Thermal and UV-curing behavior of phosphate diacrylate used for flame retardant coatings

A novel phosphorus-on-skeleton compound has been synthesized by allowing phosphorus oxychloride to react with 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (PEPA) and 2-hydroxyethyl acrylate (HEA). Its structure was characterized by Fourier transformed infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance spectroscopy (¹H NMR). The UV-curing behavior was investigated using FTIR. Results show that the conversion of the unsaturated bond of the monomer exposed to UV light for 100 s is approximately 84%. Flame-retardant effectiveness was estimated from the limiting oxygen index (LOI) and thermal stability was characterized by thermogravimetric analysis (TGA). The LOI value was 39 and the char yield was 53% at 600 °C. TG data indicate that the material undergoes degradation in three characteristic temperature stages, which may be attributed to the decomposition of the phosphate, thermal pyrolysis of aliphatic chains, and degradation of an unstable structure in char, respectively. These were further characterized by real time Fourier-transform infrared measurement. It is proposed that the flame retardant action results from decomposition of phosphate to form poly(phosphoric acid), which catalyses the breakage of bonds adjacent to carbonyl groups to form an intumescent char, preventing the sample from burning further.     

Thermal degradation behavior of the compound containing phosphaphenanthrene and phosphazene groups and its flame retardant mechanism on epoxy resin

The flame retardant epoxy resin has been prepared by mixing the flame retardant additive hexa-(phosphaphenanthrene-hydroxyl-methyl-phenoxyl)-cyclotriphosphazene (HAP-DOPO) into diglycidyl ether of bisphenol-A (DGEBA). After cured by 4,4′-Diamino-diphenyl sulfone (DDS), the flame retardant properties of thermosets were characterized by the limited oxygen index (LOI), UL-94 test and cone calorimeter. The results show the lower peak of heat release rate (pk-HRR), the higher flammability rating than that of flame retardant epoxy resin by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), hexa-phenoxyl-cyclotriphosphazene (HPCP) and their mixture cloning the ratio of group component of HAP-DOPO. The degradation route of HAP-DOPO was disclosed by thermogravimetric analysis (TGA), the real time Fourier transform infrared spectra (FTIR), thermogravimetric analysis/infrared spectrometry (TGA-FTIR), pyrolysis gas chromatography mass/spectrometry (Py-GC/MS). During combustion, HAP-DOPO continues to release the PO radicals and o-phenylphenoxyl radical during two degradation stages from 200 °C for its unstable trisubstituted methyl structure of HAP-DOPO, inhibits the chain reaction of decomposition and exerts the flame retardant effect in gas phase. The phosphazene groups link with the residual phosphate from degraded phosphaphenanthrene, which increases the crosslink density of residue, effectively promotes the formation of high-strength, high-yield and phosphorus-rich char layer. The structure of HAP-DOPO shows a remarkable flame retardant molecular structure-effect on enhancing the flame retardant efficiency on thermosets.     

Study on effect of polydimethylsiloxane in intumescent flame retardant polypropylene

The effect of polydimethylsiloxane (PDMS) in intumescent flame retarded polypropylene (PP) containing melamine phosphate (MP) was studied using limiting oxygen index (LOI), UL-94 test, thermogravimetric analysis (TG), real time Fourier transform infrared (FTIR) and pyrolysis/gas chromatogram/mass spectrometry (Py–GC/MS). It was found that the addition of PDMS into the PP/MP composites leads to a decrease in the LOI values of the PP/MP/PDMS composites, and the values increase gradually with the increase of the PDMS content. The UL-94 test results indicate that the PP/MP/PDMS composite with 30% PDMS reaches the V-0 rating compared with no rating of the PP/MP composite at the same MP loading. The water resistance of the PP/MP/PDMS composites was investigated, and the improved water leaching of MP was observed. The TG and RTFTIR results illustrate the thermal stability of the PP/MP composites containing PDMS is improved. Moreover, the pyrolysis of the PP/MP/PDMS composites was studied by the Py–GC/MS method.     

