Flame Retardant Modified Bio-Based Waterborne Polyurethane Dispersions Derived from Castor Oil and Soy Polyol

Although tremendous efforts have been dedicated to developing environmentally friendly bio-based waterborne polyurethane (WPU) dispersions from vegetable oil, the fabrication of WPU dispersions solely derived from vegetable oil-based polyol with excellent comprehensive properties is still challenging. In the present work, novel bio-based WPU dispersions derived from castor oil and soy polyol is successfully modified by phosphorus-nitrogen chain extender [bis(2-hydroxyethyl)amino]-methyl-phosphonic acid dimethyl ester (BH). The structure and properties of the dispersions and films are characterized systematically by Fourier transform infrared spectroscopy, thermogravimetric analysis , mechanical test, and limiting oxygen index (LOI), etc. The results indicate that bio-based WPU films display moderate mechanical performance by adjusting BH content, and the WPU film containing 100% BH with 47.8% biobased content has a tensile strength of 8 MPa and the highest Young's modulus of 62.3 MPa. The incorporation of BH can increase the production of char residue. The flame retardancy of WPU films increase gradually with the BH molar content, and the LOI value of the WPU100 with 1.53 wt% phosphorus content can reach as high as 28.1%. This work may provide a new approach to develop high biobased content, eco-friendly, flame retardant WPU for application in the surface coating industry.     

A novel DOPO-containing HTBN endowing waterborne polyurethane with excellent flame retardance and mechanical properties

A novel flame-retardant DHTBN (hydroxyl-terminated polybutadiene acrylonitrile modified with DOPO) with phosphorus-containing pendant groups is synthesized based on addition reaction between the hydroxyl-terminated polybutadiene acrylonitrile and DOPO, which is followed to prepare flame-retarded WPU (FR-WPU). The chemical structures of DHTBN and FR-WPU are confirmed via ³¹P NMR, XPS, and FT-IR. The mechanical properties, thermal stability, and flame retardancy of FR-WPU are conducted a series of tests. The tensile strength and elongation at break for the FR-WPU films first increased and then decreased with increasing of DOPO contents. The results show that the incorporation of DHTBN into the WPU backbone slightly reduces the thermal stability of FR-WPU. However, the incorporation of DHTBN into WPU improves the flame retardancy. The TGA-FIR and Py-GC-MS results indicate the gas phase flame-retardant effect of DHTBN. Furthermore, the morphology, elemental composition, and content of residual char from the FR-WPU exhibited condensed-phase flame-retardant effects on the WPU films.     

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.     

Synergistic effects of ammonium polyphosphate/melamine intumescent system with macromolecular char former in flame-retarding polyoxymethylene

The improvement of the flame retardancy of polyoxymethylene (POM) is a world-wide difficult problem due to its zippered decomposition property. This paper reported the preparation of the flame-retarding (FR) POM with the synergistic combination of ammonium polyphosphate (APP)/melamine (ME) intumescent flame retardant system and macromolecular char former (MC). The UL94 testing, mechanical properties testing, thermogravimetric analysis (TGA), cone calorimetry and scanning electron microscopy (SEM) were used to investigate the corresponding structure, performance and synergistic flame retardant mechanism. The experimental results showed that, in the used macromolecular char formers (novolac, PA6 and TPU), the combination of novolac with APP/ME intumescent system has the best synergism in flame-retarding POM, greatly enhancing the quality of the formed condensed charred layer and hence the corresponding flame retardancy. The obtained FR POM composite could achieve flame retardancy of UL94 3.2 mm V-0 level and remarkably decreased heat release rate relative to pure POM. The synergistic effect of novolac was shown to be the char formed cross-linking reaction of it with APP. Due to the thermodynamic compatibility of novolac and POM, the prepared FR POM composite also has fairly good mechanical performance, having tensile strength of 49.1 MPa and Izod notched impact strength of 2.60 kJ/m².     

