Добірка наукової літератури з теми "UL-94 vertical"

In order to improve fire performance of polymeric materials, phosphorus flame retardants (FRs) were studied in an attempt to obtain UL-94 ratings for materials based on unsaturated polyester. The fire behaviors and thermal stability properties were evaluated using UL-94 vertical test and thermogravimetric analysis (TGA). The UL-94 test results show that V-1 rating is achieved. TGA and UL-94 results concluded that phosphorus FRs employed in this study works on both vapor phase and condensed phase, but the vapour phase is dominant mode of action. These suggested that the addition of FRs probably does affect on the char layer formed during combustion behavior and increase the flame retardant properties in the case of condensed phase mode of action. The efficiency of flame retardant of phosphorus also highly depends upon the phosphorus moieties generated during the decomposition which further converted to radical capturing species, and consequently quenching the flame in the case of gas phase mode of action. These FRs can be promising candidates that replace the halogen-based.

In this work, polyamide 66/polyphenylene oxide (PA66/PPO) composites, including the flame retardants 98 wt% aluminum diethylphosphinate + 2 wt% polydimethylsiloxane (P@Si), Al(OH)3-coated red phosphorus (RP*), and glass fiber (GF), were systematically studied, respectively. The limiting oxygen index (LOI), UL-94 vertical burning level, and thermal and mechanical properties of the PA66/PPO composites were characterized. The results showed that the P@Si and RP flame retardants both improved the LOI value and UL-94 vertical burning level of the PA66/PPO composites, and PA66/PPO composites passed to the UL-94 V-0 level when the contents of P@Si and RP* flame retardants were 16 wt% and 8 wt%. On the other hand, the mechanical properties of the PA66/PPO composites were reduced from a ductile to a brittle fracture mode. The addition of GF effectively made up for these defects and improved the mechanical properties of the PA66/PPO composites containing the P@Si and RP*, but it did not change the fracture mode. P@Si and RP* flame retardants improved the thermal decomposition of PA66/PPO/GF composites and reduced the maximum mass loss rates, showing that the PA66/PPO/GF composites containing the P@Si and RP* flame retardants could be used in higher-temperature fields.

In order to improve the fire performance of composite materials, halogen-free flame retardant (diamonium hydrogen phosphate- DAP) was studied in an attempt to obtain UL-94 ratings for composite PVC-wood flour (PVC-WF). The fire behaviors and thermal stability properties were evaluated using UL- 94 vertical test, LOI test and thermogravimetric analysis (TGA). The UL- 94 test results show that V-0 rating is achieved at 1.5 wt% of DAP loading. The incorporation of halogene-free flame retardant (FR) increases the flame retardant properties as well as the amounts of charred residues protecting the mixture from further degradation. This assertion can be accepted when observing that the char residual of PVC-WF/DAP mixture at 600 oC is much higher than that of neat PVC-WF. The char layer may limit the amount of fuel available and insulate the underlying composite material from the flame and, thus, inhibit further degradation. This FR is a promising candidate that could replace the halogenbased flame retardant.

In this study, a novel polyhydroxy triazine charring agent (PT-CA) was synthesized through the solid-state reaction of triglycidyl isocyanurate (TGIC) and pentaerythritol. Meanwhile, the molecular structure of the chemical compound was determined by FTIR, elemental analysis and thermalgravimetric analysis (TG).Then it is combined with microencapsulated ammonium polyphosphate (MAPP) and melamine phosphate (MP) to impart flame retardance and dripping resistance for polypropylene (PP).The fire performance of treated PP was investigated by limiting oxygen index (LOI) and vertical burning test (UL-94).It has been found that the treated PP with the optimal flame retardant formulation of MAPP:MA:PTCA=18:6:6 (weight ratio, formulation 10) gives an LOI of 31.5 and UL-94 V-0 rating.

The effects of brominated flame retardant which composed of decabromodiphenyl ethane (DBDPE) and antimonous oxide (AO) on long glass fiber reinforced polypropylene (LGFPP) were investigated by means of limiting oxygen index (LOI), vertical burning (UL-94), thermogravimetry analysis (TGA), and mechanical properties. With the increase of DBDPE-AO content, the LOI values of DBDPE-AO/LGFPP composites increased from 21 to 27.6, and when the content of DBDPE-AO was 16wt%, the composites passed the V-0 rating in UL-94 testing. The experimental results showed that the brominated flame retardant improved flame retardancy of LGFPP, which was proved by the TGA testing. Whats more, the mechanical properties of composites even improved compared with pure LGFPP.

