The effect of magnesium hydroxide/ zinc borate and magnesium hydroxide/ melamine flame retardant synergies on polypropylene (original) (raw)
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Enhanced Flame Retardancy of Polypropylene with Magnesium Hydroxide, Melamine and Novolac
Journal of Fire Sciences, 1998
It has been found that, even at levels of magnesium hydroxide too low to impart flame retardancy to polypropylene, the addition of melamine makes it possible to reduce burning time under UL 94 conditions sufficiently to meet the V-2 rating. However, flaming drips still persist, so that a V-0 rating by UL 94 cannot be obtained. It was then found that by the further addition of a novolac at levels as low as 1%, together with melamine, a UL 94 V-0 rating could be reached. Levels of magnesium hydroxide could be as low as 30-50%, allowing the formulation to be flexible. The novolac caused a useful dimension-stabilizing effect above the melting point of polypropylene. Some thermal evidence suggested that a novolac-magnesia gel may be formed.
Open Chemistry, 2021
In many plastic applications, improvement of the flame retardancy is a very significant topic. Polypropylene (PP) is used in many applications such as housing industry due to its cost performance efficiency. Enhancement of flame retardancy properties of PP is necessary in many applications. In this study, the investigation focuses on the synergistic effect of mica mineral and IFR in enhancing the flame retardancy properties of PP in order to achieve cost competitive solution, so as to provide that different/various ratios of IFR and mica mineral were added into PP to compose 30 wt% of the total mass of the polymeric compounds. The synergistic effect of mica mineral with IFR in PP was investigated by limiting oxygen index (LOI), glow wire test (GWT), UL-94 test, thermal gravimetric analyses (TGA), and mechanical tests. The results from LOI, UL 94, and GWT tests indicated that mica added to PP/IFR compound has a synergistic flame retardancy effects with the IFR system. When the conten...
Combustibility of Polypropylene
1997
The combustion of a typical thermoplastic polymer, polypropylene mixed with three additive fire retardants, magnesium hydroxide, aluminium hydro- xide and antimony trioxide, was assessed in a cone calorimeter . It Is found that the increased Mg(OH) 2 content in polypropylene, further increases the ignition time and reduces the heat release rate . Its effect on smoke density is found to be somewhat different, when present at lower percentages it increases the smoke density of fire effluents.
International Journal of Polymer Science, 2015
The effect of particle size reduction of the components of a common intumescent flame retardant system, consisting of pentaerythritol (PER) and ammonium polyphosphate (APP) in a weight ratio of 1 to 2, was investigated on the flammability and mechanical performance of flame retarded polypropylene (PP) compounds. Additives of reduced particle size were obtained by ball milling. In the case of PER, the significant reduction of particle size resulted in inferior flame retardant and mechanical performance, while the systems containing milled APP noticeably outperformed the reference intumescent system containing asreceived additives. The beneficial effect of the particle size reduction of APP is explained by the better distribution of the particles in the polymer matrix and by the modified degradation mechanism which results in the formation of an effectively protecting carbonaceous foam accompanied with improved mechanical resistance. Nevertheless, 10% higher tensile strength was measured for the flame retarded PP compound when as-received APP was substituted by milled APP.
This work studied the effect of aluminum hydroxide as flame retardant chemical on the flame characteristics of high density polyethylene (HDPE) and polypropylene (PP). This was by incorporating varying percentage concentrations of the flame retardant into the samples. The results showed that the flammability properties improved. The incorporation of flame retardant reduced flame propagation rate and after-glow time whereas ignitability time was enhanced.
