Some Properties of Blends Based on High Density Polyethylene Grafted with Di-2-Ethyl-Hexyl Fumarat

Abstract

Blends based on high density polyethylene (MFI=0.3 g/10 min) and low density polyethylene grafted with di-2-ethyl-hexyl fumarate are presented.

These blends were obtained through component homogenization, in different proportions, on a Berstorff laboratory roll-mill, for 10 minutes at 180°C.

Low density polyethylene (MFI=2.0 g/10min) grafting was carried out in polymer melt, through radicalic initiation, in the presence of organic peroxides, at a temperature of 140—160°C. The content of the monomer grafted on polymer chain was determined through IR absorption spectrophotometry using the absorption band of 1735 cm^?1.

From the experimental, obtained blends plates, 1 mm thick, were manufactured with the purpose of determining the main tensile properties.

For the respective blends melt flow index evolution were followed.     

Modification of properties of ion exchange membranes V. Structure of cationic polyelectrolyte on the surface of cation exchange membranes

Summary Electrodialytic transport properties of cation exchange membrane are changed by adhesion of polyethylene imine on the membrane surface. The effect of conformation of polyethylene imine molecules on the transport properties of the membrane, thickness of adherent layer and mechanism of adhesion were discussed. Observed were relative transport numbers of calcium ions to sodium ions,P _Na ^Ca , current efficiency, electric resistance of the membrane during electrodialysis and pH-shift of anolyte after electrodialysis. P _Na ^Ca decreased remarkably, when the conformation of polyethylene imine was compact by adding salt to the solution, adjusting pH of the solution to a high value where polyethylene imine was scarcely protonated and adding water-soluble neutral polymers and multivalent anions. It was confirmed that the conformation of polyethylene imine on the membrane surface controlled the degree of the change of the transport properties of the membrane. The adherent amount of polyethylene imine on the cation exchange membrane was calculated assuming that a monolayer of polyethylene imine molecules with hydrodynamic radii was formed. This differed markedly from the amount observed. The reason for the difference was discussed. There was no observation of salting out by sodium chloride and calcium chloride. It was concluded that the polyethylene imine molecules on the cation exchange membrane are mainly bound by ion-exchange.

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Zusammenfassung Die elektrodialytischen Transporteigenschaften von Kationenaustauschmembranen werden mit Polyäthylenimin (PEI) als kationischer Polyelektrolyt verändert. Sie werden durch die Konformation des PEI in der Lösung beeinflußt.Als Transporteigenschaften werden die relativen Transportzahlen der Ca-Ionen im Vergleich zu Na-Ionen, der elektrische Widerstand der Membran während der Elektrodialyse and die pH-Änderung nach der Elektrodialyse im Anodenraum untersucht.

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With 13 figures and 3 tables     

Study of Interfacial Tension Between Glass and Polyethylene Capillaries in Highly Concentrated Electrolyte Solutions

Abstract

The polyethylene capillary used for dropping mercury electrodes (D.M.E.) has permitted the study of interfacial tension by a drop time method in highly concentrated solutions. The electrocapillary curves were obtained for the aqueous solutions of KF, NaOH and KCL. The measurements evince that there is a difference between results obtained using glass and polyethylene capaillaries. The difference increases with the concentration of the electrolyte. We attribute that fact to wetting of the polyethylene capillary by mercury.     

Determination of the Molecular Weight Distribution of Polyethylene Terephthalate by Gel Permeation Chromatography

Abstract

The determination of the molecular weight distribution of polyethylene terephthalate by GPC at room temperature is described. The solvent used is o-chlorophenol-chloroform (1:9) and pure chloroform is used as eluent. K and alpha of the Mark-Houwink equation of polyethylene terephthalate and of polystyrene in this solvent system were obtained. It was shown that the universal calibration can be applied.     