西欧阻燃塑料工业现状

论述了西欧阻燃塑料工业的现状:一是欧盟各国在建材等行业将实行统一的阻燃性能试验方法和阻燃材料分类标准;二是日益严格的环保法规对阻燃剂的危害性评估结果正挑战阻燃塑料工业;三是新阻燃系统的研发。这些变化将导致西欧阻燃剂及阻燃塑料系统的结构调整。     

Flammability and rheological behavior of mixed flame retardant modified asphalt binders

The flammability and rheological behavior of asphalt modified by mixed flame retardants was investigated using differential scanning calorimetry and dynamic shear rheometer, respectively. The mixed flame retardants used consisted of decabromodiphenyl ether, antimony trioxide and aluminium trihydroxide with the ratio of 3:1:1 by mass. Experimental results indicated that the inclusion of 6 wt% mixed flame retardants improves the flame retardancy significantly by consuming the released heat of asphalt in a temperature range of 300-500 °C. The close values of the activation energy obtained by fitting Arrhenius model demonstrate flame retardant modified asphalt exhibits similar thermal susceptibility to base asphalt in the temperature range of 30-100 °C. It can foresee that the content of flame retardant is expected to increase with respect to better flame resistance if required based upon this research.     

硼酸锌对乙烯-丙烯酸丁酯共聚物力学及阻燃性能的影响

用极限氧指数(LOI)、热重(TGA)和差示扫描量热(DSC)等方法研究了乙烯-丙烯酸丁酯共聚物(E-BA)/硼酸锌(ZB)复合材料的阻燃性能和热降解行为及ZB对EBA力学性能和熔体流动速率的影响。实验结果表明ZB的引入提高了EBA在高温下的热稳定性,恶化了材料的力学性能和加工性能,添加60%材料的LOI可达26.8%,主要通过物理方式在凝缩相和气相中发挥阻燃作用。     

塑料无卤阻燃剂研发进展

介绍了塑料无卤阻燃剂的种类以及阻燃技术的发展新动向,指出了无卤、高效、低烟、低毒、多功能的新型阻燃剂是今后的发展方向。     

Synthesis and characterization of flame retardant hyperbranched polyurethanes for nano-composite and nano-coating applications

Flame retardant hyperbranched polyurethanes were prepared by reacting phosphorous containing triol, tris(bisphenol-A) mono phosphate, castor oil, and polyethylene glycol with different diisocyanates like TDI, IPDI and HMDI via A₂+B₃ method. In this method A₂ reactants were diisocyanates along with castor oil and polyethylene glycol whereas phosphorous containing triol was used as B₃ reactant and dibutyltin dilaurate (DBTDL) was used as catalyst. Synthesized polyurethans were characterized by gel-permeation chromatography (GPC), elemental analysis, Fourier transform infrared spectroscopy (FTIR) and ¹H NMR spectroscopic techniques. Neat polyurethanes were used for preparing films. Nano-clay composites were prepared with various concentration of organomodified montmorillionite nano-clay. Flame retardant, Thermal and mechanical properties of these hyperbranched polyurethanes and their nano-composites were found out. The polyurethanes and their formulations with nano-clay were also used for the coating of mild steel panels. Scratch, pencil, and impact hardness, flexibility and adhesion properties of coated panels were also determined. Observations show an increase in the scratch hardness and flexibility with the introduction of clay. All the coatings show excellent chemical resistance properties compare to their linear counterpart.     

Carbon-family materials for flame retardant polymeric materials

As an abundant and attractive element, the emergence of new carbon-based materials brings revolutionary development in material science and technology. Carbon-based materials have spawned considerable interest for fabricating polymer composites/nanocomposites with greatly improved mechanical, thermal, gas barrier, conductivity, and flame retardant performance. In this review, the importance of carbon-based materials and the necessity of fire resistance for polymeric materials are initially introduced. Then, the fundamental flame retardant mechanisms and experimental analytical techniques are described to understand the relationship between structures and flame retardant properties. The main section is dedicated to the preparation and properties of multifunctional polymer composites/nanocomposites with carbon-based materials, with special emphasis on the flame retardant properties of these materials. A wide variety of carbon-based materials are discussed for use in flame retardant polymer nanocomposite, including graphite, graphene, carbon nanotubes, fullerenes as well as some new emerging carbon forms (carbon nitride, carbon aerogels, etc). Finally, a brief outlook at the developments in carbon-based materials for flame retardant polymeric composites is given by discussing the major progress, opportunities, and challenges.     

阻燃剂RDP的合成研究

以三氯氧磷、间苯二酚及苯酚为原料,合成阻燃剂间苯二酚双(二苯基磷酸酯)(RDP);考察了催化剂种类及用量、原料配比、反应温度和时间对合成反应的影响,确定了最佳的工艺条件:n(三氯氧磷)∶n(间苯二酚) ∶n(苯酚)=4.5∶1.0∶3.7,催化剂无水氯化镁用量约为间苯二酚质量的2.5％,第一步反应温度85～90℃,反应...     

