scholarly journals Flame-Retardant Polyamide Powder for Laser Sintering: Powder Characterization, Processing Behavior and Component Properties

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1697
Author(s):  
Kevin Schneider ◽  
Katrin Wudy ◽  
Dietmar Drummer
Keyword(s):  
Flame Retardant ◽  
Flame Retardants ◽  
Matrix Material ◽  
Laser Sintering ◽  
Polyamide 12 ◽  
The Matrix ◽  
Process Behavior ◽  
Halogen Free ◽  
Polyamide Powder ◽  
First Time

Up to now, laser-sintered components have been barely used by industries such as aerospace and transport industry due to high flammability. By the use of flame retardants, the flammability of laser-sintered parts should be reduced to extend their range of possible applications. This paper aims to investigate the influence of halogen-free phosphinate-based flame retardants on process-relevant characteristics and process behavior, as well as mechanical and physical properties. Most importantly, the flammability of the material should be reduced. Two different types of phosphinate-based fillers were used in a concentration between 10 and 25 wt % in combination with the matrix material polyamide 12 (PA12). Thermal, optical, and powder properties of the mixtures were analytically investigated. Furthermore, the mechanical characterization of the sintered specimen was carried out. The addition of filler in laser sintering changes the process behavior and properties of the component. With this investigation, the correlation among flame retardants, process-relevant characteristics, process behavior, and resulting part properties was derived for the first time. Finally, a mixture of 15–20 wt % of flame retardant leads to the best trade-off between flame retardancy and mechanical properties.

scholarly journals Selective laser sintering of copper filled polyamide 12: Characterization of powder properties and process behavior

2018 ◽  
Vol 40 (5) ◽  
pp. 1801-1809 ◽  
Author(s):  
Lydia Lanzl ◽  
Katrin Wudy ◽  
Sandra Greiner ◽  
Dietmar Drummer
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12 ◽  
Process Behavior ◽  
Powder Properties

scholarly journals Self-Extinguishing Resin Transfer Molding Composites Using Non-Fire-Retardant Epoxy Resin

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2554 ◽  
Author(s):  
Zhi Geng ◽  
Shuaishuai Yang ◽  
Lianwang Zhang ◽  
Zhenzhen Huang ◽  
Qichao Pan ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Flame Retardants ◽  
Resin Transfer Molding ◽  
Fire Retardant ◽  
Functional Materials ◽  
Building Blocks ◽  
Fire Retardancy ◽  
Limiting Oxygen Index ◽  
Transfer Molding ◽  
Halogen Free

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.

Preparation and Properties of Halogen-Free Flame Retardant Polyurethane Foams

2011 ◽  
Vol 418-420 ◽  
pp. 540-543 ◽  
Author(s):  
Ding Meng Chen ◽  
Yi Ping Zhao ◽  
Jia Jian Yan ◽  
Li Chen ◽  
Zhi Zhi Dong ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Flame Retardants ◽  
Oxygen Index ◽  
Mechanical Analysis ◽  
Polyurethane Foams ◽  
Dimethyl Methylphosphonate ◽  
Limiting Oxygen Index ◽  
Layer Composite ◽  
Halogen Free ◽  
Thermal Stable

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.

scholarly journals Chain Extension and Synergistic Flame-Retardant Effect of Aromatic Schiff Base Diepoxide on Polyamide 6/Aluminum Diethylphosphinate Composites

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2217 ◽  
Author(s):  
Tianxiang Liang ◽  
Jianan Cai ◽  
Shumei Liu ◽  
Hualin Lai ◽  
Jianqing Zhao
Keyword(s):  
Schiff Base ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Polyamide 6 ◽  
Chain Extension ◽  
Cone Calorimetry ◽  
The Matrix ◽  
Flame Retarded ◽  
Ul 94 ◽  
Synergistic Flame Retardant

A way to suppress the deterioration in mechanical properties of polyamide 6 (PA6) is required, especially with high loading of flame retardants in the matrix. In this study, a novel aromatic Schiff base diepoxide (DES) was synthesized. It exhibited an efficient chain extension effect on PA6 and a synergistic flame-retardant effect with aluminum diethylphosphinate (AlPi) for PA6. The PA6 composite with 16 wt.% AlPi only passed UL-94 V-0 rating at 1.6 mm thickness, while the combination of 1.5 wt.% DES with 13 wt.% AlPi induced PA6 to achieve a UL-94 V-0 rating at 0.8 mm thickness. The tensile, flexural, and Izod notched impact strengths were increased by 16.2%, 16.5%, and 24.9%, respectively, compared with those of V-0 flame-retarded PA6 composites with 16 wt.% AlPi. The flame-retarded mechanism of PA6/AlPi/DES was investigated by cone calorimetry and infrared characterization of the char residues and pyrolysis products. These results showed that DES had a synergistic effect with AlPi in condensed-phase flame retardation by promoting the production of aluminum phosphorus oxides and polyphosphates in the char residues.

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
Keyword(s):  
Natural Rubber ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Epoxidized Natural Rubber ◽  
Standard Type ◽  
Limiting Oxygen Index ◽  
The Usa ◽  
The Difference ◽  
Flame Retardant Properties ◽  
Halogen Free

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.

scholarly journals Selective laser sintering of polyamide 12/flame retardant compositions

2020 ◽  
Vol 181 ◽  
pp. 109318
Author(s):  
Marcos Batistella ◽  
Arnaud Regazzi ◽  
Monica Francesca Pucci ◽  
José-Marie Lopez-Cuesta ◽  
Ouassila Kadri ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12

scholarly journals Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3901 ◽  
Author(s):  
Markwart ◽  
Battig ◽  
Velencoso ◽  
Pollok ◽  
Schartel ◽  
...  
Keyword(s):  
Epoxy Resins ◽  
Chemical Structure ◽  
Flame Retardants ◽  
Complex Shape ◽  
Current Trend ◽  
Polymeric Materials ◽  
The Matrix ◽  
Decomposition Pathway ◽  
Halogen Free ◽  
Phase Activity

The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs.

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