Resorcinol Bis Research Articles

Coupled digital visualization and multi-omics uncover neurobehavioral dysfunction in zebrafish induced by resorcinol bis(diphenylphosphate)

Resorcinol bis(diphenylphosphate) (RDP) is an emerging pollutant that has been frequently detected in aquatic environments, although its toxicity is poorly characterized. To understand how RDP affects the neural system, two-month-old zebrafish were exposed to RDP at concentrations of 0.1 and 10 μg/L for 60 days. Following exposure, behavioral assessments were conducted, revealing the emergence of anxiety-like symptoms and memory deficits among the adult fish exposed to RDP, especially at the higher concentration. The increased blood–brain barrier (BBB) permeability (4.67–5.58-fold higher than the control group), reduced expression of tight junction proteins and the rapid brain RDP bioaccumulation (15.63 ± 2.34 ng/g wet weight) indicated the neurotoxicity of RDP. Excess reactive oxygen species synthesis (2.20–2.50-fold) was induced by RDP, leading to mitochondrial dysfunction and decreased production of neurotransmitters in the brain, specifically serotonin (5-HT; 16.3 %) and dopamine (DA; 18.1 %). Metabolomic analysis revealed that the low-toxicity RDP dose up-regulated lipid-related metabolites, while the high-toxicity dose up-regulated arachidonic acid metabolism and disrupted amino acid metabolism, including tryptophan and tyrosine metabolism related to dopaminergic and serotonergic pathways. The dysregulation of genes in various cellular processes was identified by transcriptomics, mainly involved in cell adhesion molecules and gap junctions, and oxidative phosphorylation, which were directly associated with BBB permeability and oxidative stress, respectively. Correlation analysis of microbiome-metabolite-host links built a mechanistic hypothesis for alterations in gut microbiota (Actinobacteriota and Proteobacteria) induced by high-dose RDP leading to the alteration of tryptophan, tyrosine, and arachidonic acid metabolism, decreasing the production of 5-HT and DA through the gut-brain axis. This study provides valuable insights into the mechanism underlying RDP-induced neurotoxicity in zebrafish, which can inform ecological risk assessments.

Migration patterns of organophosphate esters from plastic food packaging simulants to foods: Donors, behaviours, and influencing factors

In recent years, organophosphate esters (OPEs) have been widely produced and used as flame retardants and plasticizer additives, posing significant ecological and health risks. Dietary intake is considered to be the primary route of human exposure to OPEs. Plastic food packaging materials are considered a crucial source for contamination of OPEs in food. However, the migration behaviour of OPEs from plastic food packaging materials into foods has received limited attention. In this study, we employed a novel method to prepare migration donors containing 13 kinds of OPEs. The migration behaviours of OPEs from food packaging simulants (polypropylene) to foods (full-fat milk powder) were simulated, and factors influencing the migration of OPEs were examined, including the properties of the target compounds, migration temperature, fat content of the migration receptors, and mass transfer mode. The results indicated that OPEs exhibited a significant migration tendency. Low molecular weight OPEs (< 300 Da) had faster migration efficiency compared to high molecular weight OPEs. The mean migration efficiencies of various OPEs showed a significant negative correlation with their molecular weights (p < 0.01) and a significant positive correlation with temperature (p < 0.01). Except for resorcinol bis(diphenyl phosphate) (RDP), which showed almost no migration, the mean migration efficiencies of other OPEs at 25 °C, 40 °C, and 60 °C were 3.1–37.5 %, 9.0–60.0 %, and 23.9–80.4 %, respectively. Most of the OPEs demonstrated higher migration efficiency in high-fat content food than low-fat content food. The migration of OPEs from food packaging simulants to foods primarily occurred through contact rather than gas-phase mass transfer. Overall, this study uncovers the migration behaviours of OPEs from food packaging simulants to foods and scrutinized the relevant factors influencing the migration. It is expected that the research in terms of the contamination control of OPEs in food will benefit from this work.

