Retardant Performance Research Articles

A facile and sustainable preparation of effective biomass macromolecular flame retardants for epoxy resins with improved flame retardation, smoke suppression, and mechanical performance

AbstractThe preparation of biomass flame retardants with efficient flame‐retardant properties is conducive to the realization of sustainable development and is of great practical significance. In this work, a green and sustainable biomass flame retardant PATAPEI was prepared by using phytic acid (PA), tannic acid (TA), and polyethyleneimine (PEI) as reactants via a one‐step method to develop biomass flame retardants that can synchronize enhanced flame retardation, smoke suppression, and mechanical performance of epoxy resin (EP). The EP with only a 3% PATAPEI (EP/3PTP) has a LOI value of 28.5% with a UL‐94 V‐0 classification. The peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of EP/3PTP were decreased by 29.72%, 25.80%, and 21.16%, respectively, in comparison with the ones of pure EP. Additionally, the tensile and impact strengths of EP/3PTP are higher than the ones of pure EP. PATAPEI on heating decomposes to produce phosphorus‐containing acids and biphenyltriol‐containing compounds, which promote to form a good char layer with the aromatic structures during the combustion of EP/3PTP. Therefore, PATAPEI has prospects of wide application in the development of sustainable biomass flame retardant EP.

A statistical approach to predict flexural strength and flame retardation properties for natural fibre/ epoxy composites

This research investigates the development of a mathematical model to predict the influence of flame retardants (FR) on the mechanical and flame retardancy performance of natural fibre reinforced thermosetting composites. The study focuses on two types of FRs: Diammonium Phosphate (DAP) and silica fumes that were added to Jute reinforced epoxy composites (JRECs). Two mathematical models were established based on three variables and two measured responses. The variables include FRs type, FR content, and FR method of preparation, while the measured responses are Limiting oxygen index (LOI) and Flexural strength (FS). The models were developed using a statistical approach based on multiple linear regression fitting and validated using analysis of variance (ANOVA) technique. The developed models were verified using experimental result data from literature and the analysis of these models showed that the maximum discrepancy between the observed and predicted values for relative LOI and relative FS was within the range of [Formula: see text] 6% and [Formula: see text] 5%, respectively. This research contributes to the understanding of the impact of FRs on the mechanical and flame retardancy performance of natural fibre reinforced thermosetting composites, which can aid in the design and development of safer and more efficient composite materials.

Molecular level analysis of the influence of natural biomaterials on aviation flame retardant performance

The use of natural biomaterials in flame retardant formulations as sustainable alternatives has gained significant interest in recent years. Given the high-risk environment in which airplanes operate, aviation safety remains a top priority. Flame retardants (FRs) are crucial for preventing or reducing the spread of flames in flammable materials used in aircraft construction and interior furnishings, thus mitigating fire risks. This study aims to analyze the molecular-level influence of natural biomaterials on aviation flame retardant performance, with a focus on lignin. Lignin, a natural polymer derived from plant cell walls, offers an environmentally friendly alternative to conventional synthetic flame retardants. Lignin-based composites can be applied to various aircraft components, such as wings and fuselage. The study employs Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Nuclear Magnetic Resonance (NMR) to investigate the molecular interactions of these biomaterials. Additionally, to assess thermal stability and degradation, Thermo-gravimetric Analysis (TGA) is utilized. The results indicate that lignin enhances flame retardancy by promoting the formation of a protective char layer and improving thermal stability. This research also provides insights into the molecular mechanisms underlying lignin’s effectiveness as a flame retardant and explores its potential in developing high-performance aircraft flame retardants.

Nanostructured poplar wood via delignification and ammonium dihydrogen phosphate-SiO2 modification towards remarkable flame retardant performance: Synergistic effect and enhanced mechanism