Synthesis of a phosphorus‐ and nitrogen‐containing flame retardant and evaluation of its application in waterborne polyurethane

A phosphorus‐ and nitrogen‐containing intumescent flame retardant, pentaerythritol di‐N‐hydroxyethyl phosphamide (PDNP), was synthesized with phosphorus oxychloride, pentaerythritol, and ethanolamine as raw materials. Using the prepared PDNP as a chain extender, a series of flame‐retardant waterborne polyurethanes (WPU) were prepared, and their structures were characterized using NMR and Fourier transform infrared spectroscopy (FTIR). Additionally, the thermal properties and flame retardancy of WPU films were investigated by thermogravimetric analysis, limiting oxygen index (LOI) tests, cone calorimeter tests, and thermogravimetry‐FTIR. These results indicated that PDNP materials exhibit good char‐forming ability at high temperature and that PDNP‐modified waterborne polyurethane obtained an LOI value of 26.0% for a PDNP content of 9 wt %. Finally, the morphology and the element distributions of char residues of WPU were analyzed by scanning electron microscopy and energy dispersive spectrometry after combustion. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46093.     

硼酸锌协效二乙基次膦酸铝阻燃PA6

采用硼酸锌(ZB)与二乙基次膦酸铝(ADP)协同阻燃聚酰胺6(PA6).对其阻燃性能和力学性能进行了探讨,并运用垂直燃烧、极限氧指数、锥形量热、热失重分析、扫描电子显微镜以及拉曼光谱对阻燃机理进行了探究.结果表明,ZB作为协效剂,与ADP的协同阻燃效果显著;当在PA6中添加1.5％(质量分数,下同)ZB和8.5％ADP...     

Flame retardant nanocomposites of polyamide 6/clay/silicone rubber with high toughness and good flowability

A novel flame retardant, silicone elastomeric nanoparticle (S-ENP) with T_g of −120 °C and particle size of ∼100 nm has been developed and used as a modifier for polyamide 6 (nylon-6). It has been found that S-ENP can not only increase the toughness and improve the flame retardancy of nylon-6 but also helps unmodified clay exfoliate in nylon-6 matrix. It has been also found that the S-ENP and exfoliated clay platelet in nylon-6 have a synergistic flame retardant effect on nylon-6. A novel flame retardant nanocomposite of nylon-6/unmodified clay/S-ENP with high toughness, high heat resistance, high stiffness and good flowability has been prepared and a mechanism of synergistic flame retardancy has also been proposed.     

BN@APP/水性聚氨酯复合材料的制备及其阻燃性能

采用聚磷酸铵(APP)对氮化硼进行表面改性,并进一步制备出聚磷酸铵改性氮化硼(BN@APP)/水性聚氨酯(WPU)复合材料.结果 表明,当BN@APP的添加量为0.75％时,BN@APP/WPU复合材料的拉伸强度是未改性WPU拉伸强度的2.2倍,这是因为BN@APP具有较大的比表面积以及与基体产生较强的相互作用.随着B...     

Synergistic effect of carbon and phosphorus flame retardants in rigid polyurethane foams

Two kinds of carbon and phosphorus synergistic system used to improve the flame retardancy of rigid polyurethane foams (RPUF) were studied. One is the synergistic effect of expandable graphite and guanidinium phosphate; the other is red phosphorus and guanidinium phosphate. The flame retardant properties and mechanical properties of these composites were investigated by limiting oxygen index, cone calorimeter test, as well as tension and compression test. These 2 groups of mixed inorganic flame retardants can greatly improve the flame retardancy of RPUF composites, as the limiting oxygen index increases from 20.1% to about 33% and the HRR reduces from 395 kW/m² to below 200 kW/m². It provides a convenient and inexpensive way to obtain RPUF with demanding properties.     