GC/MS-Based Metabolomic Analysis of A549 Cells Exposed to Emerging Organophosphate Flame Retardants.

Emerging organophosphate flame retardants (eOPFRs) have attracted attention in recent times and are expected to gain extensive usage in the coming years. However, they may have adverse effects on organisms. Due to their novel nature, there are few relevant articles dealing with toxicological studies of the above eOPFRs, especially their information on the perturbation of cellular metabolism, which is, thus far, marginally understood. Our research initially assessed the cytotoxicity of eOPFRs, which include compounds like cresyl diphenyl phosphate (CDP), resorcinol bis(diphenyl phosphate) (RDP), triallyl phosphate (TAP), and pentaerythritol phosphate alcohol (PEPA). This evaluation was conducted using the methyl thiazolyl tetrazolium (MTT) assay. Subsequently, we utilized a gas chromatography/mass spectrometry (GC/MS)-based metabolomic approach to investigate the metabolic disruptions induced by these four eOPFRs in A549 cells. The MTT results showed that, at high concentrations of 1 mM, their cytotoxicity was ranked as CDP > TAP > RDP > PEPA. In addition, metabolic studies at low concentrations of 10 μM showed that the metabolic interference of CDP, TAP, and PEPA focuses on oxidative stress, amino acid metabolism, and energy metabolism, while RDP mainly affects energy metabolism-galactose metabolism and gluconeogenesis. Therefore, from the perspective of cytotoxicity and metabolic analysis, RDP may be a more promising alternative. Our experiments provide important insights into the possible metabolic effects of potential toxic substances and complement the evidence on the human health risks of eOPFRs.

Exposure to resorcinol bis (diphenyl phosphate) induces colonization of alien microorganisms with potential impacts on the gut microbiota and metabolic disruption in male zebrafish

Organophosphate esters (OPEs) have been demonstrated to induce various forms of toxicity in aquatic organisms. However, a scarcity of evidence impedes the conclusive determination of whether OPEs manifest sex-dependent toxic effects. Here, we investigated the effects of tris (1-chloro-2-propyl) phosphate (TCPP) and resorcinol bis (diphenyl phosphate) (RDP) on the intestines of both female and male zebrafish. The results indicated that, in comparison to TCPP, RDP induced more pronounced intestinal microstructural damage and oxidative stress, particularly in male zebrafish. 16S rRNA sequencing and metabolomics revealed significant alterations in the species richness and oxidative stress-related metabolites in the intestinal microbiota of zebrafish under exposure to both TCPP and RDP, manifesting gender-specific effects. Based on differential species analysis, we defined invasive species and applied invasion theory to analyze the reasons for changes in the male fish intestinal community. Correlation analysis demonstrated that alien species may have potential effects on metabolism. Overall, this study reveals a pronounced gender-dependent impact on both the intestinal microbiota and metabolic disruptions of zebrafish due to OPEs exposure and offers a novel perspective on the influence of pollutants on intestinal microbial communities and metabolism.

The effect of combined atmospheric plasma/UV treatments on improving the durability of organophosphorus flame retardants applied to polyester fabrics

Following application of three commercially available, flame retardants (FR) to polyester and exposure to an atmospheric plasma in the presence or absence of simultaneous UV 308 nm excimer laser radiation, the retentions to a 30 min 40 °C water-soak for the mono- and dimeric cyclophosphonate (PE-CONC and PCO 900 respectively) and a 30 min methanol-soak treatment for the resorcinol bis(diphenyl phosphate) (RDP) agents were generally enhanced with respect to unexposed controls. These results suggested that the formation of PET-FR bonding had occurred as a consequence of plasma/UV exposure. The effect of plasma/UV process sequence (pre-exposure and/or post exposure with respect to FR impregnation) as well as plasma gas type, showed that maximum post-soaking FR retentions occurred when both pre- and post-exposure conditions operated.Plasma/UV exposed fabrics both before and after soaking treatments were examined for morphological changes by SEM and surface phosphorus retention by EDX, FTIR-ATR, XPS as well as TGA/DTG/DTA, each of which showed evidence on the surface of changes in surface topography, increased phosphorus levels and modified thermal behaviour. When subjected to vertical fabric strip flammability testing, these changes were insufficient to generate significant changes in the burning rate apart from in post-methanol soaked, RDP-containing fabrics where almost all plasma/UV process sequences reduced specimen burning rates.During all experiments, the presence or absence of the UV laser radiation appeared to have no obvious effect on post-soaking FR retentions, suggesting that its presence is not required since plasma activation alone appears to be the key to improving PET-FR bonding.