阻燃剂Cyagard RF-1的应用

介绍了鏻盐阻燃剂THPC的换代产品CyagardRF-1的应用。     

Improvement in flame retardancy of polyurethane dispersions by newer reactive flame retardant

A novel phosphorus containing reactive flame retardant was synthesized and incorporated successfully in polyurethane backbone to obtain flame retardant aqueous polyurethane dispersions (FRPUDs). The reactive flame retardant compound was synthesized by using phosphorus oxychloride (1 mole) and N-methylaminoethanol (3 mole). The structure of synthesized phosphorus containing triol was confirmed by FTIR, ¹H NMR and ³¹P NMR spectrometry. Further, polyurethane prepolymer was modified with phosphorus containing triol compound in various amounts (30, 40 and 50% on equivalent basis) and FRPUDs were prepared. PUD films were applied on wood and mild steel panels and air dried. It was then characterized for mechanical, chemical, thermal and flame retardant properties. It was observed that all FRPUDs exhibited good mechanical properties and improved flame retardancy as compared to the conventional one. The maximum limiting oxygen index (LOI) value of 37 was obtained for FRPUD containing 0.8 mass% of phosphorus and 1 mass% of nitrogen. The flame retardancy was greatly depending on the phosphorus content and increased with increase in phosphorus content.     

The investigation on the flame retardancy mechanism of nitrogen flame retardant melamine cyanurate in polyamide 6

Melamine cyanurate (MCA) flame retardant polyamide 6 (PA6) shows good flame retardancy, but the corresponding mechanisms have not been completely understood. In this paper, Fourier transform infrared spectra (FTIR), elemental analysis (EA), scanning electronmicroscope (SEM), energy dispersive scanning (EDS), thermogravimeric analysis (TGA) and pyrolysis-gas chromatogram-mass spectrometer (Py-GC-MS) were conducted to investigate the processes including melt-drip phase, gaseous phase and condensed phase of MCA/PA6 system. Compared with original PA6, it is found that MCA flame retardant PA6 mainly undergoes predominant weak bond-breakage degradation forming oligomers rather than oxidative degradation producing low-boiling point fuel as original PA6 does. The produced oligomers can accelerate the formation of the melt drips which effectively removes the combustion heat and latent fuel, also the self-condensation of these oligomers is advantageous to form stable cross-linking structure, thus greatly consolidating the char layer.     

不同阻燃剂对ABS性能的影响研究

研究了不同阻燃剂种类及用量对阻燃ABS燃烧性能的影响,并考察材料的抗冲击性等力学性能和耐热性能,对其阻燃效果和其它性能的综合平衡进行了较为全面的剖析,并制备了不同耐热性能的阻燃ABS,4种重金属含量符合欧盟提出的ROHS环保要求,可满足不同用户对具有不同耐热性的阻燃ABS的使用要求。     

Preparation and characterization of tung oil-based flame retardant polyols

Three kinds of tung oil-based structural flame retardants polyols (TOFPs) were prepared by new methods in this paper. First, tung oil was used to produce monoglyceride and diglyceride by transesterification with glycerol by sodium methoxide. The products after transesterification were epoxidized by peracetic acid which was in-situ generated from acetic acid and hydrogen peroxide in the presence of sulfuric acid catalyst. And then, TOFPs were prepared from epoxidized alcoholysis tung oil (EGTO) with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), diethyl phosphate (DEP) and diethanolamine (DEA) by ring-opening reactions, respectively. GPC was used to evaluate the conversion rate, at optimum reaction conditions, selectivity for monoglyceride in transesterification. The influence of different parameters such as temperature, mole ratio or mass ratio on the conversion rate of transesterification and epoxidation were investigated. The molecular structures of TOFPs were characterized by FTIR and ¹HNMR. Finally, tung oil-based polyurethane foams (TOPUFs) were prepared by a one-shot process using TOFPs with polyisocyanate. The LOI values of TOPUFs whose content of DOPO-EGTO, DEP-EGTO and DEA-EGTO were 100 wt% can reach to 26.2%, 25.1%, and 24.4%, respectively.     

溴系阻燃剂五溴甲苯的合成新工艺研究

由甲苯经溴化制得五溴甲苯,重点考察了催化剂掺杂质量比、催化剂的用量、原料配比、反应时间等工艺参数对合成产物的影响.实验结果表明,m(Bu2SnCl2):m(AlCl3)=1:1作为复合催化剂,对合成五溴甲苯有着良好的催化活性,当m(复合催化剂):m(甲苯)=0.05,n(甲苯):n(溴)=1:7.5,n(溶剂CCl4)...     

