以副产锌泥为原料水热合成阻燃剂硼酸锌

硼酸锌是一种绿色环保型无机阻燃剂。以工业副产锌泥为锌源、硼砂为原料,利用水热法制备硼酸锌（4ZnO·B2O3·H2O）。采用X射线衍射（XRD）、热重（TG-DTA）、扫描电镜（SEM）等分析测试手段,对制备的产品进行表征,并探讨各因素对水热合成反应的影响,建立适宜的反应条件。当水热温度为140 ℃时,锌与硼砂的物质的量比为1∶1.0,固体与液体的质量比为1∶12,水热时间为7 h以上。在此条件下,所得硼酸锌粉体的XRD谱图与4ZnO·B2O3·H2O一致,失水温度高于415 ℃。若在反应体系中添加硬脂酸钠和聚乙二醇,可得到疏水型硼酸锌样品;若添加10%硼酸锌于木粉中,400 ℃时的残碳率比纯木粉高约17%~18%,表明硼酸锌有一定的阻燃性。     

模板法合成锡酸钴及其对PVC的阻燃应用

以活性炭为模板、五水四氯化锡和六水硝酸钴为原料,制备纯相的多孔锡酸钴（CoSnO3）阻燃剂,通过X射线衍射（XRD）和扫描电镜（SEM）对其结构、形貌进行表征,并将其应用于PVC的阻燃研究中。当CoSnO3的添加量为15份时,其极限氧指数（LOI）达到35.6％、烟密度等级（SDR）为75.2％、断裂伸长率为168.32%、拉伸强度为 22.50 MPa。通过热重分析（TGA）对阻燃前后PVC的热降解行为进行了初步探讨,研究发现： 经CoSnO3阻燃处理后,PVC样品的初始降解温度降低,高温时的剩炭量增加,表明CoSnO3对PVC材料具有较好的阻燃消烟性能。     

Use of zinc borate as the third component of a traditional brominated flame retardant system in acrylonitrile butadiene styrene

Because zinc borate is an effective smoke suppressant and cheaper than antimony trioxide, the main aim of this study was to investigate usability of zinc borate as the third component of a traditional binary Br/Sb₂O₃ system in acrylonitrile butadiene styrene. Limiting oxygen index, UL‐94, and mass loss cone calorimeter studies indicated that almost all flame retardancy parameters were kept when certain percentages of antimony trioxide were replaced with zinc borate. Residue analysis revealed that the predominant flame retardancy mechanism of the traditional system was gas phase action, whereas zinc borate contributes especially in the condensed phase action by forming thicker and stronger char layer. Copyright © 2012 John Wiley & Sons, Ltd.     

Investigation on effects of aluminum and magnesium hypophosphites on flame retardancy and thermal degradation of polyamide 6

Two hypophosphites, aluminum hypophosphite (AlHP) and magnesium hypophosphite (MgHP), were applied to obtain flame retardant polyamide 6 (FR-PA6) composites. UL-94 and limiting oxygen index results indicated that AlHP contributed both good flame retardance and antidripping ability for PA6, while MgHP did not. Based on thermogravimetric analysis (TGA), AlHP and MgHP presented the different thermal degradation behavior. That is, the quick decomposition of AlHP took place at lower temperature than that of MgHP. AlHP promoted the early thermal degradation of PA6 and formed more char residue. The thermal decomposition mechanisms of AlHP and MgHP in nitrogen or air were suggested. Scanning electron microscope and X-ray photoelectron spectroscopy indicated that in the existence of AlHP, the morphological structures of char residue were more homogenous, and compact, and more char residue was formed. These results well illustrated the difference of the flame retardancy between AlHP and MgHP. Mechanical properties of PA6/AlHP and PA6/MgHP were also obtained. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,thermal stability,and flame retardancy of PA66, treated with dichlorophenylphsophine derivatives