Synthesis of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative grafted polyethylene films for improving the flame retardant and anti-dripping properties

Two novel flame retardant and anti-dripping PE films were successfully synthesized in three steps. PE-g-GMA film was first prepared by simultaneous electron beam irradiation to graft glycidyl methacrylate (GMA) onto PE film. 4,4′-[1,4-phenyl-bis(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl)dimethyneimino)]diphenol (DOPO-t) and 4,4′-[1,3-phenyl-bis (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl)dimethyneimino)]diphenol (DOPO-m) were then fabricated via a one-pot method. Finally, two DOPO derivative functionalized PE films were obtained through the ring opening reactions of PE-g-GMA film with DOPO-t and DOPO-m, respectively. Combustion properties, flame retardancy, thermal performance, and thermal shrinkage of these films were evaluated. Compared with pure PE film, the burning rate of anti-dripping DOPO-t/DOPO-m functionalized PE films was reduced by 13.2% and 50.0%, and the limiting oxygen index value climbed to 18.5 and 19.5, respectively. The residual chars from DOPO-t/DOPO-m functionalized PE films at 700°C were increased, and the shrinkage ratio decreased remarkably, which could effectively prevent the spread of fire. We also discussed the effect of structural difference between DOPO-t and DOPO-m on the above properties and the flame retardant mechanism of two DOPO derivative functionalized PE films preliminarily. This work provides a method for introducing DOPO derivatives into PE molecules to improve their flame retardancy and anti-dripping properties.     

Flame retardancy,mechanical, and thermal properties of waterborne polyurethane conjugated with a novel phosphorous‐nitrogen intumescent flame retardant

A novel phosphorous‐nitrogen intumescent flame retardant with reactive diamino groups, benzoguanamine spirocyclic pentaerythritol bisphosphonate (BSPB), was synthesized and used as a chain extender, and then a series of flame retardant waterborne polyurethanes (FRWPU) were prepared by covalently conjugating the BSPB into waterborne polyurethane (WPU) backbone. Their structures were characterized by Fourier transformed infrared spectrometry (FTIR), ¹H and ³¹P nuclear magnetic resonances (NMR), respectively. Simultaneously, the flame retardancy and the thermal stability of FRWPU were systematically investigated by limiting oxygen index (LOI) test, UL‐94 vertical burning test and thermogravimetric analysis (TGA). The results indicated that with the increase of BSPB content from 0 to 8 wt%, the LOI value of FRWPU increased from 18.6 to 27.3%, showing significant improvement by 8.7%. Compared with WPU, FRWPU showed decreased thermal stability but promoted char residue ratio. Conjugation of BSPB could obviously enhance the mechanical properties of FRWPU, the Young's modulus and tensile strength dramatically increased with the increase of BSPB. Investigation of char forming mechanism of BSPB through real time Fourier transform infrared spectra (RTFTIR) and scanning electronic microscopy (SEM) revealed that the polyphosphoric acid and phosphorus oxynitrides rich outer intumescent char layer could form protective shields to inhibit effectively internal polyurethane to heat and flame diffusion during contacting fire. POLYM. COMPOS., 38:452–462, 2017. © 2015 Society of Plastics Engineers     

溴系阻燃剂阻燃ABS的制备及电性能研究

研究了十溴二苯醚(DBDPO)、四溴双酚A双(2,3-二溴丙基)醚(TBAB)及其复配对ABS阻燃性能及电性能的影响。结果表明,DBDPO与TBAB对ABS的阻燃有协同作用,在DBDPO与TBAB总用量固定为15％的条件下,两者的质量比为2：l时,氧指数达到最大值,为32．4。DBDPO及TBAB对ABS电性能均有一定损害,使ABS的电绝缘性能及电气强度降低、介电常数及介电损耗因数增加。     

EG与IFR复合阻燃EVA的动态燃烧性能和协同效应

将可膨胀石墨(EG)与P-N膨胀阻燃剂(IFR)复合阻燃EVA树脂,通过氧指数(OI)、垂直燃烧测试(UL94)、锥形量热仪(CONE)研究了EG与IFR复合阻燃EVA的协同效应。结果表明:阻燃剂总添加量为30 phr,随着其中EG含量的增加,OI呈先增加后下降趋势,确定EG:IFR=1:1为最佳配比,OI达到36.6%,UL94为V-0级;EG与IFR复合阻燃EVA,热释放速率曲线呈现"前单峰型",为凝聚相阻燃机理;燃烧后形成的炭层结构较致密,表现出一定的协同作用。     