Novel Preparation of Polyethylene from Nano‐extrusion Polymerization Inside the Nanochannels of MCM‐41/MgCl2/TiCl4 Catalysts

The MCM‐41 and SiO₂ supported TiCl₄ and TiCl₄/MgCl₂ catalysts with different molar ratios of Mg/Ti were synthesized and used for ethylene polymerization under atmospheric pressure. The nanochannels of MCM‐41 serve as nanoscale polymerization reactor and the polyethylene nanofibers were extruded during the reaction. The nanofibers were observed in SEM micrographs of resulting polyethylene. The effect of MgCl₂ on catalytic activity and thermal properties of resulting polyethylene is investigated too. In the presence of MgCl₂, the catalytic activity increased and more crystalline polyethylene with higher melting points were formed. However, no fibers could be observed in the polyethylene prepared by SiO₂ supported catalysts.     

Effect of UV Irradiation on Gas Permeability in Heterophasic Ethylene-Propylene Copolymer Films

Abstract

The permeability variations of carbon dioxide, oxygen, and nitrogen through isotactic polypropylene, heterophasic ethylene-propylene (E-P) copolymers, and polyethylene films were measured during photo-oxidation using polychromatic light at 60°C in air. For polypropylenebased samples the permeability decreases with increasing photooxidation, whereas for polyethylene and an elastomeric fraction from a heterophasic E-P copolymer an increase in permeability with photooxidation is observed.     

An efficient method for Knoevenagel condensation: a facile synthesis of 5-arylidenyl 2,4-thiazolidinedione

Abstract

Knoevenagel condensation of various aromatic aldehydes with 2,4-thiazolidinedione has been carried out in polyethylene glycol-300. The reactions were carried out at moderate temperature with very simple isolation procedure and with better yields.     

Morphologische Feinstrukturen bei Polyäthylen-Zwillingskristallen

Zusammenfassung Beobachtet wurde eine morphologische Feinstruktur bei Polyäthylen-Zwillingskristallen, die der bei Einkristallen bekannten Feinstruktur ähnlich ist. Genau wie bei Einkristallen verläuft auch bei den Zwillingskristallen die Feinstruktur in den kristallographischen Ebenen, die Faltungsberge oder Faltungstäler benachbarter Faltungsebenen enthalten.

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Summary Characteristic striations were observed in twinned crystals of polyethylene, which were analogous to the known striations in single crystals of polyethylene. As in single crystals the striations of the twinned crystals lie along lines in those crystallographic faces, which contain the upper or lower folds of successive fold planes.

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Herrn Professor Dr.K.-H. Hellwege und Herrn Dr.U. Johnsen danke ich für Anregung und wertvolle Diskussion.     

Selection of a Suitable Solvent System for the Isolation of Toxicologically Active Components of an African Arrow Poison of Plant Origin

Abstract

A method has been developed for the extraction and analysis of the antioxidant, the peroxide crosslinking agent and some decomposition products in crosslinked polyethylene. The method involves the use of high-performance liquid chromatography (HPLC) in the reverse-phase mode, with a mixture of methanol and water as the mobile phase. Samples of polyethylene are ground at low temperature into a fine powder prior to extraction by methanol. The accuracy and sensitivity limits are given for each of the separated components.     

Pyrolysis-gas chromatography with linearly programmed temperature packed and open tubular columns. the thermal degradation of polyolefins

Summary The advantages of the use of programmed temperature open tubular columns for the separation of the pyrolysis products of polymers is again demonstrated, using polyethylene samples. It is also shown that the combination of pyrolysis-gas chromatography with subsequent hydrogenation of the thermal breakdown products using open tubular columns for separation can successfully be used in the identification of the unsaturated components formed during pyrolysis.Based on the obtained results, the schematic of the thermal breakdown mechanism of polyethylene could be established.It is further proved that the investigation of the Chromatographic pyrolysis pattern permits an evaluation regarding the degree of branching in the original polyethylene molecules.

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Zusammenfassung Die Anwendung von linear-temperaturprogrammierten Capillarsäulen zur Auftrennung von Pyrolyseprodukten wird am Beispiel der Pyrolyse von verschiedenen Polyäthylenproben beschrieben. Es wird ferner gezeigt, da\ die Methode der hydrierenden Pyrolyse-Gaschromatographie ebenfalls in Verbindung mit Capillarsäulen mÖglich ist und zur Identifizierung von bei der Pyrolyse entstandenen ungesättigten Verbindungen verwendet werden kann.Auf Grund der gewonnenen Ergebnisse konnte ein Schema fÜr den thermischen Abbaumechanismus des Polyäthylens aufgestellt werden.Weiterhin ist es mÖglich, im Pyrolyse-Chromatogramm unterschiedliche Verzweigungsgrade von Polyäthylenen zu unterscheiden.

