Preparation And Properties Of Ldpe, Eva, Epdm Modified Epm Foam Materials

Ethylene-propylene copolymer (EPM) foam comprising EPM as basic material, low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), or ethylene propylene diene monomer (EPDM) as modifier resins, and rare earth aluminate modified clay as filler was prepared following the procedures of plasticizing in internal mixer, two-roll compounding and compression molding. The torque and foaming pressure were evaluated by rheometer. The pore characteristics of EPM foam materials were observed by SEM. And the effect of LDPE, EVA, EPDM, AC foaming agent and DCP cross-linker content on physical and mechanical properties of EPM foam materials were analysed.The results indicated that when the clay was modified by 4%(mass fraction) rare earth aluminates, its suction time and lipophilic degree reached 326.68 s and 17.8% respectively. Two new peaks at 2851 and 2920 cm-1 on IR Spectra of the modified clay. The physical and mechanical properties of the EPM foam materials containing 20%(mass fraction) modified clay were excellent. With the growth of LDPE content, the highest torque and the torque difference both descended during the molding foaming process of EPM/LDPE. When the content of LDPE was 30phr, the pores of EPM/LDPE foam materials were more regular and the shrinkage ratio decreased. With the growth of EAA content, the EPM/EAA/EVA's highest torque and torque difference were both decended, and its t90 was extended. The tear strength and tensile strength of EPM/EAA/EVA foam materials with 20 phr EAA were increased of 58.3% and 12.0%. With the addition of 20phr EPDM in EPM, the EPM/EPDM's t90 was raised to 77 s. Under the same condition, gelling rate, elongation at break, tear strength and tensil strength of the EPM/EPDM foam materials totally reached the bigest, but the shrinkage ratio and the density were on high term. The EPM/EPDM foam materials had smooth surface and good mechanical properties when it was prepared at 180℃, and the ratio of the rate of crosslinking reaction to of foaming agent decomposed reaction could be expressed in v/r=0.58. EPM/EPDM foam materials prepared by optimizing formula had favorable physical and mechanical properties. Its tensile strength, tear strength, elongation and shrinkage ratio reached 2.66 MPa,11.023 KN/m,599.7% and 2.5% respectively.