Flame Retardant Polyethylene with Intumescent System Containing Macromolecule-Encapsulated Low Molecular Weight Charring Agent

2007 ◽  
Vol 15 (7) ◽  
pp. 591-596 ◽  
Author(s):  
Meifang Liu ◽  
Xing Huang ◽  
Yuan Liu ◽  
Qi Wang

Intumescent flame retardants are important halogen-free products used in polyethylene. However, their thermal stability and water-resistance are major shortcomings. In this work, a composite charring agent, pentaerythritol (PER) encapsulated by thermoplastic polyurethane (TPU) was used in an intumescent system to improve the flame retardancy of high density polyethylene (HDPE). The encapsulation of macromolecular charring agent TPU can effectively suppress the esterification reaction of PER and acid source in the intumescent system during processing. It can also remarkably decrease the water absorption, thus producing flame retardant HDPE with high performance. The synergistic effects of other common flame retardants including melamine phosphate, melamine polyphosphate and ammonium polyphosphate with TPU-encapsulated PER, as well as the ratio of charring agent to acid source were investigated so as to determine the optimum formula for use in HDPE. The flame retardant HDPE can reach limiting oxygen index of 33 and achieve UL-94 V-0 rating at 3.2 mm thickness when the ratio of MP/composite charring agent is 2:1 w/w.

2019 ◽  
Vol 28 (3) ◽  
pp. 209-219 ◽  
Author(s):  
Na Wang ◽  
Lingtong Li ◽  
Yang Xu ◽  
Kun Zhang ◽  
Xiaolang Chen ◽  
...  

The flammability characterization and synergistic effects of red phosphorus masterbatch (RPM) with expandable graphite (EG) in flame-retardant polypropylene (PP)/thermoplastic polyurethane (TPU) composites are investigated by limiting oxygen index, UL-94 testing, cone calorimeter tests, thermal gravimetric analysis, Fourier transform infrared (FTIR), and scanning electron microscopy. The results show that the flame retardancy of PP/TPU/EG/RPM composites is greatly influenced by RPM. The synergistic effects between RPM and EG take place in the flame-retardant composites. The presence of RPM with EG decreases significantly the heat release rates and total heat release, and UL-94 V-0 rating is achieved when suitable amount of RPM substitutes for EG in the PP/TPU/EG/RPM composites. The T onset and T 10 wt% of the composites are improved because of the presence of RPM. The FTIR spectra show that the incorporation of RPM improves the thermo-oxidative stability of PP/TPU at higher temperatures. The morphological observations indicate the reinforcement of thermal stability, and flame-retardant performance is attributed to the compact and stable char layers promoted by RPM with EG acted as an effective heat barrier and thermal insulation.


2019 ◽  
Vol 17 (1) ◽  
pp. 980-987
Author(s):  
Ayşe Çetin ◽  
S.Gamze Erzengin ◽  
F. Burcu Alp

AbstractVarious combinations of zinc borate (ZB), alumina trihydrate (ATH) and magnesium hydroxide (MH) were used to retard the flammability of PVC composite. Flame retardancy of samples were investigated with limiting oxygen index (LOI) test. Further testing was achieved to expose the individual and synergistic effects of flame retardant additives on heat stability, Vicat softening temperature, fusion time, microstructure, mechanical and thermal characteristics. Microstructural and thermal analyses were performed by scanning electron microscopy and TG/DTA respectively. The LOI results showed that, high levels of ZB-ATH combination provided the highest LOI value of 53.4%. Although ZB and its combinations improved the fire performances of composites, they caused a small reduction at tensile strengths. When compared with plain PVC, flame retardant composites had better thermal stability. In addition to the advantages of ZB, when test results were evaluated with a holistic approach ZB-ATH-MH combination was understood to be an effective flame retardant alternative with this research.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1842 ◽  
Author(s):  
Chun Liu ◽  
Tieling Xing ◽  
Bingju Wei ◽  
Guoqiang Chen

The nano-silica sol was prepared by sol-gel method, and the boric acid, urea, cyanoguanidine, melamine cyanurate (MCA), 1-hydroxyethane 1,1-diphosphonic acid (HEDP), and 6H-dibenz (C,E) (1,2) oxaphosphorin-6-oxide (DOPO) were added to the silica sol to modify the flame retardant through physical doping and chemical bonding. According to the formula proposed by Lewin, the calculation of flammability parameters were obtained by the limiting oxygen index meter, the micro calorimeter, the vertical burner, and the thermogravimetric analyzer proved that there was a synergistic or additive effect between the B/N/P flame retardant and the silica sol. Fourier transform infrared (FT-IR) spectrum, scanning electron microscopy, and pyrolysis gas chromatography-mass spectrometry were used to characterize the morphology, structure, and pyrolysis products of treated silk fabric and residues after combustion. The results show that the flame retardancy of silica-boron sol is mainly caused by endothermic reaction and melt covering reaction. Silicon-nitrogen sol acts as a flame retardant through endothermic reaction, release of gases, and melting coverage. Silicon-phosphorus sol achieves flame retardancy by forming an acid to promote formation of a carbon layer and melting coverage. Silica sol and other flame retardants show excellent flame retardanty after compounding, and have certain complementarity, which can balance the dosage, performance, and cost of flame retardants, and is more suitable for industrial development.


