聚硅氧烷包覆改性聚磷酸铵及其阻燃聚乙烯性能的研究

分别以二甲基二乙氧基硅烷（DMDES）、甲基三乙氧基硅烷（MTES）、苯基三甲氧基硅烷（PTMS）3种硅氧烷与正硅酸四乙酯（TEOS）共同作为前驱体,采用溶胶-凝胶工艺对聚磷酸铵（APP）进行微胶囊化包覆改性,分别制备得到改性聚磷酸铵APP/DMDES、APP/MTES和APP/PTMS,以改善其阻燃性、热稳定性和疏水性。通过傅里叶红外光谱、水接触角、扫描电子显微镜、能谱仪以及热失重分析等测试与表征手段,对3种不同聚硅氧烷包覆改性聚磷酸铵（MAPP）进行了对比研究,并研究了MAPP对低密度聚乙烯（PE-LD）阻燃性能、力学性能和热性能的影响。结果表明,在合适的工艺条件下,均可以制备得到聚硅氧烷包覆改性聚磷酸铵;较改性前的APP,改性聚磷酸铵的疏水性和热稳定性均显著提高;在PE-LD/APP/PTMS/季戊四醇（PER）/三聚氰胺（MEL）的质量比为65/18.7/11.7/4.6时,PELD复合材料的综合性能最好,极限氧指数为26.6%,高于包覆前APP的23.3%,达到UL 94 V-0级别,且拉伸性能最高,为12.84 MPa。     

聚磷酸铵阻燃聚乙烯的研究

通过极限氧指数测试、力学性能测试研究了聚磷酸铵(APP)对聚乙烯(PE)的燃烧性能和力学性能的影响.结果表明Ⅱ型APP在添加量达到30%以后,PE的氧指数达到了22.4,可以实现离火后很快自熄;在添加了APP后,PE的拉伸强度在开始的时候提高,当添加量超过20%后,其拉伸强度开始缓慢降低;PE的缺口冲击强度在添加APP后,在添加量很低时就产生了大幅度下降.     

超细聚磷酸铵疏水改性研究

聚磷酸铵作为一种新型高效阻燃剂,具有价格低、无毒、热稳定性高等优点。以甲基含氢硅油为改性剂、活性白土为催化剂,滑石粉、云母粉和疏水白炭黑为辅料,利用高速混合机对聚磷酸铵进行干法改性。通过疏水保持率、红外光谱、XPS和扫描电镜等检测,研究了聚磷酸铵改性效果,讨论了改性机理。结果表明,改性聚磷酸铵的疏水性保持率达到95.4%。甲基含氢硅油在聚磷酸铵表面发生了水解、聚合反应,形成硅油膜,提高了聚磷酸铵的疏水性能。     

聚磷酸铵表面疏水改性研究

通过自制乳液吸附在聚磷酸铵(APP)表面,实现APP表面疏水改性。利用扫描电镜、傅立叶变换红外光谱仪以及接触角测量仪表征了改性前后APP的表观形貌、化学结构和疏水性能。对该吸附过程的影响因素进行了分析。结果表明:常温下,醇水比为2∶8、pH为7. 0为宜;改性聚磷酸铵(MAPP)的疏水性能与乳液吸附量相关,当吸附量达232. 0 mg/g,其接触角由改性前的8. 69°增至103. 11°,此后吸附量再增加,接触角无明显变化。     

疏水硼酸锌与氢氧化镁协同阻燃EVA的性能研究

使用硫酸锌、硼砂为原料,油酸为改性剂,采用一步法制备疏水硼酸锌(Zn2B6O11.3H2O)。用X射线衍射仪、傅里叶变换红外光谱仪、扫描电子显微镜、接触角测定仪等设备对样品的物相、形貌、疏水性进行了分析。结果表明,所制备的硼酸锌直径为1～2μm,片层厚度为0.1μm,接触角为105.1°;将硼酸锌与氢氧化镁[Mg(OH)2]复配用于乙烯-醋酸乙烯共聚物(EVA)阻燃时具有很好的协同阻燃作用,极限氧指数达到了38.5%;在EVA配方中加入疏水硼酸锌,复合材料的力学性能下降较慢,且优于加入相同量市售硼酸锌的复合材料。     