Developing efficient methods to prepare high-performance flame retardant and smoke suppression wood is crucial for the application. Herein, nanostructured poplar wood (DWI-4) with remarkable flame retardant and smoke suppression performance was fabricated by impregnating ammonium dihydrogen phosphate (ADP) and nano-silica (SiO2) into delignified wood (DW-4). With the delignification treatment, lignin was partially removed, and numerous pores and cracks were developed on the cell wall of wood, allowing more ADP-SiO2 particles to be impregnated into wood. As a result, ADP-SiO2 particle was not only anchored in the lumens (pores) of wood, but also was penetrated and embedded into the cell wall, achieving the synergistic modification of the lumen and cell wall of wood. As anticipated, the produced DWI-4 featured outstanding flame retardant and smoke suppression performance. The peak heat release rate (pHRR) of DWI-4 was as low as 38.2 kW m−2, which was only 8 % of that of natural wood (NW). And the total heat release (THR) and total smoke production (TSP) demonstrated reductions of 73.9 % and 64.4 % comparing to NW. Moreover, the compressive strength of DWI-4 increased by 31.4 % comparing to NW. The structure of residual char of DWI-4 was more stable and the gas intensity produced by the combustion of DWI-4 decreased remarkably. Therefore, the synergy of delignification and ADP-SiO2 impregnation significantly enhanced the flame retardant and smoke suppression performance of wood and the enhanced mechanism was revealed. The nanostructured poplar wood with excellent flame retardant and smoke suppression performance was prepared, providing an effective method for the functional improvement of wood and expanding the fields of application.

Construction of multi-functional silicone rubber/reduced graphene oxide/multi-walled carbon nanotube composites with segregated structure by surfactant-free Pickering emulsion method

Polymer composites with segregated structure (PC–S) have the advantages of low filler usage and excellent functionality. Emulsion blending combined with direct molding technology is the main method for the preparation of PC-S. However, due to the high fluidity of low-viscosity silicone rubber (SR), PC-S cannot be prepared by this technique. In addition, surfactants affect the heat resistance of the final SR composites (SRC). In order to solve the above problems, in this study, a Pickering emulsification combined with pre-crosslinking technology for SR was successfully developed by using graphene oxides (GO)/multi-walled carbon nanotubes (MWCNTs) hybrid fillers (GM) as emulsifiers, and SR/reduced GO (RGO)/MWCNTs composites with segregated structure (SSGM) were prepared. When RGO content is 4.5 wt%, MWCNTs content is 3.2 wt%, SSGM shows the highest electrical conductivity of 12.5 S/m, the highest electromagnetic interference shielding efficiency (EMI SE) of 41.4 dB, and an excellent flame retardant performance. The whole preparation process avoids the use of organic solvents and surfactants, which reduces the production cost of SSGM and the environmental pollution, and provides a feasible preparation route for the industrialized production of SSGM.

It’s not waste, it’s a resource: Utilizing industrial waste fibers/mineral fillers to attain flame retardant biocomposites

Integrating natural fibers derived from local industrial waste streams into thermoplastic starch (TPS) proves to be a promising approach towards sustainable flame retardant biocomposites. Initially, three types of waste fibers from the agave, coconut, and leather industries were evaluated for their flame retardant properties in combination with aluminum trihydroxide (ATH), an environmental friendly flame retardant. Leather fiber (BLF) exhibited the best flame retardant performance and were further investigated along with ATH and varying amounts of bentonite nanoclay to enhance the residual protective layer. The combination of multiple components shows improvement in performance while reducing the total load of filler. The images of the fire residues revealed that a more enclosed surface correlates with a reduction in the peak of heat release rate. Whereas higher amounts of bentonite does not deliver further inprovements, only 1 phr nanoclay in the novel multicomponent system of TPS, ATH, BLF, and bentonite synergistically improved the UL-94 rating from HB to V1. The proposed system brings together the different approaches using a renewable biopolymer, natural waste fibres, and envirnmentally friendly flame retardancy and thus, is striking for its combination of outstanding sustainablity, instant feasability, and sufficient fire performance.

Investigation of effect of recycled polyester ratio and draw frame passages on flame retardancy of chenille fabric properties