The effect of organophosphorus flame retardants on the combustion behavior and performance of poly (methyl methacrylate)

Maintaining transparency poses a challenge in the preparation of flame-retardant poly (methyl methacrylate) (PMMA). The feasibility of preparing flame-retardant transparent PMMA by incorporating oligomeric resorcinol bis(diphenylphosphate) (liquid), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and hexaphenoxycyclotriphosphazene (solid) as additives has been explored. The impact of the flame retardants on the processing performance, thermal stability, combustion behavior and mechanical properties of PMMA has been investigated. The presence of organophosphorus compounds does not impact the transparency of PMMA and has a significant plasticizing effect. The modified PMMA displays a UL94 V-2 rating largely due to the formation of noncombustible droplets. However, the blend exhibits lower heat resistance, modulus and strength than does unmodified PMMA. The presence of organophosphorus compounds induces a higher limiting oxygen index (LOI) and reduced heat release for combustion of the blends than observed for PMMA without relying on charring, among which DOPO has a higher flame retardant efficiency due to its higher phosphorus content and lower decomposition temperature.

Comparative study of flame retardancy in polyimine vitrimers and composites: Evaluating additive and reactive flame retardants acting via gas-, solid-, and combined-phase mechanisms

We developed flame retarded polyimine type vitrimers and carbon fibre reinforced composites using two additive and a reactive flame retardant containing phosphorus: ammonium polyphosphate (APP), resorcinol bis(diphenyl phosphate) (RDP); and N,N',N’’-tris(2-aminoethyl)-phosphoric acid triamide (TEDAP). We characterised the vitrimer matrix materials by differential scanning calorimetry (DSC), thermal analysis (TGA), limiting oxygen index (LOI), UL-94 test and mass loss calorimetry (MLC), while the vitrimer composites by LOI, UL-94 test, MLC and dynamic mechanical analysis (DMA). We compared the performance of the vitrimer systems to a benchmark pentaerythritol-based aliphatic epoxy resin system (PER). The vitrimer reference had higher thermal stability but lower fire performance than the PER aliphatic reference epoxy. At lower phosphorus content, the vitrimer systems exhibited a melting above their vitrimer transition temperature, which negatively affected their LOI and UL-94 results. From 2% phosphorus content, rapid charring and extinguishing of vitrimers prevented the softening and deforming. The superior performance of these same flame retardants in vitrimer systems could be attributed to the high nitrogen content of imine-based vitrimers in combination with phosphorus flame retardants, exploiting nitrogen-phosphorus synergism. In both matrices, flame retardants with solid phase action lead to better fire performance, while in composites, the lowest peak heat release rates (152 kW/m2 in vitrimer composite) were achieved with RDP acting predominantly in the gas phase, as carbon fibres hindered the intumescent phenomenon.

Biodegradation of aryl-organophosphate flame retardants by Rhodococcus pyridinivorans YC-MTN: Performance, pathway and potential in environmental remediation

