【作者】 王慧霞；

【导师】 李运涛；

【作者基本信息】 陕西科技大学 ， 无机化学， 2012， 硕士

【摘要】 聚磷酸铵（APP）是一种高效的无卤阻燃剂。但聚合度的大小直接影响APP的水溶性、热稳定性及与基材的相容性。我国目前主要采用磷酸-尿素缩合法合成APP，由于生产工艺和条件落后，所得APP产品聚合度较低（＜100），极大地限制了它的应用。本文以磷酸、尿素为原料，采用单因素实验和正交实验相结合，深入探讨了APP的合成工艺，确定了较佳工艺条件：磷酸与尿素的摩尔比为1:1.9，升温速率2～3℃/min，预聚温度135℃，固化温度230℃，固化时间2h。通过红外（IR）、X-射线衍射（XRD）、核磁共振（NMR）等手段对最佳条件下合成的APP产品进行了表征。结果表明，最佳条件下所得APP为I-型，平均聚合度为126。此工艺参数同样适用于以工业原料合成APP，平均聚合度变动不大。为解决APP应用中存在的易吸湿、热分解温度低、与基材相容性差、易迁移等问题，本文选择密胺甲醛树脂（MF）作囊壁材料，采用原位聚合技术对合成的APP产品进行微胶囊改性。深入研究了微胶囊的合成工艺，确定了较佳包覆条件：摩尔比n(MEL):n(HCHO)=1:3，预聚温度70℃～85℃，预聚时间30～60min，预聚阶段pH≈9.0，质量比m(壁材):m(芯材)=1:4，固化温度70～80℃，固化时间2h，固化阶段体系pH≈5。应用IR及X-射线光电子能谱（XPS）对囊壁的组成进行了分析，通过扫描电镜（SEM）、热重分析（TG）、粒径分析等手段对微胶囊的性能进行了表征。结果表明：APP被密胺树脂完全包覆，微胶囊表面致密，粒径分布较窄，几乎不溶于水，热分解温度显著提高到260℃，更有利于其在聚合物中的应用。选择浆内添加法将微胶囊APP应用于纸张中，极限氧指数试验（LOI）和垂直燃烧实验表明：MFAPP对纸张阻燃效果明显，添加35%可使纸张的LOI值达到25.0以上，达到难燃级别。更多还原

【Abstract】 Ammonium polyphosphate（APP）is a highly effective halogen-free flameretardant. Many properties of APP depend on the degree of polymerization, suchas solubility in water, thermal stability and compatibility with materials. Atpresent time, APP was mainly prepared using phosphoric acid and urea as rawmaterials in our country. Due to the backwardness of production processes andconditions, average polymerization degree of APP obtained was low (<100),which had greatly limited its application.Therefore, the synthetic technology of APP was deeply investigated in thispaper using phosphoric acid and urea as raw materials. The preparation processwas optimized by the combination of the single factor and orthogonalexperiments. The optimal technological conditions were as follows: the moleratio of phosphoric acid to urea1:1.9, heating rate of pre-polymerization stage2～3℃/min, pre-polymerization temperature130℃, curing temperature230℃and curing time90min. The APP synthesized under the optimal conditions wascharacterized by IR spectra, XRD and NMR. The results indicated that APP-Iwas obtained under the optimal conditions, with an average degree ofpolymerization of126. Besides, the technological parameter was equallyapplicable to the synthesis of APP by industrial phosphoric acid and urea,without great change on the degree of polymerization.However, general APP has some shortcomings: low thermal decompositiontemperature, easily attacked by moisture and migrates to the surface of polymersin the practical applications. Microencapsulated APP was prepared withmelamine-formaldehyde (MF) resin as the shell layer by in situ polymerizationto deal with the problems above-mentioned. The synthetic technology ofmicrocapsules was studied in detail and the optimum conditions were as follows: the mole ratio of melamine to formaldehyde1:3, pre-polymerization temperature70℃~85℃, prepolymerization time30~60min, pH value of pre-polymerizationstage9.0, mass ratio of the shell material to the core material1:4, curingtemperature70～80℃, curing time2h and pH value of curing stage around5.0.The component of the wall was analyzed by IR and XPS spectra, and propertiesof microcapsules were characterized using SEM, TG, particle size analysis andso on.The results showed that APP was completely covered with MF resin. Themicrocapsules obtained possessed excellent properties such as dense surface,narrow particle size distribution, almost insoluble in water，the significantlyenhanced thermal decomposition temperature of260℃, which is moreconducive to apply in polymer.The flame-retardant paper was made by adding microencapsulated APP tothe pulp. Limiting oxygen index (LOI) tests and vertical burning tests showedthat MFAPP has an obvious effect of flame retardancy. The LOI value of thepaper/MFAPP at35%loading can reach above25.0，up to non-flammable level．更多还原