The results summarize the problem associated with grafting of maleic anhydride (MAH) on polypropylene (PP) in the melt phase and also describe a new method for grafting PP with MAH in the solid phase. The effectiveness of the solid phase modified maleated polypropylene (MAH-PP) as interphase modifier has been 290 KHUNOVA AND ZAMORSKY documented by comparing the properties of calcium carbonate filled polypropylene composites (PP-CaC03) treated with solid phase modified MAH-PP with that of the melt phase modified MAH-PP treated composites. The solid-phase modification of PP by MAH is nontoxic and is also free from unreacted MAH. The modifier also improves the tensile strength and impact resistance of unmodified PP-CaC03 composites.

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The degradation of low‐density polyethylene under thermal stress in a quiet state and during processing from the melt was investigated. It was found that the limiting viscosity value decreases in both cases and the gel content increases, reaching a maximum in the range of 140–160°C. The molecular weight distribution broadens mostly toward the low fractions at the expense of the middle fractions. The main factors in the destruction are temperature and oxygen. The influence of frictions is not important.

Results of an investigation of the influence of processing conditions on the structure of branched polyethylene are presented. Under extreme conditions of processing the polymer was found to undergo changes of the molecular weight distribution, and small quantities of oxygen are bound in the form of carbonyl groups. These chemical changes act as active centers a t weathering. Abbau yon Polyethylen niedriger Dichte bei der Verarbeitung und AlterungDie Ergebnisse einer Untersuchung des Einflusses der Verarbeitungsbedingungen auf die Struktur von verzweigtem Polyethylen werden mitgeteilt. Bei extremen Verarbeitungsbedingungen erfahrt das Polymer Anderungen der Molekulmassenverteilung, und kleine Sauerstoffmengen werden in Form von Carbonylgruppen gebunden. Diese chemischen .&riderungen wirken bei der Bewetterung als aktive Zentren. decmpyxyus no~u3mmena nu3~ofi nfiomnocmu B npoyecce 0 6 p a 6 0 m~u u emapenus