aIn this study, the mechanical properties and non-isothermal degradation kinetics of polypropylene (PP), high-density polyethylene (HDPE) with dilauroyl peroxide and their blends in different mixture ratios were investigated. The effects of adding dilauroyl peroxide (0-0.20 wt%) on the mechanical and thermal properties of PP + HDPE blends have been studied. On the other hand, the kinetics of the thermal degradation and thermal oxidative degradation of PP + HDPE (80/20 wt%) blends were studied in different atmospheres, to analyze their thermal stability. The kinetic and thermodynamic parameters such as the activation energy, E a , the pre-exponential factor, A, the reaction order, n, the entropy change, the enthalpy change, and the free energies of activated complex related to PP, HDPE, and blend systems were calculated by means of the several methods on the basis of the single heating rate. A computer program was developed for automatically processing the data to estimate the reaction parameters by using different models. Most appropriate method was determined for each decomposition step according to the least-squares linear regression.

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In this study, the effect of different organic peroxides on different types of low‐density polyethylene (LDPE) was investigated. LDPE products like F2‐21T, F5‐21T, and I22‐19T were mixed in different proportions with dialkyl peroxide, dibenzoyl peroxide, and dilauroyl peroxide. Melt flow rates, mechanical properties (tensile strength at yield, tensile strength at break, elongation at break, and stress‐strain effect), thermal analysis (differential scanning calorimetric and thermogravimetric analysis), and scanning electron microscopy images of the prepared mixtures were examined. Cross‐linking occurred in the structure of LDPE types having different molecular weight distribution by the addition of even small amounts of peroxide (e.g. 0–0.12 wt%). Copyright © 2017 John Wiley & Sons, Ltd.

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In this study, the influence of dilauroyl peroxide on mechanical and thermal properties of different polypropylene (PP) matrices was investigated. Polypropylene matrices, different molecular weight isotactic PP containing 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 wt% of dilauroyl peroxide (DLP) were prepared by using a single-screw extruder. The effect of the visbreaking agent (DLP) on mechanical, physical, thermal and morphological properties of different molecular weight PP had been studied. Mechanical properties (tensile strength at break point, at yield and elongation at break point), melt flow index (MFI), scanning electron microscope (SEM) and differential scanning calorimetric (DSC) analyses of these matrices were examined. Melting (T m ) and crystallization (T c ) temperatures, crystallinity ratio (%) and enthalpies were determined. The microstructure of isotactic polypropylene matrix was investigated by scanning electron microscopy (SEM). From SEM analysis, it was observed that the surface disorder increased by the increasing amount of DLP. As a result of DSC analyses, the crystallinity ratio of the PP matrices has varied between 1.64-7.27%. Mechanical properties of the matrices have been improved. Particularly, the mechanical tests of PP have given interesting results when compounded with 0.06-0.08 wt% dilauroyl peroxide (DLP). Mechanical properties and thermal decomposition processes were all changed by increasing the amount of DLP in the matrix structure.

This study investigates how strontium (Sr) ions act on meristematic root tip cells of lentil (Lens culinaris) with changing parameters (time and concentration). Plant seeds were exposed to both a standard solution of Sr for different lengths of time (1/4, 1/2, 1, 2, 4, 8, 12, 16, 20 and 24 hours) at a fixed concentration of 1.0 molL-1 (M) and Sr ions at various concentrations (0.05, 0.1, 0.25, 0.5 and 1.0 M) for a certain length of time (12 hours). The seeds treated with Sr were made to sprout and microscopic examination focused on the root tips. The aim of microscopic examination was to clarify chromosomal abnormalities of cell division. Microscopic examination showed that various abnormalities occurred in cells of the seedlings, abnormalities such as chromosome adherence, chromosome breakings, bridge chromosomes, chromosome dispersion, chromosome shrinking, fish bones and ring chromosomes. Those abnormalities were detected several times for each treatment depending on the different periods and concentrations. Adsorption and absorption of Sr inside lentil seeds were detected by the spectroscopic method. Removed and excess amounts of Sr ions were found by spectroscopic determination. Statistical evaluation of the results was used in order to reveal the differences and similarities. The results showed that while there is a positive correlation with the concentration parameter, there is a negative correlation with the time parameter. Over 90% of Sr was removed from the solution during 12-hour exposure. Lentil seeds can be accepted as good bioaccumulators of Sr ions only for an exposure period shorter than 12 hours at an Sr concentration of 1 M.