bluuebunny/crossref_metadata_2025 huggingface dataset:
The dry spinning of dibutyrylchitin fibers
Authors: Szosland L. , East G. C.
Published: April 2003

Dibutyrylchitin was prepared by treatment of krill chitin with butyric anhydride in the presence of perchloric acid as a catalyst of reaction carried out at 25 to 30°C. Dibutyrylchitin is easily soluble in several organic solvents, such as acetone, alcohols, methylene chloride, and dimethylformamide. Samples of polymers with molecular weights high enough to form fibers were obtained, and dibutyrylchitin fibers were made by a simple method of dry spinning its 20 to 22% solutions in acetone. Select properties of dibutyrylchitin fibers were investigated. It was found that dibutyrylchitin fibers had tensile properties similar to or better than those of chitin and some chitin derivatives described in the literature. An attempt to convert dibutyrylchitin fibers to chitin fibers was made. It was found that chitin fibers with good tensile properties could be obtained by alkaline hydrolysis of dibutyrylchitin fibers without destroying the fiber structure. © 1995 John Wiley & Sons, Inc.
Distribution of GAP‐43 nerve fibers in the skin of the adult human hand
Authors: Verzé Laura , Carla Viglietti‐Panzica , Maurizo Stella , Monica Sica , Giancarlo Panzica
Published: April 2003

Skin is an important region of somatic sensory input, and is one of the most innervated areas of the human body. In this study, we investigated in human hand skin the distribution of nervous structures immunoreactive for the growth‐associated protein 43 (GAP‐43) and the protein gene product 9.5 (PGP 9.5). GAP‐43 is a neuronal presynaptic membrane protein that is generally considered to be a marker of neuronal plasticity. PGP 9.5 is a neuron‐specific soluble protein that is widely used as general marker for the peripheral nervous system. The entire neural network of the dermis and epidermis was stained with antibody to PGP 9.5. In the dermis, there were fewer GAP‐43‐immunostained nerve fibers than PGP 9.5‐immunostained nerve fibers, whereas in the epidermis the numbers were equal. Only some Merkel cells and Meissner corpuscles were GAP‐43‐immunoreactive. In conclusion, our results show that GAP‐43 protein is expressed in a subset of PGP 9.5‐immunoreactive nerve structures. Anat Rec Part A 272A:467–473, 2003. © 2003 Wiley‐Liss, Inc.
Evaluating an α–β filter in terms of increasing a track update‐sampling rate and improving measurement accuracy
Authors: Kosuge Yoshio , Ito Masayoshi
Published: April 2003

The α–β filter estimates the true values of the position and velocity of the target from the observed target position. If the driving noise indicating the ambiguity of the target motion differs, then various different α–β filters can be derived from a Kalman filter that uses a constant‐velocity linear motion model. On the other hand, the MV filter is an α–β filter that minimizes the variations of the steady error of the predicted value of the target position for a target in constant‐velocity linear motion, under the condition that the steady tracking error for the target with constant acceleration is constant. This MV filter cannot be derived from the Kalman filter. Note that there are methods of increasing the sampling rate and of improving observation accuracy for improvement of tracking capability. However, when multiple targets are tracked at the same time, the electromagnetic illumination time per target is necessarily reduced. In this paper, the tracking capability of the above α–β filter with constant gains is evaluated in terms of the tracking accuracy for a target in constant‐velocity linear motion under the condition that the steady tracking error for a target in constant‐acceleration motion is constant. It is found advantageous to increase the sample rate rather than to improve the observation accuracy if the electromagnetic illumination time is constant. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 10–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10113
Fundamental study of a λ/4 microwave‐band wave absorber using conductive paper
Authors: Otsuka Kenjiro , Hashimoto Osamu , Orita Mitsuru , Morita Yukinobu
Published: April 2003

This paper discusses a λ/4‐type wave absorber for the microwave band made with conductive paper, which is paper with a coating of conductive material. A simplified wave absorber of this type is first designed and constructed for the X band and Ku band. Using the resulting absorption characteristics, experimental formulas are derived for the relative permittivity and surface resistance. These formulas are then used to design and construct a more practical wave absorber, whose absorption characteristics are measured. Excellent absorption characteristics, better than 20 dB, are verified in the intervals from 8.2 to 10.6 GHz and from 14.1 to 17.2 GHz for wave absorption in the X band and Ku band, respectively, although there is a difference of approximately 0.4 dB between the designed matching frequency and the measured value. Design guidelines for such a microwave absorber using a conductive coating are then presented. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 100–107, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1180
State feedback control of timed hybrid Petri nets
Authors: Tanaka Atsushi , Ushio Toshimitsu , Kodama Shinzo
Published: April 2003

