Flame Retardancy Of Polycarbonate Research Articles

Rubber-based phosphaphenanthrene grafted polymer and its application to fabricate flame retardant polycarbonate blend with satisfied comprehensive mechanical properties

Grafting flame retardant groups onto common polymer molecule can be a good strategy to constructing superior flame retardant macromolecules, which provides a promising direction to fabricate fire safety polymer materials with satisfied comprehensive mechanical properties. In this thesis, a rubber-based phosphaphenanthrene grafted polymeric molecule (P-SBS) was synthesized via the grafting reaction of 9, 10-dihydro-9-oxa-10-phenanthrene-10-oxide (DOPO) with thermoplastic styrene-butadiene-styrene copolymer (SBS), and then applied to melt blending with polycarbonate (PC) to form P-SBS/PC blend with sea-island structure. The incorporated P-SBS not only brought PC much higher comprehensive flame retardancy, including higher limited oxygen index, shorter self-extinguishing time, less heat release during burning process, higher-quality char layer structure, and fewer amount of flammable volatile emission; but also endowed it with more satisfied comprehensive mechanical properties, including larger elongation at break, better anti-impact, higher flexural strength, and maintained tensile strength. By analysing burning residue, tracking thermal decomposition volatile emission, and inferring the pyrolysis route of P-SBS, the gas- and condensed-phase flame retardant mechanisms of P-SBS in suppressing the flammability of PC matrix were disclosed. The morphology analysis on the matrix fracture section and the embeded P-SBS particles before and after mechanical fracture, revealed the behavioral mechanism of P-SBS particles in improving the ductility, toughness, and stiffness of PC matrix. This study provides a beneficial reference to superior flame retardant molecule constructing and advanced flame retardant polymer material manufacturing.

Facile preparation of ladder aluminosilsesquioxanes with high flame retardancy for polycarbonate

A ladder aluminosilsesquioxanes (Al-L-PPSQ) was synthesized using AlCl3 as an auxiliary catalyst. The chemical structure of Al-L-PPSQ was confirmed by FTIR, 1H, 13C, 29Si-NMR, and MALDI-TOF MS. The well characterized Al-L-PPSQ was used for flame retardant polycarbonate (PC), and the PC/Al-L-PPSQ composite with 6 wt.% Al-L-PPSQ reached UL-94 V-0 rating (1.6 mm), with an oxygen index of 36.6 % and a decrease of 61.2 % in p-HRR. The smoke release of composite materials has also decreased. By analyzing the condensed and gaseous products during the thermal degradation process of PC/Al-L-PPSQ composite materials, it is demonstrated that Al-L-PPSQ can promote the early decomposition of PC into carbon and quickly form a stable and dense char layer to protect the internal substrate during combustion, thereby improving the flame retardancy of PC.

3D printed different polymer fuel grains for hybrid rocket engine

The advent of various additive manufacturing technologies, such as 3D printing, has changed the structural design and preparation process of rocket fuels. In order to investigate the combustion properties of various common polymer materials that can be additively manufactured by fused deposition, the combustion tests of hybrid rocket fuels prepared by 3D printing were carried out. These materials include polylactic acid (PLA), wood-like polylactic acid (Wood), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), copolymers of nylon 6 and nylon 6,6 (CoPA), polycarbonate-polybutylene terephthalate (PC-PBT), flame retardant polycarbonate (PC-FR) and polyethylene terephthalateco-1,4-cylclohexylenedimethylene terephthalate (PETG). Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis was carried out on these materials, the printing effect of the fuel grains was observed by three-dimensional X-ray microscopy (µCT) and the combustion performance of these fuels in gaseous oxygen flow (GOX) was recorded by high-speed photography at a constant pressure of 1 MPa. The results show that ASA and ABS exhibit good printing results. The regression rates of PC-PBT, PETG, ABS, ASA, CoPA and PLA are 0.792 mm/s, 0.592 mm/s, 0.536 mm/s and 0.477 mm/s, 0.368 mm/s, 0.339 mm/s (AtGOX=220kg/(m2·s)), respectively.

