Elf Atochem S.a.

Total Research & Technology Feluy

Stephane Nowe

Philippe Heim

Patrice Gaillard

Bernard Boutevin

Jacques Michel

Bruno Vuillemin

Philippe Lodefier

Laetitia Urbanczyk

Jean-Pierre Parisi

Jean-Claude Deleye

Nicolas Lambricht

Bachar Hamoui

Richard Legay

Expandable vinyl aromatic polymers may contain comminuted graphite with a polymodal particle size distribution. Foams obtained from such expandable vinyl aromatic polymers have a reduced thermal conductivity at a reduced foam density.

Expandable vinyl aromatic polymers containing graphite particles having a polymodal particle size distribution

The process consists in mixing, for a period tm less than the period of polymerization, in a micromixer, a flow Fm of monomer(s) to be (co)polymerized and a flow Fa of an initiator system leading to a propagation constant kp(t) greater than or equal to 500 l mol.sup.-1 s.sup.-1 and in injecting, in a polymerization reactor, a flow Fr resulting from the mixing of the flows Fm and Fa, the concentration of monomer(s) in the flow Fr being at least 10% by weight.

Process for the continuous anionic polymerization of at least one

Imidation-modified MMA (co)polymers, characteristically having a Tg from 20.degree. to 30.degree. C. higher than the Tg of the corresponding unmodified MMA (co)polymer, are produced by reacting an amine, e.g., methylamine or cyclohexylamine, with a suspension, in a hydrophobic nonsolvent reaction medium, of beads of such MMA polymer/copolymer.

Preparation of imide-modified methyl methacrylate (MMA)

(Meth)acrylic/glutarimide copolymers, well suited, e.g., for optical applications, having enhanced glass transition temperatures (Tg), are prepared by salifying the acid functions of (meth)acrylic ester/(meth)acrylic acid copolymers, and then imidifying such 'intermediate' salified copolymers into the subject (meth)acrylic/glutarimide polymers.

Preparation of (meth) acrylic/glutarimide copolymers

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Stephane Nowe