A system in which discrete variables and continuous variables are mixed is called a hybrid system. Many models have been proposed for description of hybrid systems. A mode graphically describing the causality relationship between the variables is the hybrid Petri net (HPN). A mode in which the concept of time is introduced into the HPN is the timed HPN (THPN). In this paper, with regard to the THPN with an external input place (THPNIP), state feedback control is discussed in the case where the control specifications are given by a description on the attainable ensemble. In THPNIP, in general there is no guarantee that the maximum allowable feedback, which is the maximum element in the ensemble of the state feedback satisfying the control specification, will exist. Hence, the necessary and sufficient conditions are presented for the existence of the maximum allowable feedback. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 1–7, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10011
Proposal of eye‐gaze character input interface with guide area
Authors: Ban Hisayuki , Sugamata Ikuma , Itakura Naoaki , Sakamoto Kazuyosi , Kitamoto Taku
Published: April 2003

It has been difficult in the past to differentiate simply an input eye‐gaze (fixation) and a noninput eye‐gaze (pause) in using an eye‐gaze character input interface. This is because there are two major gazes having two different roles, “inputting” and “searching,” which are difficult to differentiate from gazing time, etc. In this study, a new screen design interface has been proposed. In this design, input areas for inputting an “input” are assigned on the left and right side of the screen, and a guide area having a character arrangement similar to the input areas is assigned for “searching” in the center. Since the location of a character can be searched by the guide area, the eye‐gaze for “searching” can be expected to occur in the guide area and the eye‐gaze for “inputting” in the input areas. Whether noninput eye‐gazes (pauses) in the input areas are reduced by the guide method is tested by comparing the past and the guide methods. As a result, the efficacy of the guide method has been verified from the fact that the frequency of noninput eye‐gazes (pauses) is decreased about 40% from that of the past method, while the overall eye‐gaze frequency increases with the guide method, with its increased inputting time as compared with the past method. In addition, it has been found that input eye‐gazes and noninput eye‐gazes (pauses) which could not be separated based on time up to now could be separated at a rate of 88%. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 36–42, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10117
Relationship between optimum quantum detection operators for pure and mixed‐state signals
Authors: Fujihara Yuji , Sasaki Usuda Tsuyoshi , Takumi Ichi , Hata Masayasu
Published: April 2003

A significant issue at present in the field of quantum information theory is the implementation of an optimum quantum receiver in which the error probability is minimized. Because a quantum receiver is represented by detection operators, in order to implement an optimum quantum receiver, it is important to derive optimum detection operators that minimize the error probability. Although it is generally difficult to analytically derive such a detection operator, optimum detection operators have been obtained on several specific signal systems in which signals are in the pure state. On the other hand, because mixed‐state signals are associated with more general signals, including classical noise, it is more important to address mixed‐state signals. However, for these signals, only basic optimum detection operators, such as binary signals in a two‐dimensional system and M‐ary symmetric signals, have been obtained. Regarding these optimum detection operators, it has been suggested that optimum detection operators for pure‐state signals can also be a reasonably good signal detection process for mixed‐state signals. Based on this suggestion, this paper examines the extent to which the optimum detection operators for pure‐state signals can be applied to mixed‐state signals. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 8–18, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1153
Glycemic index and glycemic load in endometrial cancer
Authors: Augustin Livia S.A. , Gallus Silvano , Bosetti Cristina , Levi Fabio , Negri Eva , Franceschi Silvia , Dal Maso Luigino , Jenkins David J.A. , Kendall Cyril W.C. , La Vecchia Carlo
Published: April 2003

