Research On The Preparation、Characterization And Properties Of Rubber/Layered Double Hydroxides Composites

In this thesis, the preparation, characterization, and properties of organically-modified layered double hydroxides were studied. The application of these LDHs in rubber composites was also studied.Nitrate layered double hydroxides (LDH-NO3), sodium dodecyl benzene sulfonate intercalated layered double hydroxides (SDBS-LDH), and sodium styrene sulfonate layered double hydroxides (SSS-LDH) were prepared by cooprecipitation method. Fourier transform infrared spectrum (FTIR) and X-ray diffraction (XRD) results showed that all these layered double hydroxides were of intercalated structures. Thermogravimetric analysis (TGA) indicated that organically modified LDHs are more thermal stability than that of the pure LDH.Acrylonitrile butadiene rubber (NBR)/layered double hydroxides composites including NBR/LDH-NO3, NBR/SSS-LDH, NBR/SDBS-LDH were prepared by melt blending at different conditions; and the structure and properties of these composites were also studied. The composites made from LDHs in the presence of water showed better properties than the composites made from LDH powders without water. The XRD and SEM results have shown that a better dispersion of LDH has obtained with the assitance of water. Among the three layered double hydroxides, composites containing SSS-LDH has the best properties; and evidence obtained from FT-IR, vulcanization characteristics and DSC data indicated that vinyl group on SSS-LDH involved in curing process.Styrene-butadiene rubber (SBR)/layered double hydroxides composites including SBR/LDH-NO3, SBR/SSS-LDH, SBR/SDBS-LDH were prepared, characteristics of structure and properties were performed. Both the LDH-NO3 and organically modified LDH can greatly promote the cure time of SBR composites but the scorch time was not effected. The prophase thermal stability of SBR/LDH composites was greatly improved according to TGA data. The flammability of SBR/SDBS-LDH was better than the other composites. The mechanical properties of SBR/SDBS-LDH and SBR/SSS-LDH were significantly improved compared with that of SBR.Polybutadiene rubber (BR)/layered double hydroxides composites including BR/LDH-NO3, BR/SSS-LDH, BR/SDBS-LDH were prepared; the structure and properties of these above composites were performed. XRD results showed that LDH particles were dispersed in aggregated status in BR composites. The thermal stability of BR composites were decreased about 4-7℃compared to BR. However, the tensile strength, hardness, and crosslink density and elongation at break of BR/SDBS-LDH and BR/SSS-LDH were greatly improved compared to that of BR. LDHs/BR composites showed flame retardant based on the LOI data.