A strain capable of efficiently degrading aryl-organophosphate flame retardants (aryl-OPFRs) was isolated and identified as Rhodococcus pyridinivorans YC-MTN. The strain demonstrated high degradation efficiency within a wide range of pH (7.0–10.0), temperature (25–45 °C), and salinity (0–2%). Strain YC-MTN effectively utilized aryl-OPFRs as the sole carbon source, facilitating their rapid degradation. The estimated half-lives for four aryl-OPFRs, namely triphenyl phosphate (TPhP), tricresyl phosphate (TCrP), 2-ethylhexyl diphenyl phosphate (EHDPP), and resorcinol bis (diphenyl phosphate) (RBDPP), were found to be 8.73, 10.82, 30.28, and 16.14 h, respectively. Additionally, half of the aryl-OPFRs underwent mineralization after 7 d of incubation. In particular, hydrolysis played a dominant role in the metabolism of TPhP, EHDPP, and RBDPP by strain YC-MTN, while P–O bond cleavage generally occurred in the presence of phenol as the leaving group. In addition to hydrolysis, methylation participated in the biotransformation of TCrP. Strain YC-MTN exhibited significant degradability towards TPhP at various concentrations ranging from 1 to 1000 mg L−1. The remediation of TPhP was simulated in both freshwater and seawater, and within a span of 5 d, strain YC-MTN completely degraded the exogenous TPhP. Strain YC-MTN holds potential as a viable microbial agent in the bioremediation of aryl-OPFRs contamination.

Diverse structural reactivity patterns of a POCOP ligand with coinage metals.

We have utilised the 4,6-di-tert-butyl resorcinol bis(diphenylphosphinite) (POCOP) ligand for exploring its coordination ability towards group 11 metal centres. The treatment of the bidentate ligand 1 with various coinage metal precursors afforded a wide range of structurally diverse complexes 2-12, depending upon the metal precursors used. This furnishes several multinuclear Cu(I) complexes with dimeric (2) and tetrameric cores (3, 4, and 5). The tetrameric stairstep complex 4 shows thermochromic behaviour, whereas the dimeric complex 2 and tetrameric complex 3 show luminescence properties at cryogenic temperatures. Interestingly, the halide substitution reaction of the dimeric complex 2 with KPPh2 produces a unique mixed phosphine-based tetrameric Cu(I) complex, 5. Treatment of the POCOP ligand with [CuBF4(CH3CN)4] in the presence of 2,2'-bipyridine afforded heteroleptic complex 6, consisting of tri- and tetra-coordinated cationic Cu(I) centres. Furthermore, we could also isolate cubane (8) and stairstep (9) complexes of Ag(I). The cationic Au(I) complex (12) was obtained from the dinuclear Au(I) complex of POCOP, 11. Complex 12 revealed the presence of a strong intramolecular aurophilic interaction with an Au⋯Au bond distance of 3.1143(9) Å. Subsequently, the photophysical properties of these complexes have been studied. All the complexes were characterised by single-crystal X-ray diffraction studies, routine NMR techniques, and mass spectroscopy.

Flame retardance of a bio-based furan resin: Effects of added flame retardants

A study of the flammability of a biobased furan resin via limiting oxygen index and UL-94 has shown its inherent flame retardant properties. In a cone calorimetric test at 50 kW/m2 external irradiance, however, it ignited within 50 s and burnt, producing 489 kW/m2 peak heat release and 24 MJ/m2 total heat release but minimal smoke production. The flame retardance of the furan resin was further improved by the addition of the phosphorus-containing inorganic flame retardants, ammonium polyphosphate (APP) and melamine polyphosphate (MPP), and their well known condensed phase activity was further supported by thermogravimetric analysis (TGA). The organic flame retardants, resorcinol bis(diphenyl phosphate) (RDP) and bisphenol-A bis(diphenyl phosphate) (BAPP) had no effect on flame retardance, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) had only minimal effects in LOI and cone calorimetric tests, which was at variance to the results of TGA tests. This disconnect between the tests involving flaming combustion (LOI and cone calorimetry) and slow controlled heating (TGA) was attributed to the low flash points and high boiling points of the organic flame retardants, respectively.

