The Effects of Halogen-Free Flame Retardant Additives in Epoxidized Natural Rubber (ENR)

2015 ◽  
Vol 1107 ◽  
pp. 131-136
Author(s):  
A.I.H.Dayang Habibah ◽  
Abd Rahim Ruhida

Legislation on fire safety requirements especially in the USA and UK has been the driving force behind the use of halogen-free flame retardants (FR) in recent years. The present study describes the effect of inorganic fillers, namely aluminium hydroxides (ATH) on epoxidized natural rubber (ENR) in order to increase its flame retardant capability. Two different types of ATH, a standard type Apyral 60 CD (ATH 60) and a submicron sized Apyral 200 SM (ATH 200) were used. The flame-retardant ENR composite was characterized by limiting oxygen index (LOI), UL-94V, and thermogravimetric analysis (TGA) to study the combustion behavior and thermal stability. The finer particles size (ATH 200) as expected produced better flame retardant properties (measured by LOI) compared to ATH 60; however, the difference between the values is marginal. It was also observed that a combination of 100 pphr ATH 200 and 60 pphr ATH 60 gave the highest LOI value (29.4%) in ENR compounds. The compound was V0 rated in UL-94V burn test. Even at the higher loading, it was also found that the compound exhibited lower viscosity indicating its easier processability.

2020 ◽  
Vol 993 ◽  
pp. 669-677
Author(s):  
Hui Min Ke ◽  
Ri Peng Zhu ◽  
Jing Hong Ma ◽  
Jing Hua Gong

Polyurethane (PU) superfine fiber leathers have been widely used in people's life. However, the flammability brings potential risks to their application. Therefore, more and more attention has been paid to the flame retardant modification of PU leathers. In the 1980s, researchers found that some brominated flame retardants produced dioxins during combustion. In 2007, the EU began implementing the REACH regulation, which restricted the use of certain halogenated flame retardants, so a majority of studies focused on halogen-free flame retardant modification. In addition, the halogen-free flame retardant PU should own a better alkali resistance, because alkali treatment is needed in the forming process of the superfine fiber leather. In this paper, two different halogen-free flame retardants were blended with solvent-based PU. The flame retardant properties and alkali resistance of the flame retardant PU were studied by limiting oxygen index (LOI) test, vertical burning (UL-94) test, and thermogravimetry-infrared spectroscopy (TG-FTIR). It was found that BY-90 system flame retardant could be uniformly dispersed in the PU matrix. And when its additive volume was 27%, the LOI value of the flame retardant PU was 27.1%, the vertical burning test could reach V-0 level. Moreover, it also had good alkali resistance. The LOI value remained at 26.1% after the alkali treatment at 90 °C for 40 min in the 30g/L NaOH solution.


2015 ◽  
Vol 30 (6) ◽  
pp. 816-826 ◽  
Author(s):  
Yiren Huang ◽  
Jianwei Yang ◽  
Zhengzhou Wang

Flame-retardant properties of ammonium polyphosphate (APP) and its two microcapsules, APP with a shell of melamine–formaldehyde (MF) resin (MFAPP) and APP with a shell of epoxy resin (EPAPP), were studied in styrene–butadiene–styrene (SBS). The results indicate that APP after the microencapsulation leads to an increase in limiting oxygen index in SBS compared with APP. When dipentaerythritol is incorporated into the SBS composites containing the APP microcapsules, a further improvement in flame retardancy of the composites is observed. The microencapsulation does not result in much improvement of mechanical properties. Moreover, the effect of a compatibilizer (SBS grafted with maleic anhydride) on flame-retardant and mechanical properties of SBS/APP composites was investigated.


e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 235-243 ◽  
Author(s):  
Lin Liu ◽  
Rui Lv

AbstractA DOPO (9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide)-based halogen-free flame retardant (ODOPM-CYC) was synthesized and incorporated in rigid polyurethane foam (RPUF). The structure of ODOPM-CYC was characterized by Fourier transform infrared spectra (FTIR), 1H NMR and 31P NMR. The effects of ODOPM-CYC on the flame resistance, mechanical performances, thermal properties and cell structure of RPUF were also investigated. The results showed that the incorporation of ODOPM-CYC strikingly enhanced flame retardant properties of RPUF. The flame retarded RPUF acquired a limiting oxygen index (LOI) value of 26% and achieved UL-94 V-0 rating with the phosphorus content of 3 wt%. The smoke production rate (SPR) also showed an obvious decrease and total smoke release (TSR) was 39.8% lower than that of neat RPUF. Besides, the results demonstrated that the incorporation of ODOPM-CYC provided RPUF better thermal stability but did not show any obvious influence on its thermal conductivity.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2554 ◽  
Author(s):  
Zhi Geng ◽  
Shuaishuai Yang ◽  
Lianwang Zhang ◽  
Zhenzhen Huang ◽  
Qichao Pan ◽  
...  

Introducing fire-retardant additives or building blocks into resins is a widely adopted method used for improving the fire retardancy of epoxy composites. However, the increase in viscosity and the presence of insoluble additives accompanied by resin modification remain challenges for resin transfer molding (RTM) processing. We developed a robust approach for fabricating self-extinguishing RTM composites using unmodified and flammable resins. To avoid the effects on resin fluidity and processing, we loaded the flame retardant into tackifiers instead of resins. We found that the halogen-free flame retardant, a microencapsulated red phosphorus (MRP) additive, was enriched on fabric surfaces, which endowed the composites with excellent fire retardancy. The composites showed a 79.2% increase in the limiting oxygen index, a 29.2% reduction in heat release during combustion, and could self-extinguish within two seconds after ignition. Almost no effect on the mechanical properties was observed. This approach is simple, inexpensive, and basically applicable to all resins for fabricating RTM composites. This approach adapts insoluble flame retardants to RTM processing. We envision that this approach could be extended to load other functions (radar absorbing, conductivity, etc.) into RTM composites, broadening the application of RTM processing in the field of advanced functional materials.


