Application of waste silicon rubber composite treated by N₂ plasma in the flame‐retardant polypropylene

Abstract

The waste silicon rubber composite insulator (WSiRC) was applied along with ammonium polyphosphate (APP) and pentaerythritol (PER) to improve the flame retardancy of polypropylene (PP) in this study. Considering the compatibility among PP, WSiRC, and flame-retardant additives, WSiRC was treated by acid and N 2 plasma to obtain the plasma-treated WSiRC (PLSiR), which decreases the amount of the inorganic additive and grafts amino groups onto the surface of the silicon rubber. The infrared spectrocopy (IR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) confirm that NH 2 groups have been grafted onto the surface of PLSiR. The TGA data also show that PLSiR had the char improving ability and promote the crosslink of APP, which results in its promotion for the flame retartancy of PP proved by the data of limiting oxygen index (LOI), UL94 rating and cone tests. It is also showed that PLSiR is superior than the WSiRC treated only by acid (ASiR) due to the differences in the structure and polarity. Moreover, the improvement of PLSiR on the flame retardancy of PP is dependent on its amounts. It is indicated that the 1 wt % loading of PLSiR in PP with APP and PER has the highest LOI value of 30.9 and reached UL94 rating V-0. The peak heat release rate (pHRR) and total heat release (THR) values are also decreased by 68.7 and 15%, respectively. SEM and Raman results show the condensed mechanism is ascribed to the PP/APP-PER/PLSiR system because the quality of char affect the flame retardancy of PP.

Flame Retardant Polypropylenes: A Review

“…Symbols are indicative of different types of combinatorial flame retardant used. Here: ▲ APP-13.2/PER-6.8 [ 68 ], ▼ APP-16.7/PER-8.3 [ 143 ], APP-18.7/PER-6.3 [ 67 ], APP-22.5/PER-7.5, mc-(APP-22.5&PER-7.5) [ 144 ], APP-10.5/PER-9.8/MEL-9.1, APP-15.3/PER-9.3/MEL-8.8, APP-19.1/PER-8.9/MEL-8.2 [ 145 ], APP-10.5/PER-9.8/MEL-9.1, APP-15.3/PER-9.3/MEL-8.8, APP-19.1/PER-8.9/MEL-8.2 [ 145 ], APP-15.3/PER-9.3/MEL-8.6, APP-14.3/PER-8.7/MEL-8.1/MDH-6.2 [ 146 ], APP-15.3/PER-9.3/MEL-8.6, APP-14.3/PER-8.7/MEL-8.1/MDH-6.2 [ 146 ], APP-12/PER-4/MEL-4/C20A-1, APP-12/PER-4/MEL-4/C20A-3, APP&MMT-12/PER-4/MEL-4/C20A-1, APP&MMT-12/PER-4/MEL-4/C20A-3 [ 104 ] m-APP-16.6/DPER-4.2/MEL-4.2, m-APP-16/DPER-4/MEL-4/SEP-1 [ 147 ], APP-13.5/PER-4.5, APP-12.75/PER-4.25/MF-1, APP-12.75/PER-4.25/MFA-1 [ 148 ], APP-22.5/PER-7.5 [ 149 ], APP-12.7/PER-5.3, APP-12/PER-5/TA-FR-1 [ 150 ], APP-16.67/PER-8.33, APP-16.33/PER-8.17/NOR116-0.5 [ 72 ], APP-13.5/PER-4.5, APP-12.75/PER-4.25/G-bases-1, APP-12.75/PER-4.25/U-bases-1 [ 151 ], APP-17.2/DPER-7.8, m-APP-17.2/DPER-7.8, APP-16.2/DPER-7.8/ATH-1 [ 152 ], APP-21.4/PER-7.1, APP-20.3/PER-6.8/Kaol-1.4 [ 70 ], APP-21.75/PER-7.25, APP-19.5/PER-6.5/MMT-3, APP-19.5/PER-6.5/m-MMT-3 [ 153 ], APP-21.75/PER-7.25, APP-19.5/PER-6.5/MMT-3, APP-19.5/PER-6.5/m-MMT-3, APP-19.5/PER-6.5/m-MMT-3 [ 154 ], APP-18.75/PER-6.25, APP-18/PER-6/LDH-1, APP-18/PER-6/m-LDH-1 [ 155 ], APP-18.75/PER-6.25, APP-18/PER-6/m-SiR-1, APP-18/PER-6/m-SiR-1, APP-16.5/PER-5.5/m-SiR-3 [ 156 ], m-APP-16.7/DPER-8.3, m-APP-16.7/DPER-8.3/Z-1, m-APP-16.7/DPER-8.3/Z-1/MWCNT-0.1 […”

Solid Wastes Toward Flame Retardants for Polymeric Materials: A Review

“…Thus, the reuse of industrial waste has become a hot topic in both academia and industry (Huo et al, 2021). Fortunately, many types of industrial wastes, for example, fly ash, oil sludge, and red mud, contain different valuable flame-retardant ingredients, such as thermally stable SiO 2 , Al 2 O 3 , and Fe 2 O 3 , thus exhibiting huge potential in the fabrication of flame-retardant polymers (Cao et al, 2017;Zhang et al, 2019;Liu et al, 2020). For instance, Kusakli et al (2020) fabricated a flame-retardant epoxy resin (ER), which contained ammonium tetrafluoroborate (ATFB), aluminum hydroxide (Al(OH) 3 ), and red mud (RM).…”