改性微胶囊化聚磷酸铵阻燃天然橡胶

本文通过原位聚合法制备了聚乙烯醇（PVA）改性的三聚氰胺（MEL）-甲醛树脂（VMF）微胶囊,对聚磷酸铵（APP）/介孔分子筛MCM-41进行包覆,得到了一种新型的核壳结构的微胶囊阻燃剂（MVMF-(A/M)）。通过红外光谱分析（IR）、溶解度和扫描电子显微镜（SEM）对包覆前后的阻燃剂结构以及形貌进行表征。并将其加入到天然橡胶（NR）中,通过氧指数测试（LOI）、垂直燃烧测试（UL-94）、热失重分析（TG）、拉伸测试研究了NR复合材料的阻燃性能和力学性能。实验结果表明：制备的MVMF-(A/M)在20℃水中的溶解度为1.59mg /L,相比APP溶解度降低51.2%, MVMF-(A/M)粒子表面变得粗糙;与其他阻燃天然橡胶体系相比添加了MVMF-(A/M)的NR复合材料的极限氧指数最高, UL-94达到了V-0级别,拉伸强度为8.84MPa,断裂伸长率为310.20%。     

改性聚磷酸铵在阻燃聚丙烯中的性能研究

将聚磷酸铵(APP)、自制的哌嗪改性聚磷酸铵(Pi-APP)及其与三聚氰胺聚磷酸盐(MPP)按一定比例复配而成的复配体系用于聚丙烯(PP)的阻燃改性,采用热失重分析实验(TGA)、垂直燃烧实验、极限氧指数实验(LOI)、拉伸冲击实验和扫描电子显微镜实验等方法研究了其阻燃性能和力学性能。结果表明:Pi-APP与基体PP相容性更佳;复配体系添加20%Pi-APP、5%MPP时,可使PP达到UL 94V-0级(3.2 mm和1.6 mm),极限氧指数达到32.5%,同时保持较好的力学性能。     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

阻燃剂聚磷酸铵的改性和应用

聚磷酸铵是一种重要的阻燃剂。介绍了其改性方法以及用途,指出了其今后的发展趋势。     

Preparation and characterization of cyclodextrin microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

A novel microencapsulated ammonium polyphosphate (MAPP) with shell of crosslinked β-cyclodextrin (HDI-CD) was prepared. The HDI-CD shell had a fibrous structure and covered with good completeness on the APP core, and a solid chemical bonding was found between the APP core and HDI-CD shell. The microcapsules were more hydrophobic than the pristine APP. When compounded within polypropylene (PP), the MAPP exhibited good compatibility and dispersibility. The combustion testing results showed that the novel all-in-one intumescent flame retardant had efficient flame retardancy for PP materials.     

Microencapsulated ammonium polyphosphate by polyurethane with segment of dipentaerythritol and its application in flame retardant polypropylene

Dipentaerythritol (DPER), 4, 40-diphenylmethanediisocyanate (MDI) and melamine (MEL) are used as raw materials to microencapsulate ammonium polyphosphate (MAPP) in situ polymerization. The MAPP is characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). The results show that the coating operation can effectively improve water resistance of ammonium polyphosphate (APP), and MAPP has higher residual rate than that of APP after combustion. The flame retardant action of MAPP and APP in polypropylene (PP) is investigated by the limited oxygen index (LOI), vertical burning test (UL-94), TGA, SEM, and cone calorimeter test (CCT). The LOI value of the PP/MAPP composite at the same loading is higher than that of PP/APP composite. UL 94 ratings of PP/MAPP composites are raised to V-0 at 20 wt% loading. The results of CCT also show that MAPP is more efficient than APP. The morphological structures observed by digital photos and SEM demonstrated that MAPP could be promoted to form the continuous and compact intumescent char layer. The flame retardant mechanism of PP/MAPP is also discussed.     

High-efficiency ammonium polyphosphate intumescent encapsulated polypropylene flame retardant

The flame retardant polypropylene containing the micro-envelope core-shell structure flame retardant, which encapsulated ammonium polyphosphate into melamine-formaldehyde resin and sodium silicate through in situ polymerization was prepared with polyamide 6, added as a carbon-forming agent. The composition of ammonium polyphosphate, encapsulated ammonium polyphosphate with melamine-formaldehyde resin and the micro-envelope core-shell structure flame retardant were characterized. The fire safety and thermal stability were investigated and showed an improvement including limiting oxygen index, thermogravimetric analysis, vertical burning tests, and microscale combustion calorimeter. The burned compounds were also studied to confirm the burning mechanism. The results showed the flame retardant performance had been greatly improved, while polyamide 6 had better char-forming effect. Besides, the water solubility of flame retardants and their influence on the mechanical properties of polypropylene were also investigated. The results on the effects of additives demonstrated a high efficiency flame retardant to polypropylene. A core-shell flame retardant that sodium silicate and melamine-formaldehyde resin-coated ammonium polyphosphate had been constructed. The effect of the built flame retardant system on the combustion performance of polypropylene was studied from the mechanism and performance. The LOI of the most flame retardant polypropylene reached 28.6%, and UL-94 reached the V-0 level.     

