Poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) are brittle polymers with poor notched impact strength. Their toughening can be achieved by melt blending with different types of rubbery ethylene copolymers containing functions having potential reactivity with the hydroxy and carboxy end groups in polyesters. Two types of ethylene copolymers were investigated: ethylene/ethyle acrylate/glycidyl methacrylate (E/EA/GMA) and ethylene/ethyl acrylate/maleic anhydride (E/EA/MAH) copolymers. The blends were obtained by reactive extrusion of PBT with 10 to 25% of copolymers. PBT blends undergo a brittle to ductile transition by toughening with GMA copolymer between 10 and 20% of rubbery phase. The most effective toughening could be achieved by a partial crosslinking of the rubbery particles obtained by associating GMA and MAH copolymers and a reaction catalyst.
Influence de la masse moleculaire, de la polydispersite et de la temperature sur les phenomknes de solvatation prefkrentielle de polystyrknes linkaires dans diffkrents melanges de solvant MARIUS HERT, CLAUDE STRAZIELLE et HENRI BENOIT (Date de reception: 1 1 avril 1973) R E S U M E :Dans cet article nous presentons les resultats d'une etude de l'adsorption preferentielle du polystyrhe en melange de solvants en fonction de differents parambtres. En premier lieu, nous avons examine I'influence de la densit6 en segments intramoleculaire (effet de la masse molkculaire et de la polydispersite du polymere) sur ce phenomene. L'effet de la temperature sur le coefficient de solvatation a egalement ete considere. Pour certains de nos resultats experimentaux, il existe un bon accord avec les theories thermodynamiques de I'adsorption preferentielle, cependant le manque de connaissances relatives a la variation avec la densite en segments intramoleculaires et la temperature, des parametres d'interaction thermodynamiques, ne permet pas une etude quantitative rigoureuse. S U M M A R Y :This paper describes the study of preferential adsorption of polystyrene in a solvent mixture as a function of different parameters. In the first place the influence of the density of intramolecular segments (the effect of the molecular weight and the polydispersity of the polymer) on this phenomenon was examined. The effect of the temperature on the solvation coefficient was also considered. Certain experimental results were found to be in good agreement with the thermodynamic theories of preferential adsorption. The lack of the knowledge concerning the variation of the thermodynamic interaction parameters, with the density of intramolecular segments and the temperature, did not permit a rigorous quantitative study.
Synthbse et caract6risation de polystyrhes en 6toile A trois branches JEAN HERZ, MARIUS HERT et CLAUDE STRAZIELLE (Eingegangen am 8. Februar 1972) R E S U M E : La reaction de dhsactivation Blectrophile d'un polystyrene a4vant M monocarbanionique sur le tris(allyloxy)l.3.5-triazine, conduit B la formation de molBcules en Btoile L trois branches dans lesquelles les branches sont li6es aux trois atomes de carbone d'un hBtbrocycle triazine. La dttermination des caracthristiques molBculaires de ces polymhes par osmomBtrie, diffusion de la lumikre, viscosimdtrie et par chromatographie sur gel (GPC), montre que des moltcules-modele de structure bien dtfinie et de tres faible polydispersite ont Btt obtenues. Les propriBt6s hydrodynamiques de ces polystyrenes en &toile sont Btudites et comparhes aux previsions thhoriques.ZUSAMMENFASSUNG: Die elektrophile Desaktivierungsreaktion eines ,,lebenden" monocarbanionischen Polystyrols mit Tris(allyloxy)l.3.5-triazin fiihrt zur Bildung sternformiger Polymerer, in welchen drei Polystyrolketten mit den drei C-Atomen des Triazinrings verbunden sind. Die molekularen Eigenschaften dieser Polymeren werden durch osmometrische, viscosimetrische und Lichtstreuungs-Messungen sowie durch Gel-Chromatographie charakterisiert. Daraus geht eindeutig hervor, dal3 bei dieser Reaktion wohldefhierte Modell-Polymere mit sehr enger Molekulargewichtsverteilung erhalten werden. Die hydrodynamischen Eigenschaften dieser Stern-Polymeren werden mit den theoretischen Voraussagen verglichen.
Measurements of preferential solvation and swelling of polystyrene networks in solvent mixtures are reported. A comparison has been drawn between the results of this study and the results obtained for corresponding polystyrene solutions and it has been shown how such data can be interpreted on the basis of both thermodynamic equilibrium theory and gel elasticity theory. ZUSAMMENFASSUNG:Es wird uber Messungen der Vorzugssolvatation und Quellung von Polystyrol-Gelen in Losungsmittel-Gemischen berichtet und ein Vergleich zwischen den Ergebnissen der vorliegenden Arbeit und den fur entsprechende Polystyrol-Losungen erhaltenen Ergebnissen gezogen. Die Daten konnen sowohl auf der Basis der Theorie des thermodynamischen Gleichgewichts als auch der Theorie der Gel-Elastizitat interpretiert werden.
Etude des syst&mes ternaires polym&re/mklange de solvants en Cquilibre thermodynamique avec le solvant binaire correspondant Marius Hert et Claude Strazielle (Date of reception: 5 Octobre, 1973) RESUME:Nous avons obtenu l'quilibre thermodynamique entre les solutions ternaires de polymeres en melanges de solvants et les solvants binaires, en realisant une dialyse de la solution ternaire par rapport au melange de solvants. La solvatation preferentielk du polymere par un des deux solvants, qui se manifeste par des variations de composition du solvant binaire de part et d'autre de la membrane impermeable aux macromolecules, a ete mise en evidence par refractometrie differentielle et par mesures de densites, pour des solutions diluees et moderemment concentrees en polymere. Nous avons etudie un certain nombre de systemes, ce qui nous a permis de discuter des avantages de ces moyens detude et de confronter les r&ultats aux previsions theoriques. SUMMARY:The thermodynamic equilibrium between a ternary solution of a polymer in a solvent mixture and the corresponding binary solvent has been established by means of dialysis of the ternary solution against its solvent mixture. Preferential solvation of the polymer by one of the solvents produces variations in the composition of the solvent mixture on both sides of the membrane and has been determined from results of differential refractometry and density measurements on dilute and also moderately concentrated polymer solutions. Several ternary systems have been studied to show the advantages of such methods for investigation of preferential solvation and the results have been discussed according to recent theories.
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