Highly effective flame-retarded polyester diol with synergistic effects for waterborne polyurethane application

In this article, a novel bi-reactive flame retardant (FRD) was successfully synthesized for waterborne polyurethane (WPU). The chemical structures of FRD were characterized by Fourier-transform infrared spectra and ¹H and ³¹P nuclear magnetic resonance. Then, the FRD was incorporated into polyurethane backbone to prepare a series of flame-retarded WPU (FRWPU). The flammability characteristics of FRWPU were measured by limited oxygen index (LOI), UL-94, and cone calorimeter (CCT) tests. The FRPWU-7 had a high LOI value of 30.5% with UL94 V-0 rating. Moreover, the CCT values indicated that FRD induced the gaseous phase quenching effect of phosphorus-containing free radicals derived from the decomposed phosphaphenanthrene group on the gas-phase flame retardancy. Scanning electron micrographs and Raman spectra exhibited that FRD promoted the charring formation of phosphorus-rich char layer with graphitized surface and honeycomb-like intumescent structure in WPU matrix during burning. This study provides a new way to design a novel reactive P–P flame retardant consisted of the phosphaphenanthrene group and intumescent flame retardant for WPU application. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48444.     

阻燃聚氨酯的研究及应用进展

聚氨酯材料具有良好的物理力学性能、优异的耐候性和保温性能,应用广泛。但聚氨酯极易燃烧,极大地限制它的使用范围,所以急需提高聚氨酯的阻燃性能。本文介绍了聚氨酯的阻燃必要性,从聚氨酯结构自阻燃和引入阻燃剂等方面综述了聚氨酯阻燃方法的最新研究进展,重点介绍添加型阻燃剂复配使用、反应型阻燃剂协同阻燃以及纳米材料复合阻燃聚氨酯,同时阐述了不同类型阻燃剂的作用机理,并展望了聚氨酯阻燃的发展趋势,加强对聚氨酯结构自阻燃深入研究,阻燃剂复配技术的完善。     

Synergistic effects of aluminium hypophosphite on the flame retardancy and thermal degradation behaviours of a novel intumescent flame retardant thermoplastic vulcanisate composite

ABSTRACT

The synergistic effects of aluminum hypophosphite (AHP) on the flame retardancy, thermal degradation behaviors of a novel intumescent flame retardant thermoplastic vulcanizate (TPV/IFR) composite were investigated. The results showed that the combination of AHP with IFR showed evident synergistic effects on the increase in the LOI value and reduction of the combustion parameters for the TPV/IFR/AHP composites at the optimum weight ratio of IFR/AHP (6/1) as evidenced by LOI, UL-94 and CCT. The TGA data revealed that AHP could change the degradation behavior of TPV/IFR composites and enhance the thermal stability of the TPV/IFR composites at high temperature. The results of FTIR, EDXS, LRS and SEM demonstrated that TPV/IFR/AHP composites could form more continuous, dense and stable char layer on the materials surface, and consequently improving the flame retardancy. Based on these results, the possible condensed flame retardant mechanism of TPV/IFR/AHP composites was concluded in detail.     

含锌阻燃剂对NER/OMMT-TPP体系阻燃聚丙烯的影响

将硼酸锌和氧化锌加入到酚醛环氧树酯/有机蒙脱土纳米复合材料(NER/OMMT)与磷酸三苯酯(TPP)阻燃聚丙烯(PP)体系,考察了硼酸锌和氧化锌用量对PP阻燃、抑烟性能和力学性能的影响.在NER/OMMT与TPP总用量仅为10wt%的情况下加入4wt%的硼酸锌后,制得了氧指数高达31.5%的阻燃聚丙烯,并且烟雾产生总量比加入前下降了46.6%,在降低了材料的毒害性的同时很好地提高了其综合性能.     