PurposeIn this study, both flame retardancy and sustainability properties were combined in the chenille yarn so that functional and sustainable upholstery fabrics can be produced with optimum energy consumption. The chenille yarn samples were produced from recycled polyester (rPET)-blended binder yarns and fully drawn yarn (FDY) polyester pile yarn. While the pile component of the chenille samples was kept constant, the lock yarns were manufactured as 50% r-PET-50% virgin polyester (PES), 100% r-PET and 100% PES. The binder yarns were also produced in two groups. In the first group, a 2-passage draw frame was used, while a 3-passage draw frame was used in the second group. The chenille yarn samples were applied flame-retardant (FR) finishing.Design/methodology/approachThe knitted upholstery fabric samples were produced from chenille yarn samples via flat knitting machines. The knitted fabrics were applied flame retardancy, bursting strength and abrasion resistance tests according to related standards.FindingsThe test results were analysed, and so the effect of r-PET ratio and draw frame passage number on upholstery fabric flame retardancy, bursting strength and abrasion resistance performance properties were revealed. It was concluded that the number of draw frame passages and the recycled fibre content have no important effect on the flame retardancy. On the other hand, it has been observed that the bursting strength decreases as the recycled fibre content increases and bursting distention results are close to each other. It was seen that the draw frame passage number has no significant effect on both bursting strength and distention. It was revealed that both r-PET fibre content and draw frame passage number have significant effect on abrasion resistance. The samples with 2 draw frame passages provide higher abrasion resistance compared to those with 3 draw frame passage. The lowest abrasion resistance was obtained with 100% r-PET fibre content and the highest abrasion resistance was obtained with 50% r-PET-50% PES.Originality/valueThe results will provide enough knowledge for sustainable chenille yarn design. The recycled fibre content and draw frame passage number can be optimised, and so sustainable chenille yarns can be produced with less energy consumption. Future studies will involve producing chenille yarns with different linear densities and varying draw frame combinations, such as 1, 2 and 3 passages.

A P,N flame retardant containing flexible chain segments, imparting excellent toughness and flame retardancy to epoxy resins

AbstractIn order to enhance the flame retardancy of epoxy resin (EP) without affecting its mechanical properties, a phosphorus‐nitrogen synergistic flame retardant (MPCD) was synthesized in this paper by using melamine, paraformaldehyde, 9,10‐dihydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (DOPO) and cashew phenol as the raw materials, which was applied to the Ep in order to improve its flame retardancy and toughness. Experiments have shown that only 5% content of MPCD added into the EPs could achieve a significant LOI of 35.8% and successfully obtained a V‐0 rating in UL‐94 testing. In contrast, the PHRR with 5% additional MPCD was 456.4 kW/m2 and the THR was 80.2 MJ/m2, which were 52.6% and 29.4% lower than that of pure EPs, respectively. The PHRR of pure EPs was 963.1 kW/m2 and THR was 113.6 MJ/m2, which indicated that the addition of MPCD improved the EP system's flame retardant performance. The impact strength of pure EPs was 13.5 KJ/m2, and 5% addition of MPCD resulted in a 99% increase in the impact strength of EP/MPCD cured samples up to 26.9 KJ/m2, which was explained by the cashew phenol moiety's flexible chain segments. Furthermore, it is discovered by researching its flame‐retardant mechanism that the addition of MPCD may significantly improve the carbon layer's capacity to form char and maintain thermal stability. It can also efficiently trap free radicals and dilute the combustible gases produced during combustion. The flame retardant can increase the overall safety of the EP system by acting as a biphasic flame retardant in both the gas and the solidified phases at the same time.

Study on road performance and flame retardant properties of direct-to-plant warm mixing-flame retardant SBS composite modified asphalt

In order to mitigate the current state of the asphalt tunnel fire crisis, this study intends to prepare a novel environmentally friendly direct-to-plant warm mixing-flame retardant SBS composite modified asphalt that will slow down the burning of asphalt itself and reduce the amount of smoke that is produced. This research introduced the preparation process for direct-to-plant SBS modified asphalt. Through conventional performance experiments, flash point and oxygen index tests, and based on DSR and BBR tests, a comparative analysis of ATH and HF-216 flame retardants was conducted. Additionally, the road performance and flame retardant properties of various warm mix types were analyzed by compounding them with flame retardants. The findings indicate that ATH and HF-216 flame retardants can, respectively, raise the softening point by 13 % and 16 %, lower the ductivity by 6 % and 7 %, and decrease the needle penetration of D-SBS by 10 % and 18 %.Both can enhance asphalt's high-temperature characteristics while negatively affecting its low-temperature characteristics. Warm mixing agent and flame retardant can greatly increase the consistency and deformation resistance of direct-to-plant SBS-modified asphalt; however, they also reduce the ductility of the material by 26 %, 16 %, and 12 %, respectively, which will negatively impact its performance at low temperatures. The composite modified asphalt's high temperature stability can be enhanced by compound mixing the three types of warm mixture before and after aging; nevertheless, the fatigue performance declines to varying degrees and the fatigue factor rises by 3535, 3811, and 3889 kPa, respectively. The warm mixture and flame retardant mixture's S value is 82.5 MPa, 33.7 MPa, 13.8 MPa (-12°C), and 187.4 MPa, 90.7 MPa, and 40.6 MPa (-18°C) higher than the D-SBS mixture's, respectively. The low temperature brittleness of D-SBS can be increased by combining a heated mixture with a flame retardant. The burning times of the Marshall and rut plate specimens are shortened by 31, 46, 55, and 86 s, respectively, when compared to the D-SBS combination. The residual stability is raised by 19.2 %, 21.2 %, and 6 %, 10.7 %, respectively, while the mass loss before and after combustion is decreased by 3.9 g, 5.8 g, and 26 g, 32 g, respectively. AH type exhibits superior flame retardant performance than WH type.

