystallinity of the composites could be calculated by considering the mass fraction of the polymer matrix in the composites 66–69 . The degree of crystallinity plays a pivotal role in determining the mechanical properties of composites.…”

“…Therefore, the crystallinity of the composites could be calculated by considering the mass fraction of the polymer matrix in the composites. [66][67][68][69] The degree of crystallinity plays a pivotal role in determining the mechanical properties of composites. Specifically, the mechanical properties of semi-crystalline polymers like PP are closely tied to their crystallinity.…”

Synergistic Effects of DOPO-Based Derivative and Organo-Montmorillonite on Flame Retardancy, Thermal Stability and Mechanical Properties of Polypropylene

“…The combustion behaviour of PP composites was analysed using MCC tests. Some important parameters, such as the specific HRR, total heat release (THR) and temperature of peak HRR (T pHRR ), could be obtained from MCC tests [21,39]. The corresponding data are summarized in Table 2.…”

“…After introducing 1-7 wt% OMMT, the TpHRR value remained within 477.2-485.1 °C. The increase in TpHRR value indicated that PP/PN-DOPO/OMMT composites were more difficult to burn than PP and PP/PN-DOPO and could delay the decomposition process of the matrix [39], which enhances the flame retardancy of PP.…”