磷系阻燃剂FR/APP协效阻燃PP

采用氧指数测定仪、热重分析仪和锥形量热仪研究了磷系阻燃剂1,3,5-三(5,5-二甲基-1,3-二氧杂环己内磷酸基)苯(FR)和聚磷酸铵(APP)复配体系对聚丙烯(PP)材料阻燃性能的影响.结果表明,FR/APP提高了PP的极限氧指数(LOI)、热稳定性和残炭率,降低了热释放速率.当w(FR)为15%和w(APP)为10%复配阻燃PP时,复合材料的LOI为29.6%.阻燃级别达到UL 94 V-0级.     

Synergistic flame retardant effect of piperazine salt and ammonium polyphosphate as intumescent flame retardant system for polypropylene

Amino trimethylene phosphonic acid piperazine (ATPIP) salt, as a novel charring agent, is prepared via a simple ionic reaction in distilled water using amino trimethylene phosphate (ATMP) and piperazine as raw materials. The synergistic flame retardant effect of ATPIP and ammonium polyphosphate (APP) as an intumescent flame retardant (IFR) is investigated by various characterization and testing methods. The results show that the polypropylene (PP)/modified APP with piperazine (MAPP)/ATPIP ternary blend passes UL-94 V-0 rating and achieve a limiting oxygen index (LOI) of 30% at a loading level of 25 wt% IFR (MAPP:ATPIP = 3:1). Meanwhile, the total smoke production (TSP) value of IFR-PP samples is 3.3 m², which decreases by 93.2% compared with that of pure PP, exhibiting excellent smoke suppression performance. Besides, the analysis of gaseous pyrolysis products and char residue indicates that the IFR-PP samples show a synergistic flame-retardant mechanism including the gas phase and the condensed phase.     

高效阻燃剂聚磷酸铵的合成工艺研究

以磷酸和尿素为原料合成了高聚合度的聚磷酸铵。通过单因素实验对制备工艺进行了优化,考察了原料配比、升温速率、预聚合温度、固化温度和固化时间等对产品质量的影响,采用核磁共振法（NMR）测定了聚磷酸铵的平均聚合度,并用X射线衍射(XRD )和红外(IR)相结合的方法对产品的晶体结构进行了表征,同时测定了聚磷酸铵的溶解度和总磷含量。结果表明,最佳制备工艺条件为：n（磷酸)∶n（尿素）=1∶1.9,预聚合阶段升温速率为2～3 ℃/min,预聚合温度为130 ℃,固化温度为230 ℃,固化时间为90 min。此条件下合成的聚磷酸铵平均聚合度为114,水中溶解度为0.492 g,总磷质量分数为31.75%,XRD表征结果表明,所得产品为Ⅰ型聚磷酸铵。     

三聚氰胺-甲醛树脂微胶囊包覆聚磷酸铵阻燃PP的性能

通过原位聚合法制备三聚氰胺-甲醛树脂(MF)微胶囊包覆聚磷酸铵(APP)粒子,研究了APP粒径对微胶囊化APP(MCAPP)结构与性能的影响。将两种MCAPP(APP平均粒径分别为5,15μm)添加至聚丙烯(PP)基体中,研究了PP/MCAPP阻燃材料的性能。结果表明:不同粒径的APP均能成功被MF包覆,且包覆后的APP粒子的水溶性均大幅下降。PP/MCAPP阻燃材料的耐渗析性和极限氧指数均得到一定程度的提高。粒径小的APP有利于MF的包覆,包覆结构层更完整。MF和APP有很好的协同作用,在APP包覆不完全的情况下,能更有效地发挥两者的相互作用,提高PP复合材料的阻燃性。     

The flammability of polyacrylonitrile and its copolymers IV. The flame retardant mechanism of ammonium polyphosphate

Ammonium polyphosphate is shown to be an effective flame retardant for homopolymeric and selected fibre-forming copolymers of acrylonitrile. Compared with other phosphates and phosphorus-containing species, it significantly increases both limiting oxygen index and char levels. The mechanism of retardancy is shown to be both physical and chemical in character. When heated to 300°C, the polyphosphate melts and converts to polyphosphoric acid which acts as a physical barrier to surface polymer oxidation and promotes nucleophilic oligomerization of pendant, adjacent nitrile groups. A reduction in the activation energy of this first stage of acrylic polymer degradation suggests that the favoured decomposition route gives rise via oligomerization to char-promoting precursors. Char analyses indicate an empirical formula of C₃₀H₁₃N₇P₂, which compares favourably with that of a proposed phosphorylated, polynuclear, aromatic heterocyclic structure.