PSI - Issue 72

Anandito Adam Pratama et al. / Procedia Structural Integrity 72 (2025) 377–382

379

H5, and H5A in the material was associated with a lower amount of PA6-GF composition in the mixture and the formation of a protective structure that isolates the material from the wire; this was able to make the specimen reach a GWFI of 960 °C which is higher than the GWFI of neat PA6-GF at 650 °C. In contrast, GWIT differs according to the type of MDH used. GWIT in the mixture with H5A is the same as the neat PA6-GF material, namely 700 °C, while in the H5 mixture, the GWIT value decreases by 75 °C. In 2021, there was a study on the effect of mica minerals and intumescent flame-retardant (IFR) on the flame retardancy and mechanical properties of polypropylene materials conducted by Kahraman et al. (2021). The IFR used consisted of APP and synergist. Glow-wire testing was limited to temperatures of 750 °C and 850 °C only. The results of the glow-wire tests showed that the use of mica material in specific amounts (2, 4, 6, and 8 wt%) can increase the flame-retardant properties of the PP matrix due to better dehydration and char formation than PP material with an IFR mixture. However, when the composition of mica minerals was increased to 15 wt%, the flame-retardant properties of the PP matrix decreased because mica minerals affected the continuity of the IFR system. The latest research in 2023 was conducted by Yildiz et al. (2023), who studied the development of Acrylonitrile Butadiene Styrene (ABS) material with halogen-free flame-retardant. The flame-retardant materials used were AlPi and APP, which are included in the flame-retardant phosphorus category. In addition, other flame-retardant additives such as Magnesium hydroxide (MH), Pentaerythritol (PER), and zinc borate (ZB) were also added to the ABS composite. Based on the GWFI test results, all ABS composite specimens with various additional flame-retardant material configurations could meet the high GWFI value of 960 °C. In contrast, the neat ABS material did not. Table 1 presents the GWFI and GWIT data for various polymer materials mixed with flame-retardant additives. While not all materials display complete data for both GWFI and GWIT, several neat polymers — such as PP, EBA30, EPDM, and PLA — sufficiently meet the glow-wire test criteria with a GWFI above 650 °C, without needing any flame retardants addition. Neat ABS (Yildiz et al., 2023) is the only material that fails to meet the GWFI criteria. However, neat PP (Bernardes et al., 2019) has the lowest GWFI value of 650/7.0, among other neat polymer materials. According to Table 1, glass fiber is often mixed as an additive substance in polymer materials, and glass fibers are generally added to polymers. Although they increase mechanical strength, it is unclear whether they can also act as a fire retardant. Overall, flame-retardant additives enhance the fire resistance of polymers, though not all can withstand the maximum test temperature of 960 °C. Common flame-retardant materials, such as aluminum diethyl-phosphinate (AlPi), pentaerythritol (PER), and ammonium polyphosphate (APP), are frequently used. According to the data in Table 1, only polymers like PP (Bernardes et al., 2019; Tang et al., 2023), PC (Krämer and Blomqvist, 2007), polyamide (Krämer and Blomqvist, 2007; Jimenez et al., 2013; Casetta et al., 2018; Naik et al., 2013), HDPE (Krämer and Blomqvist, 2007), and ABS (Yildiz et al., 2023; Krämer and Blomqvist, 2007) can achieve a maximum GWFI value of 960 °C. Additionally, the results of GWFI and GWIT also differ depending on the thickness of the specimen, even on the same material. Thicker specimens provide better fire protection as they contain more flame-retardant material.

Table 1. The data series of glow-wire test results on polymer materials. Base Polymer Material Source

Flame-Retardant Additive

GWFI 800/1.5 850/3.0 750/- 650/7.0 960/7.0 960/7.0 725/3.0 825/3.0 960/3.0

GWIT 825/1.5 850/3.0 850/- 700/7.0 875/7.0 850/7.0 750/3.0 775/3.0 850/3.0 725/3.0 800/3.0 750/3.0 725/1.0 675/3.0 650/1.0 750/3.0 725/1.0

(Krämer and Blomqvist, 2007)

Unspecified (metal hydroxide)

(Kahraman et al., 2021)

IFR + mica mineral Neat/no flame-retardant

(Bernardes et al., 2019)

Zeolite Silicate

PP

Neat/no flame-retardant

(Tang et al., 2023)

MCA/APP MNSi/APP

Neat/no flame-retardant Kenaf + wool + APP

- - -

(Subasinghe et al., 2016)

(Acquasanta et al., 2011a; Acquasanta et al., 2011b)

Glass-fiber

PBT

Glass-fiber + BrPS

-

(Acquasanta et al., 2011b)

Glass-fiber + AlPi

-