Emerging organophosphate ester resorcinol bis(diphenyl phosphate) exerts estrogenic effects via estrogen receptor pathways

Environmental occurrence and human exposure of emerging organophosphate esters (eOPEs) have increased significantly in recent years. Resorcinol bis(diphenyl) phosphate (RDP) is one of the major eOPEs detected in indoor dust, but the knowledge on its toxicities and health risks is rather limited. In this study, we investigated the in vitro estrogenic effects and underlying mechanism of RDP in comparison with a legacy OPE triphenyl phosphate (TPHP). Our results showed that RDP promoted MCF-7 cell proliferation with the lowest effect concentration of 2.5 μM, and the maximum enhancement of 1.6 folds is greater than that of TPHP (1.3 folds). The effect was inhibited completely by an estrogen receptor (ER) antagonist, suggesting that ER activation was responsible for the enhancement. In luciferase reporter gene assays both RDP and TPHP activated ER transcriptional activity at 2.5 μM, but RDP activity was higher than TPHP. Competitive fluorescence binding assays showed that RDP bound to ER with an IC10 of 0.26 μM, which is 20 folds lower than TPHP (5.6 μM). Molecular docking simulation revealed that both RDP and TPHP interacted with ER at the binding pocket of estradiol, although the hydrogen bonds were different. Taken together, RDP exerted stronger estrogenic effects than TPHP through ER-mediated pathways and may pose more health risks.

High-resolution mass spectrometry-based screening and dietary intake assessment of organophosphate esters in foodstuffs from South China

Organophosphate esters (OPEs) are a group of emerging contaminants with widespread environmental occurrence, yet research on their occurrence in foodstuffs is limited. We collected 100 foodstuff samples in South China using a market basket method, and analyzed food extracts for the presence of OPEs and organophosphite antioxidants (OPAs) by suspect and nontarget screening through high-resolution mass spectrometry. Our analysis resulted in the identification of 30 OPEs, comprised of 25 OPEs with a confidence level (CL) of 1 (unequivocal identification using standards) and five OPEs with CL = 2b (probable structure based on diagnostic evidence). Interestingly, 11 of these identified OPEs had not been previously reported in food. No OPA was identified. The occurrence of identified OPEs within the food samples was further investigated. The highest median concentration of OPEs in all food samples was reached by tris(2-chloroisopropyl) phosphate (TCPP) (1.55 ng/g ww, range < 0.74–12.0 ng/g wet weight (ww)). Cereals demonstrated the highest median concentration of the cumulative 30 OPEs. Tris(2-chloroethyl) phosphate (TCEP), TCPP, and triethyl phosphate (TEP) predominantly contributed to OPEs contamination in most food categories. Eight OPEs, namely TEP, tris(2-ethylhexyl) phosphate (TEHP), TCEP, triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), bis(2-ethylhexyl) phenyl phosphate (BEHPP), resorcinol bis(diphenyl phosphate) (RDP), and methyl diphenyl phosphate (MDPP) exhibited significantly higher concentrations in the processed group as compared to non-processed group, suggesting that food processing may result in contamination of these OPEs. The median sum of estimated dietary intake (ΣEDI) of all OPEs was determined to be 161 ng/kg body weight/day. Cereals (38.5 %) and vegetables (23.5 %) were the predominant food categories contributing to ΣEDI, and TEP (29.0 %), TCEP (20.2 %), and TCPP (18.3 %) were three major OPEs contributing to ΣEDI. This study for the first time offered a comprehensive overview of OPE species and revealed their occurrence in foodstuffs from South China.

Prenatal exposure to emerging and traditional organophosphate flame retardants: Regional comparison, transplacental transfer, and birth outcomes

