硅锡协同阻燃尼龙6

采用氯化亚锡(SnCl2)/聚氨丙基苯基倍半硅氧烷(PAPSQ)复合阻燃剂阻燃改性尼龙6(PA6)。测定了阻燃PA6的氧指数(LOI),利用锥形量热仪测定了阻燃PA6的释热速率、总释热量、有效燃烧热等多种阻燃参数,并用扫描电镜(SEM)观察了阻燃PA6残炭的形貌。实验表明,当SnCl2用量为4%,PAPSQ用量为1%时,PA6的LOI为31%,PA6的释热速率、总释热量和有效燃烧热均明显下降,PAPSQ对SnCl2有协同阻燃效果。     

Flame retardant properties of polyamide 6 with piperazine pyrophosphate

Piperazine pyrophosphate (PAPP) was mixed in polyamide 6 (PA6) to investigate its flame retardant properties. The PAPP was characterised by Fourier transform infrared (FT-IR), elemental analysis, proton nuclear magnetic resonance (1H-NMR) spectroscopy and thermogravimetric analysis (TGA). The elemental analysis and TGA results of PAPP indicated it had a high P element content and good thermal stability. The flame retardancy of PA6/PAPP was also characterised by TGA, limiting oxygen index (LOI), UL-94 vertical test and microscale combustion calorimetry (MCC). The TGA results showed that the PAPP increased the stability of the PA6/PAPP and resulted in a significant increase of char residue. PA6/PAPP passed the UL94 V-0 rating with a LOI value of 42 vol %. The MCC test indicated that the PAPP can greatly decrease the peak heat release rate (PHRR) and total heat release (THR). The results of scanning electron microscope (SEM) illustrated that PAPP can promote the formation of compact char layer.     

Valorization of kapok fiber by phosphorylation with a reactive phosphorus- and nitrogen-containing flame retardant for enhanced fire safety

Kapok fiber (KF) with a naturally hollow structure has found an increasing application in filling and composite materials, most of which have a demand of flame retardancy. To realize this high-value utilization, KF was phosphorylated by a reactive phosphorus- and nitrogen-containing flame retardant for enhanced fire safety. The flame retardant was first synthesized by the reaction of urea and diethylene triamine pentakis (methyl phosphonic acid) (a commercially available scale inhibitor) with low cost, and then, applied in the phosphorylation of KF in the presence of dicyandiamide. In thermogravimetric analysis, phosphorylated KF showed 38.1% residue weight in nitrogen and 10.2% residue weight in air at 700°C, whereas the residue weight of KF was 8.4% in nitrogen and 1.5% in air. In microcalorimetric analysis, the heat release capacity and total heat release of phosphorylated KF displayed a reduction of 81% and 55%, respectively. In vertical combustion test, phosphorylated KF was difficult to ignite and had no afterburning or smoldering. The tests indicated that phosphorylated KF had excellent charring properties, low heat release, and good flame retardancy. This work suggests a promising strategy of enhancing the flame retardancy of KF and increasing its applicability in filling and composite materials.     

Synthesis of carborane acrylate and flame retardant modification on silk fabric via graft copolymerization with phosphate‐containing acrylate

A novel carborane acrylate monomer (1‐acryloyloxyethyl carborane) was synthesized by addition reaction, hydrolysis, and esterification and characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy and Fourier transform infrared spectroscopy (FT‐IR) analysis. Subsequently, the carborane monomer and a phosphate‐containing methacrylate monomer were applied on the modification of a silk fabric. The heat resistance and flame retardancy of the silk fabric before and after modification were compared. Energy‐dispersive X‐ray spectrometer (EDS) and FT‐IR showed that carborane monomer and phosphate‐containing methacrylate were grafted onto the surface of the fibers. The cross‐sectional morphology of silk fabrics after burning was observed by scanning electron microscope (SEM), and the flame‐retardant mechanism was analyzed. Thermal‐gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis revealed that the thermal stability of the modified silk increased with the increase of the grafting yield. The MCC‐2 microcalorimeter (MCC) test showed that, when using 1‐acryloyloxyethyl carborane as monomer and blending with phosphate‐containing methacrylate, the maximum heat release rate (PHRR) of the modified silk fabric decreased from 97.6 W/g (before grafting) to 51.3 and 45.8 W/g, respectively, and the total heat release (THR) decreased from 10.2 kJ/g (before grafting) to 5.9 and 5.2 kJ/g, respectively. The limiting oxygen index (LOI) test revealed that using 1‐acryloyloxyethyl carborane and phosphate‐containing methacrylate as mixed monomers to modify the silk fabric obtained good flame retardancy, whose LOI value reached 29.8%.     

