Abstract: The invention relates to a process for the preparation of a block copolymer comprising a sequence successively comprising a semicrystalline and/or hydrolysable block, an elastomeric block and an amorphous block, comprising the following stages: a) a stage of 1,2-addition, to a terminal ethylenic group of a semicrystalline and/or hydrolysable polymer, of an alkoxyamine which can correspond to the following formula (II): b) a stage of addition, to the medium resulting from stage a), of one or more monomers which are precursors of the elastomeric block, in return for which a semicrystalline and/or hydrolysable block-b-elastomeric block diblock copolymer is obtained; c) a stage of addition, to the medium resulting from stage b), of one or more monomers which are precursors of the amorphous block, in return for which the semicrystalline and/or hydrolysable block-b-elastomeric block-b-amorphous block triblock copolymer is obtained.

Abstract: The present invention relates to a novel process for preparing alkoxyamines from a nitroxide and a dithiocarbamate by photolysis reaction. This process, which does not generate effluent containing metals, may be carried out in batch or in continuous mode and takes place at a lower temperature than the known processes for synthesizing alkoxyamines.

Abstract: The invention relates to a method for the polymerization of one or more methacrylate and/or methacrylic monomers, for the synthesis of methacrylate or methacrylic polymers or of exclusively methacrylic and/or methacrylate copolymers, comprising a step of bringing said monomer(s) into contact with one at least of the compounds of formula (I) and (II) below: in which: R1 and R2 may represent a phenyl group, R3 and R4 may together form an ?N-phenyl group, Z represents a group of formula —CR8R9R10, in which R8 and R9 may represent methyl groups and R10 may represent a —COO-phenyl group.

Abstract: The invention relates to the use of alkoxyamines of formula (I): for the preparation of polymerized or non-polymerized mono- or polyalkoxyamines of formula (II):

Abstract: The invention relates to the use of alkoxyamines of formula (I): for the preparation of polymerized or non-polymerized mono- or polyalkoxyamines of formula (II):

Abstract: A subject-matter of the invention is alkoxyamines resulting from ?-phosphorated nitroxides corresponding to the formula: These compounds can be used as initiators for the (co)polymerizations of at least one monomer which can be polymerized by the radical route.

Abstract: The invention relates to the production and use of block copolymers which are obtained by means of controlled radical polymerisation in the presence of nitroxides for the purpose of reinforcing fragile polymer matrices. The invention offers advantages such as (i) simplicity of copolymer synthesis and use and (ii) fine dispersion of the copolymer molecules in the fragile matrix, which ensures both the transparency of the material and high reinforcement against impact. More specifically, the invention relates to the radical synthesis of block copolymers comprising at least three blocks, which include one block having a glass transition temperature of less than 0° C. and a thermoplastic end block having a glass transition temperature of more than 0° C., thereby guaranteeing compatibility with the fragile matrix to be reinforced against impact.

Abstract: The invention relates to a process for the polymerization of at least one monomer which can be polymerized via a radical route, in the presence of a stable free radical and of a polymerization initiator, such that, per 100 mol of monomer, the molar amounts of stable radical (SFR) and of initiator (INIT) are such that [(SFR)×FSFR]/[(INIT)×FINIT]<0.15 and FSFR×(SFR)<0.2 mol, in which FSFR represents the functionality of the stable free radical and FINIT represents the functionality of the initiator. The process according to the invention has advantageous kinetics, allows the production of grafted or block copolymers and can be carried out in an extruder.

Abstract: The invention relates to the use of alkoxyamines of formula (I): for the preparation of polymerized or non-polymerized mono- or polyalkoxyamines of formula (II):

Abstract: This process for the production of a controlled-rheology resin of a propylene homopolymer or copolymer or a composition that comprises a propylene homopolymer or copolymer in the absence of a functional monomer, whereby said process brings about an increase of the fluidity index of the resin by cuts of the chains, is characterized by the fact that at least one stable free radical is incorporated into said resin in the viscous state, since a solid product that has an increased fluidity index is formed. In particular, the stable free radical or radicals is or are selected from among nitroxyl radicals, comprising at least one ═N—O′ group.

