Image analysis of flame behavior for polyolefins and polystyrene in vertical flame test

Abstract

Although the UL-94 vertical flame test is often used to evaluate the flammability of polymers based on ignition time and combustion duration parameters, a significant amount of information regarding the time course of combustion is difficult to analyze in detail. Herein, image analysis of the time course of the upper and lower end heights, total area, and color division of flame was performed for polyolefins and polystyrene with different molecular weights in the vertical flame test. The combustion process was classified into two stages: before and after the first drip. In the first stage, the upward spread velocity, oscillation, and color of flame were analyzed. It was assumed that the difference in the fuel production rates or thermal decomposition products depends on the molecular structure. In the second stage, the melt flowability, flame position, and combustion continuity differed vastly depending on the molecular structure or molecular weight.

Synergistic flame retardancy of solid acid, hindered N‐alkoxy amine, and halogen compound for polypropylene

“…25 We have been studying the flame retardancy of polymeric materials by analyzing the relationship between pyrolysis modes and combustion behavior. 26,27 In vertical combustion tests, we found that olefin resins were not ignited and achieved V-0 in specific molecular regions (M w = 10 3 $ 10 4 ). 28,29 Therefore, if the cleaved main chain of PP is accelerated and the molecular weight of PP is reduced to about M w = 10 3 $ 10 4 just before combustion, it can be expected that flame retardancy can be obtained in the vertical combustion test.…”

“…The height and area of the upper and lower flames were measured from the lower edge of the specimen before combustion using an analysis method developed by the authors. 27…”