Glycemic index (GI) and glycemic load (GL) are measures of the metabolic effects of dietary carbohydrates. The higher their value, the greater the glucose and insulin responses. Raised insulin levels are associated with endometrial cancer and with its risk factors including obesity, diabetes and hypertension. To study the role of the GI and GL we analyzed the data of two hospital‐based case–control studies on endometrial cancer conducted between 1988–98 in Italy and Switzerland, including a total of 410 women with incident, histologically confirmed endometrial cancer and 753 controls admitted for acute, non‐neoplastic diseases. A food frequency questionnaire was used to assess the subjects usual diet and to derive estimates of dietary GI and GL. The odds ratios (OR) of endometrial cancer, after adjustment for major risk factors, for the highest versus the lowest quintile of dietary GI and GL were 2.1 (95% confidence interval [CI] = 1.4–3.2) and 2.7 (95% CI = 1.8–4.2), respectively. The associations were stronger in older women, in those with higher body mass index and in hormone replacement therapy users. Our study supports the hypothesis of a direct association between GI and endometrial cancer risk. © 2003 Wiley‐Liss, Inc.
Five new human cancer‐germline genes identified among 12 genes expressed in spermatogonia
Authors: Loriot Axelle , Boon Thierry , De Smet Charles
Published: April 2003

An important class of tumor‐specific antigens is encoded by male germline‐specific genes, such as MAGE genes, that are activated in many cancers of various histological types as a result of the demethylation of their promoter region. A number of these genes were shown to be expressed exclusively during the spermatogonia stage of spermatogenesis. A recent study reported the isolation of a new set of mouse genes that are expressed in spermatogonia but not in somatic tissues. Here, we tested the tumoral expression of the human orthologs of 12 of these genes. A remarkably high proportion, i.e., 5 of 12 genes, was found to be activated in a significant fraction of tumor samples of various histological types. Expression levels of the 5 genes, namely, NXF2, TAF2Q, FTHL17, TDRD1 and TEX15, were evaluated in normal and tumoral tissues. Except for TEX15, these genes showed sufficiently high expression levels in tumors and low background transcription in normal somatic tissues to qualify them as genes that potentially code for tumor‐specific antigens. Like previously described cancer‐germline genes, the 5 genes were induced in cells treated with a demethylating agent. © 2003 Wiley‐Liss, Inc.
Kinetics for the gas‐phase reactions of OH radicals with the hydrofluoroethers CH2FCF2OCHF2, CHF2CF2OCH2CF3, CF3CHFCF2OCH2CF3, and CF3CHFCF2OCH2CF2CHF2 at 268–308 K
Authors: Chen L. , Kutsuna S. , Tokuhashi K. , Sekiya A. , Takeuchi K. , Ibusuki T.
Published: April 2003

Rate constants were determined for the reactions of OH radicals with the hydrofluoroethers (HFEs) CH2FCF2OCHF2(k1), CHF2CF2OCH2CF3 (k2), CF3CHFCF2OCH2CF3(k3), and CF3CHFCF2OCH2CF2CHF2(k4) by using a relative rate method. OH radicals were prepared by photolysis of ozone at UV wavelengths (>260 nm) in 100 Torr of a HFE–reference–H2O–O3–O2–He gas mixture in a 1‐m3 temperature‐controlled chamber. By using CH4, CH3CCl3, CHF2Cl, and CF3CF2CF2OCH3 as the reference compounds, reaction rate constants of OH radicals of k1 = (1.68) × 10−12 exp[(−1710 ± 140)/T], k2 = (1.36) × 10−12 exp[(−1470 ± 90)/T], k3 = (1.67) × 10−12 exp[(−1560 ± 140)/T], and k4 = (2.39) × 10−12 exp[(−1560 ± 110)/T] cm3 molecule−1 s−1 were obtained at 268–308 K. The errors reported are ± 2 SD, and represent precision only. We estimate that the potential systematic errors associated with uncertainties in the reference rate constants add a further 10% uncertainty to the values of k1–k4. The results are discussed in relation to the predictions of Atkinson's structure–activity relationship model. The dominant tropospheric loss process for the HFEs studied here is considered to be by the reaction with the OH radicals, with atmospheric lifetimes of 11.5, 5.9, 6.7, and 4.7 years calculated for CH2FCF2OCHF2, CHF2CF2OCH2CF3, CF3CHFCF2OCH2CF3, and CF3CHFCF2OCH2CF2CHF2, respectively, by scaling from the lifetime of CH3CCl3. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 239–245, 2003
Fractionation of high polymers by lowering the temperature of the solution
Authors: Sihtola Hannes , Kaila Ermo , Virkola Nils
Published: April 2003