Preparation of acylated microcrystalline cellulose using olive oil and its reinforcing effect on poly(lactic acid) films for packaging application

A novel poly(lactic acid) (PLA) based composite, reinforced by microcrystalline cellulose (MCC) was prepared. MCC was modified by esterification reaction using olive oil for improving the compatibility with PLA matrix. The acylated microcrystalline cellulose (AMCC) exhibited reduced polarity in comparison to unmodified MCC. AMCC/ PLA composite films were prepared using solvent casting technique. The effects of the MCC surface modification on morphological, mechanical, physical, thermal, biodegradability and barrier properties of the PLA based MCC composites were studied. FTIR analysis confirmed acylation reaction of MCC. Scanning electron microscopy analysis exhibited a uniform distribution of AMCC in PLA matrix. Barrier properties of AMCC based composites were improved as compared to MCC based composites. The tensile strength and tensile modulus of composite films (at 2 wt.% AMCC) were improved about 13% and 35% as much as those of the pure PLA films, respectively. These biodegradable composite films can be a sustainable utilization of olive oil and microcrystalline cellulose in the food packaging application.     

Melamine polyphosphate/silicon‐modified phenolic resin flame retardant glass fiber reinforced polyamide‐6

The halogen‐free flame retardance of glass fiber reinforced polyamide‐6 (PA6) is an everlastingly challenge due to well‐known wick effect. In this research, a novel system composed of a nitrogen–phosphorous flame retardant, melamine polyphosphate combined with a macromolecular charring agent, silicon‐modified phenolic resin (SPR), was employed to flame‐retard glass fiber reinforced PA6. It exhibited obvious synergistic effect between the two components at a proper ratio range. The flame retardance of the composites can be remarkably improved due to the increased amount and improved thermal stability of the produced char. The flame resistance tests indicated that the synergism system with an optimized ratio achieved V0 (1.6 mm) rating of UL94, 25.2% of Limited Oxygen Index, and only 338.2 W/g of the heat release peak rate. The corresponding synergistic mechanisms were investigated by the characterizations including the thermal gravimetric analysis, carbonation test, and the char morphology observation. It confirmed that the introduced SPR could accelerate the carbonation of PA6 resin, which was in favor of the construction of denser and more continuous charring structure. In addition, the flame retardant materials also indicated the acceptable mechanical properties, showing the advantages in the overall performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

次磷酸盐⁃环四硅氧烷双基化合物复配二乙基次磷酸铝对PA6的阻燃性能研究

将次磷酸盐?环四硅氧烷双基化合物（MVC?AlPi）与二乙基次磷酸铝（AlPi）复配阻燃聚酰胺6（PA6）。目的是考察外加的富磷酸铝化合物中磷酸铝基团和环四硅氧烷基团之间的配比对PA6阻燃效率的影响。结果表明, PA6/8.8 %AlPi/2.2 %MVC?AlPi具有协同屏障效应,可使复合材料的极限氧指数（LOI）值提高到31.5 %,并通过UL 94 V?0级别。相比于纯PA6,PA6/8.8 %AlPi/2.2 %MVC?AlPi的热释放速率峰值（PHRR）降幅近50 %、总热释放量（THR）也降低了15 %,PA6/8.8 %AlPi/2.2 %MVC?AlPi的残炭率虽略低于11 %MVC?AlPi,却形成了内层坚硬,外层类陶瓷化的双层炭层结构,MVC?AlPi、AlPi与PA6的相互作用可以锁定更多P、C碎片,促进由含硅富磷残渣组成的屏障保护炭层的形成。在阻燃剂添加总量不变的情况下,通过调节各组分的比例,发挥出更好的协同阻燃效果。     

聚乳酸/苯基次膦酸铝复合材料的制备及其阻燃性能研究

采用共沉淀法制备了苯基次膦酸铝(AlP)并对其进行表征。在此基础上,通过熔融共混法制备了一系列聚乳酸/苯基次膦酸铝（PLA/AlP）复合材料,采用热重分析（TG）、极限氧指数测试（LOI）、UL 94垂直燃烧测试、微型量热测试研究AlP对复合材料热稳定性、阻燃性能、燃烧性能的影响。结果表明,AlP可以有效提高PLA/AlP复合材料的阻燃性能, 当AlP含量为30 %（质量分数,下同）时,PLA/AlP30的极限氧指数达到25.6 %,并达到UL 94 为V-0级;AlP可以提高PLA/AlP复合材料初始分解温度和成炭性; PLA/AlP复合材料的热释放速率峰值和总热释放随着AlP添加量增大呈现先增高再下降的趋势。     

