Flame-Retardant Polyamide 6/Carbon Nanotube Nanofibers: Processing and Characterization

2015 ◽  
Vol 10 (3) ◽  
pp. 155892501501000 ◽  
Author(s):  
Xiaoli Yin ◽  
Mourad Krifa ◽  
Joseph H. Koo

Polyamide 6 (PA6) was melt-blended with an intumescent flame retardant (FR), multi-wall carbon nanotubes (MWNTs), and nanoclay particles to produce multi-component FR-PA6 nanocomposites. FR-PA6 nanofibers were processed from varied nanocomposite formulations via electrospinning. Electrospinnability, morphology, along with combustion and thermal properties of the nanofibers were investigated. Both the bulk-form nanocomposites and the electrospun nanofiber membranes exhibited significantly improved combustion properties, including both Heat Release Rate and Total Heat Release. On the other hand, thermal stability appeared compromised. With proper FR additive concentrations, synergism between MWNTs and nanoclay was observed.

2021 ◽  
pp. 096739112110245
Author(s):  
Jiangbo Wang

A novel phosphorus-silicon containing flame-retardant DOPO-V-PA was used to wrap carbon nanotubes (CNTs). The results of FTIR, XPS, TEM and TGA measurements exhibited that DOPO-V-PA has been successfully grafted onto the surfaces of CNTs, and the CNTs-DOPO-V-PA was obtained. The CNTs-DOPO-V-PA was subsequently incorporated into epoxy resin (EP) for improving the flame retardancy and dispersion. Compared with pure EP, the addition of 2 wt% CNTs-DOPO-V-PA into the EP matrix could achieve better flame retardancy of EP nanocomposites, such as a 30.5% reduction in peak heat release rate (PHRR) and 8.1% reduction in total heat release (THR). Furthermore, DMTA results clearly indicated that the dispersion for CNTs-DOPO-V-PA in EP matrix was better than pristine CNTs.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1997 ◽  
Author(s):  
Zhi Wang ◽  
Ruichao Wei ◽  
Xuehui Wang ◽  
Junjiang He ◽  
Jian Wang

To fill the shortages in the knowledge of the pyrolysis and combustion properties of new and aged polyvinyl chloride (PVC) sheaths, several experiments were performed by thermogravimetric analysis (TG), Fourier transform infrared (FTIR), microscale combustion calorimetry (MCC), and cone calorimetry. The results show that the onset temperature of pyrolysis for an aged sheath shifts to higher temperatures. The value of the main derivative thermogravimetric analysis (DTG) peak of an aged sheath is greater than that of a new one. The mass of the final remaining residue for an aged sheath is also greater than that of a new one. The gas that is released by an aged sheath is later but faster than that of a new one. The results also show that, when compared with a new sheath, the heat release rate (HRR) is lower for an aged one. The total heat release (THR) of aged sheath is reduced by 16.9–18.5% compared to a new one. In addition, the cone calorimetry experiments illustrate that the ignition occurrence of an aged sheath is later than that of a new one under different incident heat fluxes. This work indicates that an aged sheath generally pyrolyzes and it combusts more weakly and incompletely.


Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1062 ◽  
Author(s):  
Junlei Chen ◽  
Jihui Wang ◽  
Aiqing Ni ◽  
Hongda Chen ◽  
Penglong Shen