A method has been developed to determine the distribution of the molecular weights of the high polymers. The basis of this method is the separation of the fractions by lowering the temperature of a solution of the polymer containing a precipitant. Experiments have shown that the reproducibility of the method is good. By using a constant solvent/precipitant ratio in different fractionations, it is possible, from the temperature of precipitation, to estimate approximately the limiting viscosity number of the fraction obtained.
Zur feinstruktur von ramie
Authors: Vogel von Alfred
Published: April 2003

Gereinigte Ramiefasern wurden auf verschiedene Weise mechanisch zertrümmert. In doppelt beschatteten elektronenmikroskopischen Präparaten wurden durchschnittliche Mikrofibrillenbreiten von 173–203 Å gemessen. Die Dicke der Mikrofibrillen, die mit ihrer Breitseite der Unterlage aufliegen, beträgt etwa 30 Å. Bei der Hydrolyse in H2SO4 werden die Fibrillen zu unregelmäßigen „Hydrolyseteilchen”︁ quergespalten. Diese sind aus kleineren Partikeln von 80–100 Å Breite und 300–1000 Å Länge zusammengesetzt, die wahrscheinlich den röntgenometrischen Micellen entsprechen.
2,4‐Dinitrophenylderivate der aminocapronsäure und des hexamethylendiamins
Authors: Zahn von H. , Kockläuner R. , Rathgeber P. , Gerstner W.
Published: April 2003

Im folgenden werden einige, für Untersuchungen an Polyamiden wichtige 2,4‐Dinitrophenylverbindungen und deren Darstellungsweise beschrieben.
Über Polyacetale des Formaldehyds mit Methylsilanolen
Authors: Henglein von F. A. , Schmulder P.
Published: April 2003

Es wurde versucht, durch Einwirkung von Methylsilanolderivaten auf Formaldehydverbindungen polymere Silylformale darzustellen. Bei der Kondensation von Dimethyldichlorsilan mit Methylenglykol bildeten sich uneinheitliche Substanzen. Definierte Diathoxypolymethylsilylformale konnten durch eine neue katalytische Umacetalisierungsmethode gewonnen werden.

Die Hydrolysebeständigkeit der polymerhomologen Silylformale ist gering.

Die Umacetalisierung mit Schwefelsäure als Katalysator führte zu einer neuen Darstellung für Silikone.
Über Esterkondensationen an Polyestern und die Herstellung reaktionsfähiger Polyester 409. Mitteilung über makromolekulare Verbindungen 14. Mitteilung über Polyester
Authors: Holtschmidt von Hans
Published: April 2003

Unterwirft man einen Bernsteinsäurepolyester den Bedingungen einer Claisen schen Esterkondensation, so zerfällt er in monomere Spaltstücke völlig neuer Konstitution. Es entsteht ein Diol der Formel
magnified image
in etwa 60%iger Ausbeute, wobei die Ausbeute vom Molekulargewicht des Polyesters unabhängig ist.

Aus diesem Diol lassen sich durch Kondensation in Lösung erneut lineare Polyester herstellen, die ein gutes Faserbildungsvermögen besitzen.

Mit aliphatischen und aromatischen Aminen setzen sich die neuen, reaktionsfähigen Polyester quantitativ zu substituierten Polyestern der Formel
magnified image
um. Durch Wahl der Amine lassen sich so die verschiedensten Seitenketten in den Polyester einführen. Auf diese Weise ist es möglich, den Einfluß verschiedener Substituenten auf die physikalischen Eigenschaften wie Faserbildungsvermögen, kautschukelastisches Verhalten, Erweichungspunkt, Löslichkeit usw. zu studieren. An einigen Produkten werden Viskositätsmessungen und osmotische Molekulargewichtsbestimmungen durchgeführt.
The preparation of polyamides containing heterocyclic groups from furfural and levulinic acid
Authors: Hachihama Yoshikazu , Hayashi Izumi
Published: April 2003

New fiber‐forming polyamides containing heterocyclic groups were prepared form furan 2,5‐dipropionic acid and the corresponding tetrahydrofuran compound which were found to be prepared easily from furfural and levulinic acid. For example, poly‐decamethylenetetrahydrofuran 2,5‐dipropionamide (intrinsic viscosity 0.74) gave a fiber having, when cold drawn to 350%, tensile strength 3.1 g./denier and elongation 25%.
Die reaktion des α, α‐diphenyl‐β‐pikryl‐hydrazyls mit langkettigen freien radikalen, die beim ultraschallabbau von polymethacrylsäuremethylester gebildet werden
Authors: Henglein Von Arnim
Published: April 2003

