PF/PDMS-OH流变性能对其泡沫材料泡孔结构的影响

分别将质量分数为10%,15%和20%的端羟基聚硅氧烷(PDMS–OH)通过机械共混的方法改性酚醛树脂(PF),进而采用化学发泡的方法制备PF/PDMS–OH泡沫复合材料。采用旋转式流变仪表征共混体系的稳态及动态流变性能,研究黏弹性对树脂发泡过程的影响。傅立叶变换红外光谱表征PDMS–OH与树脂在固化过程中的化学反应。扫描电镜表征不同共混体系下泡孔的结构与形态。结果表明,加入15%PDMS–OH的共混体系具有最利于发泡成型的黏弹性,且可与PF形成化学交联作用,对PF泡沫的泡孔形态影响显著。同时红外表征显示,PDMS–OH与PF在固化过程中发生化学交联,这种互穿交联网状结构为PF及泡沫提供了更多稳定的柔性链段。

Effect of Rheological Properties of Phenolic Resin/PDMS-OH Blend on Its Foam's Cell Structure

The phenolic (PF) resin was modified by hydroxyl terminated polysiloxane (PDMS–OH) with different mass fraction of 10%,15% and 20% though mechanical blending respectively. A series of PF/PDMS–OH foam composites,based on the modified resin were prepared by chemical foaming method. The static/dynamic rheological behavior of PF/PDMS–OH foam composites was characterized by rotary rheometer to study the effect of viscoelastic response of resin blends on the foaming behavior. Fourier transform infrared spectroscopy (FTIR) was used to study the chemical reaction between PF resin and PDMS–OH during the curing process. Scanning electron microscope (SEM) was used to observe the cell structure of PF foam. The results indicate that the resin blend with 15% PDMS–OH present thebest viscoelasticity for foaming. There is chemical cross-linking between PDMS–OH and PF,which all contribute to impact the cell morphology of PF/PDMS–OH foam. Meanwhile,FTIR results show that the chemical bond between phenolic resin and PDMS–OH is built during the curing process,the cross-linking structure provide resin and foam with more stable soft segment.