During gestation, organophosphate flame retardants (OPFRs) have the potential to pose health risks to fetuses due to their ability to cross the placental barrier. However, data are scarce regarding the transplacental transfer of these compounds, particularly concerning emerging OPFRs and regional variations. In this study, we analyzed 14 traditional OPFRs and 5 emerging OPFRs in maternal and cord serum samples from Mianyang and Hangzhou, two cities in eastern and western China, respectively. The results revealed marked disparities in the overall levels of OPFRs between the two cities (p < 0.05), with the average concentration in maternal serum being higher in Hangzhou (14.55 ng/mL) than in Mianyang (8.28 ng/mL). The most abundant compounds found in both cities were tris (2-chloroethyl) phosphate (TCEP), Triphenyl phosphate (TPHP), and Tri-n-butyl phosphate (TnBP). Additionally, this study marked the first detection of novel OPFRs, including resorcinol bis (diphenyl phosphate) (RDP), isodecyl diphenyl phosphate (IDDPP), cresyl diphenyl phosphate (CDP), and bisphenol A bis (diphenyl phosphate) (BPA-BDPP) in maternal and cord serum simultaneously with the detection frequencies higher than 45%. This study also found that transplacental transfer efficiencies for OPFRs varied by ester group, with Aryl-OPFRs exhibiting the highest transfer rates (0.90–1.11) and Alkyl-OPFRs exhibiting the lowest (0.66–0.83). Transfer efficiencies exhibited a positive correlation with log Kow values (p < 0.05), suggesting that hydrophobic OPFRs with higher log Kow values are more likely to permeate the placental barrier. Moreover, the exposure levels of Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP), Tri (Chloropropyl) Phosphate (TCIPP), TPHP, and CDP in cord serum were negatively associated (p < 0.05) with birthweight of newborns. This research adds to our understanding of the transplacental transfer of OPFRs and the possible health risks associated with prenatal exposure.

Coating Composites Based on Polyurea Elastomers with Increased Fire Resistance and Their Use as Roofing Systems

This paper presents the results of tests on elastomer coatings based on polyurea–polyurethane formulation with increased fire parameters. Coatings modified with flame retardants: bis(phenylphosphate) resorcinol (RDP), trischloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) were tested. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA/DTG) were used to investigate the structure and thermal stability. The effectiveness of resorcinol bis(phenylphosphate) (RDP), tris chloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) on heat release rate (HRR), smoke release rate (RSR), and oxygen consumption was evaluated using cone calorimetry. The cone calorimetry results were correlated with the mechanical properties of the coatings. The cone calorimetry analysis showed suitable organophosphorus flame retardant (FR) performance, significantly decreasing HRR and oxygen consumption. Additionally, 15% TCPP caused a reduction of HRR by over 50%, obtaining 211.4 kW/m2 and pHRR by over 55%, reaching 538.3 kW/m2. However, organophosphorus flame retardants caused a significant deterioration of mechanical properties simultaneously. Introducing a mixture of two FRs (RDP/TCPP) resulted in obtaining a coating with improved fire resistance and maintained good mechanical strength. The polyurea–polyurethane coating, modified with a mixture of two RDP/TCPP retardants (10:5), was simulated for the burning of roof systems. The result of the simulation was assessed positively. Thus, finally, it was confirmed that the proposed polyurea–polyurethane coating achieved the assumed flame retardant level.

How Phosphorous Flame Retardant Additives Affect Benzoxazine‐Based Monomer and Polymer Properties

AbstractThe phosphorous‐based flame retardant additives poly(m‐phenylene methylphosphonate) (PMP) and resorcinol bis(diphenyl phosphate) (RDP) are reacted with bisphenol F and aniline–based benzoxazine (BF‐a). DSC, rheological analysis, FT‐IR, and soxhlet extraction reveal the covalent incorporation of both FR additives—initiating phenols in PMP structure as well as free phenols generated via transesterification reaction in the case of RDP. In contrast to PMP, RDP elongates the processing window but decreases the thermo–mechanical properties. Both additives increase the resistance in reactions against small flames with solely a phosphorous loading of 0.3 wt%, resulting in a V‐0 rating and an improvement in the OI value by up to 2% for RDP and 4% for PMP. Both FRs reduce the heat release rate but increase the smoke production and the smoke toxicity in the case of RDP.

