Flame Retardation Performances of Novel Aryl Cyclic Phosphorus Flame Retardants When Applied to Highly Flammable Polymers

DongQuy Hoang,김진환 한국고분자학회 2013 Macromolecular Research Vol.21 No.2

A series of novel aryl cyclic phosphorus flame retardants (FR) has been synthesized in order to investigate their flame retarding performances for acrylonitrile-butadiene-styrene copolymer (ABS). They were synthesized in an attempt to obtain UL-94 V-0 rating when added to ABS as a single component FR. The fire behaviors and thermal stabilities of these compounds were investigated by micro calorimeter, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). V-0 ratings are achieved at 20-30 wt% loadings of FR. FTIR results reveal that a part of the combusted phosphorus compound generates phosphorus volatiles, which are radical capturing species and actively quench the flame. The rest of the phosphorus compounds which are not volatile contribute to the formation of the residual char, which acts as a barrier layer protecting the intact portion of the ABS/FR mixture from further combustion. The evidence of interaction between FR and ABS can be obtained by observing the difference in the thermal behaviors of experimental determined and the calculated TGA thermograms. The presence of FR enhances the thermal stability significantly as well as decreases the peak heat release rate (PHRR) and total heat release (THR). This suggests that there is a considerable amount of contribution from the condensed phase action of FR although the gas phase action is dominant.

Flame-Retarding Behaviors of Novel Spirocyclic Organo-Phosphorus Compounds Based on Pentaerythritol

DongQuy Hoang,김진환 한국고분자학회 2015 Macromolecular Research Vol.23 No.7

In order to find effective flame retardant for charrable polycarbonate (PC) and non-charrable acrylonitrilebutadiene- styrene copolymer (ABS), a series of novel organo-phosphorus compounds derived from 4-(hydroxymethyl)- 1-oxido-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (HPO) flame retardant (FR) were synthesized and their flame retardancies were investigated for the mixtures containing PC or ABS. The successful synthesis of high purity FRs was verified by spectroscopic analysis, 1H and 31P nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR). In an attempt to provide a basis to understand the flame retardancy behaviors of synthesized FRs, various other techniques such as thermal analysis and micro-scale calorimetry were employed. The flame retardancies were determined by UL-94 vertical test methods. The results show that V-0 ratings are achieved at 3-5 wt% loadings of FR for PC and V-1 rating at 30 wt% for ABS. This big difference is believed to be resulted from the fact that the main mechanism of flame retardancy is based on the condensed phase in the case of PC. Nevertheless, effective gas phase acting FR is needed for ABS containing mixtures. Both peak heat release rate obtained from micro-calorimeter experiments and the decomposition activation energy determined from differential scanning calorimetry (DSC) results are greatly reduced for the PC/FR mixtures, indicating that a stable insulating barrier is formed between fire and charrable PC containing substrate. On the other hand, ABS is a non-charrable polymer and the flame retardant acting in the gas phase is more desirable. The findings obtained in this study clearly implies that it would not be easy to find a promising phosphorus based FR which is good not only in flame retardancy but also in other properties such as hydrolytic and thermal stability for non-charrable polymer like ABS.

Organo-Phosphorus Flame Retardants for Unsaturated Polyester Derived from Recycled Poly(ethylene terephthalate)

DongQuy Hoang,ThuHien Nguyen,Haiyan An,김진환 한국고분자학회 2016 Macromolecular Research Vol.24 No.6

In an attempt to suppress the flammability of unsaturated polyesters (RUP) derived from recycled poly(ethylene terephthalate) (PET) and investigate the relationship between flame retardant (FR) chemical structures and their flame retardancy, RUP was incorporated with four organo-phosphorus FRs; triphenyl phosphate (TPP), aluminum hydrogen phosphonate (AHP), diammonium hydrogen phosphate (DAP), and aluminum diethyl phosphinate (OP). The effects of adding FR with regard to the thermal stability of RUP/FR mixtures were investigated via thermogravimetric analysis (TGA). The chemical structure of FR and its mixtures with RUP were determined via FTIR and X-ray photoelectron spectroscopy (XPS). The morphology of the residual char was investigated using a field emission scanning electron microscope (FE-SEM). Flame retardancies were evaluated by a UL-94 vertical test and limiting oxygen index (LOI) measurements. The results indicated that the presence of FR significantly improved the flame retardancy and thermal stability of RUP. LOI values increased from 20 to 28 and V-0 ratings were obtained with an 8 wt% FR loading for DAP and with a 10 wt% FR loading for OP. In contrast, no ratings were recorded for the mixture containing 30 wt% of TPP or AHP. These findings clearly indicate that the efficiency of a phosphorus-based FR depends on the quantity of phosphorus elements within the FR itself, although interactions of the FR with the target polymer should also be accounted for when determining its effectiveness as a FR.