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Dedicated to Professor Dr. Dr. h. c. Stefan Goldschmidt on the occasion of his 75th birthday.

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This paper is part of the work carried out by K. H. Kaiser at the Technikum fÜr Chemie und Physik Dr. GrÜbler, Isny/Allgäu, for his chemical engineering degree.

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Part I: Cieplinski, E. W., and co-workers.     

A Source of Fluorescent Impurities: Polyethylene Containers

Abstract

Emission spectra of water samples stored in polyethylene botles show the pressence of impurities whose concentration roughly parallels the length of storage. With excitation at 280 nm, water stored for 3 months in polyethylene gave a blank signal equivalent to the emission of 10^?7 M bovine serum albumin. Caution should be exercised in using plastic bottles for fluorometric reagents.     

Compatible Polyethylene/Polyvinyl Chloride Particle Hybrids Prepared by in‐situ Polymerization

Polyethylene/polyvinyl chloride (PE/PVC) hybrids were successfully prepared by a polymerization‐filling method. The catalyst for ethylene polymerization was supported on PVC particles, and ethylene was then polymerized in‐situ on the surface of the activated PVC. PVC particles could be well segmented and dispersed during in‐situ polymerization, and the prepared hybrids had an additional tangent peak between the glass transitions of polyethylene and PVC, indicating the formation of a compatible interlayer between nascent polyethylene and PVC during polymerization.     

Calibration in High Temperature Gel Permeation Chromatography of Linear Polyethylenes

Abstract

The mathematical relationship between the gel permeation chromatography calibration curves of polystyrene and linear polyethylene has been determined in 1,2,4-trichlorobenzene at 130, 135 and 140°C. The experimentally determined relationship is in good agreement with that predicted from application of the principles of the universal calibration technique and published Mark-Houwink coefficients. Definition of this relationship enables the use of polystyrene as a secondary standard for gel permeation chromatographic determination of linear polyethylene molecular weight determinations.     

Spurennachweis und quantitative Bestimmung von grenzfl?chenaktiven Poly?thylenoxidverbindungen und von Poly?thylenglykolen

Zusammenfassung Es wird eine neue Arbeitsweise zur quantitativen Spurenbestimmung von grenzflächenaktiven Polyäthylenoxidverbindungen und von Polyäthylenglykolen mittels eines modifizierten Reagenses nachDragendorff (Tetrajodowismutsäure + Bariumchlorid) beschrieben. Die Bestimmung erfolgt durch Sedimentation in eine Capillarküvette mit Hilfe einer Zentrifuge und nachfolgender Messung der Sedimenthöhe in Millimetern. In Verbindung mit der selektiven Trennung mit Butanon-Wasser (siehe II. Mitteilung) können in einer Probe die grenzflächenaktiven Kondensate und die Polyäthylenglykole getrennt bestimmt werden.

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Summary The quantitative determination of traces of surface-active polyethylene oxide compounds and of polyethylene glycols is achieved by use of a modifiedDragendorff reagent (tetraiodobismuthic acid + barium chloride). The precipitate is centrifuged into a capillary tube and the sediment height is measured (in mm). Surface-active condensates and polyethylene glycols can be determined separately in one sample by a combination of this method and the selective separation using butanone-water (as described in the second communication of this series).

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Methoden zur quantitativen Mikrobestimmung und zum Spurennachweis grenzflächenaktiver Verbindungen. III. Mitteilung.

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II. Mitteilung: Z.196, 22 (1963).     

Gas Liquid Chromatographic Determination of Promethazine Hydrochloride in Polyethylene Glycol Suppositories Using the Hall's Electrolytic Conductivity Detector

Abstract

A gas liquid chromatographic method using the Hall's electrolytic conductivity detector is described for the determination of promethazine hydrochloride in polyethylene glycol suppositories. This method is capable of distinguishing the intact drug from its thermal degradation products. A linear relationship between peak height ratio (promethazine/promazine) and promethazine hydrochloride concentration is found up to a concentration of 600 μg/ml. In the presence and absence of polyethylene glycol vehicle the recovery of promethazine hydrochloride is found to be 100.2 and 99.7 percent respectively. The percent coefficient of variation is 0.62 and 0.94 in the absence and presence of polyethylene glycol vehicle.     

