scholarly journals Synergistic Flame-Retardant Mechanism of Dicyclohexenyl Aluminum Hypophosphite and Nano-Silica

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1211 ◽  
Author(s):  
Heng Zhang ◽  
Junliang Lu ◽  
Hongyan Yang ◽  
Heng Yang ◽  
Jinyan Lang ◽  
...  

The flame retardant dicyclohexenyl aluminum hypophosphite (ADCP) and nano-silica are added to PA66 to improve flame retardant property of the composite. The flame-retardant property of the composite is tested via oxygen index test, vertical burning test, and cone calorimetry test. Combustion residues are tested using scanning electron microscopy, EDS spectroscopy, and Fourier infrared analysis. Results show that flame-retardant ADCP can effectively promote the formation of a porous carbon layer on the combustion surface of PA66. Nano-silica easily migrates to the material surface to improve the oxidation resistance of the carbon layer and the density of the carbon layer’s structure. It can also effectively prevent heat, flammable gases, and oxygen from entering the flame zone and enhance the flame retardant properties of ADCP.

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 430
Author(s):  
Kai Xu ◽  
Xing Tian ◽  
Ying Cao ◽  
Yaqi He ◽  
Yanzhi Xia ◽  
...  

Calcium alginate (Ca-Alg) fibers are renewable fibers obtained from the ocean with essential flame retardancy, which have recently been applied as components of flame-retardant paper. However, the application of Ca-Alg fibers is limited because of their tendency to smolder. Therefore, composites papers were fabricated by blending using flame-retardant polyamide-66 (FR-PA), with a 5 wt% content of phosphorous flame retardant, which will form molten carbon during combustion. When the FR-PA content is 30% of the composite paper, FR-PA forms a compact carbon layer on the surface of the Ca-Alg fibers during combustion, which isolates the mass/heat transfer and effectively suppresses the smoldering of Ca-Alg. This consists of a condensed flame retardant mechanism. Furthermore, the combustion and thermal degradation behavior of paper were analyzed by cone calorimetry (CONE), TG and TG-IR. Ca-Alg in the composite paper decomposed and released CO2 before ignition, which delayed the ignition time. Simultaneously, the FR-PA contained in the composite paper effectively inhibited the combustion of volatile combustibles in the gas phase. Overall, FR-PA and Ca-Alg improve the thermal stability of the composite paper in different temperature regions under air atmosphere. Ca-Alg reduces the formation of aromatic products and NH3 in the composite paper under N2 atmosphere. Ca-Alg-based paper with excellent flame retardancy was successfully prepared.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 479 ◽  
Author(s):  
Lu Fang ◽  
Xizhen Lu ◽  
Jian Zeng ◽  
Yingyi Chen ◽  
Qiheng Tang

To improve the flame-retardant performance of bamboo fiber (BF) reinforced polypropylene (PP) composites, melamine pyrophosphate (MPP) and aluminum hypophosphite (AP) at a constant mass ratio of 2:1 were added. The influence of the MPP/AP mass fraction on the mechanical and flame-retardant properties of the BF reinforced PP composites were evaluated by mechanical testing, limiting oxygen index (LOI) and cone calorimetry. Mechanical tests demonstrate that tensile properties of BF/PP decreased with the increase of MPP/AP mass fraction, while flexural properties of composites exhibited very different tendencies. Both flexural strength and modulus increased slightly with the addition of MPP/AP at first, and then decreased significantly after a relatively high content of MPP/AP was loaded. This was due to the poor interfacial compatibility between PP and MPP/AP. The flame retardancy of BF/PP composites has been greatly improved. When 30% MPP/AP was loaded into the composites, the LOI increased to 27.2%, which was 42.4% higher than that of the composite without flame retardant addition. Cone calorimetry results indicated that MPP/AP worked in both gas and condensed phases during the combustion process. Peak heat release rate, total smoke production and mass loss of the composites were significantly reduced because of the addition of MPP/AP.


2010 ◽  
Vol 123-125 ◽  
pp. 1259-1262
Author(s):  
Chen Feng Kuan ◽  
Shu Wei Hsu ◽  
Wei Jen Chen ◽  
Yi Luen Li ◽  
Chia Hsun Chen ◽  
...  

Polypropylene (PP) has the disadvantage of flammability and easy dripping, flame retardant was incorporated into polymer to improve the thermal and flame retardant property. Conventional flame retardant containing halogen would release toxic gases when the materials got fire and let the people died in the fire and destroy the environment. Intumenscent flame retardant consists of three key components: acid source, carbon source and blowing agent. Acid source is phosphoric acid, which can dehydrate the materials. Carbon source can form char layer to prevent further thermal degradation. The blowing agent can swell the carbon layer to avoid heat and mass transfer during material get fire. Novel intumenscent flame retardant which contains phosphorus and nitrogen was successfully prepared. FTIR, TGA, LOI and UL-94 were used to characterize the structure, flame retardant mechanism and thermal property of the composites. LOI and UL-94 data showed the composites possess excellent flame retardant property. For kinetic of thermal degradation.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1286
Author(s):  
Kyung-Who Choi ◽  
Jun-Woo Kim ◽  
Tae-Soon Kwon ◽  
Seok-Won Kang ◽  
Jung-Il Song ◽  
...  