Flame Retardancies of Novel Organo-Phosphorus Flame Retardants Based on DOPO Derivatives When Applied to ABS

DongQuy Hoang,김진환,김우중,Haiyan An 한국고분자학회 2015 Macromolecular Research Vol.23 No.5

A series of novel organo-phosphorus flame retardants (FR) derived from 9,10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide (DOPO) have been synthesized in order to investigate their flame retarding performances for acrylonitrile-butadiene-styrene copolymer (ABS). The success of synthesis was confirmed by 1H and 31P NMR. The flame retardancy performances evaluated by UL-94V test revealed that V-0 ratings are achieved when 27.5-30.0 wt% of FRs are added to the ABS/FR mixtures. The most dominating factors affecting the flame retardancy of phosphorus containing FR are the phosphorus (P) content in the mixture and the chemical structure of FR incorporated. It was found that 4.86-5.05 wt% P in the formulation is required to exhibit self-extinguishing ability when phosphinate or phophonate FRs are employed. On the other hand, no rating is obtained for phosphate type FR containing mixture even though higher amount of P, that is, 5.07 wt% is present in the mixture, indicating that oxidation state of the phosphorus element in FR is very important in governing the flame retardancy. The modes of actions of FRs in terms of gas versus condensed phase are also discussed. Thermogravimetric analysis (TGA) results showed that the FR containing compounds possess inferior thermal stability compared to neat ABS at the beginning of decomposition, suggesting that the thermal degradation of ABS is accelerated by the presence of FR at earlier stage of degradation and then hindered by the char formed at later stage of degradation.

Synthesis, Flame Retardancy, and Thermal Degradation Behaviors of Novel Organo-Phosphorus Compounds Derived from 9,10-Dihydro-9-oxa- 10-phosphaphenanthrene-10-oxide (DOPO)

김진환,김우중,DongQuy Hoang,Hai Vothi,Congtranh Nguyen,Thanhkieu Giang,Haiyan An 한국고분자학회 2016 Macromolecular Research Vol.24 No.1

A series of novel organo-phosphorus compounds was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide (DOPO) in an attempt to obtain high phosphorus (P) containing halogen-free flame retardant (FR). The success of synthesis was confirmed by 1H and 31P NMR spectra. The P content of FR varied from 12.95 to 19.22 wt%. Thermal stabilities of synthesized FRs and their flame retardancy for Acrylonitrile-Butadiene- Styrene copolymer (ABS) were investigated by thermal gravimetric analysis (TGA) and the classification of UL-94 V-0 rating, respectively. 27.5-30.0 wt% FR loadings gave the V-0 rating for the ABS/FR mixtures and no fume emission was observed. It was found that the flame retardancy strongly depends on the P content of FR and 5.03-5.30 wt% P is required in the formulation to exhibit self-extinguishing ability when phosphinate or phosphonate FRs are employed. The mode of flame retardancy action is also discussed.

Effect of Ammonium Polyphosphate and Melamine Pyrophosphate on Fire Behavior and Thermal Stability of Unsaturated Polyester Synthesized from Poly(ethylene terephthalate) Waste

ThuHien Nguyen,DongQuy Hoang,김진환 한국고분자학회 2018 Macromolecular Research Vol.26 No.1

The fire behavior and thermal stability of unsaturated polyester prepared from recycled poly(ethylene terephthalate) (RUP) in the present of two phosphorus- nitrogen flame retardants (FRs) including ammonium polyphosphate (APP) and melamine polyphosphate (MPP) have been investigated. The effectiveness of FRs on the fire proofing of material was test by UL-94 vertical classification and limiting oxygen index (LOI). The obtained data showed that the fire retardancy and thermal stability were remarkably enhanced with addition of FRs. The best grade of UL-94V standard, V-0 ranking was attained as loading of 25 wt% of APP or 30 wt% of MPP. LOI significantly were enhanced from 20 to 36%. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Scanning electron microscope (SEM) were applied to determine the structure and morphology of char layers of RUP and RUP/FR mixtures. Thermogravimetric analysis (TGA) method was applied to investigate thermal stability of neat RUP, FRs, and RUP/FR and to evaluate kinetic parameters of the decomposition of RUP/FR. The mechanism of action of FRs, schemes for the possible decomposition mechanism RUP and FRs, and the cooperation of matrix and additives were also discussed.

