Micro-morphology and mechanical properties of organic montmorillonite/polyurethane elastomer composite

Sodium montmorillonite (MMT) was modified by octadecyl trimethyl ammonium chloride (OTAC) via cation exchange and organic montmorillonite (OMMT) was got. Polyurethane elastomer (PUE) was synthesized taking 4,4'-diphenylmethane diisocyanate (MDI) and polypropylene glycol (PPG) as the raw materials and 1,4-butanediol (BDO) as chain extender, and then OMMT/PUE composite was prepared by the prepolymer method. The results of FTIR and XRD show that the characteristic peaks of -CH₂(2 921 cm^-1 and 1 469 cm^-1) appear and indicate that the new groups have been introduced into the layers of OMMT, the intercalation quantity of OTAC is about 24% by the heat resistance of MMT and OMMT, and the interlayer spacing of OMMT is 0.7 nm larger than that of MMT. The analytical results of SEM and XRD of OMMT/PUE composites reveal that proper OMMT disperses evenly in the PUE matrix, and OMMT is peeled completely. This phenomenon can be explained by two main reasons, i.e. one is the strong interaction between OTAC molecular and soft segments of PUE, and the other is the interface interaction amid the active groups of OMMT and PUE matrix. The test results of mechanical properties of OMMT/PUE composites display that the maximum tensile strength, elongation at break and breaking tensile strength of OMMT/PUE composite are 37%, 28% and 34% higher than that of PUE matrix, respectively, when the content of OMMT is 3wt%, and the mechanical properties of OMMT/PUE composites are significantly improved.