Surface layer reinforcement modification for wood with high strength and flame retardancy performances

The high-value utilization of low-value wood can effectively address the shortage of wood resource, while also contributing to the global green sustainable development and the implementation of “dual carbon” strategy. The present study employed an innovative technology to achieve controllable surface reinforcement modification of fast-growing poplar wood, resulting in improved strength and exceptional flame retardancy for structural applications. The achievement was realized through a three-step method, involving delignification, impregnation, and surface densification, while minimizing the loss of wood volume. The results demonstrated that surface functional densification can significantly improve the mechanical properties of fast-growing poplar wood, with the modulus of rupture (MOR) and modulus of elasticity (MOE) reaching 140.6 MPa and 11.8 GPa, respectively, representing a 3.4-fold and 2.5-fold increase compared to the control group (CK). The samples were found to possess thin surface-densified layers, while the core layer remained unaltered, thereby exhibiting a sandwich structure with significant disparity in density between the layers, reaching up to a factor of 2. The pores structure of the surface layers underwent significant densification, with a gradual deformation distributed throughout its thickness direction. A process optimized for surface densification involving a 2-hour delignification duration and a pressure of 3 MPa. The sample subjected to surface functional modification exhibited a 90-second delay in the peak of heat release compared with the CK. The heat release rate (HRR) experienced a significant deceleration, accompanied by notable reductions in total heat release (THR) and smoke production rate (SPR). The mechanisms underlying the enhancement of surface functionality were elucidated from the perspectives of physical mechanics, microstructure, and flame retardancy, providing a theoretical foundation for the efficient utilization of fast-growing wood.

Enhancing wave retarding and sound absorption performances in perforation-modulated sonic black hole structures

Sonic black hole (SBH) effects in a retarding duct can be exploited for sound wave manipulation and absorption. The phenomenon relies on two fundamental physical mechanisms: wave speed reduction and energy dissipation. In this study, we demonstrate that these two physical processes can be meticulously balanced through adjusting the perforation parameters in a perforation-modulated SBH (PMSBH). To elucidate the mechanism of slow wave generation and the effect of perforation parameters, an analytic model based on the Wentzel-Kramers-Brillouin (WKB) solutions to the linear acoustic wave equation is established. Alongside transient finite element simulations, the study unveils the roles that major physical parameters play in terms of regulating sound speed and sound absorption. The perforation ratio of the PMSBH is identified as the dominant factor affecting the slow-sound effect, with an optimal range of above 10 % for a PMSBH with densely segmented internal rings. Owing to the inclusion of the perforated boundary, prominent slow wave effects can still be maintained even with a reduced number of rings, provided that the perforation ratio is properly chosen within a reduced variation range. In both cases, the identified perforation ratio largely exceeds the conventional range widely adopted in the micro-perforation community when the slow wave effects are absent. On top of this, tuning the hole size can further enhance air friction for better sound absorption. Theoretical and numerical findings are experimentally validated, and the performance of the PMSBH is demonstrated. While bringing forward the concept of tunable design, this study offers physical insights and guidance for realizing effective sound absorbers embracing slow wave principles and perforation-induced sound absorption.