Fire performance and mechanical properties of phenolic foams modified by phosphorus-containing polyethers

Two kinds of novel phosphorus-containing polyether toughening agents were synthesized and characterized by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectra (FTIR). Afterwards, a series of phenolic foams with different loadings of phosphorus-containing toughening agents were prepared. The apparent density and scanning electron microscopy (SEM) results showed that the addition of 5 wt% toughening agents increased the expansion ratio and promoted the formation of uniform cells. The limiting oxygen index (LOI) values of modified phenolic foams decreased with the increase of modifier content, but it still remained at 40% even if the amount of modifier loadings was 10 wt%. UL-94 results showed all samples can pass V0 rating, indicating the modified foams still have great flame retardance. Microscale combustion calorimetry (MCC) results indicated that the peak heat release rate (PHRR) and total heat release (THR) of the modified foams were reduced by 42% and 35%, respectively, compared to the pure phenolic foams. Moreover, the thermal stability of samples was investigated by thermogravimetric analysis (TGA). The mechanical properties were evaluated and correlated with composition and structural features.     

聚磷酸蜜胺系膨胀型阻燃剂阻燃PA6的燃烧行为及热裂解研究

采用以聚磷酸蜜胺(MPP)为基的三元膨胀型阻燃剂阻燃聚酰胺6(PA6)，测定了阻燃PA6的氧指数(LOI)、UL94V阻燃性及热稳定性，以傅立叶变换红外光谱(FT—IR)分析了阻燃PA6的热分解残余物，以锥形量热仪(CONE)测定了阻燃PA6的诸多与火灾有关的阻燃参数(包括释热速度、质量损失速度、有效燃烧热、比消光面积等)，并以光电子能谱(XPS)测定了阻燃PA6残炭表面的元素组成及XPS曲线拟合数据。     

酚醛在丙烯酸树脂防火改性中的应用

以酚醛树脂为主防火剂、胺类为协效剂,研究了其种类、用量对丙烯酸树脂防火性能的影响,采用锥形量热仪和热重分析仪对酚醛改性丙烯酸树脂的燃烧性能和热稳定性进行了测试,并对燃烧后的炭层结构进行了电镜分析。结果表明,硼酚醛树脂能显著提高丙烯酸树脂的防火性能,硅酸铝、六次甲基四胺具有有良好的协效作用;当丙烯酸树脂与硼酚醛树脂质量比为50:50,硅酸铝质量分数为7%,六次甲基四胺为2%时,改性树脂耐燃时间达到39min,点燃时间(TTI)及热释放速率峰值出现时间明显延长,热释放速率明显降低,800℃时残炭率为45%,热稳定性明显提高,燃烧烧后形成了表面为致密网状、断面为微细泡孔状的炭层结构,防火性能提高。     

An efficient approach to improving fire retardancy and smoke suppression for intumescent flame‐retardant polypropylene composites via incorporating organo‐modified sepiolite

In this work, an efficient approach to improving the fire retardancy and smoke suppression for intumescent flame‐retardant polypropylene (PP) composites is developed via incorporating functionalized sepiolite (organo‐modified sepiolite [ONSep]). The PP composites with different amounts of intumescent flame retardants and ONSep were prepared by melt compounding. The morphology, thermal behavior, fire retardancy, smoke suppression, and mechanical property of flame‐retardant PP composites were studied. The results indicate an appropriate amount of ONSep in the flame‐retardant PP composites can increase thermal degradation temperature and char formation as well as a reduction of the peak heat release rate and total heat release; moreover, the addition of ONSep significantly decreases the CO production, total smoke production, smoke production rate, and smoke temperature. Simultaneously, the impact strength of intumescent flame‐retardant PP composite is also maintained by introducing an appropriate amount of ONSep as compared with that without ONSep.     