Effective Phosphorus/Phosphorus-Nitrogen Fire Retardants Applied to Biocomposites Based on Polypropylene-Wood Flour: Flammability, Thermal Behavior, and Mechanical Properties

Lam H Pham,Linh T Pham,DongQuy Hoang,김진환 한국고분자학회 2019 Macromolecular Research Vol.27 No.12

By adding diammonium phosphate (DAP) or aluminum diethyl phosphinate (OP) as flame retardants, flame retardancy of composites based on polypropylene and wood flour (PP-WF) improved significantly. A loading of 25 wt% DAP achieved a UL-94 V-0 rating as well as LOI value of 29%, which increased by 52.6% compared with that of the PP-WF composite alone. A 30 wt% OP loading provided a rating of UL-94 HB standard, and achieved LOI value of 28%. Meanwhile, the PPWF composite without flame retardant, completely burned to the sample holder clamp with low LOI value (19%). Thermal properties of the PP-WF composite with and without DAP and OP flame retardants, were investigated using TGA and DSC. Flame retardant performance was also studied, through the morphology and chemical structure of residual char by TGA, FTIR, SEM, and XPS analyses. There was interaction between DAP and the composite, which played a key role in maintaining mechanical properties of the material.

Thermal Properties and Fire Retardancy of Polypropylene/Wood Flour Composites Containing Eco-friendly Flame Retardants

Lam H Pham,Hai D Nguyen,김진환,DongQuy Hoang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.11

Thermal properties and the flame retardancy of polypropylene/wood flour (PP-WF) composite were improved byadding aluminum hydrogen phosphonate (AHP) and triphenyl phosphate (TPP) flame retardants. PP-WF compositescontaining 30 wt% of AHP and 30 wt% of TPP achieved UL-94 HB standard with the horizontal burning rate of 20.8 mm/min and of 11.5 mm/min, respectively. Thermal properties of PP-WF composite with and without flame retardant, as well asthe interaction between PP-WF and flame retardant were investigated through TGA analysis. The flame retardant mechanismis mainly in condensed phase for AHP and in gas phase for TPP. The residual char after the decomposition of PP-WF/AHPcomposite was analyzed by FTIR to understand how the formation of char affected on the flame retardancy and thermalstability PP-WF composite.

The advancement of bis(2-hydroxyethyl)terephthalate recovered from post-consumer poly(ethylene terephthalate) bottles compared to commercial polyol for preparation of high performance polyurethane

Chi Thi Pham,Binh Tan Nguyen,Minh Tuyet Nguyen,ThuHien Nguyen,Cuong Ngoc Hoang,Nguyen Ngan Nguyen,이평찬,김진환,DongQuy Hoang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-

The behavior of rPUf (polyurethane foam derived from bis(2-hydroxyethyl) terephthalate (BHET)recovered from post-consumer poly(ethylene terephthalate)-PET bottles) and cPUf (polyurethane foambased on a commercial polyol) were evaluated by comprehensive characterizations, and their thermalstabilities,flammabilities, and physical properties were compared. Without using aflame retardant, rPUfpassed the UL-94HB standard, whereas cPUf burned rapidly to the holding clamp. Various formulationsof rPUf and cPUf with established eco-friendlyfire retardants (FRs), including triphenyl phosphate,aluminum diethylphosphinate, and aluminum trihydroxide, exhibited notably higherfire resistance. Thedifferences between the experimental and calculated densities showed the effectiveness of the foamingprocess. A larger difference indicated that the FR improved the foaming process more. The BHET structurecontains an aromatic moiety that strongly enhanced the compressive strength and protected the rPUf/FRsfrom biodegradation, as evidenced by sorption isotherm experiments. For that reason, the rPUf/FRs couldbe used as building materials, especially under high humidity conditions. These are the advantages ofBHET over the commercial polyol for PUf preparation. Chemical recycle of post-consumer PET bottles toproduce high performance PUf could be applied on an industrial scale and then it creates the sustainablerecycling industry.

The extraction of lignocelluloses and silica from rice husk using a single biorefinery process and their characteristics

Ngoc Thuy Nguyen,Nhat Thong Tran,Tan Phat Phan,Anh Thu Nguyen,My Xuyen T. Nguyen,Nguyen Ngan Nguyen,Young Ho Ko,Dai Hai Nguyen,Tran T.T. Van,DongQuy Hoang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

While the efficient usage of biomass waste can significantly help in addressing environmental issues,there are only a few reports that discuss about processing such waste effectively at a low-cost. Such challengearises from the strong association between the components biomass. In this study, an abundantagricultural byproduct, rice husk (RH), was used as the starting resource. A simple biorefining processof alkaline peroxide treatment followed by acid precipitation and ethanol extraction was performed onRH to obtain cellulose, hemicellulose, lignin, and silica. The chemical structures, morphologies, andphysic-chemical properties of the separated components were identified through a wide range of characterizationapproaches. The final products obtained from of this process were (i) bundles of fiber-likecellulose with a fiber width of 6 mm and (ii) small particles of hemicellulose and lignin with nonuniformshapes. The lignocelluloses products had over 90 wt% carbon with 52.28% crystalline ratio. Meanwhile, the other products comprising hemicelluloses, lignin, and silica were amorphous. The outcomeof this study contributes to expanding and developing the simple and efficient conversion processof biomass waste into sustainable value-added materials. It is crucial to reduce the environmental impactby using renewable materials as the new building block resources for synthetic chemicals.