A New Approach for Improving Flame Retardancy of Automotive Interior Upholstery

This study presents the flame retardant (FR) performance of chemically treated automotive upholstery fabrics using two different impregnation methods of Resin Transfer Molding (RTM) and supercritical carbon dioxide (scCO2). Referring to the related standards, untreated seat fabric obtained from seat upholstery of a bus (neat fabric, NF) and treated fabric samples underwent burning rate (BR) and limiting oxygen index (LOI) tests to compare effect of treatment and impregnation methods on FR performance. Thermal analysis was also conducted on the samples considering onset degradation temperatures and char yields. The results showed that BR and LOI of all samples were in acceptable range and treatment provided enhancement in FR performance of NF. The treated sample using scCO2 method gave the highest LOI value of 32% and the lowest BR of 21 mm/min subtending to 18.5% increase in LOI and 30% reduction in BR compared to those of NF. The performance of treatment in RTM was worse than that of scCO2 and better than that of NF. The results confirm that both treatment and methods used in this study give promising results for safety against fire in transportation vehicles.

Importance of adsorption compared with complexation for retarding C3S hydration via adding sodium gluconate

Adsorption effect on particle surfaces and complexation effect with free Ca2+ mostly determine the retarding performance of organic admixtures on cement hydration. However, it is difficult to identify which effect plays a more important role in retarding hydration by experimental methods. Here, a theoretical model was developed to investigate the retarding mechanisms of sodium gluconate (SG) on hydration of tricalcium silicate (C3S). Based on obstruction theory and complexation reaction kinetics, effects of adsorption and complexation were simulated to examine the retarding performance of C3S hydration with addition of SG. The proposed model well predicted the effect of additional dosing of SG on the retarding performance of C3S hydration. Theoretical parameter studies demonstrated that adsorption ratio contributed much largely to the delays in C3S hydration, compared with rate constant of complex generation. Therefore, it is confirmed that adsorption plays a more important role in regulating the retarding mechanism of C3S hydration.

Development and Application of a Chelating Acid for Water Injection Wells of Chang 6 Reservoir of An-Sai Oilfield

Abstract Ansai oilfield is a typical low permeability, low pressure, low yield and serious heterogeneity oilfield. Chang 6 play of Triassic YanChang Formation is a typical ultra-low permeability reservoir. The average porosity of the reservoir is 10 % ~ 14 %, and the average permeability is (0.2 ~ 4.0) × 10−3 μm2. The absolute content of clay minerals in the reservoir is relatively high, with an average content of 18.61 %. The main components are kaolinite, chlorite, illite and illite/montmorillonite interlayer. Due to the reservoir blockage caused by scaling, water sensitivity and formation particle migration in the process of water injection, high injection pressure and under injection wells is increasing dramatically. In view of the above challenges, a fit-for-purpose acid, which contains organic acids and chelating agents, was developed for injection pressure reduction and injection enhancement. It has the characteristics of strong dissolution, good retarding and corrosion inhibition performance. Corrosion rate is 0.5632 g / (m2·h) for J55 steel in 24h, and the core permeability increases by 74.57 % after acid flooding. It has been applied in field test of 3 wells in Chang 6 layer of Ansai oilfield since March 2024. The average daily injection volume increased by 37.87 %, and the validity period was more than 180 days.

Synergistic effect of Co-MOF/epoxy modified tannic acid/ammonium polyphosphate on flame retardancy, anti-melt dripping and mechanical properties of polylactic acid

Achieving flame retardancy and anti-dripping properties in polylactic acid (PLA) while preserving its mechanical integrity remains a significant challenge. In this study, a novel organic ligand rich in phosphorus (P) and nitrogen (N) was synthesized and coordinated with Co2+ions to form a cobalt-based metal–organic framework (Co-MOF) with a multilayer mesoporous structure, acting as an effective carbonization agent. This Co-MOF was then compounded with epoxy-modified tannic acid (eTA) and ammonium polyphosphate (APP) to create a synergistic flame-retardant system for PLA (PLA/MAT). The Co-MOF provides numerous active sites for catalytic oxidation, promoting the formation of a uniform, hill-like expanded carbon layer. During pyrolysis, the Co-MOF and APP yield cobalt oxides and polyphosphates, which catalyze the dehydration of PLA and eTA, facilitating carbonization and forming a continuous, dense protective layer. Consequently, the PLA/MAT system exhibits both robust mechanical properties and excellent flame retardancy, as demonstrated by a limiting oxygen index (LOI) of 27.0 % and a UL-94 V-0 rating, with no melt dripping observed during combustion tests. This work offers a novel approach for enhancing the flame retardancy and anti-dripping performance of PLA, with potential applications in engineering, electronics, and the automotive industry.

