Flammability polymer composite combustion

TG-DTA Characterisation of carbon black [149], flammability evaluation [64], polymer degradation studies [65], ageing studies [70-72], product control [77, 81], combustion performance [83], safety evaluation [83], antioxidation activity [68], pyrolysis of rubbers [82], thermal stability [67, 69, 76, 77], interfacial junctions in viscoelastic composites [78], weathering [72], vulcanisation [73], oxidative behaviour [79], materials evaluation [80], failure analyses [81],... 

However, a common feature of the PNs is that, based on the flammability of various polymers that have been studied with a single nanoadditive, like clay, they can only show a retarded combustion process (i.e., the peak HRR and the average HRR can be lowered), while almost all the carbon sources will eventually burn out in most cases. The total heat released (THR) in CCA is not changed compared with that of the same amount of base polymer. Furthermore, like many flame-retardant composites, an earlier time to ignition (and perhaps also the time to peak HRR) for most PNs than the base polymer is also seen in the CCA experiment.117... 

The degree of flammability of a polymeric material may be predicted from its chemical structure. One of the most valuable criteria in fire research, the so-called limiting oxygen index (LOI) may be estimated either from the specific heat of combustion or from the amount of char residue on pyrolysis. Since both quantities can be determined if the chemical structure is known, also the LOI can be estimated. An approximate assessment of the LOI value direct from the elementary composition of the polymer is also possible. 

Moreover, the sensitivity of the effect of a flame retardant to the ambient pressure should also be taken into account. Flame retardants that are active only in the gas phase usually fail to affect the composition of the volatile pyrolysis products and the coke yield. In this case whatever the nature of the polymer, the flame retarding element is released into the gas phase during combustion the type of oxidant (O /Nj, N O/N ) strongly affects the flammability. On the other hand the effect of flame retardants active in the solid phase depends on the polymer nature, but is independent of the nature of the oxidant. Variations of the pressure of the oxidative environment affect the rates of gas-phase as well as heterogeneous (interfacial solid-gas) reactions. 

Masarik, J. and Ryska, M. Inflammation of plastics and composition of their combustion products. Proc. Zrd Conf. on Non-Flammability of Polymer Materials, Wood and Textiles, Dom Techniky SVTS, Bratislava, 1974... 

Thermal relationships between flammability and structure/composition of these polymers was explored. It is found that BPC Il-polyarylate is an extremely fire-resistant thermoplastic that can be used as an efficient flame-retardant agent to be blended with the other polymers. Chakon Il-polyarylate is of interest as a UV/visibk-sensitive polymer with a relatively low HRR and a high char yield. Pyrolysis combustion flow calorimetry (PCFC) results show that the total heat of combustion of the copolymers or blends changes linearly with the composition, but the change of maximum HRR and char yield depends greatly on the chemical structure of the components. 

Combustion of polymeric materials involves a complex process, where both condensed and vapor-phase reactions occur at exposed surfaces that are sources of flame and/or thermal radiation of the most common parameters measuring the flammability of polymeric materials are heat release rate (HRR) and mass loss rate (MLR) from cone calorimetry. Recently, nanocomposites containing nanoparticles have been of great interest in the composite industries. In particular, polymer blends containing clays have not been comprehensively studied for their flammability, in spite of the fact that most plastic products are made out of blends of more than two polymer. Furthermore, because the dispersion of nanoparticles is a key factor in determining the HRR and MLR of nanocomposites [23-26], we investigated correlations between flammability and dispersion in air and under nitrogen, especially for polymer blends. 

Flammability and Combustion of Polymeric Compositions Reactivity of Polymer Solutions Analytical Calorimetry Ions and Ion Pairs in Non-Solvolytic Organic Reactions Fibers of Thermally Resistant Organic Polymers Chemistry of Polyurethanes Water Vapor Transport in Polymers... 

---