1.北方民族大学材料科学与工程学院，宁夏 银川 750021;2.1. 北方民族大学化学与化学工程学院，宁夏 银川 750021;3.2. 宁夏太阳能化学转化技术重点实验室，宁夏 银川 750021;4.3. 化工技术基础国家民委重点实验室，宁夏 银川 750021
以正硅酸四乙酯（TEOS）和乙烯基三乙氧基硅烷（A-151）对聚磷酸铵（APP）和三聚氰胺尿酸盐（MCA）进行改性，制备了Si-MAPP和Si-MMCA，解决了APP和MCA疏水性差的问题。将Si-MAPP和Si-MMCA与双季戊四醇（DPER）复配得到一种新的膨胀型阻燃剂（IFR）并用于LDPE阻燃。利用红外光谱、扫描电子显微镜、热重分析证明了APP和MCA成功被TEOS和A-151涂层修饰。采用万能材料试验机、极限氧指数仪、UL-94垂直燃烧试验和锥形量热试验测试了LDPE复合材料的阻燃性能。研究结果表明，经TEOS和A-151涂层修饰后，Si-MAPP和Si-MMCA疏水性能优异，与LDPE相容性好。加入含Si-MAPP/DPER/Si-MMCA的IFR大幅提高了LDPE复合材料的阻燃性。当加入43.75 wt%的Si-MAPP/DPER/Si-MMCA后，复合材料极限氧指数为30.3%并达到V-0级别，抗张强度达12.92 MPa，比同比例无Si-MMCA的LDPE/IFR高出了3.79%，比含量为41.6 wt%无Si-MAPP的LDPE/IFR高出了6.81%。烟密度试验表明，Si-MAPP和Si-MMCA的加入有效提高了LDPE复合材料的残炭含量和热稳定性，并使烟气排放明显改善。
Si-MAPP and Si-MMCA were prepared by modifying ammonium polyphosphate (APP) and melamine urate (MCA) with tetraethylorthosilicate (TEOS) and vinyltriethoxysilane (A-151). And a new intumescent flame retardant (IFR) was obtained by mixing Si-MAPP, Si-MMCA and dipentaerythritol (DPER) and used for LDPE flame retardant. The structure, morphology and mechanical properties of flame retardants and LDPE composites were characterized by FTIR, SEM, TG and universal material testing machine. The flame retardant properties of LDPE composites were investigated by LOI, UL-94 and cone calorimetry tests. The results show that Si-MAPP and Si-MMCA have excellent hydrophobic properties and good compatibility with LDPE after being modified by TEOS and A-151. And the problem of poor hydrophobicity of APP and MCA was resolved. The flame retardant properties of LDPE composites are greatly improved by adding IFR containing Si-MAPP/DPER/Si-MMCA. FTIR, SEM and TG results showed that APP and MCA were successfully modified by TEOS and A-151 coatings. The flame retardancy of LDPE composites was tested by universal material testing machine, limiting oxygen index, UL-94 vertical combustion test and cone calorimetry test. When 43.75 wt% Si-MAPP/DPER/Si-MMCA was used, the LOI of LDPE composites was 30.3% and reached V0 level. And the tensile strength reached 12.92 MPa, which was 3.79% higher than that of LDPE/IFR without Si-MMCA in the same proportion and 6.81% higher than that of 41.6 wt% LDPE/IFR without Si-MAPP. The smoke density tests show that the addition of Si-MAPP and Si-MMCA effectively improve the residual carbon content and thermal stability of LDPE composites, and significantly improve the smoke emission.