Synthesis, thermal stability, and flame retardancy of PA66, treated with derivatives of dichlorophenylphosphine, are reported. With an aim to improve the thermal stability and flame retardancy of PA66, along with improving its consistency, several new derivatives of dichlorophenylphosphine, namely bis-(4-carboxyanilino) phenyl phosphamide (BNPO), N-benzoic acid-(ethyl-N-benzoic acid formamide) phosphamide (NENP), poly-N-aniline-phenyl phosphamide (DPPD), and bis-N-benzoguanamine-phenyl phosphamide (MCPO), were synthesized, which resulted in end amino or carboxyl. FTIR, ¹H NMR, MS, and elemental analysis confirmed the chemical structures of the synthesized flame retardants. Interestingly, thermal stabilities and flame retardancies of PA66 improved, however, the intrinsic viscosities ([η]) and viscosity average molecular weights (M_η) decreased with grafting of the flame retardants. Moreover, the consistency was overcome conformingly using SEM without interfacial effect.     

Flame retardancy and thermal stability of polyhedral oligomeric silsesquioxane nanocomposites

The flame retardancy and thermal stability of polyhedral oligomeric silsesquioxane (POSS) nanocomposites are reviewed. Results are summarized and compared on the basis of structure–property relationships. Because of the variability of groups attached on POSS, they exhibit different performance in polymer nanocomposites: metal‐containing POSS show good catalytic charring ability; vinyl‐containing and phenyl‐containing POSS promote the strength of char. Improvements in the cone calorimeter (such as reduced peak heat release rate) are advantages of POSS as preceramics for fire retardancy compared with traditional flame retardants, and it will pave the way to the design of inorganic–organic hybrid polymer nanocomposites with enhanced flame retardancy and thermal stability. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of talc on thermal stability and flame retardancy of polycarbonate/PSBPBP composite

A novel flame retardant poly(3-aminopropyl methylsiloxane bis(3-hydroxy phenyl spirocyclic pentaerythritol bisphosphate)) (PSBPBP) in combination with talc was blended into polycarbonate (PC) by melt compounding. The flame retardancy and thermal stability of PC/PSBPBP/talc composites were investigated by limiting oxygen index (LOI) test, UL-94 rating test, thermogravimetric analysis (TGA), Raman spectroscopy (RS), and scanning electron microscope (SEM). The mechanical properties were also measured in this work. Increasing talc content leads to observed improvement on flame retardancy of PC composites. LOI value of PC/PSBPBP/10 wt % talc system was 34, and this system passed V0 rating in the UL-94 test. The char yield at 700°C was 28.2% and the onset decomposition temperature shifted up to 540°C for PC/10% PSBPBP/10% talc system in TGA. In the Raman measure, the R value and G linewidth of PC/PSBPBP with 10 wt % talc composite increased to 1.41 and 65 cm⁻¹ from 1.12 and 43 cm⁻¹ of pure PC, respectively. The Raman results suggest that the char residue of PC/PSBPBP with talc composites was denser and had better barrier property, which is agreement with the SEM results. Besides, talc had no remarkable influence on the mechanical properties of PC/PSBPBP composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigation of flame retardancy and physical–mechanical properties of zinc borate/boric acid polyester composites

The glass fiber reinforced polyester composite materials were prepared with varying contents of boric acid, zinc borate, and magnesium hydroxide as flame retardants to improve the flame retardancy of the composites. Experimental results showed that boric acid exhibited a good flame retardant effect on the polyester composite. When boric acid content is used as 15 wt %, the Limiting Oxygen Index (LOI) value of the composite reached upto 25.3. The increase in boric acid content from 15 to 30 wt %, the LOI values of composite were enhanced from 25.3 to 34.5 by 9.2 units. The LOI values of the composite samples increased with increasing boric acid content. The smoke density results showed that the addition of glass fiber and flame retardants decreased the smoke density of the unreinforced polyester resin. The mechanical properties of the composites have decreased by the addition of flame retardants. The scanning electron micrographs taken from fracture surfaces were examined. The flame retardants, such as boric acid, were well dispersed in the glass fiber reinforced polyester composites and obviously improved the interfacial interaction between glass fibers and polyester composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of expandable graphite on flame retardancy and thermal stability property of unsaturated polyester resins/organic magnesium hydroxide composites