微胶囊红磷阻燃剂在低密度聚乙烯材料中的应用研究

研究了微胶囊红磷不同包覆、用量、粒径及与其它阻燃剂的协效作用等因素对低密度聚乙烯(LDPE)材料的阻燃性、力学性能及抑烟性能的影响。蜜胺树脂囊材包覆与蜜胺树脂／硼酸锌双层囊材包覆微胶囊红磷在聚乙烯(PE)中的阻燃性最好；8phr的微胶囊红磷添加量即可使材料的阻燃性能达UL 94V-0级，极限氧指数(LOI)从17．4％上升到22．5％；在添加量范围内对材料的力学性能影响很小；二元体系中，微胶囊红磷／氢氧化铝，微胶囊红磷／氢氧化镁与微胶囊红磷／硼酸锌复配具有良好的阻燃协效作用，协效指数分别为1．6、1．4和2．3，微胶囊红磷／硼酸锌二元复合体系有良好的抑烟协效作用，三元体系中，微胶囊红磷／硼酸锌／十溴联苯醚、微胶囊红磷／氢氧化铝／氢氧化镁和微胶囊红磷／硼酸锌／三聚氰胺体系有很好的阻燃协效作用，协效指数分别为2．6、2．1与2．0。     

Enhanced flame retardancy and mechanical properties of waterborne polyurethane based on the phosphorus and nitrogen containing polybutadiene acrylonitrile

To further improve fire resistance of waterborne polyurethane, the macromolecular intumescent flame retardant (APBDH) was designed and prepared from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 4-aminothiophenol, benzaldehyde, and hydroxyl-terminated polybutadiene acrylonitrile (HTBN). Then, it was incorporated into waterborne polyurethane (WPU) to preparing flame retarded WPU (FR-WPU). TGA results suggested that the incorporation of APBDH into WPU increased thermal stability of FR-WPU. The fire resistance of FR-WPU were investigated by limiting oxygen index (LOI) test, the vertical burning test (UL-94), SEM-EDS analysis, the Laser Raman test, and cone calorimeter test. An LOI value of 28.82% and a UL-94 V-0 rating can be achieved when the WPU sample conjugated with 7.5 wt% APBDH. It indicated that the fire resistance of FR-WPU remarkably improved and displayed both gas and condensed phase mechanism. As the content of APBDH increased, the tensile strength and the elongation at break of FR-WPU increased firstly and then decreased. The thermo-mechanical behaviors indicated that the storage modulus increase at first and then descend with the addition of APBDH, while the T_gs firstly decreased and then increased. Additionally, the T_gh increased with the addition of APBDH.     

Effect of zinc oxide on properties of phenolic foams/halogen‐free flame retardant system

A halogen‐free flame retardant system consisting of ammonium polyphosphate (APP) as an acid source, blowing agent, pentaerythritol (PER) as a carbonific agent and zinc oxide (ZnO) as a synergistic agent, was used in this work to enhance flame retardancy of phenolic foams. ZnO was incorporated into flame retardant formulation at different concentrations to investigate the flammability of flame retardant composite phenolic foams (FRCPFs). The synergistic effects of ZnO on FRCPFs were evaluated by limited oxygen index (LOI), thermogravimetric analysis (TGA), cone calorimeter tests, and images of residues. Results showed that the flame retardant significantly increased the LOI of FRCPFs. Compared with PF, heat release rate (HRR), total heat release (THR), effective heat of combustion (EHC), production or yield of carbon monoxide (COP or COY) and Oxygen consumption (O₂C) of FRCPFs all remarkably decreased. However specific extinction area (SEA) and total smoke release (TSR) significantly increased, which agreed with the gas‐phase flame retardancy mechanism of the flame retardant system. The results indicated that FRCPFs have excellent fire‐retardant performance and less smoke release. And the bending and compression strength were decreased gradually with the increase of ZnO. The comprehensive properties of FRCPFs were better when the amount of ZnO was 1～1.5%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42730.