In this work, a novel phosphorous–nitrogen based charring agent named poly(1,3-diaminopropane-1,3,5-triazine-o-bicyclic pentaerythritol phosphate) (PDTBP) was synthesized and used to improve the flame retardancy of high-density polyethylene (HDPE) together with ammonium polyphosphate (APP). The results of Fourier transform infrared spectroscopy (FTIR) and 13C solid-state nuclear magnetic resonance (NMR) showed that PDTBP was successfully synthesized. Compared with the traditional intumescent flame retardant (IFR) system contained APP and pentaerythritol (PER), the novel IFR system (APP/PDTBP, weight ratio of 2:1) could significantly promote the flame retardancy, water resistance, and thermal stability of HDPE. The HDPE/APP/PDTBP composites (PE3) could achieve a UL-94 V-0 rating with LOI value of 30.8%, and had a lower migration percentage (2.2%). However, the HDPE/APP/PER composites (PE5) had the highest migration percentage (4.7%), lower LOI value of 23.9%, and could only achieve a UL-94 V-1 rating. Besides, the peak of heat release rate (PHRR), total heat release (THR), and fire hazard value of PE3 were markedly decreased compared to PE5. PE3 had higher tensile strength and flexural strength of 16.27 ± 0.42 MPa and 32.03 ± 0.59 MPa, respectively. Furthermore, the possible flame-retardant mechanism of the APP/PDTBP IFR system indicated that compact and continuous intumescent char layer would be formed during burning, thus inhibiting the degradation of substrate material and improving the thermal stability of HDPE.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1251
Author(s):  
Yilin Liu ◽  
Bin Li ◽  
Miaojun Xu ◽  
Lili Wang

Ethylene vinyl acetate (EVA) copolymer has been used extensively in many fields. However, EVA is flammable and releases CO gas during burning. In this work, a composite flame retardant with ammonium polyphosphate (APP), a charring–foaming agent (CFA), and a layered double hydroxide (LDH) containing rare-earth elements (REEs) was obtained and used to improve the flame retardancy, thermal stability, and smoke suppression for an EVA matrix. The thermal analysis showed that the maximum thermal degradation temperature of all composites increased by more than 37 °C compared with that of pure EVA. S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA, and S-NdMgAl/APP/CFA/EVA could achieve self-extinguishing behavior according to the UL-94 tests (V-0 rating). The peak heat release rate (pk-HRR) indicated that all LDHs containing REEs obviously reduced the fire strength in comparison with S-MgAl. In particular, pk-HRR of S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA and S-NdMgAl/APP/CFA/EVA were all decreased by more than 82% in comparison with pure EVA. Furthermore, the total heat release (THR), smoke production rate (SPR), and production rate of CO (COP) also decreased significantly. The average mass loss rate (AMLR) confirmed that the flame retardant exerted an effect in the condensed phase of the composites. Meanwhile, the combination of APP, CFA, and LDH containing REEs allowed the EVA matrix to maintain good mechanical properties.


2016 ◽  
Vol 30 (2) ◽  
pp. 255-272 ◽  
Author(s):  
Xilei Chen ◽  
Lili Huo ◽  
Jianbo Liu ◽  
Chuanmei Jiao ◽  
Shaoxiang Li ◽  
...  

Flame-retardant polyurethane elastomers (PUEs) have been prepared using trichloroethyl phosphate (TCEP) as flame retardant. The combustion performances and thermal decomposition properties of PUEs were studied using cone calorimetry test and thermogravimetric analysis, respectively. Kissinger method and Flynn–Wall–Ozawa (FWO) method were adopted to discuss the pyrolysis kinetics of PUEs. The experimental results showed that TCEP has good flame-retardant effect for PUE. With the increase of TCEP, the peak heat release rate and total heat release values decrease. A good diagram of linear regression can be obtained from both Kissinger and FWO methods. The activation energy values of flam- retardant PUE can be calculated from FWO method at different conversion rates.


2014 ◽  
Vol 881-883 ◽  
pp. 863-866
Author(s):  
Chao Peng ◽  
Shi Bin Nie ◽  
Lei Liu ◽  
Qi Lin He ◽  
Yuan Hu ◽  
...  

Nanoporous nickel phosphates (VSB-1) was synthesized by hydrothermal method. Then VSB-1 was added to the ammonium polyphosphate and pentaerythritol system in polypropylene (PP) matrix.The synergistic effect of VSB-1 with intumescent flame retardants (IFR) was studied by cone calorimetry test. The results of cone calorimetry show that heat release rate peak (pHRR) and total heat release (THR) of intumescent flame retardant PP with 2wt% VSB-1 decrease remarkably compared with that of without VSB-1. The pHRR and THR decrease respectively from 1140 to 286.0 kW/m2, and from 96.0 to 63.2 MJ/m2.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4216
Author(s):  
Peixin Yang ◽  
Hanguang Wu ◽  
Feifei Yang ◽  
Jie Yang ◽  
Rui Wang ◽  
...  