An eco-friendly flame retardant unsaturated polyester resin (UPR) material was prepared by combination organic magnesium hydroxide (OMH) and expandable graphite (EG). Different from direct addition of magnesium hydroxide (MH) in UPR matrix-like traditional method, OMH as a reactive monomer participates in the polycondensation reaction of UPR was more effective in improving the compatibility of flame retardant with matrix. Interestingly, the flame retardant UPR composites exhibited a more satisfactory flame retardant effect when a certain amount of 8 wt % EG was added into UPR/OMH matrix because of the synergistic effect between OMH and EG, resulted in the limited oxygen index from 21.7 to 28.5% and UL-94 test passed V-0 rating. Moreover, the peak heat release rate, total heat release, and smoke production rate of flame retardant UPR composites significantly reduced. The excellent flame retardancy was due to the formation of a dense and continuous carbon layer in the later stages of combustion. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47881.     

Effects of zinc borate and microcapsulated red phosphorus on mechanical properties and flame retardancy of polypropylene/magnesium hydroxide composites

In this paper, the mechanical properties and flame retardancy of zinc borate (ZB) and microcapsulated red phosphorus (MRP) with modified magnesium hydroxide (MH) in flame-retardant polypropylene (PP) were studied by mechanical properties test, UL-94 test, and thermogravimetric analysis (TGA). The crystallization behaviors of the composites were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The addition of ZB could improve tensile strength and elongation at break of PP/MH composite. The MRP powders had a little effect on the mechanical properties of the PP composites. DSC results showed the addition of ZB and MRP weakened the heterogeneous nucleation effect of MH on PP. The addition of ZB and MRP had a great effect on the flammability of the PP/MH/EG composites. The thermal stability of PP/MH/ZB and PP/MH/ZB/MRP composites was better than that of PP/MH composite.     

Improved flame retardancy and ceramifiable properties of PE composites by the combination of aluminum hypophosphite and zinc borate

Ceramifiable polyolefin materials protect circuits by forming compact ceramic layers under fire conditions, and can have an excellent application prospect in the refractory cable field. In this paper, Aluminum hypophosphite (AHP) and zinc borate (ZB) were added to further improve flame retardancy and ceramifiable properties of polyethylene (PE)/silicon powder (SP)/wollastonite (WS)/glass frits (GF) composites. The LOI values of composites with AHP/ZB can reach 23.5%, significantly higher than that of PE/SP/WS/GF composites (19.6%). The thermal stability behavior and char yield behaviors of composites could also be characterized by the TG test. The incorporation of AHP/ZB enhances the flexural strength of residue formed at 1000°C from 0.1 to 20.5 MPa. In addition, a new crystal is formed at high temperatures and is identified as the calcium aluminum phosphate phase [CAP, Ca₉Al (PO₄)₇] by XRD analysis. The flow of molten ZB accelerates the reaction of AHP and WS, and this eutectic reaction promotes the formation and stability of ceramics. Furthermore, the SEM analysis reveals the fluxing effect of ZB at low temperatures and AHP at high temperatures. The incorporation of AHP/ZB with a ratio of 1:1 could effectively avoid the vitrification of ceramics and improve their dimensional stability.     

Metal-phenolic networks: A biobased synergist for EVA/APP composites toward enhanced thermal stability and flame retardancy

In the present study, a biomass-derived metal-phenolic networks (MPN) were used as charring agent and flame-retardant synergist for Ethylene-vinyl acetate/Ammonium polyphosphate (EVA/APP) composites. Compared with the polyphenol, the thermal stability of MPN was improved remarkably, making it a good match for EVA. Meanwhile, Limit oxygen index test revealed that MPN endowed EVA/APP composites with enhanced flame-retardant performance. The reason on improvement in the flame retardancy of composites was also discussed and the corresponding mechanism was proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47243.     