Neurotoxicity of an emerging organophosphorus flame retardant, resorcinol bis(diphenyl phosphate), in zebrafish larvae

Resorcinol bis(diphenyl phosphate) (RDP), an emerging organophosphorus flame retardant and alternative to triphenyl phosphate (TPHP), is a widespread environmental pollutant. The neurotoxicity of RDP has attracted much attention, as RDP exhibits a similar structure to TPHP, a neurotoxin. In this study, the neurotoxicity of RDP was investigated by using a zebrafish (Danio rerio) model. Zebrafish embryos were exposed to RDP (0, 0.3, 3, 90, 300 and 900 nM) from 2 to 144 h postfertilization. After this exposure, the decreased heart rates and body lengths and the increased malformation rates were observed. RDP exposure significantly reduced the locomotor behavior under light-dark transition stimulation and the flash stimulus response of larvae. Molecular docking results showed that RDP could bind to the active site of zebrafish AChE and that RDP and AChE exhibit potent binding affinity. RDP exposure also significantly inhibited AChE activity in larvae. The content of neurotransmitters (γ-aminobutyric, glutamate, acetylcholine, choline and epinephrine) was altered after RDP exposure. Key genes (α1-tubulin, mbp, syn2a, gfap, shhα, manf, neurogenin, gap-43 and ache) as well as proteins (α1-tubulin and syn2a) related to the development of the central nervous system (CNS) were downregulated. Taken together, our results showed that RDP can affect different parameters related to CNS development, eventually leading to neurotoxicity. This study indicated that more attention should be paid to the toxicity and environmental risk of emerging organophosphorus flame retardants.

Thermal and Flammability Properties of Flame Retardant Phase Change Material for Buildings Applications

Phase Change Materials (PCMs) have attracted growing attention recently in the renewable energy utilization and building energy efficiency due to their high capacity for storing thermal energy but their applications have been restricted by leakage, poor thermal conductivity, and high flammability. In this work, the flame retardant phase change material has been successfully prepared through integrating Resorcinol bis (diphenyl phosphate) (RDP) as a flame retardant into lauric acid (LA) as a phase change material. The DSC (differential scanning calorimeter) test is used to measure the thermal properties of LA_RDP. The thermogravimetric analysis (TGA) test demonstrates that the thermal stability of composite LA_RDP is improved. Cone calorimeter is applied to study the flammability properties of the flame retardant phase change material. As a result, the RDP-based flame-retardant PCMs developed could be used for safe and efficient solar energy storage applications.

Abstract Number ‐ 127: Poly(vinyl alcohol) grafts of brain aneurysms with patient‐specific morphologies

Introduction Current animal models of brain aneurysms used for testing neuro‐interventional devices have highly simplistic vascular anatomy in comparison with human aneurysm‐parent vessel complexes. Poly(vinyl alcohol) (PVA) is a leading biomaterial for manufacture of artificial vascular grafts because of its biocompatibility, hemocompatibility, availability, low cost, moldability/castability, and tunable mechanical properties to match arterial compliance [1,2]. However, PVA is non‐cell adhesive and requires modification with additives to promote endothelialization of the luminal surface to maintain long‐term graft patency [1,3]. We have previously studied the biocompatibility of resorcinol bis(diphenyl phosphate) (RDP) coated clays blended with polymers and have found excellent cell adhesion and proliferation with human dermal fibroblasts as well as dental pulp stem cells [4]. Our overall goal is to develop a new in vivo model of brain aneurysms by manufacturing patient‐specific aneurysm anatomies with a blend of PVA and RDP clay and grafting them into animals. Here, we evaluate the casting of PVA in the shape of patient‐specific aneurysms. Methods 10% PVA (w/w) (99% hydrolyzed, 85–124K molecular weight, Sigma Aldrich) was dissolved in deionized water, to which 1% RDP clay (ICL Industrial Products, Be’er Sheva, Israel) was added. The PVA was crosslinked using 15% (w/w) of sodium trimetaphosphate and 30% (w/w) of sodium hydroxide, after which rheological studies (stress sweeps using a Bohlin Gemini rheometer) were conducted. In the casting procedure, negative molds of both simple tubes and complex aneurysm geometries were designed using Rhinoceros 3D software (Robert McNeel &amp; Associates, Seattle, WA) and 3D printed in ABS plastic. The negative mold was then filled with beeswax, resulting in a positive wax mold that was dip‐coated 8 times in PVA solution, and spun on a two‐axis spinner in between each dip to ensure even coverage. After overnight drying in a fume hood, the model was placed in heated water, allowing the wax to melt out and leaving behind the luminal PVA cast. Results Rheology on the crosslinked polymers showed that the PVA/RDP blend exhibited over twice the elastic modulus of unblended PVA (Figure A). Such enhanced mechanical properties are consistent with previous studies [5]. Both simple tubular geometries and patient‐specific anatomies were able to be successfully cast using the methodology developed here (Figure B). Conclusions This proposed casting methodology demonstrates a realistic, efficient way to replicate complex aneurysm geometries with comparatively inexpensive materials and short time frame. Future endeavors will include further exploration of the PVA/RDP biocompatibility as well as completing the casting procedure with a PVA/RDP blend.

