scholarly journals Poly(ether imide)/Epoxy Foam Composites with a Microcellular Structure and Ultralow Density: Bead Foam Fabrication, Compression Molding, Mechanical Properties, Thermal Stability, and Flame-Retardant Properties

ACS Omega ◽  
2020 ◽  
Vol 5 (40) ◽  
pp. 25784-25797
Author(s):  
Junjie Jiang ◽  
Weiwei Feng ◽  
Dan Zhao ◽  
Wentao Zhai
2021 ◽  
Author(s):  
Yajun Chen ◽  
Jingxiu He ◽  
Zhe Sun ◽  
Bo Xu ◽  
Juan Li ◽  
...  

Abstract Cellulose nanocrystals (CNCs) have been used as bio-based carbon source in intumescent system. However, CNCs have the disadvantages of low onset decomposition temperature and decompose and carbonize during processing. We, herein, demonstrated the design of phosphazene-containing CNCs (P/N-CNCs) with great thermal stability and outstanding charring ability. The TGA results showed that the initial decomposition temperature of P/N-CNCs was increased from 202.4 ℃ to 272.2 ℃ (increased by 34.5%), and the residual char at 700 ℃ was increased from 24.9 wt% to 55.8 wt% compared with CNCs. Then, flame retardant PLA composites were prepared by blending PLA, P/N-CNCs with ammonium polyphosphate (APP), melamine (MPP), aluminum hypophosphite (AHP) and piperazine pyrophosphate (PPAP), respectively. The thermal stability, flame retardant properties and mechanical properties of PLA composites were investigated. The results showed that the flame retardant system constructed by 7 wt% APP and 3 wt% P/N-CNCs had the best effect in PLA. PLA/7APP/3P/N-CNCs had the highest limit oxygen index value (28.1%), the lowest peak heat release rate (266 kW/m2) and reached UL 94 V-0 rating. Moreover, the tensile strength, impact strength and elongation at break of PLA/7APP/3P/N-CNCs were increased by 7.3%, 18.6% and 29.4%, respectively, compared with these properties of PLA/7APP/ 3CNCs. This work provides a new idea for the design of CNCs with great thermal stability and outstanding charring ability, and offers a new method for the preparation of high-performance flame-retardant PLA composites.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1562
Author(s):  
Yunxian Yang ◽  
De-Yi Wang ◽  
Laia Haurie ◽  
Zhiqi Liu ◽  
Lu Zhang

Some crop by-products are considered to be promising materials for the development of novel biobased products for industrial applications. The flammability of these alternatives to conventional materials is a constraint to expanded applications. Polylactide (PLA) composites containing a combination of oxidized corn pith fiber (OCC) and a biobased flame retardant (PA-THAM) have been prepared via an in situ modification method. SEM/EDS, FTIR and TGA were performed to establish that PA-THAM was coated onto the surface of OCC. The mechanical properties, thermal stability and fire behavior of PLA-based biocomposites were investigated. The incorporation of 5 phr PA-THAM imparted biocomposite good interfacial adhesion and increased decomposition temperature at 10% mass loss by 50 °C. The flame retardant properties were also improved, as reflected by an increased LOI value, a UL-94 V-2 rating, reduction of PHRR, and increased formation of char residue. Therefore, the introduction of 5 phr PA-THAM can maintain a good balance between flame retardancy and mechanical properties of this PLA/OCC system.


2011 ◽  
Vol 393-395 ◽  
pp. 1012-1017 ◽  
Author(s):  
Yu Feng Ma ◽  
Wei Zhang ◽  
Ling Li ◽  
Ming Ming Zhang ◽  
Zeng Hui Cheng ◽  
...  

New composite foams were prepared by co-foaming of Melamine-Urea-Formaldehyde (MUF) resin and wood fiber in the closed mould at 70°C. The effects of amount of wood fiber on mechanical properties, brittleness, flame-retardant, insulation and microscopic structures of wood fiber-MUF foam were investigated. Results indicated that the flame-retardant properties increased, and the brittleness and mechanical properties decreased with the increase of the amount of wood fiber in composite foams. The addition of wood fiber resulted in more uniform cell size distribution and irregular cell shape, but had little effect on insulation properties.


2012 ◽  
Vol 125 (2) ◽  
pp. 1219-1225 ◽  
Author(s):  
Yuan-Qin Xiong ◽  
Xu-Yong Zhang ◽  
Jia Liu ◽  
Ming-Ming Li ◽  
Fei Guo ◽  
...  

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.


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.


2019 ◽  
Vol 2019 ◽  
pp. 1-25 ◽  
Author(s):  
Shaolin Lu ◽  
Wei Hong ◽  
Xudong Chen

Polymer materials are ubiquitous in daily life. While polymers are often convenient and helpful, their properties often obscure the fire hazards they may pose. Therefore, it is of great significance in terms of safety to study the flame retardant properties of polymers while still maintaining their optimal performance. Current literature shows that although traditional flame retardants can satisfy the requirements of polymer flame retardancy, due to increases in product requirements in industry, including requirements for durability, mechanical properties, and environmental friendliness, it is imperative to develop a new generation of flame retardants. In recent years, the preparation of modified two-dimensional nanomaterials as flame retardants has attracted wide attention in the field. Due to their unique layered structures, two-dimensional nanomaterials can generally improve the mechanical properties of polymers via uniform dispersion, and they can form effective physical barriers in a matrix to improve the thermal stability of polymers. For polymer applications in specialized fields, different two-dimensional nanomaterials have potential conductivity, high thermal conductivity, catalytic activity, and antiultraviolet abilities, which can meet the flame retardant requirements of polymers and allow their use in specific applications. In this review, the current research status of two-dimensional nanomaterials as flame retardants is discussed, as well as a mechanism of how they can be applied for reducing the flammability of polymers.


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