PAM material that instantly gives ordinary fabrics excellent flame retardant and thermal insulation properties for fire rescue

To effectively reduce the damage caused by flame burns or heat transfer to the human body during fire, we used PAM aqueous solution as the matrix, XG as the thickener, HPMC as the water-retaining agent to form the basic material system, and added different functional particles (APP, PTW, HCB) to prepare a fire-proof and heat-insulating PAM flame-retardant material for fire emergency rescue. Ordinary cotton fabrics were impregnated into PAM flame-retardant materials using a simple impregnation process. After the impregnation, the test was performed in a non-dropping state (simulating the thermal protection effect of PAM flame retardant materials directly acting on the outside of the human body at the fire scene). The results show that the PAM flame retardant material prepared by adding 4 wt% HCB has the best comprehensive performance. TPP test shows that spraying PAM flame retardant material on the outside of the fabric can instantly give the fabric a higher thermal protection performance. Under the total heat flux of 84 kW/m2, the thermal performance protection value of the fabric is 2641.8 kW·s/m2, and the second-degree burn time can reach 31.45 s. PAM flame retardant material does not damage the fabric. After soaping, the air permeability of the fabric decreases slightly, the moisture permeability and wettability are improved, and the breaking strength is almost unchanged. The CCT test showed that the thermal radiation flux was 50 KW/m2, the PHRR value of PAM flame retardant material was 10.64552 KW/m2, the THR was 6.9 MJ/m2, and the flame retardant performance was excellent. The PAM flame retardant material prepared in this project can be applied to the fire scene and directly sprayed on the outside of the clothing of rescuers and recipients, giving the fabric a better thermal protection effect. It can also be used to extinguish fires in the external environment. This material offers a novel solution for enhancing fire rescuers' and victims' safety protection levels.

Evaluation of the Na-EDTMP/borax system as a non-dispersing, high temperature retarder for oil well cement

For well cementing at temperatures above 120 °C, thermal thinning depicts a major problem, promoting particle sedimentation via decreasing slurry viscosities. This is partly caused by dispersing properties of common high temperature retarder systems and can lead to imperfect zonal isolation, endangering the stability of the wellbore. Counteracting additives tend to start losing their effectiveness at temperatures >140 °C. Other options are often not economically sufficient, increase system complexity or show negative interactions with other additives.Hence, this work presents a comprehensive study on the sodium ethylenediamine tetra(methylene phosphonate) (Na-EDTMP)/borax retarder system, which was found to combine sufficient retardation with low thermal thinning, leading to an enhanced slurry stability at high temperatures. Thickening times (TT's) from 7 to 13 h (increasing with temperature) were achieved from atmospheric pressure and 50 °C up to high pressures and temperatures (HP/HT) of 19.0 kpsi and 200 °C bottom hole circulating temperature (BHCT). Furthermore, On/off-cycle HP/HT consistometer tests at 160 and 190 °C and rheological measurements were performed to examine stability of the slurry's viscosity. Experiments with fluid-loss additives show potential compatibility with other additives.Total retarder dosages of 0.97–2.64 % bwoc (by weight of cement) were applied. Compared to prior literature, higher Na-EDTMP/borax ratios (0.29–0.34 vs. 0.055) were found to improve retarding performance probably by enhancing synergetic effects. The slurries featured a sufficient initial viscosity (<40 Bc) and a constant pumpability (10–25 Bc) during the tests followed by a swift setting and compressive strength (CS) development. Additionally, high slurry stability was shown and compatibility with common fluid-loss additives is probable. Main disadvantage was the relatively high sensitivity of the system, especially at moderate temperatures, requiring exact dosage.Summarizing, the Na-EDTMP/borax retarder system might present a low-complexity opportunity for common high temperature retarders, avoiding thermal thinning while improving slurry stability.