Al2O3/h-BN/epoxy based electronic packaging material with high thermal conductivity and flame retardancy

The long-term and stable operation of integrated circuits and microelectronics requires packaging epoxy resin (EP) exhibit high thermal conductivity for efficient heat dissipation, and excellent flame retardancy in case of thermal runaway. We achieved such EP composite via filling poly-dopamine (PDA) modified nanoscale Al₂O₃ spheres and microscale h-BN sheets. The PDA modification increases the compatibility between fillers and EP and largely reduces the viscosity, improving the dispersion of fillers in EP thus the thermal conductivity of EP composites. In addition, NH₃, H₂O, and N₂ generated during the combustion of phenolic hydroxyls and aminos in PDA combined with the physical barrier effect of Al₂O₃ and h-BN can improve the flame retardancy of EP composites. As a consequence, the EP composite filled with PDA modified Al₂O₃ (26.67 wt%) and h-BN (13.33 wt%) (i.e., PDA-BNAO/EP) shows a thermal conductivity of 1.192 W/mK (654.9% of EP), a peak heat release rate of 194.9 W/g (33.8% of EP), and total heat release of 15.2 kJ/g (54.5% of EP), respectively. What's more, the viscosity of PDA-BNAO/EP is 20,443 mPa s, which is only 20% of BNAO/EP (whose viscosity is 102,281 mPa s). More importantly, the PDA-BNAO/EP has good dynamic mechanical properties with the storage modulus of 14.69 Gpa, glass transition temperature of 91.9°C and good electrical insulation, which is desired for packaging of microelectronics. PDA-BNAO/EP composite should be a promising candidate for widespread packaging materials of microelectronics.     

Effect of water erosion on flame retardancy of high-impact polystyrene/magnesium hydroxide composite and its mode of action

High-impact polystyrene (HIPS) flame retarded by magnesium hydroxide (MH) was treated in water at different conditions. The effect of water erosion on flame retardancy of the HIPS/MH composite and its mode of action was investigated by various means. The results indicate that both limiting oxygen index value and UL-94 rating of the HIPS/MH composite decrease observably after water erosion. The average heat release rate, average mass loss rate, total heat release, and total smoke release of the composite all increase remarkably after water erosion. The MH content in the surface layer of the HIPS/MH composite reduces, and the surface of this composite becomes rough and porous after erosion. The water-eroded composite shows a loose and discrete surface morphology after subjected to fire, which favors heat transfer and mass exchange between flame area and the underlying polymers. Consequently, both flame retardancy and smoke suppression of the polymer composite decrease significantly. The decrease in flame retardancy occurs in condensed phase. The result of this work has provided a basis for further investigations to prevent this detrimental effect induced by water erosion.     

The flame retardant and smoke suppression effect of fullerene by trapping radicals in decabromodiphenyl oxide/Sb2O3 flame‐retarded high density polyethylene

To improve the large release of smoke and heat for brominated flame retardants (BFRs) in fire hazard, fullerene (C₆₀) had been introduced in high density polyethylene (HDPE)/bromine flame retardant (Deca/Sb₂O₃, BFR in short) system in this study. The effects of C₆₀ on the thermal properties, flame retardant properties, rheological behaviors, and smoke release behaviors in HDPE/BFR blends were researched. During polymer thermal degradation, C₆₀ and BFR exhibited the trapping radical ability in condensed phase and gaseous phase, respectively. The intergrated effects of C₆₀ and BFR on the thermal stability and flammability of HDPE were studied by thermo‐gravimetry and cone calorimeter. It was indicated that the introduction of C₆₀ improved the thermal and thermo‐oxidative stability of HDPE/BFR blends. A remarkable advantage of adding C₆₀ was to reduce the peak heat release rate and the average specific extinction area, especially at higher concentration of C₆₀. The analysis of rheological behaviors and pyrolysis products revealed that C₆₀ can capture alkyl radicals, chain radicals, and bromine radicals in the condensed phase, which was in favor of terminating the thermo‐oxidative decomposition and inhibiting the heat and smoke release of HDPE/BFR blends during combustion.     

