Peroxi̇de effects on thermoplasti̇c polymer and exami̇nati̇on of thei̇r rheologi̇c behavi̇or

Polymers are generally used by adding various additives to strengthen their various properties even though they can be used in the industry by their own, Many of these additives will serve without joining the structure of the polymer but some additives contribute by changing the structure and the physical properties of the polymer. According to literature, while organic peroxides are known to cause cross-linking between polyethylene molecules, they also cause to degradation with polypropylene. In this study, the effect of adding organic peroxides with different ratios on rheological behaviors (shear rate, elasticity, viscoelasticity, shear stress) of low density polyethylenes such as (AYPE-T) F2-21T, (AYPE-T) I22-19T, (AYPE-T) F5-21T at different temperatures that are produced via tubular method in Petkim's was investigated. And also, the flows such as Newtonian flow, plastic flow, pseudo plastic flow and dilatant flow that are shown by behaviors of the polymers were examined. Cross-linking occurred in the structure of LDPE types having different molecular weight distribution (MWD) by the addition of even small amounts of peroxide. Shear stress values of the samples varied after crosslinking. Viscosity of F2-21T with %0 peroxide was different from viscosity of F2-21T with %0.12 peroxide. Increase in crosslinking because of increasing the peroxide amount in the samples showed a raise in viscosity values. The same change happened among the same sample with different temperatures. At constant peroxide ratio, the raise in temperatures caused a decrease in viscosity. The change in viscosity of different samples with same amount of peroxide has happened as I22-19T < F5-21T< F2-21T. With increasing amount of peroxide, while the highest change has occurred in F2-21T sample, the lowest change has taken place in I22-19T sample. Ratio of peroxide has affected the crosslink at most in F2-21T sample.