A novel halogen-free flame retardant containing sulfonamide, 1,3,5,7-tetrakis (phenyl-4-sulfonamide) adamantane (FRSN) was synthesized and used for improving the flame retardancy of largely used polycarbonate (PC). The flame-retardant properties of the composites with incorporation of varied amounts of FRSN were analyzed by techniques including limited oxygen index, UL 94 vertical burning, and cone calorimeter tests. The new FR system with sulfur and nitrogen elements showed effective improvements in PC’s flame retardancy: the LOI value of the modified PC increased significantly, smoke emission suppressed, and UL 94 V-0 achieved. Typically, the composite with only 0.08 wt% of FRSN added (an ultralow content) can increase the limiting oxygen index (LOI) value to 33.7% and classified as UL 94 V-0 rating. Furthermore, the mechanical properties and SEM morphology indicated that the FRSN has very good compatibility with PC matrix, which, in turn, is beneficial to the property enhancement. Finally, the analysis of sample residues after burning tests showed that a high portion of char was formed, contributing to the PC burning protection. This synthesized flame retardant provides a new way of improving PC’s flame retardancy and its mechanical property.

A rigid polyurethane (PU) flame retardant composite foam was prepared by the compounding of polyols and diisocyanates with a modified intumescent flame retardant (MIFR). The MIFR was based on the three components of intumescent flame retardant normally used and was modified in a surfactant TX-10 solution. The flame retardancy of the PU flame retardant composite foams were evaluated by using the limiting oxygen index (LOI), the UL-94 (vertical flame) test and scanning electron microscopy (SEM). When MIFR was fixed at 20.0 wt% in PU/MIFR composite foams, the MIFR could enhance the flame retardancy and pass V-0 rating of UL-94 test. The microstructures observed by SEM demonstrate that a suitable amount of MIFR can promote formation of compact intumescent charred layers in PU foams.

A novel intumescent flame retardant oligomer containing phosphorous-nitrogen structure (PSPTR) was synthesized and characterized by Fourier Transform Infrared (FTIR) and Mass Spectrometry (MS). The thermal behavior of PSPTR was investigated by thermogravimetric analysis (TGA). The TGA data shows that PSPTR has a high initial temperature of thermal degradation and a high char residue of 41.18wt% at 700 . A novel intumescent flame retardant (IFR) system, which is composed of PSPTR and novolac phenol (NP), was used to impart flame retardancy of ABS. The combustion behaviors of the ABS/IFR composites were investigated by Limiting Oxygen Index (LOI) and UL-94 tests. When the content of IFR (PSPTR:NP=1:1 mass ratio) is 30 wt%, the LOI value of ABS/IFR reaches 28.2, and the vertical burning test reaches UL-94 V-1 rating.