Preparation and characterization of HNTs@ZIF enhanced intrinsic flame retardant RTV silicone rubber

Phenylphosphonyl dichloride (BPOD) and 3-aminopropyltriethoxysilane (APTES) were used to prepare phosphorus-nitrogen hexaethoxysilane (BPTES). BPTES was then used for cross-linking and curing hydroxyl-terminated room-temperature vulcanized (RTV) silicone rubber, providing intrinsic flame retardancy. In addition, halloysite (HNTs) is a kind of tubular silicate, taking advantage of its large aspect ratio, HNTs were used as a template to load ZIF67 on the surface of halloysite to obtain HNTs@ZIF tubular filler. It was added to the above system as a reinforcing and flame-retardant filler by physical blending, and the RTV elastomer with excellent performance was prepared. The successful preparation of phosphorus-containing crosslinkers (BPTES) was demonstrated by FT-IR. After the introduction of the new crosslinker, RTV not only has improved flame retardant performance, but also improved mechanical properties. The tensile strength and elongation at break of RTV with 20 wt.% BPTES are increased by 151% and 211%, respectively. The peak heat release rate (pHRR) and the peak of smoke production rate (pSPR) are reduced by 55.9% and 48.6%, respectively, and the thermal stability is also improved. In addition, the successful preparation of HNTs@ZIF was confirmed by FT-IR, XRD, XPS, and TEM. By introducing 2 wt.% HNTs@ZIF into 20 wt.% BPTES cured RTV, the intrinsically flame-retardant RTVs with enhanced performance were prepared. It is worth noting that when 2 wt.% HNTs@ZIF is added, the flame retardant and smoke suppression properties of phosphorus-containing silicone rubber are further improved. Because the ZIF contains cobalt metal ions that can be catalyzed into carbon. The pHRR and pSPR decrease by 18.3% and 16.3%, respectively, and the total heat release (THR) and total smoke production (TSP) decrease by 23.6% and 24.4%, respectively. This work will provide enlightenment for the study of intrinsic flame-retardant RTVs enhanced by modified halloysite.

Study on A New Type of High Temperature Resistant Adsorption Type Retarded Acid System

Abstract Deep carbonate reservoirs present significant hurdles for reservoir stimulation due to extreme temperatures and rapid acid-rock reactions. The dense adsorption layer has the ability to postpone the interaction between rock and hydrogen ions, which is crucial for lowering the acid rock reaction rate. Based on the surfactant and film-forming agent’s synergistic impact, the retarding agent SH-1—which has the ability to generate a dense adsorption film on the surface of rock samples—was chosen for this study. After adding synergist and corrosion inhibitor, a new type of high temperature resistant adsorption type retarding acid system ’ 0.9% SH-1 + 20% HCl + 0.1% synergist + 1.5% corrosion inhibitor ’ was developed. The retarding performance of the retarding acid system at high temperature and various parameters of acid rock reaction kinetics were studied. The results show that the new adsorption-type retarded acid system can achieve good retarding effect at high temperature and ultra-high temperature, and the retarding rate is 90 % at 180 °C. In comparison to traditional hydrochloric acid, the new adsorption-type retarded acid exhibits a lower hydrogen ion mass transfer rate and a higher acid-rock reaction activation energy. These differences can effectively lower the acid-rock reaction rate. Additionally, an examination of the etching morphology reveals that the retarded acid is more easily etched along the cracks leading to the deep core. The novel adsorption-delayed acid offers excellent retarding power, high temperature resistance, and minimal damage. Consequently, it has certain reference value for the study of acidification transformation of ultra-high temperature deep carbonate reservoirs.

Preparation of vanillin-based polyurethane/SiO2 nanocomposite foams with excellent flame retardancy and thermal insulation performance

In this work, vanillin based inherently flame retardant polyurethane/SiO2 composite foams were designed. Firstly, the vanillin based flame retarding diol (VDP) was synthesized. Then, the KH550 modified nano-SiO2 (KH550-g-SiO2) was prepared as the reinforcement. Subsequently, a series of flame-retardant polyurethane/SiO2 composite foams (PUF-0.5P-xSiO2) were synthesized by tailoring the hard-soft segments and KH550-g-SiO2 contents. The results showed that KH550-g-SiO2 significantly improve the thermal stability of the PUF-0.5P-xSiO2 foams. In addition, the compressive strength of PUF-0.5P-xSiO2 foams was enhanced from 0.18 MPa (PUF-0.5P) to 0.45 MPa (PUF-0.5P-2.0SiO2) under 20 % strain. The flame retardant properties of PUF-0.5P-2.0SiO2 reached UL-94 V-0 grade. Meanwhile, the addition of KH550-g-SiO2 also decreased the thermal conductivity from 0.046 W/m·k to 0.037 W/m·k for PUF-0.5P-2.0SiO2. This work may provide an approach to obtain the biobased lightweight polyurethane foams for the application in packaging and building areas.