2011 ◽  
Vol 418-420 ◽  
pp. 540-543 ◽  
Author(s):  
Ding Meng Chen ◽  
Yi Ping Zhao ◽  
Jia Jian Yan ◽  
Li Chen ◽  
Zhi Zhi Dong ◽  
...  

Polyurethane foams (PUFs) filled with several halogen-free flame retardants and composite halogen-free flame retardants were prepared. The flame retardant, thermal stable and mechanical properties of the PUFs were investigated. The results of limiting oxygen index (LOI) and thermogravimetric analysis (TGA) revealed that PUFs filled with dimethyl methylphosphonate (DMMP) had better flame retardancy compared with other flame retardants and DMMP degraded at a low temperature to form several phosphorated acids which accelerated the formation of char layer. Composite flame retardant of DMMP and melamine (MA) had a synergistic effect between phosphorus and nitrogen. The combination of DMMP and MA slightly altered the density of the PUFs. Results from the mechanical analysis revealed that with the increase in concentration of MA in the composite flame retardant of DMMP and MA, the tensile strength of PUFs reduced firstly and then increased up to a constant.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1956 ◽  
Author(s):  
Heng Zhang ◽  
Junliang Lu ◽  
Hongyan Yang ◽  
Jinyan Lang ◽  
Heng Yang

Three metal salts of dicyclohexyl hypophosphite, namely dicyclohexyl aluminum hypophosphite (ADCP), dicyclohexyl magnesium hypophosphite (MDCP), and dicyclohexyl zinc hypophosphite (ZDCP), were synthesized. These flame retardants were subjected to thermogravimetric analysis, and the results showed that ADCP and ZDCP had higher thermal stabilities than MDCP. They were then separately mixed with polyamide 66 (PA66)to prepare composite materials, of which the combustion properties were determined by the limiting oxygen index method and horizontal/vertical burning experiments. The mechanical properties of the materials were further evaluated using an electronic universal testing machine. The results showed that all the three flame retardants exerted a flame-retardant effect on PA66, but the flame-retardant effect of MDCP was inferior to those of ADCP and ZDCP. All the composites also showed similar mechanical properties. Among the three flame retardants, ADCP had the best overall performance for raw materials, showing good flame-retardant properties while maintaining the mechanical properties of the raw materials. The optimal dosage of ADCP was 15 wt %, at which a V-0 rating in the vertical burning test (UL 94 test) can be obtained.


2011 ◽  
Vol 284-286 ◽  
pp. 1831-1835
Author(s):  
Zheng Zhou Wang ◽  
Lin Liu ◽  
Gan Xin Jie ◽  
Ping Kai Jiang

Flame retarded ethylene-vinyl acetate copolymer (EVA) was prepared in a melt process containing melamine phosphate (MP), or MP in combination with dipentaerythritol (DPER) as flame retardants. The influence of MP and MP/DPER on flame retardant properties of EVA was investigated by limiting oxygen index (LOI) and UL 94 test. Thermal decomposition of the flame retardants and flame retarded EVA composites was studied by the thermogravimetric analysis. The results show that MP used alone in EVA does not exerts good flame retardancy, even at a loading of 50wt%. It is found that the flame retardant properties of the EVA/MP/DPER composites is greatly improved when a suitable amount of MP substituted by DPER. Moreover, mechanical properties of the EVA composites were studied.


1997 ◽  
Vol 15 (1) ◽  
pp. 3-13 ◽  
Author(s):  
A.R.R. Menon

Natural rubber (NR) in a typical semi-efficient vulcanization system was modified with flame-retardant additives such as bromo derivative of phosphorylated cashew nut shell liquid, antimony trioxide and alumina tri hydrate (ATH). Improvement in the flame retardancy of the vulcanizates was shown by the progressive increase in Limiting Oxygen Index with the concen tration of ATH. Besides, the smoke density and the smoke release rate were reduced substantially in the presence of 100 phr of ATH in the vulcanizate. Thermogravimetric analysis showed higher activation energy for decomposi tion and higher yields of decomposition residue for the ATH-filled NR vulcanizates. Also, the vulcanizate modified with the flame retardants showed improvements in tensile and tear strengths in presence of 50 phr of the filler.


Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3100 ◽  
Author(s):  
Mayer-Gall ◽  
Plohl ◽  
Derksen ◽  
Lauer ◽  
Neldner ◽  
...  

Poly- and cyclophosphazenes are excellent flame retardants but currently, are not used as textile finishing agents because water-soluble and permanent washing systems are missing. Here, we demonstrate for the first time, the successful usage of a water-soluble cyclotriphosphazene derivative for textile finishing for cotton, different cotton/polyester, and cotton/polyamide blend fabrics. A durable finish was achieved using a photoinduced grafting reaction. The flame retardant properties of the various fabrics were improved with a higher limiting oxygen index, a reduced heat release rate, and an exhibition of intumescent. Furthermore, the finished textiles passed several standardized flammability tests.


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