Interfacial condensation polymerization of bischloroformates of bisphenol A with bisphenol A results in the formation of cyclic aromatic polycarbonates of high molecular weight. Products made by this technique show a significant reduction (up to 95%) in their end group content. Also, in comparison to molecular weights determined by light scattering, these products show markedly lower molecular weights by solution viscosity measurements and by applying the Mark-Houwink equation for linear polycarbonates. The existence of high molecular weight cyclic polycarbonates is confirmed by a controlled saponification reaction using piperidine as a basic compound. The saponification reaction causes nearly no change in the number average molecular weight of the polymer and causes an increase in the number of end groups of up to 2 end groups per molecule. The observed increase in the intrinsic viscosity data is similar to what would be expected from linear polycarbonates. It is shown that cyclic polycarbonates with molecular weights exceeding 100000 are easily obtained.

ZUSAMMENFASSUNG:Fur Polytetramethylenterephthalat wird an Fraktionen -ausgehend von der Molekulargewichtsbestimmung mit der Absolutmethode der Streulichtmessung -die Mark-Houwink-Beziehung fur das Losemittel Phenol/l,2-Dichlorbenzol Aus den an den Fraktionen durchgefuhrten Viskositats-und Molekulargewichtsmessungen werden die ,,ungestorten" Knaueldimensionen von Polytetramethylenterephthalat nach Stockmayer-Fixman berechnet, die friiher gefundene Werte bestatigen. Der fiir Polytetramethylenterephthalat ermittelte Behinderungsparameter zeigt, da8 innerhalb der Polyalkylenterephthalatreihe Estergruppen die Polymerkette flexipilisieren, was auch fur Polyester aus aliphatischen Dicarbons2uren und aliphatischen Diolen bekannt ist. SUMMARY:Using fractions, the Mark-Houwink relationship is established for poly(tetramethylene terephthalate) in the solvent phenol/l ,Zdichlorobenzene (1 : 1) at 25 "C, based on absolute determination of molecular weight by light scattering. As shown, the relationship is also valid for commercial poly(tetramethy1ene terephthalate)-products.To compare with poly(tetramethy1ene terephthalate) the [q]-M relationships for poly(ethy1ene terephthalate) and poly (hexamethylene terephthalate) are determined.The values of the exponents a in the Mark-Houwink relationship increase in the order aPET < apTMr c apHMT, indicating the increasing thermodynamical quality of the solvent phenol/dichlorobenzene with increasing number of methylene groups of the diol. From the viscosity data obtained for the fractions, the unperturbed dimensions of poly(tetramethy1ene terephthalate) are evaluated using the Stockmayer-Fixman method. The values agree with former investigations. The flexibility factor obtained for poly(tetramethy1ene terephthalate) indicates, that the flexibility of poly (alkylene terephthalates) increases with increasing content of ester groups, as known for polyesters from aliphatic dicarboxylic acids and aliphatic diols.

ZUSAMMENFASSUNG:An einer Reihe von fraktionierten Polycarbonaten werden in zwei Losungsmitteln die Diffusions-und Sedimentationskonstanten, die Viskositatszahlen, die osmotischen Drucke sowie die Lichtstreuung gemessen. Daraus wird eine Eichkurve zur viskosimetrischen Molekulargewichtsbestimmung abgelcitet und aus einem Vergleich der verschiedenen Mittelwerte des Molekulargewichts die Uneinheitlichkeit der Fraktionen abgeschatzt.Aus den Reibungs-und Lichtstreuungsdaten werden die Knauelabmessungen berechnet und mit Hilfe der gemessenen zweiten Virialkoeffizienten a d das indifferente Losungsmittel reduziert. Die Volumbeanspruchung der Polycarbonatmolekiile in Losung ist grol3er als die vergleichbarer Polyvinylverbindungen und etwas kleiner als bei Cellulosederivaten. Der EinfluuB der Kettengliedlange und der Drehbehinderung auf die Knauelabmessungen wird im Vergleich zum Polymethylmethacrylat diskutiert. SUMMARY:Measurements of sedimentation and diffusion constants, intrinsic viscosity, osmotic pressure and light scattering are performed on fractions of polycarbonates. From this a calibrating curve for viscometric molecular weight determinations is established. The differences between x,, and H, render possible the evaluation of the inhomogenity of the fractions.From friction dates, viscosity and light scattering the end to end distances of the molecular coiles are calculated. They have values between the diameters of cellulose derivatives and substituted paraffin chains. The intluence of the length of the chain elements and the hindrance of rotation is examined by comparing polycarbonates with polymethyl methacrylates.

The Kuhn-Mark-Houwink-Sakurada relationship for poly(a-caprolactam), (polyamide 6 ) , is established, based on the absolute determination of the weight-average molecular weight by light scattering. It is obtained ([q] in cm3. g-I):[ q ] = 3,3 1 . 10-M0779 for sulfuric acid (96%) as solvent at 25 "C and[q] = 2,29. 10-Mops3 for phenol/l,2-dichlorobenzene (I : 1 by weight) at 25 "C.The unperturbed dimensions of this polymer in both solvents are also determined by using the Stockmayer-Fixman method.

A new method was developed for the determination of the content of secondary amino groups and thus of the corresponding trifunctional branching points in polyamides-6.6 introduced by thermal treatment. Bis(6-aminohexy1)amine is formed by total acid hydrolysis of the polyamide and determined by reversed-phase high-performance liquid chromatography using off-line pre-column derivatization with 4'-dimethylaminoazobenzene-4-sulfonyl chloride. In comparison to former analytical procedures described in literature, using paper chromatography, the new HPLC method has the advantage of higher sensitivity and better reproducibility.