Flame retardancy,antifungal efficacies,and physical–mechanical properties for wood/polymer composites containing zinc borate

This work aimed to examine flame retardancy, antifungal performance and physical–mechanical properties for silane‐treated wood–polymer composites (WPCs) containing zinc borate (ZnB). ZnB with content from 0.0 to 7.0 wt% was added to WPCs, and silane‐treated wood contents were varied. The polymers used were poly(vinyl chloride) (PVC) and high‐density polyethylene (HDPE). The decay test was performed according to the European standard EN 113. Loweporus sp., a white‐rot fungus, was used for antifungal performance evaluation. Antifungal performance was observed to decrease with wood content. Incorporation of ZnB at 1.0 wt% significantly increased the antifungal performance of WPCs. ZnB content of greater than 1.0 wt% lowered the antifungal properties of WPCs. The results suggested that the wood/PVC composite exhibited better antifungal performance than the wood/HDPE composite. The addition of wood flour to PVC and HDPE decreased flame retardancy, whereas the incorporation of ZnB retained the flame retardancy. ZnB was found to be more appropriate for wood/PVC than wood/HDPE as a result of hydrogen chloride generated from the dehydrochlorination reaction of PVC. The results indicated that the addition of ZnB did not affect the physical‐mechanical properties of neat polymers and the composites. Copyright © 2016 John Wiley & Sons, Ltd.     

Influence of zinc borate on flame retardant and thermal properties of polyurethane elastomer composites containing huntite‐hydromagnesite mineral

The effect of zinc borate (ZnB) was studied on the flame retardant and thermal properties of thermoplastic polyurethane containing huntite‐hydromagnesite. The flame retardant properties of thermoplastic polyurethane–based composites were investigated using limiting oxygen index, vertical burning test (UL 94), thermogravimetric analysis, and mass loss calorimeter. No remarkable effect of ZnB was observed on the flammability properties of composites. UL 94 rating did not change regardless of the added amount of ZnB, and the slight increase in limiting oxygen index value was observed at ratio of 1:1. The adjuvant effect of ZnB was observed during the mass loss calorimeter studies by increasing the barrier effect of the residue in the condensed phase and by increasing the formation of incombustible gasses in the gas phase. The highest fire performance was achieved at ratio of 1:1.     

Enhanced flame retardancy,smoke suppression,and acid resistance of polypropylene/magnesium hydroxide composite by expandable graphite and microencapsulated red phosphorus

Low flame retardant efficiency and poor acid resistance of filled polymer composites are two main drawbacks of magnesium hydroxide (MH) as a flame retardant (FR). To solve these problems, expandable graphite (EG) and microencapsulated red phosphorus (MRP) were introduced into polypropylene/magnesium hydroxide (PP/MH) composite by melt compounding. The obtained PP/MH/EG/MRP quadruple composite was studied regarding its fire behavior as well as acid resistance. Obvious flame retardant synergism among MH, EG, and MRP is found in PP, which diminishes the loading of FR from 63.0 to 37.5 wt% to obtain V-0 rating in UL-94 test and low smoke release. Compact intumescent char with high thermo-oxidative stability was generated on composite surface, which plays a vital role in flame retardancy. The removal of MH by acid erosion on PP/MH/EG/MRP composite surface does not affect production of intumescent char and fire behavior of this composite. The composite displays good fire retardancy, smoke inhibition, and acid resistivity concurrently. This article renders an easy and cheap route to overcome the main faults of MH.     

Hydrated and anhydrous zinc borate fillers for tuning the flame retardancy of epoxy nanocomposites

In this study, hydrous (Zn₃B₆O₁₂·3.5H₂O) and anhydrous (ZnB₂O₄) forms of zinc borates were synthesized at 150 and 175°C under moderate pressure conditions (85 and 150 psi, respectively). Synthesized zinc borates were controllably incorporated (1, 5, and 10 wt%) in epoxy resin to prepare their nanocomposites. The flame-retardant and mechanical properties of these nanocomposites were determined and compared in terms of their flame spread testing, smoke density, limiting oxygen index, and flexural strength. Superior properties in terms of flame retardancy were observed for epoxy composites containing hydrous filler as compared to anhydrous zinc borates. Although flexural strength was observed to be decreased with increasing filler concentration, the marked drop is lower for composites with hydrous zinc borate as compared to the anhydrous one. The variations in flame-retardant and mechanical properties of composites with both types of fillers are related to their morphological (field emission scanning electron microscopy), X-ray diffraction (XRD) analysis, Fourier Transform Infrared (FTIR), differential scanning calorimetry, and thermogravimetry analysis and explained with condensed phase mechanism.