论文部分内容阅读
以聚丙二醇(PPG2000)和二苯基甲烷二异氰酸酯(MDI)为原料合成了异氰酸根封端的聚氨酯预聚体(PUP),分别以合成的预聚体和市售的聚氨酯预聚体为增韧剂改性酚醛泡沫,研究了PUP用量及异氰酸根含量对酚醛泡沫力学性能、热稳定性能、导热性能及阻燃等性能的影响,并对改性前后的酚醛泡沫进行了电子显微镜扫描泡孔结构和红外光谱分析。结果表明,聚氨酯预聚体用量为5%(wt,质量分数,下同),异氰酸根含量为4.1%时,酚醛泡沫的韧性和保温性能最好,其中相对弯曲强度和相对压缩强度分别为5.11kPa·m~3/kg和3.33kPa·m~3/kg,分别比纯泡沫提高了86.5%和43.5%;改性泡沫导热系数为0.057W/m·K,比纯泡沫导热系数(0.064W/m·K)低;增韧的酚醛泡沫热稳定性能略有降低,但下降幅度不大;此外,聚氨酯增韧后的酚醛泡沫阻燃性能均大于34%,具有优良的阻燃性能,且酚醛泡沫闭孔率高、泡空分布均匀。
Isocyanate-terminated polyurethane prepolymers (PUPs) were synthesized from polypropylene glycol (PPG2000) and diphenylmethane diisocyanate (MDI), respectively, using a synthetic prepolymer and a commercially available polyurethane prepolymer The effects of PUP content and isocyanate content on the mechanical properties, thermal stability, thermal conductivity and flame retardancy of phenolic foam were studied. The phenolic foam before and after modification was scanned by electron microscope Pore Structure and Infrared Spectroscopy. The results show that the toughness and thermal insulation properties of phenolic foam are best when the amount of polyurethane prepolymer is 5% (wt, mass fraction), and the isocyanate content is 4.1%. The relative flexural strength and relative compressive strength are respectively Kg and 3.33 kPa · m ~ 3 / kg respectively, which were respectively 86.5% and 43.5% higher than that of pure foam. The thermal conductivity of modified foam was 0.057 W / m · K, which was higher than that of pure foam W / m · K). The thermal stability of toughened phenolic foam decreased slightly, but the decrease was not significant. In addition, the phenolic foam toughened by polyurethane showed greater than 34% flame retardance, excellent flame retardancy, And phenolic foam closed cell rate, Bubble distribution.