| The compatibility, processability, curing system, reinforcement system and phase structure of chlorinated polyethylene (CM) and ethylene propylene terpolymer (EPDM) blends have been investigated. The improved of processiblity, physical-mechanical properties, flame resistance, oil resistance, and low cost of EPDM compounds were achieved by blending with CM.(1) The miscibility of CM/EPDM blends were studied by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), phase-contrast microscope analysis and calculation of the heat of mixing. Theoretical computation and the experimental results showed that CM and EPDM had some interaction with each other, and their Tgs were close to each other after blending, and they also has good phase distribution and fuzzy phase interface. It is found by thermal degradation analysis that the blend's initial decomposition temperature increased gradually, thermal stability dropped but flame resistance improved with the decrease of the blend ratio of CM/EPDM. By scanning electron microscopy (SEM) observation, addition of the compatibilizer ethylene-propylene-diene monomer grafted maleic anhydride (EPDM-g-MAH) improved microcosmic morphology and compatibility of the blend. At the same time, uniformly blend interface without or decreased phase separation was formed, and the interface became fuzzy, interface thickness as well as bonding strength enhanced between them. FTIR and DSC displayed there was some interaction in some degree between the compatibilizer and CM/EPDM blends. The improvement of physical properties showed that the blends had good compatibility after the addition of the compatibilizer.(2) The curing properties and physical-mechanical properties of CM/EPDM blend corresponding to eight different vulcanizing systems were investigated by Uniform Design, it was found that the CM/EPDM blend vulcanized by peroxide-sulfur (DCP-S) vulcanizing system had the appropriate vulcanization time and better physical properties, and the optimum ratio was 3/0.5. The optimum amount of DCP and the Triallyl isocyanurate (TAIC) inducted by RCAD ranges from 2.8 to 4.0 phr and 3.0-5.0 phr respectively. In addition, the influence of assistant crosslinking agents S and N, N-m-phenylene bismaleimide(PDM) on the co-vulcanized properties of CM/EPDM blend was also investigated, and the results showed that the blends exhibited optimum properties when the amounts of S and PDM was 0.3 and 1.5-2 phr respectively. The effect of S in improving peroxide co-vulcanizition of CM/EPDM is the best.(3) The influence of different trademarks of carbon black on the properties of CM/EPDM blend was investigated. The results indicated that the trademark of carbon black and the content have important influence on the dynamic properties, processability, the curing characteristic, dispersibility and the mechanical properties of CM/EPDM blends. CM/EPDM compound filled with Carbon black N330 and N550 showed better properties compared with other carbon black trademark. Compared with the ordinary trademark carbon black N330, carbon black CD2110 showed stronger Payne effect and the similar curing rate, in addition, and had good performance on the tensile strength, modulus and tear strength, especially the wear resistance and heat aging resistance were obviously improved.(4) The physical-mechanical properties of precipitated silica filled CM/EPDM blend were investigated. The results showed that the Payne effect, the tensile strength, modulus, hardness, tear strength and abrasion resistance increased with increasing silica loading, elongation at break increased firstly and decreased then. The CM/EPDM showed best properties when the content of silica was 30 phr. The silica surface was modified with bis-(3-triethoxysilylpropyl) terasulfane (Si-69), and the modified silica filled CM/EPDM compound showed higher Payne effect and crosslink density. When the Si-69 dosage was 1-3 phr, the CM/EPDM blend had optimum properties.
|
PDF Full Text Request