Flame retardant polycarbonate with ultralow loading 1,3-benzenedisulfonate

Polycarbonate (PC) is one of the major engineering plastics. For the flame retardant PC, there are still obstacles to the development of high performance thin-walled PC. 1,3-Benzenedisulfonic acid dipotassium salt (KSP) was successfully synthesized by the electrophilic reaction of octaphenylsilsesquioxane (OPS) with excess chlorosulfonic acid (ClSO3H), and the structure of KSP was characterized using Fourier-transform infrared (FTIR), nuclear magnetic resonance (NMR), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) measurements. PC/KSP composites with different KSP contents were prepared. It is obtained that the PC with only 0.01 wt% KSP exhibits superior flame retardant properties: the thin-walled PC (1.1 mm) sample reached UL-94 Vertical burn tests V-0 rating, the peak heat release rate (p-HRR) decreased by 16.2% and the limiting oxygen index (LOI) increased to 32.5%, while maintaining the mechanical properties. By analyzing the condensed-phase and gas-phase products during the thermal degradation of the PC/KSP composites, it is demonstrated that KSP can promote the early decomposition of PC into carbon and rapidly form a stable carbon layer to protect the internal substrate during combustion.

Fabrication and mechanism research of high-efficiency water-resistant flame retardant, transparent and mechanically reinforced polycarbonate composites

In the emerging applications of optoelectronics and mobile, it has always been an urgent problem in fire safety field to ensure the excellent transparency, water resistance and mechanical properties of flame retardant polycarbonate (PC). Unfortunately, the high-efficiency flame retardants used in PC often endow it with satisfied flame retardancy at the cost of the mechanical properties, transparency of composites. Hence, in this work, the high-quality pentaerythritol phosphate flame retardant (PBPP) was successfully prepared by novel synthesis method. The results indicated that the introduction of only 2 wt% PBPP and 0.1 wt% polytetrafluoroethylene (PTFE) enabled PC to obtain a UL-94 V-0 rating and the melt dripping of PC composites was inhibited during combustion. Meanwhile, the PC/PBPP composites still maintained its original transparency. With the introduction of PBPP, the PHRR and THR of PC/PBPP were reduced by 36.0% and 11.4%, respectively. This was mainly attributed to the catalytic charring and gas-phase suppression effect of PBPP. To our surprise, the introduction of PBPP obviously increased the tensile properties and ductility of PC composites. Besides, the PC/PBPP composites still retained excellent flame retardancy and mechanical performance before and after water resistance tests due to the hydrophobicity of PBPP and its excellent compatibility with the PC matrix. This work provided a simple and effective method to prepare PC composites with excellent water resistance, flame retardancy, transparency and mechanical enhancement, which possessed great significance for the application of PC composites in emerging fields.

High-performance flame-retardant polycarbonate composites: Mechanisms investigation and fire-safety evaluation systems establishment

Polycarbonate (PC) is highly attractive for applications in high-speed railways and airplanes as engineering materials, but suffers from high fire hazards with severe melting dripping during burning. To overcome the challenge, highly effective flame retardants , such as sulfonate derivatives and silicon-based compounds have been developed. Unfortunately, there is still lacking of a systematic method to evaluate the fire risk of these flame-retardant PC composites. Herein, we propose a comprehensive and innovative approach to assess the fire safety of flame-retardant PC composites containing potassium perfluorobutane sulfonate (PPFBS) and a silicon-based flame retardant (PSR) through combining numerous combustion parameters obtained from different measurements. The pyrolysis and combustion characteristics of PC/PPFBS and PC/PSR were studied in detail and revealed that PPFBS and PSR could effectively reduce the activation energy of PC. PSR is effective at reducing the heat and smoke release due to the formation of a Si–C protective layer during combustion. In contrast, PPFBS has no obvious suppression effect on smoke generation, and even shows a combustion-supporting effect under high radiation flux. Based on the analytic hierarchy process (AHP), a comprehensive evaluation model has been established to achieve an objective and comprehensive evaluation of the fire hazards of PC and its composites. This works provides a universal guidance for evaluating fire hazards of flame-retardant polymer composite . • The pyrolysis mechanism of PC composite has been revealed. • The flame-retardant mechanism of PC composite has been revealed. • A comprehensive safety evaluation system for flame-retardant PC has been established.