Aujourd'hui, le secteur des transports est en pleine mutation avec la transition des véhicules thermiques vers les véhicules électriques. Par conséquent, les matériaux largement utilisés dans les véhicules, tels que le PPE, doivent également évoluer en raison d'exigences plus strictes en matière de propriétés ignifuges.Dans cette thèse, trois approches ont été envisagées pour améliorer les propriétés ignifuges du PPE et atteindre une classification V0 lors du test vertical UL-94, selon les trois différentes étapes de fabrication du PPE. Ces étapes sont : (1) le mélange du polypropylène (PP) avec divers additifs par un processus d'extrusion, (2) l'expansion du PP formulé, et (3) le moulage des billes de PPE dans la forme désirée. Avant d'étudier les différentes approches d'ignifugation de l'EPP, le test feu vertical UL-94 a été instrumenté afin d'en obtenir plus d'informations et de mieux comprendre les propriétés feux des différents matériaux. Les différentes approches envisagées ont été les suivantes : (1) l'incorporation de retardateurs de flamme (RF) et d'agents de synergie dans la matrice de PP avant l'expansion, il s'agit de l'approche la plus courante. Dans cette approche, la comparaison entre différent RF ayant des modes d'action différents (RF intumescent, générateur de radicaux libres, etc.) a été plus particulièrement étudiées. Une optimisation de la combinaison des RF et une étude de l'influence du mode de fabrication (étape d'expansion) ont été nécessaire. En effet, en raison de la grande quantité nécessaire et de leur potentiel rôle d'agents de nucléation, les RF peuvent perturber l'expansion du PP. Le mécanisme d'action des RF choisis a été étudié avant et après l'étape d'expansion. Il s'avère que l'étape d'expansion est une étape très complexe pour la conservation des propriétés feu qui a induit l'étude d'approches alternatives pour la validation de concept différents. L'alternative (2) concerne l'application d'un revêtement ignifuge sur les billes de PPE (avant le moulage) et la (3), l'application d'un revêtement ignifuge sur la pièce finale moulée (barreaux de PPE). Cependant, ces approches présentent également certains inconvénients. En effet, le PPE présente de faibles propriétés adhésions car il ne possède pas de groupes fonctionnels. Ainsi, une optimisation par traitement plasma est nécessaire pour augmenter l'adhésion du PPE. Plusieurs revêtements ignifuges ont été appliqués en surface et le moulage des billes de PPE revêtues a été étudiée. Les propriétés ignifuges des billes de PPE moulées revêtues et des barreaux de PPE revêtues ont été étudiées en utilisant le test vertical UL-94
Today the sector of transport is changing with the transition from thermal vehicles to electrical vehicles. Thus, the materials widely used in vehicles as EPP also have to change due to higher requirements in terms of fire properties.In this thesis, three approaches were considered to increase the fire properties of EPP and reach a V0 rating at UL-94 vertical test, according to the three steps of manufacturing EPP. In fact, to manufacture EPP, three steps are necessary: (1) the polypropylene (PP) is melt blended with various additives via an extrusion process, (2) the blended PP is expanded, i.e. an expansion gas is introduced into it to form EPP beads and (3) the EPP beads are then molded into the desired shape. Before investigating the different approaches, the UL-94 vertical test was instrumented in order to obtain more information and have a better understanding in terms of fire properties. The different approaches considered were: (1) incorporating flame retardants and synergists into the PP matrix before expansion, this is the most common approach. This approach was deeply investigated with a comparison between several FRs with different modes of action (intumescent FR, free radical generator, etc), an optimization of the most efficient FRs combination and a study of the influence of industrial manufacturing, especially the expansion step. Indeed, the FRs can disrupt the foaming processability (expansion step), due to the high amount of FRs needed and the fact that FRs can play the role of nucleating agents. Moreover, the mechanism of action of the chosen FRs was studied before and after the expansion step. To counter the complexity of the expansion step in the approach (1), alternative approaches were studied in order to validate others concept. The alternative (2), applying a flame-retardant coating on the EPP beads (before molding) and (3) applying a flame-retardant coating to the molded final piece (EPP bars). However, these approaches have also some drawbacks. Indeed, the EPP has poor adhesion properties because it has no functional groups. Thus, an optimization of a plasma treatment was needed in order to increase the adhesion of EPP. Several flame retardant coatings were applied on the surface and the moldability of the coated EPP beads was studied. Finally, the fire properties at UL-94 vertical test of the molded coated EPP beads and coated EPP bars were studied

Polyetheretherketone (PEEK) is a special set of thermoplastic polymers that possess fascinating mechanical, chemical, and electrical properties for various industries, such as aircraft, biomedical, automotive, satellite, energy, and defense. Recently, sulfonated PEEK (SPEEK)-based fiber-reinforced composites have been designed and fabricated for the same purposes. However, manufacturing PEEK fiber composites is considerably difficult because of the inertness and high melting point of PEEK; thus, the sulfonation process is a necessary step to make the PEEK composites in many cases. About 5 wt% PEEK powder was initially dried for 24 hours at 100°C and then sulfonated in a 98% sulfuric acid solution for 12 hours at 65°C while continuously stirring in a closed glass beaker. The precipitation was performed afterward using the water bath technique by pouring the PEEK/acid solution into the cold water to make the SPEEK polymer particles. After washing several times in DI water (until neutralizing the pH to 6-7) and drying in an oven at 100°C for a minimum of 24 hours, the SPEEK polymer is obtained. The dry SPEEK polymers were dissolved in dimethylformamide (DMF) with a ratio of 1/2 and mixed well with Kevlar and Glass fibers in different layers by the wet layup process to produce SPEEK fiber composites under vacuum bagging at a higher temperature (200°C) till all the solvent was removed. The UL 94 standard vertical flame test results showed that the SPEEK composites had very high flame-resistant properties. The water contact angle studies indicated that the composites were highly hydrophobic. The maximum tensile strengths of glass and Kevlar fiber composites were found to be 234,99 and 376.8 MPa and flexural strengths of 51.14 and 92.95 MPa, respectively. SEM testing helped analyze the resin interaction's topology on the composite samples. The smoke density test confirmed that light visibility decreased with increased burning time.