การดัดแปรโครงสร้างและผิวของเลเยอร์ดับเบิลไฮดรอกไซด์สำหรับสารยึดติดฐานพียู

Abstract

This work studied the structural modification of magnesium-aluminum layered double hydroxides (MgAl LDH) by intercalation with sodium dodecyl sulfate (SDS) and surface modification of MgAl LDH by silylation with (3-aminopropyl)triethoxysilane (APS), methyl(trimethoxy)silane (MTMS) and octadecyl (trimethoxy)silane (OTMS). The effect of SDS : Al molar ratio silane coupling agent and APS : Al molar ratio on the physicochemical properties of modified MgAl LDH were also investigated. The results showed that LDHw-SDS1.0-APS2.4 exhibited the highest interlayer spacing. The APS had better dispersibility on metal hydroxides layer than MTMS and OTMS, as APS dispersed thoroughly in ethanol. The higher amount of APS was increased the rate of self-condensation. The effect of addition and type of modified MgAl LDH on the mechanical and physicochemical properties of PU adhesive/modified MgAl LDH nanocomposites were also investigated. The results showed that 3 % LDHw-SDS1.0-APS2.4 loading had good dispersion in PU adhesive because the LDHw-SDS1.0-APS2.4 easily exfoliated. The PU/LDHw-SDS1.0-APS2.4-3% possessed the highest shear strength, as a result of the bonding between the amine group of APS and urethane group. The PU/LDHw-SDS1.0-OTMS2.4-3% exhibited the lowest shear strength and elongation at break because of the OTMS aggregation, reducing the PU chains ability to rearrange.