Targeted modification of black phosphorus by MIL-53(Al) inspired by “Cannikin's Law” to achieve high thermal stability of flame retardant polycarbonate at ultra-low additions

To tailor the enhancement strategies for polymers according to structure, inspired by the concept of “Cannikin's Law”, this work proposes and exemplifies a novel strategy for reinforcing the carbonate linkages to simultaneously improve the thermal and fire safety of polycarbonate (PC). Herein, we introduce MIL-53(Al) to functionalize black phosphorus (BP@MIL-53) via a simple method of hydrothermal. As expected, the incorporation of BP@MIL-53 (1.0 wt%) in PC, resulted in an increase in T1% of 32 °C and 41 °C under nitrogen and air respectively, along with the reduction of 49.4% and 19.3% for peak heat release rate and total heat release. Moreover, PC/BP@MIL-53-1.0 passed the V-0 rating of UL-94 with a high limiting oxygen index (LOI) value of 30.5%, which achieved the dual purpose of simultaneously enhancing the thermal stability and flame retardancy of PC. In addition, the addition of flame retardants had no effect on the tensile strength of the PC. These results demonstrate the high flame retardant efficiency of BP@MIL-53 at ultra-low addition levels. Moreover, these results also illustrate the forward-looking nature of the strategy of tailoring flame retardants to the properties of the substrate. This work combines the advantages of black phosphorus (BP) and Mental organic frameworks (MOFs) materials. The carbonate linkages reinforcement approach provides a viable, new, and scalable idea for polyester compounds' thermal and fire safety properties.

KCl nanoparticles-loaded octaphenylsilsesquioxane as an efficient flame retardant for polycarbonate

In this work, potassium chloride loaded octaphenylsilsesquioxane (OPS-K) was synthesized by pre-dispersing the solution of potassium chloride (KCl) in solvent. The micro-nano structure of OPS-K not only achieves the good dispersion of KCl nanoparticles in OPS, but also helps improve its thermal stability. Furthermore, the flame retardancy of OPS and OPS-K on polycarbonate (PC) was studied by oxygen index (LOI), vertical combustion (UL-94) and cone calorimeter (CONE) tests. Compared with OPS, OPS-K confers better flame retardancy upon PC matrix. With the loading amount of 4 wt%, OPS-K is able to increase the LOI value from 28.1% to 34.5% and can reach the V-0 rating easily. Furthermore, the peak heat release rate (PHRR) was decreased by 35%. Studies on the fire properties of flame retardant PC demonstrate that OPS-K contributes to the formation of a compact and uniform char during combustion. The formation of a continuous and homogeneous surface shielding over the PC matrix protects the underlying polymer and inhibits the transfer of heat and mass, thereby improving the flame retardant performance of PC.

Light diffusing and flame-retardant polycarbonate modified by highly efficient and multifunctional organosilica microspheres

Polycarbonate (PC) is widely used as a matrix in light diffusing material due to its high transparency. To prepare a light diffusing material, PC is blended with microparticles to scatter the incoming light and create haze without suffering much detriment in light transmittance. It also becomes critical to endow light diffusing PC with concurrent flame retardancy to extend its advanced application. A highly efficient and multifunctional potassium sulfonate functionalized organosilica microspheres (OM-SO3K) were synthesized and employed to produce light diffusing and flame-retardant PC. When the addition of OM-SO3K was only 0.4 mass%, the transmittance and haze of the composite were 78.6% and 90.2%, respectively, while the limiting oxygen index was increased significantly to 37.5% and the V-0 rating of UL 94 test was attained. The flame-retardant mechanism was studied by the characterization of pyrolysis gas, TGA, cone calorimeter test and the analysis of charred residue.