Red phosphorus–controlled decomposition for fire retardant PA 66

The thermal degradation and the combustion behavior of glass fiber–reinforced PA 66 materials containing red phosphorus were investigated. Thermogravimetry (TG), TG coupled with FTIR, and TG coupled with mass spectroscopy were used to investigate the thermal decomposition. The flame retardant red phosphorus was investigated with respect to the decomposition kinetics and the release of volatile products. The combustion behavior was characterized using a cone calorimeter. Fire risks and fire hazards were monitored versus external heat fluxes between 30 and 75 kW/m². Red phosphorus acts in the solid phase and its efficiency depends on the external heat flux. The use of red phosphorus results in an increased amount of residue and in a corresponding decrease in total heat release. The decrease of the mass loss rate peak results in a corresponding decrease of the peak heat release. With increasing external heat flux applied the first effect on the total heat release decreases linearly, whereas the second effect on the peak heat release expands linearly. The investigation provides insight into the mechanisms of how the fire retardant PA 66 is achieved by red phosphorus controlling the degradation kinetics. Taking into account that a decrease of the volatile products also leads to a decrease of heat production in the flame zone and that the char acts as heat transfer barrier, a reduced pyrolysis temperature is suggested as a further feedback effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2060–2071, 2002     

纤维素的酸处理及醋酸酯化表面改性研究

分别用HCl和H2SO4处理从棉纤维中提取的纤维素,100℃下回流水解30～60 min得到微晶纤维素(MCC),并对其进行醋酸酯化表面改性.采用X-射线衍射(XRD)、热重分析(TG)、红外光谱(IR)技术研究酸处理对MCC的聚合度、结晶度和热稳定性的影响,探讨了改性方法对产物性能的影响.结果表明,纤维素微晶化后仍保持原来的晶型以及晶区和非晶区共存的微细结构,结晶度不能达到100%.扫描电子显微镜(SEM)测试结果表明,不同酸处理后所得产物的形态和热性能有所不同,MCC的最高适用温度不宜超过270℃.适宜的醋酸酯化改性条件为:硫酸和水体积比1∶8、温度60～70℃、改性处理3～5 h.改性后微晶纤维素的内部结晶区结构没有变化,在有机溶剂中的分散性得到良好的改善.     

A void surface flame retardant strategy for polymeric polyHIPEs

Effective flame retardant strategy for open-cell foam (e.g., polyHIPE) remains of a great challenge. Herein, a void surface flame retardant strategy for polyHIPE was presented. An open-cell polystyrene (PS) polyHIPE was fabricated through an emulsion-templating technique. Polyphosphazene (PSZ), a highly efficient flame retardant polymer, was then in situ fabricated and covalently attached to the void surface of the foam to be a uniform flame retardant protective layer, while the open-cell structure of the foam was perfectly preserved. Compared with the pristine PS polyHIPE, the PSZ modified one had significantly improved thermal stability (char residues yield at 800°C increased from 3.36 to 16.53 wt%) and mechanical properties (Young's modulus increased by 2.6 times); the values of average heat release rate and total heat release of combustion were reduced by 62.36% and 41.57%, respectively. While, the value of limiting oxygen index was increased from 17.39% to 19.75%, owing to the combined action of condensed phase flame retardant and gas phase flame retardant. These results indicate that the in situ surface modification strategy is effective for improving the flame retardancy of highly interconnected polymer foams.     

Polyurethane Composites Reinforced with Walnut Shell Filler Treated with Perlite,Montmorillonite and Halloysite

In the following study, polyurethane (PUR) composites were modified with 2 wt.% of walnut shell filler modified with selected mineral compounds–perlite, montmorillonite, and halloysite. The impact of modified walnut shell fillers on selected properties of PUR composites, such as rheological properties (dynamic viscosity, foaming behavior), mechanical properties (compressive strength, flexural strength, impact strength), dynamic-mechanical behavior (glass transition temperature, storage modulus), insulation properties (thermal conductivity), thermal characteristic (temperature of thermal decomposition stages), and flame retardant properties (e.g., ignition time, limiting oxygen index, heat peak release) was investigated. Among all modified types of PUR composites, the greatest improvement was observed for PUR composites filled with walnut shell filler functionalized with halloysite. For example, on the addition of such modified walnut shell filler, the compressive strength was enhanced by ~13%, flexural strength by ~12%, and impact strength by ~14%. Due to the functionalization of walnut shell filler with thermally stable flame retardant compounds, such modified PUR composites were characterized by higher temperatures of thermal decomposition. Most importantly, PUR composites filled with flame retardant compounds exhibited improved flame resistance characteristics-in all cases, the value of peak heat release was reduced by ~12%, while the value of total smoke release was reduced by ~23%.     