A novel click-chemistry approach to flame retardant polyurethanes

The low thermo-oxidative properties of PU foams somewhat limits their practical application, particularly as heat sensitive materials. The introduction of a covalently linked flame retardant organophosphonate ester into the PU foam was achieved using the CuAAC ‘click’ reaction of an alkyne-polyol and azidoalkylmonophosphonate. These functionalised materials were prepared in four steps: first, a number of azidoalkyl monophosphonate compounds were formed via nucleophilic substitution of bromoalkylphosphonates with NaN₃; next, polyols bearing terminal alkyne groups were prepared by anionic ring opening copolymerization between propylene oxide and glycidyl propargyl ether; followed by ‘clicking’ the azidoalkylphosphonate to the polyol and finally, synthesis of the PU foam with 2.4 wt% of “click-polyol”. The functionalised PU foam demonstrated a well-formed polyhedral cell structure and an increase in the fire resistance, according to the SEM and thermogravimetric analysis, respectively. Even after thermal treatment at 400 °C, the new PU foam material displayed enhanced flame resistant properties by forming a char layer on the surface of the polymer, whilst maintaining its polyhedral structure.     

Synergistic effects of hydroxy silicone oil on intumescent flame retardant polypropylene system

The effects of hydroxy silicone oil as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene composites (IFR-PP) were studied, and the IFR system mainly consisted of the ammonium polyphosphate (APP), melamine (MEL) and pentaerythritol (PER). The UL 94 rating, thermogravimetric analysis (TGA), cone calorimeter (CONE) and digital photograph were used to evaluate the synergistic effects of hydroxy silicone oil (HSO). It has been found that the PP composite containing only APP, MEL and PER does not show good flame retardancy at 30% additive level. The cone calorimeter results show that the heat release rate, mass loss rate, mass, total heat release, carbon monoxide and carbon dioxide of PP/APP/MEL/PER/HSO composites decrease in comparison with the PP/APP/MEL/PER composite. The digital photographs demonstrated that HSO could promote to form the homogenous and compact intumescent char layer. Thus, a suitable amount of HSO plays a synergistic effect in the flame retardancy.     

Preparation and characterization of flame retardant solvent base and emulsion paints

In this research solvent base alkyd and emulsion paint formula were made flame retardant (FR) by incorporation of hexachlorodiphosh (V) azane of types (I–III). Elemental analysis was used to characterize the structure of these compounds. These additives are physically incorporated into the paint formula through grinding in a pebble mill until all particulates have a size below 38 μm. Experimental coatings were manufactured on a laboratory scale, applied by brush on wood and steel panels. Results of an oxygen index value indicated that coating with these compounds containing chlorine, nitrogen and phosphorus exhibit very good flame retardant effect when mixed with solvent base alkyd and emulsion paint. The physical, mechanical and corrosion resistance were studied to evaluate the additives drawbacks. The additives did not affect the flexibility and pinholes of paint formula. The gloss and the impact strength were decreased by the additives, the hardness and adhesion resistance increased by the additives. However, corrosion resistance was not significantly changed by these additives.     

Graft copolymerization coating of methacryloyloxyethyl diphenyl phosphate flame retardant onto silk surface

This paper reports an efficient surface modification methodology to increase fire resistance properties of silk fabric performed by radio frequency (RF) plasma-induced graft copolymerization of vinyl phosphate ester as nanometer coating. Methacryloyloxyethyl diphenyl phosphate (MEDP) monomer was prepared and graft-copolymerized onto the surface of silk fabric by argon RF plasma at ambient temperature. Under optimum RF power (30 W), amounts of MEDP and N,N methylenebisacrylamide cross linking agent were varied to obtain optimum graft copolymerization conditions. Untreated and treated silk were characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy to investigate their functional group characteristics. This showed a strong covalent attachment between the surface of silk and flame retardant material as the carbonyl functionality of the MEDP was clearly observed in the spectra. Scanning electron microscopic (SEM) analysis also showed grafted material as nanometer residue on silk surface. Thermogravimetric analysis (TGA) revealed that the decomposition of phosphorus compound which occurs at lower temperature than that of silk itself resulted in the formation of char which covers the surface of the fabrics. This protects the fabric surface from further burning, therefore, higher amounts of remaining materials were observed as char in all cases. Furthermore, the limiting oxygen index (LOI) increased from 25.5 for untreated to 28.0 (ca. 10%) for the MEDP-grafted silk. Higher amounts of char were also observed in the case of MEDP-treated silk. After 5 dry cleaning cycles, the LOI of the treated silk dropped only very slightly. Detailed analysis on structural and thermal properties as well as surface grafting efficiency are presented.