Synthesis of Polyacrylamide Flocculants with Polyethylene Glycol Segments by Photopolymerization

Abstract

Macro photoinitiators possessing polyethylene glycol(PEG) segments were used for radical polymerization of acrylamide(AAm) to yield high molecular weight block copolymers (PAAm-b-PEG-b-PAAm) composed of PEG and polyacrylamide(PAAm) as the inner segment and outer segment respectively. The block copolymers were used as flocculates to clear a saturated borax solution prepared from tincal concentrate and showed good flocculating properties.     

Theory of elasticity for the polyethylene crystal

Summary For the polyethylene crystal, a local, non-linear, static theory of elasticity is established. This theory takes into account the complete microstructure of the material. Within the framework of differential geometry, dislocations and disclinations are introduced. Non-linear, local constitutive equations are established and the equations of elastic equilibrium are derived. The theory may be applied to calculate the deformations and the stress of defects in the polyethylene crystal.

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Zusammenfassung Für den Polyäthylenkristall wird eine lokale, nichtlineare, statische Elastizitätstheorie entwickelt, welche die volle Mikrostruktur des Materials berücksichtigt. Mit differentialgeometrischen Methoden werden Versetzungen und Disklinationen eingeführt und die nichtlinearen Gleichgewichtsbedingungen werden abgeleitet. Die Theorie kann zur Berechnung der Deformationen und Spannungen von Defekten im Polyäthylenkristall herangezogen werden.

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With 3 figures     

Bestimmung von Blei, Chrom, Kupfer und Nickel in Polyethylen mit der direkten Zeeman-Atomabsorptionsspektralphotometrie

Zusammenfassung Die Möglichkeiten der Bestimmung von Blei, Chrom, Kupfer und Nickel in Polyethylen mit der direkten Zeeman-AAS sind untersucht worden. Dabei wurde festgestellt, daß Blei bis 0,2%, Chrom bis 0,03%, Kupfer bis 0,05% und Nickel bis 0,06% in Polyethylen als Obergrenze bestimmt werden kann, indem Probestückchen von bis zu 1 mg direkt auf einer Mikrogrammwaage in ein Graphitschiffchen eingewogen werden. Die Analyse kann ohne chemische Vorbereitung durchgeführt werden. Die Feststoffanalyse ermöglicht gleichzeitig Studien zur Homogenität des Polyethylens.

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Determination of heavy metals (Pb, Cr, Cu, Ni) in polyethylene using direct Zeeman-AAS

Summary The determination of lead, copper, chromium and nickel in polyethylene by means of direct Zeeman-AAS was investigated. It has been found that lead up to 0.2% and Cr up to 0.03%, copper up to 0.05% and nickel up to 0.06% in polyethylene can be determined by weighing polyethylene up to 1 mg into a graphite boat by means of a microbalance. Putting the boat directly into the graphite furnace the analysis was done without chemical pretreatment. The solid sampling analysis technic by direct Zeeman-AAS allows homogeneity studies in polyethylene.

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Wir danken der Firma Bischof + Klein Verpackungswerke, Lengerich, für die Beschaffung von Rohstoffen zur Probenherstellung und Klaus Will vom Laborbereich Kunststofftechnologie des Fachbereichs Chemieingenieurwesen der Fachhochschule Münster für die Unterstützung bei der Probenherstellung.     

Ultrathin Hydrophobic Coatings Obtained on Polyethylene Terephthalate Materials in Supercritical Carbon Dioxide with Co-Solvents

The surface properties of ultradisperse polytetrafluoroethylene coatings on polyethylene terephthalate materials modified in a supercritical carbon dioxide medium with co-solvent additions (aliphatic alcohols) were analyzed. An atomic force microscopy study revealed the peculiarities of the morphology of the hydrophobic coatings formed in the presence of co-solvents. The contribution of the co-solvents to the formation of the surface layer with a low surface energy was evaluated from the surface energy components of the modified polyester material. The stability of the coatings against dry friction was analyzed.