Transparent, highly thermostable and flame retardant polycarbonate enabled by rod-like phosphorous-containing metal complex aggregates

It has been desirable to create flame retardant, transparent polycarbonate (PC) materials while retaining high thermostability and mechanical strength to meet its practical applications in the electrical, optical lighting, automobile and mobile fields. Unfortunately, current flame retardants offer satisfactory flame retardancy at the expense of other properties because of improper designs. For this reason, it has remained a grand challenge to achieve an integrated performance portfolio. Herein, we report rod-like phosphorus-containing metal complex aggregates (CePn) by one-step solvothermal method. The results show that the peak heat release rate (PHRR) and total smoke release (TSR) of the bulk PC are respectively reduced by 46% and 26% in the addition of 4 wt% of CePn, in addition to a desired UL-94 V-0 rating and a limiting oxygen index (LOI) of 27.3% because of dual-phase flame retardant mechanisms of CePn. Moreover, the final PC maintains a high transparency of 90.1% and a comparable tensile strength to the bulk PC. Moreover, the final PC composite shows enhanced thermal stability noticeably which is superior to that of any other reported systems. This work offers an innovative methodology for the design of flame retardants with tunable aggregated morphologies, and the creation of high-performance PC composites combining exceptional flame retardancy, transparency, thermostability and mechanical strength.

Deposition growth of Zr-based MOFs on cerium phenylphosphonate lamella towards enhanced thermal stability and fire safety of polycarbonate

The fabrication of engineering plastics combining high efficiency flame retardancy and thermal resistance are essential for practical applications. A novel halogen-free binary hybrid with lamellar and porous structure, Zr-BDC@CeHPP, was created by hydrothermal reaction, thereafter blended with polycarbonate (PC) to improve its thermostability and fire safety. With 2 wt% Zr-BDC@CeHPP, temperatures under peak decomposition rates (Tmax1 and Tmax2) of PC were increased by 28 and 34 °C under oxidizing atmosphere. Time to reach PHRR (t-PHRR) and time to ignition (TTI) and of PC were effectively prolonged to 145 and 18 s, respectively. In comparison with pure PC, the peak of heat release rate (PHRR), total heat release (THR), peak specific extinction area (PSEA) and total smoke release (TSR) of PC composites were reduced by 45%, 20%, 74% and 18%, respectively. Moreover, the flame retardant PC reached V-0 rating in UL-94 vertical burning test. The results indicated that the hybrid was able to fully utilize the advantages of Zr-BDC and CeHPP. In the ignition and middle periods of combustion, Zr-BDC@CeHPP played roles in delaying and suppressing explosive combustion. In severe combustion stage, Zr-BDC@CeHPP could catalyze the char-forming process and serve as a barrier.

Hybrid Nanorods Composed of Titanium, Silicon, and Organophosphorus as Additives for Flame-Retardant Polycarbonate

Upon fabrication of a high-performance functional polymer, an ideal additive should be material that may endow the polymer with an appointed function and meanwhile does not damage or even improve the other properties. Novel nanoparticles have a potential value in achieving the above-mentioned ideal. In this work, a novel hybrid nanorod OPTS containing organophosphorus–titanium–silicon (P–Ti–Si) was synthesized via a hydrothermal reaction using tetraethyl orthosilicate, tetrabutyl titanate, and diphenylphosphinic acid as raw materials. Different tests were used to illustrate the structure of OPTS nanorods and demonstrate the formation mechanism. On the basis of the structural characteristic of OPTS, it was used to fabricate high-performance flame-retardant polycarbonate (PC). Experimental results confirmed that only 0.10 wt % of OPTS endowed PC with a UL-94 V-0 rating and a limiting oxygen index of 29.7%. Meanwhile, the flame-retardant PC with 0.10 wt % of OPTS had a higher tensile strength and a higher elongation at break than pure PC, correspondingly increased by 8.0 and 8.3%. Therefore, high-performance flame-retardant PC was prepared after the incorporation of a small amount of OPTS. The reasons for the flame retardance and excellent mechanical properties of PC/OPTS are discussed thoroughly.

