Abstract: Polymers and copolymers of propylene are modified by grafting with polyalkenylenes having a trans double bond content of higher than 30%. The preparation is carried out via thermic treatment of the propylene (co)polymer with said polyalkenylene at a temperature comprised between 200.degree. and 350.degree. C. an the presence of a free radical initiator other than peroxide.

Abstract: The present invention relates to a process for the production of homopolymers of ethylene and copolymers of ethylene with olefins CH.sub.2 .dbd.CHR, wherein R is an alkyl or aryl radical having a number of carbon atoms of from 1 to 10, and having a density greater than 0.86 g/cm.sup.3, comprising at least one (co)polymerization step in the gas phase, in the presence of an active catalyst obtained from a titanium compound supported on a magnesium halide in active form and an Al-alkyl compound. The process is characterized in that a small amount compared with the polymer is fed to the gas-phase reactor of a polyfunctional compound having at least two groups, the same or different, capable of reacting with the alkyl aluminum compound and capable of selectively inhibiting the reactivity of the polymer particle fines compared with the average granulometric size of the polymer present in the bed of a gas-phase polymerization reactor.

Abstract: Expanded articles of biodegradable plastics are produced by the extrusion of a composition including starch, a polymer compatible with starch, in particular, an ethylene-acrylic acid copolymer and/or ethylene-vinyl alcohol copolymer, and an expanding agent. Preferably use is made of sodium bicarbonate as expanding agent in the presence of a polymeric acid.

Abstract: A process for the dehalogenation of 1,3-dioxolanes of formula: ##STR1## wherein X.sub.1 and X.sub.3, like or different from each other, are Cl or Br, X.sub.2 and X.sub.4, like or different from each other, are F or H. Said process consists in contacting the dioxolane of formula (I) with metallic zinc at a temperature ranging from +30.degree. to 130.degree. C. The corresponding dioxoles are obtained.