The effect of peroxides on low density polyethylene (LDPE), inspection of mechanical and physical properties

In this study, the effect of different organic peroxides on different types of low density polyethylene was investigated. For this purpose, Petkim's low density polyethylene (LDPE) products F2-21T, F5-21T and I22-19T was mixed in different proportions with dialkyl peroxide (DAP), dibenzoyl peroxide (DBP) and dilauroyl peroxide (DLP). Melt flow rates, mechanical tests, thermal analysis (DSC and TG) and SEM images of the prepared mixtures were examined. Melt flow rates of the samples altered with the increasing amount of peroxides. By the addition of peroxides, cross-linking occurred in the structure of LDPE types and it caused decline in melt flow rates. Mechanical tests showed that mechanical strength of F2-21T and I22-19T have increased by peroxide addition. However peroxide addition made a negative effect on F5-21T and decreased its mechanical strength. The maximum effect has been caused by DAP addition. Organic peroxide addition changed the melting and crystallinity entalpies and crystallinity ratios of the samples. According to thermo-gravimetric analysis results, thermal stability of the polymers increased by the addition of peroxides. Examination of SEM images of the samples revealed that dialkyl peroxide had the best dispersion in the polymer matrix. In terms of uniform distribution dibenzoyl peroxide took the place after DAP and dilauroyl peroxide took the place after DBP.