1993 ◽  
Vol 11 (5) ◽  
pp. 442-456 ◽  
Author(s):  
Jun Zhang ◽  
Michael E. Hall ◽  
A. Richard Horrocks

This paper is the first in a series of four which investigates the burning behaviour and the influence of flame retardant species on the flam mability of fibre-forming polymer and copolymers of acrylonitrile. A pressed powdered polymer sheet technique is described that enables a range of polymer compositions in the presence and absence of flame retardants to be assessed for limiting oxygen index, burning rate and char residue deter minations. The method offers a rapid, reproducible and convenient means of screening possible flame retardant systems, and LOI values compare favourably with those of films and fabrics comprising the same polymeric type. Burning rates, however, are sensitive to changes in physical sample character such as form (film vs. powder sheet) and density. Thus the technique forms an excellent basis for the generation of burning data which will enable comprehensive studies of acrylic polymer flammability and flame retardancy to be undertaken.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1487 ◽  
Author(s):  
Sihao Yin ◽  
Xinlin Ren ◽  
Peichao Lian ◽  
Yuanzhi Zhu ◽  
Yi Mei

We applied black phosphorene (BP) and hexagonal boron nitride (BN) nanosheets as flame retardants to waterborne polyurethane to fabricate a novel black phosphorus/boron nitride/waterborne polyurethane composite material. The results demonstrated that the limiting oxygen index of the flame-retarded waterborne polyurethane composite increased from 21.7% for pure waterborne polyurethane to 33.8%. The peak heat release rate and total heat release of the waterborne polyurethane composite were significantly reduced by 50.94% and 23.92%, respectively, at a flame-retardant content of only 0.4 wt%. The superior refractory performances of waterborne polyurethane composite are attributed to the synergistic effect of BP and BN in the gas phase and condensed phase. This study shows that black phosphorus-based nanocomposites have great potential to improve the fire resistance of polymers.


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.


2014 ◽  
Vol 1033-1034 ◽  
pp. 931-936
Author(s):  
Cong Yan Chen ◽  
Rui Lan Fan ◽  
Guan Qun Yun

A novel intumescent flame retardant (IFR) containing ferrocene and caged bicyclic phosphate groups, 1-oxo-4-[4'-(ferrocene carboxylic acid phenyl ester)] amide-2, 6, 7-trioxa-1-phosphabicyclo- [2.2.2] octane (PFAM), was successfully synthesized. The synthesized PFAM were added to flammable polyurethane (PU) as flame retardants and smoke suppressants. The structure of PFAM was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR) and elemental analysis. Thermal stability of PFAM was tested by themogravimetric analysis (TGA). The results revealed that PFAM had good thermal stability and high char weight, the char weight up to 54% at 600 °C. Flammability properties of PU/PFAM composites were investigated by limiting oxygen index (LOI) test and UL-94 test, respectively. The results of LOI tests showed that the addition of PFAM enhanced flame retardancy of PU. When the content of PFAM reaches to 3%, the LOI value is 22.2. The morphologies of the char for PU and PU/3% PFAM composite can be obtained after LOI testing were examined by SEM. The results demonstrated that PFAM could promote to form the compact and dense intumescent char layer. Experiments showed that, the PFAM application of polyurethane showed positive effect.


2020 ◽  
Vol 38 (6) ◽  
pp. 485-503
Author(s):  
Benjamin Tawiah ◽  
Bin Yu ◽  
Anthony Chun Yin Yuen ◽  
Bin Fei

The demand for environmentally benign flame retardants for biodegradable polymers has become particularly necessary due to their inherently “green” nature. This work reports intrinsically non-toxic polydopamine (PDA) particles as an efficient and environmentally friendly flame retardant for polylactic acid (PLA). 5 wt% PDA loading resulted in a 22% reduction in the peak heat release rate, 34.7% increase in the fire performance index, and lower CO2 production compared to neat PLA. A limiting oxygen index (LOI) value of 27.5% and a V-2 rating was achieved in the UL-94 vertical burning test. Highly aggregated amorphous particulate char was formed with the increasing content of PDA, and a significant reduction in evolved pyrolysis gaseous products was achieved for the PLA/PDA composites as compared with control PLA. This work provides important insight into the potential commercial application of PDA alone as an efficiently green, environmentally benign flame retardant for bioplastic PLA.


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.


Sign in / Sign up

Export Citation Format

Share Document