Zum Mechanismus der inhibierenden Reaktion phenolischer Anitioxydantien bei der Verarbeitung von Polypropylen. III. Bestimmung der einbaurate des 1,3,5-Trimethyl-2,4,6-tris-(3,5-ditert.-butyl-4-hydroxybenzyl)-benzols

Polypropylene (PP) containing 0.5 wt.-% of the ¹⁴C-labelled antioxydant 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert.-butyl-4-hydroxy-benzyl-¹⁴C)benzene (I-¹⁴C) was kneaded for 50 min the presence of air at 200°C and then exhaustingly extracted with chloroform. The loss of radioactivity of the PP during the thermal-oxidative treatment was found to amount to ca. 4% only; in contrast to this, we found a residual radioactivity of ca. 39% in the extracted PP; calculated on the radioactivity of the heat-treated PP this is 41 %. Apart from oxidation products of I-14C which are not chemically combined to PP, the chloroform extract contains oxidized PP portions to which possibly up to 44% of the radioactivity present in the heat-treated PP is fixed. The residual radioactivity in the extracted PP thus gives convincing evidence for the chemical incorporation of the central molecule body of the antioxidant I into autoxidizing PP. Although only part of the actual incorporation rate is being detected by the residual radioactivity, the result nevertheless supports the inhibition reaction formulated in part II.     

抗氧剂1，3，5-三甲基-2，4，6-三（3，5-二叔丁基-4-羟基苄基）苯的合成

1,3,5-三甲基-2,4,6-三(3,5-二叔丁基-4-羟基苄基)苯为一种高相对分子质量的受阻酚类抗氧剂,具有挥发性低、绝缘性好、与聚合物树脂相容性好等优点。本文介绍了分别以2,6-二叔丁基-4-羟基苄醇、2,6-二叔丁基-4-羟基苄基醚和2,6-二叔丁基苯酚为原料合成该抗氧剂的合成方法。     

Morphologiebildungs- und dispergiermechanismen bei der herstellung und verarbeitung von polymer-blends aus acrylnitril-butadien-styrol-(ABS)- bzw. Styrol-acrylnitril-(SAN)-copolymerisaten mit thermoplastischem polyurethan (TPU)

ABS/TPU- und SAN/TPU-blends were investigated on the basis of the analysis of viscoelastic behaviour of the components for characterization of the formation of morphology in melt mixing processes. Blends mixed in a laboratory kneeder and extruded from a high pressure capillary viscosimeter under definite conditions were characterized concerning their phase morphology by transmission electron microscopy. The types of morphology predicted by the help of rheological analysis could be confirmed by electron micrographs and quantitative analysis of morphology. It becomes evident, that the ratio of viscosity of the components has the primary influence on the formation of morphology in the blends. But also thermomechanically induced molecular destruction processes and thermodynamic interactions as well as connecting crystallisation conditions for the TPU-phase are not negligible with regard to resulting phase morphology.     

Antioxidants and stabilizers. IL. 1,3,5-trimethyl-2,4,6-tris (1-tert-butylperoxy-3,5-ditert-butylcyclohexa-2,5-diene-4-onylmethyl)benzene: Formation,properties and effect on the oxidation of tetralin and isotactic polypropylene

The transformation of the antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene (I) by the oxidation with tert-butyl hydroperoxide in the presence of Co(II)acetylacetonate was investigated. The reaction in tert-butyl alcohol gives rise to product II of partial oxidation, while in benzene cyclohexadienone III is formed. The oxidation products were defined, and their thermal properties and behaviour in light were determined. The oxidative transformation of trisphenol I leads to a loss of its antioxidative activity. The oxidation products II and III at the temperature of their formation do not exhibit an unfavourable effect on the process of thermal oxidation. However, after heating of the hydrocarbon substrate containing them to a temperature close to their decomposition point they act as initiators. They undergo photochemical transformation already at room temperature and give colour to the polymer.     

