Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6

Yuan

Polymers for Advanced Techs

et al. 2019

To achive excellent fire resistance, new microcapsule flame retardants (DMCAD and DMPPD) were prepared using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide combined with melamine cyanurate or melamine polyphosphate as the shell material and diatomite as the core material. The successful assembly of DMCAD and DMPPD was detailed characterized by Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Meanwhile, the flame retardancy and thermal stability of the unsaturated polyester resin (UPR)/DMCAD and UPR/DMPPD composites were also studied. The addition of DMCAD and DMPPD effectively improves the flame retardance properties of UPR, and the effect of DMPPD was better. The limiting oxygen index (LOI) of UPR/DMPPD-3 increased by 11.6% when compared with that of UPR, and the sample achieved V-0 rating. Moreover, the peak heat release rate (pHRR) and the total heat release (THR) rate of UPR/DMPPD-3 were reduced by 67% and 26%, respectively. Under nitrogen condition and air condition, UPR/DMPPD showed better thermal stability and char-forming ability from the thermogravimetric (TG) results. Residual char of the UPR composites was systematically analyzed with SEM and XPS. Finally, the flame retardant mechanism of DMPPD was proposed. K E Y W O R D S diatomite, flame retardancy, microencapsulation, unsaturated polyester resin 1 | INTRODUCTION Unsaturated polyester resin (UPR) is widely used in transportation,chemical production, construction, sports, clothing, and other fields because of its convenient processing, low raw material cost, good water and chemical resistance, etc. 1-3 However, wider application of UPR is limited due to its extremely flammable properties during combustion. Therefore, improving the flame retardancy of UPR can further expand its application. In the last decades, halogen-based flame retardants have been widely applied but their pollution and toxicity limit their large-scale application. 4 Presently, environmentally halogen-free flame retardants have attracted widespread attention. In particular, the phosphorus and phosphorus-nitrogen containing flame retardants are mainly used as intumescent flame retardants (IFRs), which produce fewer toxic gases and smoke than halogen-based flame retardants. 5,6 Melamine (Mel) and its derivatives are promising candidates, for they are effective, economical, and environmentally friendly. Mel cyanurate (MCA) is a popular Mel-based flame retardant, which has significant advantages for its low cost, high nitrogen content, noncorrosiveness, and nontoxicity. 7 The nitrogen-containing inert gas generated by MCA during combustion can effectively dilute

Section: Resultsmentioning

confidence: 96%

Fabrication of diatomite‐based microencapsulated flame retardant and its improved fire safety of unsaturated polyester resin

Yuan

Polymers for Advanced Techs

et al. 2019

“…Heat hazard is an important parameter in a fire. MCC test took a convenient and efficient method, using only a few milligrams of the sample to evaluate the combustion properties of the polymer under controlled conditions . The heat release rates (HRRs) of the samples were shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Fire‐safe agent integrated with oyster shell and melamine polyphosphate for thermoplastic polyurethane

Polymers for Advanced Techs

Zhang

Wang

et al. 2019

At present, thermoplastic polyurethane (TPU) is widely used, but there are still many defects in fire safety, such as burning with heavy smoke and dripping. In this article, OS@MP was synthesized by modifying oyster shell (OS) powder with melamine polyphosphate (MP) and then served as fire‐safe agent for TPU. The fire performance of TPU composites were investigated using microscale combustion colorimeter (MCC), cone calorimeter test (CCT), smoke density test (SDT), and thermogravimetric analysis/Fourier transform infrared (TG‐FTIR) spectrum analysis. The MCC and CCT results revealed that OS@MP could reduce the fire hazards of TPU composites. The peak heat release rate (pHRR) of the sample with 10.0 wt% OS@MP decreased to 170.86 kW/m2 from 1772.37 kW/m2 for pure TPU. And, the SDT results showed that OS@MP could significantly reduce the smoke production of TPU composites. The TG‐FTIR also confirmed that the noncombustible gases (including CO2, ammonia, and water vapor) produced by OS@MP have played a reinforcing role in TPU composites as well as a char formed on the surface of composites, which could act as a barrier to prevent the heat and air, reinforce the fire safety of TPU.

“…Although AHP is a halogen free-flame retardant, it can release phosphine during its thermal or impact decomposition which can ignite itself in air. In order to prevent the spontaneous flammability of decomposed AHP, the microencapsulated technique was applied [69]. Through this method AHP was microencapsulated by MCA.…”

Section: Inorganic-based Flame Retardantsmentioning

confidence: 99%

Halogen-free flame retardants for application in thermoplastics based on condensation polymers

et al. 2019

Future materials in the field of thermoplastics require a lower impact on the environment. Actual thermoplastic materials also require "greener" additives for thermal and fire resistance profile. In this work, some of the recent solutions for halogen-free flame retardants were discussed in the context of viable routes with economical and industrial relevance. The fire retardant mechanism was discussed in order to imagine new solutions for future additives. Some of the main (inorganic, organic or hybrid) flame retardants can be used as common platform for the next classes of thermoplastic composites (synthetic, natural, or bio-based). The new generation of flame retardants (based on the emerging solutions) will have to surpass two major barriers: the cost effectiveness and the need for high concentration (which usually affects other properties).