电子模块灌封用柔性阻燃型改性环氧树脂研究

选用柔性环氧树脂、活性增韧剂、磷系列阻燃剂FR-P和复合阻燃剂FR-A对环氧树脂CYD128进行改性,提高环氧树脂的柔韧和阻燃等性能,取得良好的改性效果,成功制备出柔性阻燃环氧电子灌封材料, 有利于解决环氧树脂在电子工程应用过程中的问题。     

The synthesis of biphenyl ether/vanillin-based flame retardants for enhancing both the flame retardant properties and mechanical performance of epoxy resin

Imparting good flame retardancy and mechanical properties to epoxy resin (EP), while pursuing the sustainable and safe application of EP, we synthesized a novel reactive phosphorus/nitrogen flame retardant for biomass through nucleophilic addition reaction, which contains flexible ether bonds and rigid aromatic ring structure (DVD). Owing to the cooperative effect of aryl ether diamine, phosphorus phenanthrene, and biomass vanillin, the DVD exhibited excellent flame retardancy. EP/DVD-1 (0.4 wt% phosphorus content) achieved UL-94 V-0 rating, with an improvement in limiting oxygen index value from 26.5% (pure EP) to 32.5%. In the CCT, the modified DVD EP showed a 44.5% reduction in peak peak of heat release rate (PHRR) and a 38.0% reduction in total heat release compared to pure EPs. And flame retardant epoxy resin (FREP) still had good transparency after the addition of DVD, which indicated the nice compatibility between DVD andEP. What was noteworthiness was that at high levels of addition, the mechanical properties of modified EP for DVD was still improved compared to pure EP. These results demonstrate that DVD is an excellent and multifunctional bio-based flame retardant with broad application prospects in the field of EP material modification.     

新型含磷阻燃环氧树脂的合成与表征

以2-(5,5-二甲基-4-苯基-2-氧代-1,3,2-二氧磷杂环已烷膦酸酯基)-对苯二酚和双酚A 二缩水甘油酯合成了一新型的含环状膦酸酯结构的阻燃环氧树脂(DPODB-EP).采用元素分析、红外光谱(FTIR)和凝胶渗透色谱(GPC)对该含磷环氧树脂的结构和相对分子质量分布进行了表征.采用示差扫描量热法(DSC))和热失重法(TG)对DPODB-EP/PN固化物热性能进行了测试,发现该固化物具有较高的玻璃化转变温度(165℃)和较高的燃烧残炭率(700℃,31%).阻燃性能测试表明该固化物具有较好的阻燃效果,在磷的质量分数为2.25%时其极限氧指数可达29.5%.     

A P/N-containing flame retardant constructed by phosphaphenanthrene,phosphonate, and triazole and its flame retardant mechanism in reducing fire hazards of epoxy resin

A P/N-containing flame retardant (PPT) constructed by phosphaphenanthrene, phosphonate, and triazole groups was successfully synthesized and used as a reactive co-curing agent for epoxy resin (EP). The curing behavior, thermal property, combustion behavior, and flame retardant mechanism of EP thermosets were comprehensively investigated. According to the analysis of DSC and TGA, PPT accelerated the crosslinking reaction and enhanced the charring ability for EP thermosets at high temperature. The results of combustion test indicated that PPT endowed epoxy thermoset with outstanding flame retardancy. When the phosphorus content was 0.71 wt%, EP/DDS/PPT-2 achieved a LOI value of 33.2% and passed V-0 rating in UL-94 test, and its peak heat release rate and total heat release were decreased by 63.7 and 30.5%, respectively, relative to EP/DDS. Moreover, the FIGRA of EP/DDS/PPT-2 was reduced from 9.7 to 3.5 kW m⁻² s⁻¹, manifesting the significantly improved fire safety of EP thermoset. The flame retardant mechanism was summarized as two parts: (a) the barrier effect of continuous phosphorus-rich char layers in condensed phase, (b) the quenching effect of phosphorous radicals and diluting effect of nonflammable gases in gaseous phase.     