Beiträge zur Schmelzepolykondensation von Polyäthylenterephthalat im offenen System. III. Zum Einfluß von Transportvorgängen bei der Schmelzepolykondensation von Polyäthylenterephthalat (Vorkondensation)

By considering the melt polycondensation of polyethylene terephthalate as an example, the overall reaction rate is shown to be determined by expelling the glycol formed in the reaction. The investigations performed are limited to the first stage of the polycondensation process, the pre-condensation, in which the turbulence caused by the given off glycol is comparatively high. In a reactor having only stationary internal parts the polycondensation process of PETP was traced by volumetric measurement of the glycol given off. Besides the layer thickness, the pressure was varied between 40 and 100 Torr. In some experiments up to 10 l/h nitrogen was injected for more intimate mixing and nucleation. In evaluating the kinetic equations the order of the overall reaction was found to vary between about 2 and 7.5, depending on the turbulence in the system. These high values suggest the overall rate of reaction to depend on the mass transport of the glycol evolved. The validity of this suggestion was investigated by a double layer method base on some simplified assumptions. In analogy to the determination of the SHERWOOD number the expression F. β = C. Re′^m, with Re′ as modified REYNOLDS number to the power m, F area of the phase interface and β mass transfer coefficient, was used. While the values of the chemical mechanism, as expressed in the order of the rate constant, are subject to extremely high variation, the values of C and particularly those of the REYNOLDS index m keep fairly close to one another. This leads to results allowing to describe the precondensation within the variables of the expression proposed for the mass transfer.     

Zur Rhodium-katalysierten Carbonylierung aromatischer Nitroverbindungen zu Isocyanaten. III. Zur Sauerstoffübertragung bei der Carbonylierung von Nitromesitylen in Gegenwart von Rhodium(I)carbonylchlorid und Molybdänoxychlorid

Rhodium Catalyzed Carbonylation of Aromatic Nitro Compounds to Form Arylisocyanates. III. On Oxygen Transfer in the Carbonylation of Nitromesitylene in the Presence of Rhodium(I)Carbonyl Chloride and Molybdenum Oxytrichloride Rh₂Cl₂(CO₄) and MoOCl₃ or MoOCl₄ catalyze the carbonylation of nitromesitylene to form mesityl isocyanate at 100⁰C and normal pressure. Experiments with Mo¹⁸OCl₃ show that the deoxygenation of the nitro group proceeds directly by the CO ligand. The ¹⁸O-atom of the cocatalyst is not involved in the oxygen transfer process. Experimental evidence is given for the formation of an oxomolybdenum complex in situ containing the deoxygenated nitromesitylene as a structure unit.     

Chemische veränderungen der polyacrylnitrilfaser „bulana”︁ bei der behandlung mit 2-phenyl-2-(3,5-dinitro-4-hydroxyphenyl)-propan als erste stufe der Herstellung von Kohlenstoff-Fasern

Physicochemical transformations of PAN-fibres ?Bulana”? as a result of their treatment with a solution of 2-phenyl-2-(3,5-dinitro-4-hydroxyphenyl)propane in nitrobenzene as the first step of carbon fibre production were studied. Intra- and intermolecular cyclization of the nitrile groups, partial dehydrogenation of the naphtiridine rings and oxidation connected with a weight increase were observed. The part of the gel-fraction was found to be 93,5%, the residue concentration of nitrile groups 81%, and the concentration of methylene groups 86%. As a result of the treatment the exothermic effect (ΔT) decrease from 9.1 to 6.2 cm. A quantitative technique for determination of nitrile groups in PAN-fibres by means of IR-spectroscopy was developed.     

Synthese und charakterisierung von stationären phasen auf der basis von mit epoxidiertem polybutadien (PBDE) modifizierten polykieselsäuren. I. Untersuchungen zur oberflächenmodifizierung von polykieselsäuren mit epoxidierten polybutadienen

The surface modification of silicas with epoxidized polybutadienes succeeds completely under optimal conditions of the synthesis with combination of properties of the polymer (functionality, pH-stability) and of the inorganic support (pressure stability, special surface properties). The best results are obtained using epoxidized zeigten unsere Untersuchungen, daß die Reaktionskomposite aus anorganischen Tragermaterialien auf Basis von SiO₂ eine erhohte pH-Stabilitat aufweisen²³. In Fortfuhrung der hier dargestellten Ergebnisse konnten wir zeigen, daß die erhaltenen Reaktionskomposite aufgrund von an der Oberflache vorhandenen und spektroskopisch nachweisbaren Epoxidfunktionen ein hohes Synthesepotential bezuglich ihrer weiteren Modifizierung zu speziellen Anwendungszwecken besitzen. Diese Modifizierungsmoglichkeiten sowie die Ergebnisse der Testung der Materialien in der HPLC bzw. anderen Gebieten des Einsatzes funktionalisierter stationarer Phasen sind Gegenstand weiterer Veroffentlichungen.