Abstract: The invention concerns a method for preparing resins branched or crosslinked by heat treatment with a polymer in the presence of a multinitroxide and optionally a free radical initiator, to obtain a resin exhibiting properties of beat reversibility. The initial polymer can be a rubber or a thermoplastic polymer. The resins obtained provide conditions for use similar to those of the initial polymers while exhibiting enhanced mechanical properties.

Abstract: The invention relates to a thermoplastic composition comprising: a matrix-forming thermoplastic polymer (M), rigid nodules obtained by radical polymerization, and optionally an impact modifier (S). It also relates to a process comprising, in a first stage, forming a homogeneous solution of precursor of the nodules in the thermoplastic (M) in the molten state, in a second stage, introducing the initiator while remaining at a temperature below which the initiator becomes active, and, in a third stage, heating to a temperature sufficient to cause crosslinking of the precursor and to form rigid nodules while kneading the composition, the impact modifier being introduced during the first or the second stage.

Abstract: The invention relates to a composition based on an ethylene-vinyl alcohol copolymer comprising: 50 to 98% by weight of an EVOH copolymer 1 to 50% by weight of a polyethylene (A) 1 to 15% by weight of a polymer (B) resulting from the reaction (i) of a copolymer (B1) of ethylene and of an unsaturated monomer X grafted or copolymerized with (ii) a polyamide (B2). It also relates to a multilayer structure comprising a layer consisting of this composition. This structure is useful for making packaging. The composition of the invention also adheres well to PET, this property being useful in coinjection to make bioriented preforms.

Abstract: The invention relates to a composition based on an ethylene-vinyl alcohol copolymer comprising:

Abstract: The present invention relates to a rigid material based on PPO and an aromatic vinyl resin with improved impact strength comprising:

Abstract: The invention relates to a process comprising a stage of polymerization or copolymerization of at least one polymerizable or copolymerizable monomer by a radical mechanism in the presence of a stable free radical and of an initiator of formula: R1—O—O—R2 wherein R1 and R2, which can be identical or different, represent an alkyl, aryl, alkylaryl or aralkyl radical comprising, for example, from 1 to 20 carbon atoms. The process is fast, allows the initiator to act more efficiently and results in polymers or copolymers exhibiting a low yellowing index.

Abstract: The present invention relates to a grafted copolymer bearing grafts of formula (I): —O—PM1—(PM2)—T  (I) in which: PM1 represents a polymer block obtained by (co)polymerization of at least one monomer M1 via a radical route; and PM2, which is optionally present, represents a polymer block obtained by (co)polymerization of at least one monomer M2 via a radical route; and T represents the residue of a stable radical T•.

Abstract: Particularly useful as a barrier layer in packaging, e.g. multilayer structures, is a composition based on an ethylene-vinyl alcohol copolymer comprising: 50 to 98% by weight of an EVOH copolymer 1 to 50% by weight of a polyethylene (A) 1 to 15% by weight of a polyethylene (B) being a blend of a polyethylene (B1) and a polyethylene (B2) chosen from elastomers, very-low-density polyethylenes and metallocene polyethylenes, the blend of (B1) and (B2) being cografted by an unsaturated carboxylic acid or a functional acid derivative thereof.

Abstract: The invention relates to a process for the polymerization or copolymerization of at least one monomer which can be polymerized or copolymerized by the radical route in the presence of a stable free radical and of an iniferter. The presence of the stable free radical greatly modifies the behavior of the iniferter during the polymerization or copolymerization, so that undesirable reactions are much reduced. It is possible, rapidly and with a high yield, to polymerize or copolymerize in the presence of an iniferter in order to result in a polymer or copolymer with a reduced polydispersity and with a monomodal molecular mass distribution.

Abstract: The invention relates to a process for the polymerization or copolymerization of at least one monomer which can be polymerized or copolymerized by the radical route in the presence of a stable free radical and of an iniferter.