摘要:
The present invention relates to a process for obtaining semiordered polyamides-imides.More particularly it consists in performing the polycondensation in two separate stages:1) reaction between a part of an aromatic diisocyanate and all of the trimellitic anhydride in the presence of dimethylalkyleneurea of pH.ltoreq.7 until the intermediate compound has dissolved,2) successive addition of one or more aromatic diacids and of the remainder of the diisocyanate in the dimethylalkyleneurea of pH.ltoreq.7 until the polyamide-imide obtained has dissolved completely.The semiordered polymers thus obtained have a Tg lower than the random polymers, and this makes them easier to convert.
摘要:
A crosslinking process wherein at a temperature of about 10.degree. to 160.degree. C., under a pressure of about 1 to 300 bars and for at least about 0.5 hour, a polymer, containing from about 42 to 99% by weight of units derived from ethylene and, where appropriate, also from an .alpha.-olefin, from about 1 to 8% by weight of units derived from maleic anhydride and from 0 to about 50% by weight of units derived from at least one additional monomer selected from an ester of an unsaturated carboxylic acid with an alcohol containing from 1 to 12 carbon atoms, is reacted with at least one polyepoxide compound, preferably present in an amount of from about 1 to 10 parts by weight, based on 100 parts by weight of the polymer, in the presence of at least one catalyst suitable for reacting the anhydride functions with the epoxide functions. The catalyst is preferably present in an amount from about 0.02 to 2 parts by weight, based on 100 parts by weight of the polymer. The crosslinkable compositions may be used to coat a substrate such as an electric cable.
摘要:
Polyphenylene sulphide-based compositions with high impact strength essentially comprising, by weight, 60 to 99.5 parts of polyphenylene sulphide and 0.5 to 40 parts of a combination C comprising at least one compound Cl chosen form olefinic elastomers comprising epoxy groups and at least one tertiary amine C2. During the preparation of these compositions, the tertiary amine C2 is preferably incorporated in last place with respect to the other constituents.
摘要:
There is disclosed a process of dispersion-polymerizing vinyl monomers promoted by free-radical catalysts. This process comprises dispersing under stirring in water a block copolymer of the A-B type wherein A represents a lipophilic block and B a hydrophilic block, adding one or more vinyl monomers containing the promoter and heating the mixture with stirring to the desired temperature. This process enables beads or balls of the desired polymer to be obtained having very regular size distribution.
摘要:
Polyphenylene sulphide-based compositions essentially containing 60 to 99.5% by weight of polyphenylene sulphide and 0.5 to 40% by weight of a combination (C) containing a compound (C1) chosen from olefinic elastomers containing epoxy groups and a compound (C2) chosen from crosslinking agents containing functional groups which are reactive towards the epoxy groups of the compound (C1) and are chosen from amino, hydroxyl, carboxyl and carboxylic acid anhydride groups. They are obtained by melt-blending polyphenylene sulphide with each of the compounds (C1) and (C2) of the combination (C) successively and in any order.
摘要:
Polyphenylene sulphide-based compositions essentially containing 60 to 99.5% by weight of polyphenylene sulphide and 0.5 to 40% by weight of a combination (C) containing a compound (C1) chosen from olefinic elastomers containing epoxy groups and a compound (C2) chosen from crosslinking agents containing functional groups which are reactive towards the epoxy groups of the compound (C1) and are chosen from amino, hydroxyl, carboxyl and carboxylic acid anhydride groups. They are obtained by melt-blending polyphenylene sulphide with each of the compounds (C1) and (C2) of the combination (C) successively and in any order.
摘要:
Propylene polymer obtained by melt-blending of:100 parts by weight of polypropylene;from 0.01 to 10 parts by weight of a functional compound (a) comprising at least 2 acrylate groups;at least 0.005 part by weight of a sulphur-containing compound (b) chosen from thiuram sulphides; andfrom 0.01 to 5 parts by weight of a compound (c) capable of generating free radicals.
摘要:
Composition based on propylene polymer obtained by melt-blending of:35 to 98.98% by weight of a polymer (a) chosen from propylene homopolymers and propylene copolymers containing at least 50 mol % of propylene,1 to 50% by weight of a polymer (b) chosen from ethylene homopolymers and ethylene copolymers containing at least 90 mol % of ethylene, withfrom 0.01 to 10% by weight of a functional compound (c) chosen from compounds including at least 3 acrylate groups;from 0.01 to 5% by weight of a compound (d) capable of generating free radicals.
摘要:
A crosslinking process wherein at a temperature of about 10.degree. to 160.degree. C., under a pressure of about 1 to 300 bars and for at least about 0.5 hour, a polymer, containing from about 42 to 99% by weight of units derived from ethylene and, where appropriate, also from an .alpha.-olefin, from about 1 to 8% by weight of units derived from maleic anhydride and from 0 to about 50% by weight of units derived from at least one additional monomer selected from an ester of an unsaturated carboxylic acid with an alcohol containing from 1 to 12 carbon atoms, is reacted with at least one polyepoxide compound, preferably present in an amount of from about 1 to 10 parts by weight, based on 100 parts by weight of the polymer, in the presence of at least one catalyst suitable for reacting the anhydride functions with the epoxide functions. The catalyst is preferably present in an amount from about 0.02 to 2 parts by weight, based on 100 parts by weight of the polymer. The crosslinkable compositions may be used to coat a substrate such as an electric cable.