Preparation of Graphene Nanoplatelets by Thermal Shock Combined with Ball Milling Methods for Fabricating Flame-Retardant Polymers

Graphene nanoplatelets were successfully prepared from graphite powder by simple and scalable thermal shock combined with ball milling methods. The formation of the graphene nanoplatelets were observed by field-emission scanning electron microscopes and Brunauer–Emmett–Teller methods with the much smaller number of layers and the considerable increase of specific surface area in comparison to the initial expanded graphite material. The other characterizations such as Fourier transform infrared spectroscopy and X-ray powder diffraction methods of graphene nanoplatelets showed unchanged structure. These graphene nanoplatelets were combined with aluminum trihydroxide and zinc borate to prepare flame-retardant polycarbonate plastic and chlorine-sulfonated polyethylene rubber. The prepared composites showed the improvement of flame resistance properties with V0 level according to the UL-94 test method, and the limiting oxygen index value was higher than 27.

A novel organic-inorganic hybrid SiO2@DPP for the fire retardance of polycarbonate

To enhance the fire retardance of polycarbonate (PC), a novel organic-inorganic hybrid particle containing phosphorus and silicon (SiO2@DPP) was synthesized through a facile hydrothermal reaction. Different measurements verified that the SiO2@DPP was prepared successfully. After incorporation of the SiO2@DPP into PC, it was found that the flame retardancy of PC was greatly affected by only small amount of SiO2@DPP. The PC containing only 0.8 wt% SiO2@DPP passed the UL-94 V-0 rating in vertical combustion test and had the limiting oxygen index (LOI) of 29.3%. Moreover, the dripping behavior of PC was also restricted in this case. In cone calorimetry test, the peak heat release rate (PHRR) and the peak smoke production rate (PSPR) of PC were correspondingly remarkably reduced by 41.6% and 15.4% in the presence of only 0.8 wt% SiO2@DPP. Moreover, the flame-retardant mechanism of the SiO2@DPP was also investigated in detail through different measurements. The results demonstrated that the phosphorus-containing substances and SiO2 left in the condensed phase and some structures containing phosphorus in gaseous phase had great contribution to excellent fire retardance of PC/SiO2@DPP. All these results demonstrate that the SiO2@DPP is an efficient organic-inorganic hybrid material for preparing fire-retardance PC.

Synergistic flame retardant mechanism of lanthanum phenylphosphonate and decabromodiphenyl oxide in polycarbonate

Lanthanum phenylphosphonate (LaHPP) was synthesized through solution reflux method with a hydrothermal reaction. The synergistic effect of decabromodiphenyl oxide (DBDPO) and LaHPP on thermal stability and flame retardancy of polycarbonate (PC) were investigated. Transmission electron microscope graphs showed that LaHPP dispersed well in the PC matrix. Thermogravimetric analyses indicated that the addition of LaHPP into PC/DBDPO composites led to better thermal stability. An appropriate content (1 wt%) of LaHPP could improve the UL94 rating (from V‐2 to V‐0) and limiting oxygen index value (from 32.8 to 40.5%) dramatically, and also brought an effective reduction in peak heat release rate and smoke release rate in cone calorimeter. Investigation of gaseous pyrolysis products and char residues demonstrated that LaHPP promoted the formation of more compact and solid chars, which acted as physical barriers to inhibit heat and oxygen transfer. The inside char layers also provided more space and time for DBDPO to play its flame retardant role in gaseous phases. POLYM. COMPOS., 40:986–999, 2019. © 2018 Society of Plastics Engineers

Experimental study of commercial flame-retardant polycarbonate under external heat flux

The commercial flame-retardant polycarbonate samples were investigated in a cone calorimeter with a piloted ignition under different heat fluxes to study the fire characteristics and quantitatively analyze the ignition time, ignition temperature and mass loss rate. It was found that the transformed ignition time $$(1/t_{\text{ig}} )^{n}$$ increased linearly with heat flux when index n = 0.3, which was lower than 1, 0.55 and 0.5 that were employed in previous study, due to the intumescence of the material. The calculation temperature was more accurate with the minimum heat flux and a variable $$h_{\text{c}}$$ depending on external heat fluxes. The peak heat release rate of commercial flame-retardant was lower than others due to the formation of charred layer and the additives which could repair the rupture produced by evolution gas emitting. The average mass loss rate at 50% was taken on linearly with heat fluxes, density and thickness. These data and models could be used to evaluate the fire risk of polycarbonate as the main high-speed train carriage interior material.

