Abstract: Disclosed are polymers and copolymers containing at least one repeating unit of the formula ##STR1## in which X is O or NH; R is a single bond or a hydrocarbon chain; R' is a hydrocarbon chain containing one or two carbon atoms, and P is the residue of an oligomer HX--P--XH whose solution viscosity determined in meta-cresol at 30.degree. C. at concentrations of 0.5 g/dl is lower than 0.50 dl/g.sup.-1. Also disclosed is a process for obtaining the polymers and copolymers.

Abstract: Polyetheresteramides, characterized in that they comprise both of the following repeating entities: ##STR1## in which X represents the residue of a polyamide-diacid oligomer with an Mn of between 300 and 8000, Y represents the residue of a polyetherdiol with an Mn of between 200 and 5000, and Z represents the residue of a polyetherdiamine with an Mn of between 200 and 5000, wherein the proportion by mass of the entities Z resulting from the condensation of the polyetherdiamine with respect to the total amount of the entities resulting from the polyetherdiol and polyetherdiamine, i.e. Z/(Z+Y), is between 1 and 50%. The polyetheresteramides according to the invention can be used as is and are suitable for the production of mouldings, extrudates, films, sheaths, or composite materials such as multi-layer film. They can also be mixed with other polymers and in particular with polyamides.

Abstract: The present invention relates to new polyamides comprising, on a mass basis:(a) 45 to 75% of an x,T unit, x being between 4 and 12 inclusive, the x,T unit being the condensation product of a diamine having x carbon atoms and of terephthalic acid, and(b) 55 to 25% of an aliphatic unit -HN-(CH.sub.2).sub.n -CO, n being between 6 and 14 inclusive. and the terpolyamides obtained by including a monomeric unit (c) such as the unit 6 or 6,I as a replacement for part of the aliphatic unit (b).The polyamide compositions thus obtained exhibit a Tg lower than 130.degree. C., a Tm higher than 230.degree. C. and a good crystallizability.

Abstract: A process for the manufacture of polyamides consisting essentially of the stages of:(i) reacting 10 to 90% by weight of the aliphatic and/or cycloaliphatic and/or aromatic-aliphatic diamines (c) with a lactam and/or corresponding amino acid (a) or the substantially stoichiometric combination of one or more aliphatic diamine(s) and of one or more dicarboxylic aliphatic acid(s) and with the aromatic diacid (b); and(ii) reacting the remainder of the aliphatic and/or cycloaliphatic and/or aromatic-aliphatic diamine (c) with the oligomer produced in stage (i) in one or more substages.

Abstract: Novel thermotropic semialiphatic copolyesteramides having relatively low melt temperatures contain the following recurring structural units: ##STR1## in which Ar.sub.1 is a divalent aromatic and/or cycloaliphatic radical, Ar.sub.2 is a divalent aromatic radical, X is --NH-- or --CO--, and A includes a divalent aliphatic hydrocarbyl radical.

Abstract: Novel thermotropic aromatic copolyesters comprise the following recurring structural units: ##STR1## and are prepared by polycondensing p-(p-hydroxyphenoxy)-benzoic acid with an aromatic or cycloaliphatic diacid, a diphenol and, optionally, p-hydroxybenzoic acid.

Abstract: Polyester amides and polyether thioether ester amides of the formula ##STR1## wherein A is a polyamide sequence,R.sub.1 and R.sub.2 can be the same or different and each represents a linear or branched C.sub.2 to C.sub.98 alkyl radical,m is an integer between 1 and 50, andn is one or greater; and the process of making such amides by reacting specific diols with a dicarboxylic polyamide having terminal acid functional groups.

Abstract: Novel polyesteramides and polyetheresteramides are provided which have the formula: ##STR1## wherein A represents a divalent polyamide group,R.sub.3 and R.sub.4 represent hydrogen, or only one of R.sub.3, or R.sub.4 is an alkyl radical containing from 1 to 24 carbon atoms,R.sub.1 is a linear or branched, alkyl radical, or an unsaturated radical containing from 1 to 24 carbon atoms or an aromatic or cycloaliphatic radical,y+z has a value between 2 and 100,n represents a number such that the recurring units constitute a macro molecular chain. These products are obtained by polycondensation of a dicarboxylic polyamide with .alpha., .omega. diol which is a hydroxylated beta-tertiary amine or a polyoxyalkyleneglycol containing in the chain one tertiary amine function.