Development of Multifunctional Flame-Retardant Gel Coatings for Automotive Applications

Due to strict safety regulations, the automotive industry requires an effective reduction of flammability in polymer components. Flame retardants are usually added to the polymer matrix, affecting the viscosity of the matrix. Another possible solution is the application of coatings containing flame retardants, which can additionally ensure good surface quality and protection against external influences. In our research, the flammability of reference and flame retarded gelcoat base materials was investigated using oxygen index (LOI), UL-94, and mass loss type cone calorimetry (MLC) tests. Based on the flammability tests, the best results were obtained with the gelcoat formulation containing 15%P ammonium polyphosphate (APP) and the mixed formulation containing 5%P APP and 5%P resorcinol bis(diphenyl phosphate) (RDP), with a 55% and 64% reduction in the total heat release compared to the reference gelcoat, respectively. The two best-performing coatings were applied to polypropylene (PP) samples. 15%P APP reduced the peak heat release rate of PP by 89% compared to the reference. The gelcoat formulation containing 15%P APP was applied to polyurethane (PUR) automotive components, where the coating reduced the maximum heat release rate by 53% and shifted the time to peak heat release rate by 447 s.

Experimental investigation on thermal properties and fire performance of lauric acid/diphenyl phosphate/expanded perlite as a flame retardant phase change material for latent heat storage applications

The form-stable composite energy storage developed in this study was produced by integrating a novel flame retardant phase change material formed of 90 wt% lauric acid (LA) as a phase change material and 10 wt% resorcinol bis(diphenyl phosphate) (RDP) as a flame retardant into a supporting material of expanded perlite (EP) without leakage. A differential scanning calorimeter (DSC) test is employed to characterize the mass ratio of LA_RDP, and a filter paper is used to assess the leakage test of LA_RDP/EP. Results from scanning electron microscopy (SEM) show that the flame retardant phase change material of LA_RDP has been successfully embedded into EP’s porous structure. Moreover, chemical compatibility of composites is analyzed by fourier transform-infrared spectrometer (FT-IR). According to the DSC test, the flame retardant phase change material developed of LA_RDP/EP has an appropriate phase transition temperature of ∼ 40–45 °C and fusion latent heat range of ∼ 86.02–88.29 J/g for thermal control in buildings. After 50 thermal cycles, the thermal cycling test depicted that the composite PCM possess outstanding thermal reliability. By incorporating 5 wt% expanded graphite (EG), the thermal conductivity of the LA_RDP/EP composite is enhanced by about 41.6%. In accordance with the thermogravimetric analysis (TGA) test, the produced flame retardant and EP reduces the mass loss of LA. Cone calorimetry is also utilized to examine the flame retardant phase change material composite’s flammability characteristics. LA_RDP/EP demonstrates valued thermal properties while lowering the flammability of LA. The findings demonstrated that the formed LA_RDP/EP composite might be assessed as a suitable material in thermal applications for effective and sustainable energy use.