Flame resistance and aging mechanism of flame retardant polycarbonate sheet containing linear phenolic resin charring agent

The preparation of halogen-free flame retardant thin-wall polycarbonate (PC) sheet with high performance is a global challenge. In our research, a composite flame retardants system composed of polysiloxane and perfluorinated sulfonate combined with a macromolecular charring agent, linear phenolic resin (LPR) could endow PC sheets (thickness: 0.4 mm) with UL94-V0 rating, showing high flame resistance efficiency. Regrettably, this efficient flame retardant system made the aging properties of PC seriously deteriorated due to the transesterification reaction between the phenolic hydroxyls and PC macromolecular chains, thus losing practical applied value. Introducing a small amount of boron acid (HB) could solve the fatal shortcoming through a quick coordination reaction between the boron atom and phenolic hydroxyl to effectively protect the PC backbone chains, and meanwhile further improve the flame retardance by increasing the charring stability of LPR due to the formed B–O bond with higher energy.

Synergism of polysiloxane and zinc borate flame retardant polycarbonate

Abstract Liquid polysiloxane (PSI) and zinc borate (ZB) were combined for the flame retardance of polycarbonate (PC). During polymer combustion, for the PC flame-retarded with PSI only, PSI can form char residue containing silica on the material surface. But the liquid silicone tends to drip with melting polymer and volatilize in high temperature, thus decreasing the charring performance. In the case of only ZB flame retardant involved, this inorganic flame retardant and possible some of its decomposition products (B2O3) more difficultly move to the surface and it appears that they do not effectively contribute to the char formation. Present study suggests that the existing synergism between PSI and ZB is the result of chemical reaction via forming cross-linking B–O–Si structure. As results, the loss of Si/silicone is reduced by eliminating the melt dripping. Meanwhile, boron species can be “dragged” by PSI (in the form of borosiloxane) to the surface of the char residue. Consequently, Si and B elements together contribute to the integrity of char residue layer with better quality, achieving obviously improved flame retardance compared with only PSI and only ZB flame retardant systems.

Flame retardancy and thermal properties of carboxyl‐containing polysiloxane derivatives in polycarbonate

ABSTRACTCarboxyl‐containing polysiloxane (LCCP) has been successfully applied in the flame retardancy of polycarbonate (PC). The LCCP was synthesized by hydrosilylation and condensation reaction. The presence of carboxyl groups has been demonstrated to be crucial to provide high flame retardant effectiveness. The flame retardancy of LCCP–PC composites is investigated by limiting oxygen index (LOI), vertical burning tests (UL‐94). At the mole ratio of diethoxymethyl (1‐propionyloxy) silane/diethoxydimethylsilane = 8/100 in LCCP(3), the best flame retardant performance of LCCP‐PC composites was obtained. The LOI value of the composites is 38.5 and the UL‐94 rating reaches V‐0 when the content of LCCP(3) is as low as 0.5 wt %. Evolution of the thermal behaviors of the composites tested by thermogravimetric analysis shows that addition of LCCP(3) in PC can reduce the degradation speed of PC and induce a reduction of the initiated decomposition temperature of PC. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39814.

아드만탄 기반의 새로운 설포네이트 폴리카보네이트 난연제 성능 연구

A novel sulfonate flame retardant, 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (FR-A), was successfully synthesized from 1-bromoadamantane in sequential four-step reactions involving Fiedel-Crafts phenylation, sulphonation, hydrolysis, and neutralization. The success of synthesis was confirmed by FTIR spectra, <TEX>$^1H$</TEX> NMR spectra, elemental analyses and mass spectra. The effect of FR-A on the flame retardacy of polycarbonate (PC) has been studied. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) showed that this novel sulfonate flame retardant had effective flame retardancy on polycarbonate (PC). With a small amount (0.08 wt%) of FR-A, the flame retardancy of PC was improved obviously, which got to UL 94 V-0 rating. TGA and DTA curves demonstrated that the additive raised the degradation rate of PC by promoting the quick formation of an insulating carbon layer on the surface, and confirmed that the flame retardant mechanism of PC/FR-A system was similar to potassium diphenylsulfone sulfonate (KSS).