Polymers for Advanced Technologies, 2008
Fire retardancy behavior of polypropylene-magnesium hydroxide-clay composites of different morphologies is presented. Layer-and needle-like clay nanoparticles in natural and organically surface modified form have been compared. Fire retardant performance of the composites was evaluated by conical combustor and by horizontal burning test, while the structure was characterized by SEM. Rheological analysis of varied temperature provided further information about the strength of the formed combustion residue. The results confirm that fibrous and layered clay nanofillers act synergistically and can be combined with MH microfillers advantageously for improving the flame retardancy of PP composites. Significant improvements were observed in combustion parameters, as well as in flammability classifications. Combination of montmorillonite and sepiolite type of clays resulted in the increased time to ignition, and markedly decreased heat release rate. These advancements are ascribed to the char stabilizer effect of nanofillers leading to increased strength of the residue. It is also concluded that not only the interaction between micro-and nanofillers, but also the nanofillers-nanofillers interaction plays a key role in fire retardant mechanism.
A synergistic flame-retardant compound containing magnesium hydroxide (MH) and melamine cyanurate (MCA) ingredients was prepared with ethylene-propylene-diene monomer (EPDM) composite to find a highly efficient, halogen-free, and phosphorus-free flame retardant. The flame-retardant MH/MCA compound particles were modified by a silane coupling agent to increase surface activity. Two series of EPDM/MH/MCA composites were prepared by direct blending methods. The mechanical and flame-retardant properties of the composites were investigated by various methods. The Rockwell hardness and tensile strength of EPDM/MH/MCA composites significantly increased after adding MH/MCA compound particles compared with EPDM composites. Results showed that incorporating MH/MCA compound particles evidently improved the flame-retardant and mechanical properties of EPDM. Both of these properties increased, and the flame-retardant properties of the materials met the UL94 V-1 requirements. The excellent properties of the composites were obtained after adding 40 phr MH and 20 phr MCA with a silicane coupling agent. Results indicated that the EPDM/MH/MCA composite with the appropriate MH/MCA mass ratio had the highest LOI, UL94 V-0 rating, lowest heat release rate, and highest residue yield. These results implied that the appropriate MH/MCA mass ratio formed a better flame-retardant system and adequately exerted their synergistic effects. Different flame-retardant performances should be attributed to their own characteristics, dispersion state in EPDM matrix, and the change of structure during burning.
Materials, 2020
The fire behavior of polymers is examined primarily with the time-dependent heat release rate (HRR) measured with a cone calorimeter. The HRR is used to examine the fire behavior of materials with and without flame retardants, especially Polypropylene (PP-Copo) and Polyethylene (PE-LD). Polypropylene is stored for up to 99 days under normal conditions and the heat release rate shows especially changes about 100 s after irradiation with cone calorimeter, which may be caused by aging effects. The effect of crosslinking to the burning behavior of PP was examined too. Polyamides (PA 6) are irradiated with a radiation intensity of 25 kW/m2 to 95 kW/m2 and fire-related principles between radiation intensity and time to ignition can be derived from the measurement results. In order to comprehensively investigate the fire behavior of PP (also with flame retardant additives), the samples were also exposed to a flame, according to UL 94 with small power (50 W) and is inflamed with the power o...
Effect of Fillers on the Fire Retardant Properties of Intumescent Polypropylene Compounds
Polymers and Polymer Composites, 2008
The effects of fillers, including ammonium polyphosphate (APP), aluminium trihydrate (ATH) and talc, and the effect of polyethylene vinyl acetate (EVA) as an interfacial agent, were investigated on the flame retardant properties of intumescent polypropylene (PP), by using mechanical testing, to measure the tensile and Izod impact strengths, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the limiting oxygen index (LOI) test method. SEM studies showed that the dispersion of flame retardant particles in the PP matrix improved with the use of EVA. Tensile strength decreased but elongation at break and impact resistance of PP/APP/EVA and PP/ATH/EVA composites increased by using 10 wt.% of EVA. Using 12 wt.% of talc in PP/APP/PA-6/EVA led to increasing impact resistance and decreasing tensile strength and elongation at break of the composite. EVA prevented the exudation of additives to the composite surface, and consequently the fire retardant properties of the c...