Abstract: The present invention relates to a process for improving the water wettability of polyolefins, especially under the form of fibers, fibrils or powders.The thus treated polyolefins have an improved wettability, which in the treatment conducted in aqueous suspension facilitates their dispersion in water. This is among others the case in the production of at least partially synthetic papers.

Abstract: The invention concerns a low-density polyethylene-based polymer composition for producing films or sheaths. The present invention provides a low-density polyethylene-based polymer composition for manufacturing films or sheaths, particularly thin films or sheaths having a thickness of less than twenty microns, said polymer composition being constituted by a graft copolymer comprising at least one styrene monomer, possibly mixed with at least one acrylic monomer, said monomer or monomers being grafted onto a trunk constituted by a pre-formed combination or alloy containing by weight, 50 to 95% low-density polyethylene and 50 to 5% high density polyethylene and/or polypropylene, the proportion of the grafted styrene monomer or mixture of monomers being comprised between 5 and 50% by weight of said graft copolymer.

Abstract: A process for chemical modification of polyolefins, particularly fibrillar, powder, granular or film polyolefins, in which one or more polar monomers are grafted to the polyolefins in an aqueous dispersion, by means of a free-radical generator.Grafting is done in the presence of a wetting agent and a particular additive derived from alkanes and possessing at least 1 thiol function; the dispersion contains 0.1 to 50 parts weight of monomer, 0.1 to 3 parts weight of wetting agent, and 0.1 to 3 parts weight of additive, for 100 parts weight of polyolefin.Polyolefins that have undergone this process have an improved wettability and, in applications requiring treatment in an aqueous suspension, such as the production of partly synthetic paper, this facilitates their dispersion in water.

Abstract: The present invention relates to a new manner of grafting various organic groups or polymers; it is concerned particularly with the grafting of vinyl, acryl, vinylidene or other chains on polymers of olefines, diolefines, aromatic vinyl compounds and similar compounds; a new catalytic system is used for effecting such a grafting, wherein a deactivated polymer is brought into contact with at least one organometallic compound and at least one generator of free radicals out of the presence of air.

Abstract: The present invention describes a process of producing block copolymers from monomers of different types by polymerization in two successive steps. The first step consists in polymerizing monomers of a first type by means of coordinated anionic catalysts comprising organo-metallic compounds of a metal of the Group IA, IIA, IIIA, or mixtures thereof of Mendeleev's Periodic Table of Elements, associated with a transition metal compound of Group IV to VIII and the second step comprises polymerizing a second type of monomer in the presence of the polymer formed in the first step and in the presence of free radical catalysts, wherein 0.01 to 100 moles of an adjuvant per mole of transition metal compound is added to the reaction medium of the first step and this adjuvant consists of a compound MY.sub.

Abstract: A process for the preparation of polymers containing peroxide end-groups, in which one or more monomers, particularly alpha-olefins, are polymerized by means of a co-ordination catalyst in the presence of an adjuvant with the formula M(X)p, where M is boron or a metal in column IIb of the Periodic Table of Elements, p is the valency of M, and X is at least one monovalent organic radical, a hydrogen atom or a halogen, the polymer obtained is treated with a peroxidizing agent, without being de-activated, and the resulting polymer containing peroxide groups is collected.Polymers with peroxide end-groups obtained by this process, particularly olefins with peroxide end-groups, can be used to initiate polymerization of vinylic monomers, and are accordingly useful in the synthesis of block copolymers, in which one part is formed from the polymeric part of the macromolecular peroxide and the other part is derived from the vinylic monomer or monomers polymerized by means of this peroxide.