环氧树脂体系阻燃技术的发展

阐述了改善热固性环氧树脂体系阻燃性能的目的和意义，介绍了环氧树脂体系的阻燃方法。以气相机理和凝聚相机理为基础，讨论了几种常用阻燃剂的阻燃机理。分析了环氧树脂体系阻燃技术的研究现状，指出环氧树脂阻燃技术将向着安全化、复合功能化、新技术化和研究系统化的趋势发展。     

Strengthen flame retardancy of epoxy thermoset by montmorillonite particles adhering phosphorus-containing fragments

Phosphaphenanthrene derivative tri-(3-DOPO-2-hydroxypropan-1-yl)-1,3,5-triazine-2,4,6-trione (TGD) and organo-modified montmorillonite (OMMT) were jointly introduced into the diglycidyl ether of bisphenol A cured by 4,4-diamino-diphenylmethane (EP) to investigate their flame retardant behaviors. With only addition of 0.5%OMMT and 2.5%TGD, epoxy thermoset achieved a limiting oxygen index value of 33.7% and passed UL 94 V-0 rating test. Compared with the combustion behaviors of 3%OMMT/EP and 3%TGD/EP, an obvious synergistic flame retardant effect between OMMT and TGD can be concluded in OMMT/TGD/EP. Meanwhile, the FTIR spectra of gas-phase and condensed-phase products further proved this synergistic effect working in a physical way. On one hand, the co-existence of hydroxyl-containing TGD enabled montmorillonite (MMT) particles to filtrate and adhere more smoke fragments. On the other hand, the co-action of MMT help the polar phosphorus-containing fragments from TGD better strengthened char layer, enhancing the barrier and protective effect of residue. The synergistic flame retardant effect from OMMT/TGD system endowed themselves with higher flame retardant efficiency, and epoxy thermoset with better flame retardant performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47500.     

新型磷硅改性环氧树脂阻燃性能研究

采用聚苯基硅氧烷(PPMS)、9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)与双酚A型环氧树脂合成了新型的含磷硅环氧树脂(Si-P-EP),通过红外谱确认了其结构。将Si-P-EP与纯环氧树脂复配制备得到复合物Si-P-EP/EP,对其进行了氧指数和水平燃烧测试并通过红外光谱对燃烧后的残炭结构进行了分析。结果表明,Si-P-EP/EP的氧指数有所提高,水平火蔓延速率由27.27 mm/min降低到20.13 mm/min,Si-P-EP/EP燃烧后生成了含磷硅的炭层,从而提高了环氧树脂的阻燃性能。     

Preparation of novel biomass humate flame retardants and their flame retardancy in epoxy resin

Humic acid (HA), a biomass material with plentiful oxygen-containing functional groups, showed huge potential to be considered as a promising charring agent in flame retardancy. In this study, this HA was modified with four different metal ions like Fe²⁺, Mn²⁺, Al³⁺, and Cu²⁺ and finally, introduced into the epoxy resin (EP) to enhance the flame retardancy of the EP and the dispersion of these flame retardants into the EP matrix. When 10 wt% of HA-Fe and HA-Mn were incorporated into EP matrix, the limiting oxygen index (LOI) was increased from 21.2% for EP to 26.6 and 25.3% for the EP composites and the peak heat release rate (pHRR) was reduced by 36 and 35.5%, respectively. Such a significant improvement in flame retardancy was attributed to the catalytic charring of HA in the presence of metal ions, which ultimately increased the residual char formation and produced compact char layers during the combustion process to retard the transfer of heat and combustible gases between the EP composites and the flame zone. Finally, this kind of application provided a feasible way for the development of an environmentally friendly flame retardant with high efficiency, which improved the fire safety of EP matrix.     

改性三聚氰胺氰尿酸盐阻燃环氧树脂研究

采用分子复合技术合成了改性MCA(M-MCA)阻燃环氧树脂,采用UL94垂直燃烧测试及微型量热分析对其性能进行了研究,同时采用热失重分析方法研究其降解历程和阻燃机理。结果表明,该材料实现了阻燃剂粒子在环氧溶液及基材中超细及均匀分散,解决了常规MCA阻燃剂在环氧树脂胶液中分散困难、易团聚等问题,改性MCA阻燃树脂比传统MCA具有更佳阻燃效果,该体系阻燃机理以气相阻燃为主。     

Effect of Ni2+ chelated to the surface of PBFA on the charring flame retardant and smoke suppression properties of epoxy resin

Here, a phosphazene-based flame retardant (PBFA) containing active amine groups was synthesized by hexachlorocyclotriphosphazene and N-aminoethylpiperazine and nickel ion (Ni²⁺) was chelated to the surface of PBFA (named as PBFA-Ni²⁺). Incorporation into epoxy resin (EP) with a loading of 6 wt% (named as EP/PBFA-Ni²⁺-6.0), enabled the composite to pass the vertical burning test (UL-94) V 0 rating. Peak heat release rate and the total smoke release of EP/PBFA-Ni²⁺-6.0 were decreased by 41.02% and 22.74% as measured by cone calorimeter tests. The production rate of CO was inhibited when PBFA-Ni²⁺ was incorporated into EP.     

