| 초록 |
Rheological and thermal properties of ethylene vinyl acetate copolymer (EVA) were investigated by DMTA and DSC. The samples of EVA varying the vinyl acetate (VA) and dicumyl peroxide (DCP) contents were prepared by screw extrusion. For the EVA (26 wt% VA content) containing 0 phr DCP as a crosslinking agent, the storage modulus showed higher than those of the EVA (26 wt% VA content) containing 0.5, 1.0, 1.5, and 2.0 phr DCP (0~50oC) and the loss factor showed the another relaxation process. Also, the heat of fusion (ΔH) was decreased from 31.4 J/g to 23.9 J/g for the EVA (26 wt% VA content) containing 0.0 and 2.0 phr DCP, respectively. Therefore, it was thought that the another relaxation process of the EVA (26 wt% VA content) containing 0.0 phr was come from the interphase between the crystalline and amorphous phase of the EVA. From the DMTA result of EVA with VA content, the storage modulus was decreased with the increasing the VA content in the EVA, and the sample of EVA became flexible with the increasing of the VA content. Also, the crystallinity of EVA was decreased as increasing the VA content. From the study of thermal analysis and DMTA, it is suggested that the crystallinity of the EVA decreases with the DCP, and also the chain flexibility of the EVA is mainly influenced by the crystallinity of the EVA. The effects crystallinity of EVA are investigated by XRD. |