In this study, a novel flame retardant (PMrG) was developed by self-assembling melamine and phytic acid (PA) onto rGO, and then applying it to the improvement of the flame resistance of PLA. PMrG simultaneously decreases the peak heat release rate (pHRR) and the total heat release (THR) of the composite during combustion, and enhances the LOI value and the time to ignition (TTI), thus significantly improving the flame retardancy of the composite. The flame retardant mechanism of the PMrG is also investigated. On one hand, the dehydration of PA and the decomposition of melamine in PMrG generate non-flammable volatiles, such as H2O and NH3, which dilute the oxygen concentration around the combustion front of the composite. On the other hand, the rGO, melamine, and PA components in PMrG create a synergistic effect in promoting the formation of a compact char layer during the combustion, which plays a barrier role and effectively suppresses the release of heat and smoke. In addition, the PMrGs in PLA exert a positive effect on the crystallization of the PLA matrix, thus playing the role of nucleation agent.


2019 ◽  
Vol 38 (1) ◽  
pp. 28-52 ◽  
Author(s):  
Alexander B Morgan ◽  
Vladimir Benin ◽  
Donald A Klosterman ◽  
Abdulhamid Bin Sulayman ◽  
Mustafa Mukhtar ◽  
...  

For structural composites used in vehicles and aircraft, flame retardant chemistries which enhance char formation and reduce heat release are preferred. Phosphorus-based and phosphorus–nitrogen flame retardants for epoxies have been well studied to date, but phosphorus hydrazides have not been studied for their flame-retardant potential in epoxy. These hydrazides offer some novel structures and they can potentially offer a combination of vapor and condensed phase flame retardant action. A series of eight compounds were systematically investigated in this study as reactive flame retardants in a bisphenol F epoxy/aliphatic amine resin system at a level of 2.5 wt% phosphorus. Results suggest that the phosphorus hydrazides react with the epoxy during thermal decomposition, and they also release nitrogen during flaming combustion of the epoxy matrix. The observed reactions resulted in increased char yields and reduced total heat release, while simultaneously lowering heat of combustion and total smoke release.


2012 ◽  
Vol 554-556 ◽  
pp. 110-114
Author(s):  
Da Ming Ban ◽  
Yang Min ◽  
Yong Hang Zhang ◽  
Ou Zhao

Two phosphorus-containing flame retardant (FR) were synthesized and incorporated in the backbone of polyamide 6(PA6) by polymerization. The structure and spectroscopic data of these flame retardant were determined by Fourier Transform Infrared Spectroscopy (FTIR) and Elemental analysis. Flame-retardancy and thermal property of PA6 modified with CEP, and MMP were examined by LOI and TGA. The LOI value of PA6 shows ascending trend by adding FRs, and it rise from 24 to 31%. TGA data revealed that FR improves thermal stability of PA6. The on-set temperature was added at least 20°C.


2011 ◽  
Vol 391-392 ◽  
pp. 200-203
Author(s):  
Xiao Ping Hu ◽  
Shao Xian Li ◽  
Liang Jun Li ◽  
Yu Yang Guo ◽  
Hui Min Heng ◽  
...  

The intumescent flame retardant poly-pentaerythritol diphosphonate dichloride- hexamethylendiamine (PSPHD) grafting sepiolite (PSPHD-SEP) and LDPE/PSPHD-SEP/IFR composites have been prepared. Cone calorimeter technique was employed to characterize the combustion behavior of LDPE/PSPHD-SEP/IFR composites. The results show that the peak and average heat release rates decreased significantly when 5% PSPHD-SEP was added in LDPE. The PSPHD-SEP can promote the char layer to form earlier and be more compact and increase the char residue yield. The compact char residue layer can prohibit the transfer of gas and heat during the burning, showing the improvement of flame retardance.


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