Of Epdm With The Study

The effects on properties of ethylene-propylene-diene terpolymer (EPDM) compounds and vulcanizates caused by the state of dispersed and the size of particle of magnesia and cure systems as well as EPDM/NR > EPDM/NBR blends were studied in this thesis.1 The common rules and the trend of optimal design in cure system of EPDM with high properties were studied. Five results were found. (1) The optimum ratio of the sulpher cure system in common using consisting of accelerator M, TRA, BZ and sulfur was found as the conventional vulcanization system. The level of accelerator TRA, BZ had better be less than 0.8phr, and the level of sulpher should be increased when the total level of accelerater is very low. The physical-mechanical properties of vulcanizates of EPDM cured by these cure systems are excellent, moreover, they have no trend of blooming. (2) The kinds of accelerators of monosulfide can improve the cure velocity of EPDM compounds rapidly while the speed of scorch of EPDM compounds were mainly influenced by the level of accelerators of zinc dithiocarbamate. Accelerater DM and accelerater CZ can improve the properties of anti-scorch of EPDM compounds while accelerater TMTD, PX, DTDM may make EPDM vulcanizates blooming easily. (3)The activity of cure in EPDM compounds is weaken gradually with the increase of the size of groups replaced on the amido of monosulfide and zinc dithiocarbamate accelerators but the trends of blooming of the vulcanizates are also slacking. (4)The vulcanization properties of compounds of mult-crosslinking EPDM consisting of sulpher cure systems and peroxide cure systems are changed slightly compared to sulpher cure systems when the recipes of cure systems and the process techniques are propriety. The physical-mechanical properties of vulcanizates of EPDM cured by mult-crosslinking recipes are excellent, moreover, their anti-aging properties are also improved. (5) The level of accelerators and sulpher had better be less than conventional vulcanization system when EPDM was mult-crosslinked, and DCP also need to be mixed in the compounds laterly.2 The problems of co-crosslinking between EPDM and other incompatible rubbers such as NR and NBR were solved through specifical process techniques and modification. The results show as following: (1) The good compatibility of epoxy nature rubber(ENR) to both NR and EPDM was used to co-vulcanization NR/EPDM blends through particular process technology of pre-dispersing the cure systems in ENR and the problems of bad co-vulcanization of NR/EPDM blends were improved. The vulcanizates of NR/EPDM blends have excellent physical-mechanical properties. (2)The compatibility of EPDM/NR were improved with the level of ENR were increased but its aging-resistance properties have a bit descent when the level of ENR was near to 10 phr. (3) The multiplicity crosslinking systems consisting of different levels of Dicumyl peroxide (DCP) by pre-dispersed in ENR and constant sulfur cure system pre-mixed in compounds...