Improved flame retardancy by synergy between cyclotetrasiloxane and phosphaphenanthrene/triazine compounds in epoxy thermoset

A siloxane compound (MVC) and a bi‐group phosphaphenanthrene/triazine compound (TGD) were employed in epoxy thermosets to explore high‐efficiency flame retardant systems. With only 1 wt% MVC and 3 wt% TGD, an epoxy thermoset passed UL 94 V‐0 rating test and achieved a limiting oxygen index value of 34.0%, exhibiting an excellent flame retardant effect. The MVC/TGD system not only decreased the peak value of heat release rate and effective heat of combustion but also imparted an improved charring ability to thermosets, thereby outstandingly reducing the flammability of 1%MVC/3%TGD/EP. Compared with the fire performance of 4%TGD/EP and 4%MVC/EP, the MVC/TGD system showed an obvious flame retardant synergistic effect, mainly depending on the general improvement of flame inhibition, charring and barrier effects of the thermoset during combustion. Evolved gas analysis combined with condensed‐phase pyrolysis product analysis jointly revealed the details of the changed pyrolysis mode. © 2017 Society of Chemical Industry     

Synthesis of aluminum methylcyclohexylphosphinate and its use as flame retardant for epoxy resin

A novel aluminum phosphinate—aluminum methylcyclohexylphosphinate (Al(MHP))—was synthesized by reacting n‐butyl methylphosphonite with cyclohexene, followed by reacting with anhydrous AlCl₃. The products were characterized with gas chromatography, Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance, phosphorus nuclear magnetic resonance, X‐ray fluorescent spectroscopy, and thermogravimetric (TG) analyses. After blending with epoxy resin (EP), flame retardancy was estimated with the use of limited oxygen index (LOI) and UL‐94 test, and thermal stability was investigated using TG analysis. The morphologies and composition of the char obtained after being heated at 300 °C for 20 min followed by 500 °C for 3 min in the muffle furnace were characterized by scanning electron microscopy (SEM) with energy‐dispersive X‐ray (EDX) analysis. Results showed that Al(MHP) is an efficient flame retardant for EP, and Al(MHP)/EP can pass UL‐94V‐0 rating with an LOI of 28.8% by adding 15 wt.% of Al(MHP). TG results showed that the presence of Al(MHP) in EP increases the char yield and depresses the thermal decomposition. SEM‐EDX analysis showed that the char obtained at 300 °C is coherent and consists of P‐rich components; at higher temperature (500 °C), the char becomes tiny and loose and phosphorus element is released into gas. Compared with neat EP, composites have lower water absorption. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis of a novel DOPO‐based polyphosphoramide with high char yield and its application in flame‐retardant epoxy resins

A novel and highly effective flame retardant (FR), DOPO‐TPMP oligomer, was synthesized by a simple condensation of 4‐(hydroxymethyl)‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐1‐oxide and phosphorus oxychloride followed by a polycondensation reaction with 6‐(2,5‐dihydroxyphenyl)‐6H‐dibenzo[c,e][1,2]oxaphosphinine‐6‐oxide. The chemical structure of DOPO‐TPMP was well characterized using Fourier transform infrared and NMR spectra. DOPO‐TPMP was used as an additive‐type FR for epoxy resin (EP). The FR properties of the resultant EP composites were investigated by limiting oxygen index (LOI) test, UL‐94 vertical burning test and cone calorimeter measurements. Specifically, the EP composite containing 10.0% DOPO‐TPMP achieved a LOI value of 36.1%, V‐0 rating in the UL‐94 test and a 58% reduction in peak heat release rate. Further mechanism analysis attributed the enhanced flame retardancy to the increased char yield on the addition of DOPO‐TPMP. © 2019 Society of Chemical Industry     

Use of a combination of phosphorous-containing epoxy resin and silica fillers for development of flame retardant thermoset polymer composites

In this paper, we report a method of preparation of ambient temperature curable phosphorous containing epoxy resin-based composites and their flame retardant behavior. The phosphorous containing resin, prepared by reacting the epoxy resin with 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), shows higher limiting oxygen index (LOI) in the cured state compared to the pure epoxy network. The LOI value is further enhanced due to the incorporation of phosphorous-containing silica, although the same remains unchanged when pure silica is added. The composites made with phosphorous-containing resin and pure silica exhibits UL-94 V-1 class rating whereas the same made with phosphorous-containing silica offers V-0 rating under UL-94 classification. This observation clearly indicates that the performance is enhanced when phosphorous in incorporated in the resin as well as in the inorganic reinforcing filler.     