The use of halogen-based materials has been regulated since toxic substances are released during combustion. In this study, polyurethane foam was coated with cationic starch (CS) and montmorillonite (MMT) nano-clay using a spray-assisted layer-by-layer (LbL) assembly to develop an eco-friendly, high-performance flame-retardant coating agent. The thickness of the CS/MMT coating layer was confirmed to have increased uniformly as the layers were stacked. Likewise, a cone calorimetry test confirmed that the heat release rate and total heat release of the coated foam decreased by about 1/2, and a flame test showed improved fire retardancy based on the analysis of combustion speed, flame size, and residues of the LbL-coated foam. More importantly, an additional cone calorimeter test was performed after conducting more than 1000 compressions to assess the durability of the flame-retardant coating layer when applied in real life, confirming the durability of the LbL coating by the lasting flame retardancy.


2019 ◽  
Vol 37 (2) ◽  
pp. 137-154 ◽  
Author(s):  
Xi Cheng ◽  
Jianming Wu ◽  
Yulin Li ◽  
Chenguang Yao ◽  
Guisheng Yang

Aluminum hypophosphite combined with melamine cyanurate and poly(phenylene oxide) was applied to flame-retard TPE-S system (blends of SEBS and polyolefin). The flame-retardant properties of the TPE-S/AHP/MCA/PPO were investigated by LOI and vertical burning test (UL-94). The results indicated that TPE-S containing 16 wt% AHP, 20 wt% MCA, and 10 wt% PPO reached a V-0 rating in the UL-94 test, and its LOI value was 28.2%. It performed well in the cone calorimeter (reduction in peak heat release rate from 2001 to 494 kW m−2). Thermogravimetric-Fourier transform infrared spectroscopy tests showed that AHP and MCA acted in gaseous phase, while AHP and PPO helped to form char residue. The SEM graphs demonstrated that continuous and compact films cover bubbles of the char layer in TPE-S/AHP/MCA/PPO. The proposed flame-retardant mechanisms of such systems were summarized.


2017 ◽  
Vol 41 (8) ◽  
pp. 983-992 ◽  
Author(s):  
Shenghui Tian ◽  
Hui He ◽  
Dekang Wang ◽  
Peng Yu ◽  
Yunchao Jia ◽  
...  

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 13 ◽  
Author(s):  
Rosica Mincheva ◽  
Hazar Guemiza ◽  
Chaimaa Hidan ◽  
Sébastien Moins ◽  
Olivier Coulembier ◽  
...  

In this study, a highly efficient flame-retardant bioplastic poly(lactide) was developed by covalently incorporating flame-retardant DOPO, that is, 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide. To that end, a three-step strategy that combines the catalyzed ring-opening polymerization (ROP) of L,L-lactide (L,L-LA) in bulk from a pre-synthesized DOPO-diamine initiator, followed by bulk chain-coupling reaction by reactive extrusion of the so-obtained phosphorylated polylactide (PLA) oligomers (DOPO-PLA) with hexamethylene diisocyanate (HDI), is described. The flame retardancy of the phosphorylated PLA (DOPO-PLA-PU) was investigated by mass loss cone calorimetry and UL-94 tests. As compared with a commercially available PLA matrix, phosphorylated PLA shows superior flame-retardant properties, that is, (i) significant reduction of both the peak of heat release rate (pHRR) and total heat release (THR) by 35% and 36%, respectively, and (ii) V0 classification at UL-94 test. Comparisons between simple physical DOPO-diamine/PLA blends and a DOPO-PLA-PU material were also performed. The results evidenced the superior flame-retardant behavior of phosphorylated PLA obtained by a reactive pathway.


2017 ◽  
Vol 52 (10) ◽  
pp. 1295-1303 ◽  
Author(s):  
Yijiao Xue ◽  
Mingxia Shen ◽  
Fengling Lu ◽  
Yongqin Han ◽  
Shaohua Zeng ◽  
...  

To improve the flame resistance of polystyrene, three kinds of organophilic heterionic montmorillonites (Na-montmorillonite, Ca-montmorillonite, and Fe-montmorillonite) reinforced polystyrene nanocomposites were prepared by melt dispersion method. The structure and composition of the organo montmorillonites were characterized by using X-ray diffraction and Fourier-transform infrared analysis. The adhesion between organo montmorillonites and polystyrene was investigated by scanning electron microscopy. The flame resistance and thermal stability of the polystyrene/organo montmorillonites were evaluated by cone calorimeter test and thermogravimetric analysis. The interlayer space of organo montmorillonites increased with the increase of the oxidation state of the cations. With the addition of organo montmorillonites, the peak values of all the flame resistance indexes of the polystyrene/organo montmorillonites nanocomposites decreased, among which the PHRR values have decreased the most, compared with those of polystyrene. Their corresponding test times have all been delayed following almost precisely the same trend. Therefore, their flame retardant ability come from their lamellated structures, their charring forming abilities, and the reducing power of Fe3+ in polystyrene/Fe-montmorillonite. Organo montmorillonites mainly act as a kind of intumescent flame retardants. The flame resistance of polystyrene/Na-montmorillonite nanocomposite was the best, and the polystyrene/Ca-montmorillonite came second, which is slightly better than that of polystyrene/Fe-montmorillonite.


RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49143-49152 ◽  
Author(s):  
Ningjing Wu ◽  
Zhaoxia Xiu

Silicone-microencapsulated aluminum hypophosphite (SiAHP) improved effectively the flame retardancy and significantly enhanced the notched impact strength of ABS/SiAHP composites.


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