چكيده به لاتين
In this study, hydrolysis of ethylene vinyl acetate copolymer (EVA) with different percentage for use as an adhesive interface between the metal and polyethylene was investigated. Hydrolysis effect on copolymer crystallinity by DSC, showed an increase in melting temperature and crystallization enthalpy of 88.9 OC to 102.5 OC and 92.39 to 145.16 J g-1 Respectively, for modified sample relative to the pure EVA. Also identification of composition and calculation of the percentage of hydrolyzed copolymer were evaluated by FTIR and H NMR tests. The effect of copolymer Hydrolysis on copolymer wetting conducted by contact angle test. Polar liquid drop contact angle decrease from 80.4 to 57 degree for modified sample with 5% of hydrolysis agent ( EVA5%H ). Interfacial energy of the film samples with metal and polyethylene sheet were calculated by this test. In addition, the mechanical tensile tests to measure the amount of adhesion of the adhesive films and tensile strength of them were made. Thus, the amount of energy in shear strength test had a growth of about three times and it receipt from 270.79 kN/m2 for pure EVA to 724.24 kN/m2 for modified sample of EVA5%H. The force for peel test on metal increased from 20.47 N m-1 for pure EVA to 850.39 N m-1 for EVA5%H, and for a peel test on polyethylene it had a decrease from 6.32 kN m-1 for pure EVA to 1.36 kN m-1 for EVA5%H. The hydrolysis effect on crack growth was conducted using the wedge test and it was found that the adhesion energy increased of the 35.1 J/m2 in the case of pure EVA to 202.5 J/m2 in EVA5% H sample. The results of the test films made from EVA copolymer and its modified examples showed that by increasing the presence of OH groups rather than acetate groups, Young's modulus grows about 4 times but, the tensile strength decrease from 5.87 kPa for pure EVA to 5.01 kPa for the EVA5%H sample. Then, for more polarity of hydrolyzed EVA copolymers, we have a try on a study of the isocyanate and amine groups subject acts on them. This means that a fixed amount of ( gr ) PMDI was added to the hydrolyzed copolymer with different percentages and the results of FTIR, contact angle, shear strength and tensile strength tests of the film was evaluated for these samples. In FTIR analysis showed the present of isocyanate and amine groups in the composition of the samples. For these samples, a significant increase in shear strength for samples with less hydrolysis values was obtained. In such a way that the shear strength, for EVA1% HN, was found that the amount of 555.98 kN/m2 that it was 296.39 kN/m2 for EVA1%H.
