What Reacts with What in Bisphenol A Polycarbonate/Silicon Rubber/Bisphenol A Bis(diphenyl phosphate) during Pyrolysis and Fire Behavior?

Abstract

The pyrolysis and flame retardancy of a bisphenol A polycarbonate/silicon rubber/bisphenol A bis(diphenyl phosphate) (PC/SiR/BDP) blend were investigated and compared to those of PC/BDP and PC/SiR. The impact modifier SiR consists mainly of poly(dimethylsiloxane) (PDMS > 80 wt %). The pyrolysis of PC/SiR/BDP was studied by thermogravimetry (TG), TG–FTIR to analyze the evolved gases, and a Linkam hot stage cell within FTIR as well as 29Si NMR and 31P NMR to analyze the solid residue. The fire performance was determined by PCFC, LOI, UL 94, and a cone calorimeter under different external irradiations. The fire residues were studied by using ATR-FTIR as well as the additional binary systems PC + PDMS, PC + BDP, and BDP + PDMS, focusing on the specific chemical interactions. The decomposition pathways are revealed, focusing on the competing interaction between the components. Fire retardancy in PC/SiR/BDP is caused by both flame inhibition in the gas phase and inorganic-carbonaceous residue formation in the condensed phase. The PC/SiR/BDP does not work as well superimposing the PC/SiR and PC/BDP performances. PDMS reacts with PC and BDP, decreasing BDP’s mode of action. Nevertheless, the flammability (LOI > 37%, UL 94 V-0) of PC/SiR/BDP equals the high level of PC/BDP. Indeed, SiR in PC/SiR/BDP is underlined as a promising impact modifier in flame-retarded PC/impact modifier blends as an alternative to highly flammable impact modifiers such as acrylonitrile–butadiene–styrene (ABS), taking into account that the chosen SiR leads to PC blends with a similar mechanical performance.

Flame‐retardant behavior of a phosphorus/silicon compound on polycarbonate

“…The results confirmed that the addition reaction between CC bonds in MVC and PH bonds in DOPO had happened. The other three typical absorption bands (at 1080 cm −1 , associated with the vibrations of SiOSi; at 797 cm −1 , corresponding to the SiC bond; and at 904 cm −1 , representing the PO bond in phosphaphenanthrene, all appeared in the spectrum of MVC‐DOPO, further testifying that MVC‐DOPO had been synthesized successfully.…”

Improved flame retardancy by synergy between cyclotetrasiloxane and phosphaphenanthrene/triazine compounds in epoxy thermoset

“…The spectrum of EP dominated the spectra of all composite specimens by showing the characteristic peaks for H 2 O (3400–4000 and 1700–2200 cm −1 ), free OH (3649 cm −1 ), C aromatic‐H (3035, 831, 746 cm −1 ), CH 4 (3016 cm −1 ), C aromatic &bond;C aromatic stretch (1606, 1508 cm −1 ), C aliphatic‐H (2974, 2935, 2881, 1460 cm −1 ), CO 2 (2359 cm −1 ), CHO (2814 cm −1 ), lactones (1797, 1772 cm −1 ), C&dbond;O (1716 cm −1 ), C&bond;H of bisphenol A (1331, 1176 cm −1 ), RC&dbond;CH 2 (887 cm −1 ), and C&bond;O and C&bond;H of bisphenol A (1259 cm −1 ). Most peaks of the spectra are attributed to bisphenol A, which is the main part of DGEBA resin . Bisphenol A fragment dominates the FTIR spectrum of EP pyrolysis gas, as it did those of all the other materials investigated.…”

Enhanced flame-retardant effect of a montmorillonite/phosphaphenanthrene compound in an epoxy thermoset

“…All spectra were dominated by the spectrum of EP, showing the release of H 2 O (4000 cm À1 to 3400 cm À1 and 2200 cm À1 to 1700 cm À1 ), free OH (3649 cm À1 ), C aromatic -H (3035 cm À1 , 831 cm À1 , 746 cm À1 ), CH 4 (3016 cm À1 ), C aromatic -C aromatic stretch (1606 cm À1 , 1508 cm À1 ), C aliphatic -H (2974 cm À1 , 2935 cm À1 , 2881 cm À1 , 1460 cm À1 ), CO 2 (2359 cm À1 ), CHO (2814 cm À1 ), lactones (1797 cm À1 , 1772 cm À1 ), C]O (1716 cm À1 ), C-H of bisphenol A (1331 cm À1 , 1176 cm À1 ), RC]CH 2 (887 cm À1 ), C-O and C-H of bisphenol A (1259 cm À1 ). Most peaks of the spectra are associated with bisphenol-A, 36 which is part of the DGEBA resin component. 1,10 Bisphenol A actually dominates the spectrum of EP, as it does for all of the other investigated materials.…”