Study On The Mechanical Properties And Compression Set Of EPDM

Firstly, The influences of different vulcanization systems, cross-linking additive, antioxidant on the properties of Ethylene-copropylene-codiene polymer (EPDM) were investigated. The study not only included the use of one antioxidant alone,but also two or more combined use, in order to get the better formulation which has a better properties. The experimental results show that the mechanical properties of EPDM with efficient vulcanization system (EV) and complex crosslinked vulcanization system (CRV) were better, but anti-aging properties and compression set were quite poor, while the good performance can be obtained when dicumyl peroxide (DCP) vulcanization system was used. The cure rate and the crosslinking density increased,anti-aging properties improved and the compression set reduced when N, N'-phenylene bismaleimide (PDM), triallyl isocyanurate (TAIC) and sulfur (S) was used incorporated with DCP. When one antioxidant was used, the compression set of vulcanizate which used 2-Mercaptobenzimidazole zinc (MB) was lower. When two antioxidants were used with the same mount, the value of compression set was 2,2,4-trimethyl-1,2-dihy droquinoline (RD)/ nickelous N,N-dibutyldithiocarbamate (NBC) > MB/NBC > RD/MB. When NBC was incorporated with MB, the lower compression set can be obtained when the content ratio was 1.5phr/0.5phr.Secondly, the paper examines the curing process conditions including the curing temperature, curing time, post vulcanization time on properties of EPDM. The experimental results show that the interaction between filler and crosslinking density decreased with the curing temperature increased, but the cure rate and compression set increased. With curing time and post-curing time increased, the compression set was improved. Reasonable choice of curing temperature and curing time, can make vulcanized rubber with good comprehensive performance. Post vulcanization can also improve the physical mechanical properties of vulcanized rubber, the optimal performance was obtained when post vulcanization time was 2h. At last, the curing characteristics, mechanical properties, aging resistance and compression permanent deformation properties of carbon black (N234, N330, N550 and N774), montmorillonite (DK2-OMMT, DK3-OMMT), nano-barite (BaSO₄) and and nano-attapulgite (AT) filled EPDM were invesigated and analysed from the filler size, structure, morphology, so as to provide theoretical and experimental basis for formulation screening, exploration of new packing ,the application of nanomaterials and so on.The experimental results show that the properties of EPDM vulcanizate differ from the filler type and amount, but were mainly affected by filler particle size, surface activity, structure and other factors. With the increase of the filler amount, the physical mechanical properties and compression set of EPDM which was filled by carbon black, DK2-OMMT, DK3-OMMT and AT increased, but the physical mechanical properties increased, the compression set increased first and decreased afterwards when the filler was BaSO₄. The smaller particle size and the higher surface, the filler had the higher reinforcement effect, but elongation at break also influenced by the structure. The vulcanizate anti-aging properties were differ from the type and amount of carbon black and inorganic nano-filler, but the influence of particle size declined, the influence of structure and other factors increased.The compression set decreased when the carbon black particle size increased. Highly structured carbon black can improve the compression set. The similar conclusion was obtained when the fillers were DK2-OMMT, DK3-OMMT and AT, but with the increased content of BaSO₄, its value increased frist and then decreased.