A new intumescent flame retardant containing phosphorus and nitrogen: Preparation,thermal properties and application to UV curable coating

A novel intumescent flame retardant piperazine-N,N′-bis(acryloxyethylaryl-phosphoramidate) (N-PBAAP) containing phosphorus and nitrogen used for UV curable coating was synthesized and characterized by Fourier transform infrared spectrometry (FTIR), ¹H and ³¹P nuclear magnetic resonances (NMRs). The thermal degradation and volatilized products of the N-PBAAP cured film were monitored by real time Fourier transform infrared (RT-FTIR) and thermal gravimetric-Fourier transform infrared (TG-FTIR) technique, respectively. Scanning electron microscopy (SEM) was employed to investigate the surface morphology of the residual char. And possible mechanism for the thermal degradation of N-PBAAP film was proposed. To investigate the flame retardancy of N-PBAAP in UV curable coatings, a series of UV curable intumescent flame retardant resins were obtained by blending N-PBAAP with EA (epoxy acrylate oligomer) in different ratios. The flammability and thermal properties of the cured films were studied by Microscale Combustion Calorimeter (MCC) and thermogravimetric analysis (TGA). In MCC test, the peak heat release rates (pHRRs) of the blends were all lowered by the addition of N-PBAAP comparing with the pure EA. And TG results revealed that N-PBAAP can greatly enhance the char residues of EA films at high temperature region.     

Studies on intumescent flame retardant polypropylene composites based on biodegradable wheat straw

Wheat straw (WS) has numerous advantages compared with traditional bioadditives such as starch and lignin. So in this work, based on WS and silica microencapsulated ammonium polyphosphate, flame retardant polypropylene/wheat straw (WSP) composites were prepared by melted blend method. Flame retardant and thermal properties of WSP composites have been investigated. The results of cone calorimeter show that peaks of heat release rate and total heat release of the flame retardant WSP composite decrease substantially compared with those of pure polypropylene. The peak of heat release rate value of the flame retardant WSP composite decreases from 1290.5 to 247.9 kW/m², and the total heat release value decreases from 119.4 to 46.3 MJ/m². Meanwhile, thermal degradation and gas products of the flame retardant WSP composite were monitored by thermogravimetric analysis and thermogravimetric analysis‐infrared spectrometry. The result of thermal analysis shows that the flame retardant WSP composite has a high thermal stability and has a 30.0 wt% residual char at 600°C. From this work, we hope to provide a method to prepare flame retardant polymer composites with a biodegradable natural material‐WS.     

超声-微波共辐射法合成纤维素-MMA接枝共聚物

引言纤维素作为一种天然的可再生高分子材料,存在于丰富的绿色植物中,是自然界取之不尽用之不竭的清洁资源。因此,在煤、石油、天然气的储量日益减少的今天,纤维素可作为一种可持续发展的绿色资源来研究和开发。而且天然植物纤维资源丰富、价格低廉,并且具有较好的生物可降解性,在     

Synthesis and properties of new polyamide/multiwalled carbon nanotube nanocomposites containing a pyridine group

The effects of multiwalled carbon nanotubes (MWCNTs) on the thermal properties and flame retardancy of a new polyamide (PA) derived from glutaric acid and aromatic diamine were investigated in this work. The synthesized PA containing pyridine and trialkylamine groups was characterized by ¹H NMR and SEC. The PA unit structure was geometrically optimized at the B₃LYP/6‐311⁺⁺G(d, p) level of theory. PA showed a glass transition temperature of 151 ºC. PA nanocomposites containing two different amounts of MWCNTs were prepared via the solution intercalation technique with the solvent N,N‐dimethylacetamide. Transmission electron microscopy showed that MWCNTs were exfoliated in the polymer matrix, resulting in well‐dispersed morphologies at 3 wt% MWCNT content. The redox behaviors of PA and the nanocomposites were examined using cyclic voltammetry (CV). PA showed a reversible oxidation process in the CV scan. Thermal and flammability properties of the nanocomposites were studied by TGA in nitrogen and air, DSC and with a microscale combustion calorimeter. The TGA results showed that the addition of MWCNTs resulted in a substantial increase in the thermal stability and char yields of the nanocomposites compared with neat PA. The heat release rate and total heat release were significantly reduced in the presence of MWCNTs. © 2013 Society of Chemical Industry