环氧树脂纳米阻燃材料研究进展

综述了目前环氧树脂纳米阻燃材料的制备方法,介绍了环氧树脂/层状硅酸盐纳米阻燃材料和环氧树脂/SiO2纳米阻燃材料的优异性能并展望了环氧树脂阻燃材料的应用前景。     

Preparation of DOPO-derived magnesium phosphate whisker and its synergistic effect with ammonium polyphosphate on the flame retardancy and mechanical property of epoxy resin

In this study, a magnesium phosphate whisker (DPM-H) was synthesized by the acid–base neutralization reaction between magnesium hydroxide and 10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-OH) at 120°C. A new synergistic intumescent flame retardant (IFR) for epoxy resin (EP), which was composed of DPM-H and ammonium polyphosphate (APP) was thoroughly studied. When the IFR loading was 8%, with the DPM-H to APP weight ratio at 1:7, the prepared flame-retardant EP (EPDA-2) passed the vertical burning tests (UL-94) V-0 rating and obtained the limiting oxygen index (LOI) value of 29.3%. Microscale combustion calorimetry (MCC) results showed that the total heat release (THR) of EPDA-2 reduced by 32.1% compared with pure EP. Meanwhile, the addition of DPM-H can partially solve the problem of the decrease of the EP mechanical property caused by the addition of APP. Compared with the flame-retardant EP with the 8% loading of APP, the impact strength of EPDA-2 increased 152.3%.     

Organophosphorous additive for fortification,processibility, and flame retardance of epoxy resins

Amine‐cured epoxy resins are prepared containing an aliphatic phosphonate additive which aids in the processing of the epoxy by reducing the viscosity of the resin mixture. The additive also acts as an antiplasticizer in the cured epoxy by increasing the modulus and yield strength under uniaxial tension and compression. Additionally, phosphonates are known to behave as flame retardants and dimethyl methyl phosphonate (DMMP) demonstrates a reduction in the rate of thermal degradation and the heat‐release rate upon pyrolysis. Addition of the antiplasticizer reduces the T_g and suppressed β‐relaxations, while effectively increasing the density of the material. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 302–309, 2002; DOI 10.1002/app.10329     

Reactive cyclic phosphonamide flame retardant for epoxy resins

To take the advantage of reactivity of five-membered cyclic phosphorus compounds, 1,2,3-tri-phenyl-1,3,2-diazaphospholidine-2-oxide (TPDPO) was explored as a reactive flame retardant for epoxy resins (EPs). Through model compounds, it has been established that TPDPO selectively reacts with the secondary hydroxyl group and is inert toward both aryl amino groups and epoxide groups. The result of Soxhlet extraction supports that TPDPO is permanently bonded to the cured EPs. At a loading of only 8 wt % (0.74 wt % phosphorus), TPDPO enables the cured epoxy to achieve a UL-94 V0 rating. The thermogravimetric analysis–Fourier transform infrared analyses of the gaseous products suggest that the excellent flame retardancy of EP–TPDPO is partly due to the enhanced dehydration process of the epoxy. Also an increased char yield and the formation of a coherent char layer contribute to the good fire performance of EP–TPDPO. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47411.     

In situ synthesized and dispersed melamine polyphosphate flame retardant epoxy resin composites

The dispersion of flame retardants in polymer matrix has significant impact on the final properties of the final materials. Homogenous dispersion for additive type flame retardant powder in polymer melt or solution with high viscosity is a challenge all the time. In the present research, melamine polyphosphate (MPP) is employed to flame-retard the epoxy resin (EP). Different from direct addition of MPP powder in viscous EP glue like conventional means, MPP is firstly synthesized by melamine and polyphosphoric acid in a good solvent for EP. Keeping fine and even dispersion of the produced MPP particles, EP prepolymer is added into the MPP containing solution. By this way, perfect dispersion of the flame retardant can be achieved both in the glue and the cured resin. A series of tests such as the particle size analysis, flammability evaluation, and mechanical properties tests are conducted to compare the MPP flame retardant EP obtained by this method and the conventional one. It shows that the in situ synthesis and compounding method can endow the MPP incorporated EP glue system with better homogeneity and stability, hence leading to higher flame retardancy and obviously improved mechanical performance of the final composite. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47194.     

新型磷／氮协同阻燃环氧树脂的合成与性能

以双酚A环氧树脂E－51与DOPO（9,10-dihydrooxa-20－phosph henanthrene－10-oxide）合成含磷环氧树脂（ED）,以三聚氰胺与苯酚反应制备含氮的酚醛固化剂MFP。采用红外光谱对产物进行分析表征,采用热失重分析和UL94V垂直燃烧测试考查树脂的热性能和阻燃性能,同时探讨了阻燃环氧树脂的力学性能。结果表明,随着含磷量的增加,环氧树脂的热稳定性和阻燃性能得到改善,当含磷量为3％时,环氧树脂的初始分解温度高达330℃以上,在700℃下的残炭率达到30％以上,阻燃性能均达到了UL－94 V—0级。而试样的力学性能则随含磷量的增加而降低。