Beim Abbau des Polymethacrylsäuremethylesters durch Ultraschallwellen entstehen langkettige freie Radikale, die mit gleichzeitig vorhandenem α,α‐Diphenyl‐β‐pikryl‐hydrazyl (DPPH) reagieren. Erfolgt der Abbau unter Ausschluß von Sauerstoff, werden pro gespaltene Bindung zwei Moleküle DPPH verbraucht. Spektroskopische Untersuchungen zeigen, daß nur etwa die Hälfte des verbrauchten DPPH in die langkettigen Bruchstücke eingebaut wird. Es wird die Bildung zweier verschiedener polymerer Radikale und eine Beteiligung des Lösungsmittels an der Reaktion diskutiert. Die Reaktionsprodukte des DPPH lassen sich mit Bleidioxyd oxydieren; dem hierbei entstehenden, schwach violett gefärbten Polymeren wird auf Grund seiner Entstehungsweise, seines Absorptionsspektrums und seiner leichten Reduzierbarkeit mit Hydrochinon die Struktur eines stabilen, langkettigen freien Radikals zugeschrieben. Erfolgt der Abbau bei Anwesenheit von Sauerstoff, so wird im Verlauf einer Reaktionskette mehr DPPH verbraucht als der Zahl der gebildeten langkettigen Radikale entspricht.

Da der spektrophotometrisch leicht meßbare Verbrauch des DPPH der Zahl der gespaltenen Bindungen proportional ist, ergibt sich so eine neue Methode zur Untersuchung der Kinetik der Ultraschalldepolymerisation. In verdünnten Lösungen gilt das Abbaugesetz:

während für konzentrierte Lösungen des Polymeren das Abbaugesetz

gefunden wird; diese Abhängigkeit des Abbaugesetzes von der Konzentration des Polymeren wird diskutiert.
Über die umsetzungen aromatischer ätherdialdehyde mit aliphatischen diaminen. 433. Mitteilung über makromolekulare verbindungen2
Authors: Krässig Von H. , Greber G.
Published: April 2003

Bei der Umsetzung der Methylenglykol‐, Diäthylenglykol‐ und Triäthylenglykol‐bis‐(4‐formylphenyläther) mit aliphatischen Diaminen entstehen überwiegend Gemische von linearpolymeren, niedermolekularen Schiff schen Basen. Mit den ätherdiaminen und mit β,β′‐Diaminodäthylamin dagegen werden vielgliedrige, monomere und dimere Ringprodukte erhalten, die zu den entsprechenden sekundären Aminen reduziert wurden.
Polyvinylsulfonsäure als katalysator hydrolytischer reaktionen
Authors: Kern Von W. , Herold W. , Scherhag B.
Published: April 2003

Es wird ein vereinfachtes Verfahren zur Darstellung der freien Polyvinylsulfonsäure beschrieben. Sie ist eine starke, polybasische Säure. Ihr Dissoziationsverhalten wird elektrometrisch untersucht und mit dem der Schwefelsäure und der Polyacrylsäure verglichen. Die Ergebnisse werden an Hand der Henderson‐Hasselbalch‐Gleichung diskutiert.

Bei der Untersuchung ihrer Wirksamkeit als hydrolysierender Katalysator wird festgestellt, daß die Polyvinylsulfonsäure gegenüber Kohlehydraten und Polypeptiden ein verschiedenes Verhalten zeigt. Sie spaltet Rohrzucker mit der gleichen Geschwindigkeit wie Schwefelsäure; bei Proteinen und Peptiden verläuft die Spaltung jedoch 3–5 mal schneller. Es wird versucht eine Erklärung für diese Erscheinung zu geben.
Polychelatsiloxane. 3. Mitt.: Untersuchungen zur thermischen beständigkeit
Authors: Sander Von M.
Published: April 2003

Die gut herstellbaren Polychelatsiloxane mit einer aliphatischen β‐Diketonatgruppierung und einem Trimethylen‐Zwischenglied zwischen Chelat und Silicium, zersetzen sich auch in reinem Zustand ab 200°C, wobei in erster Linie eine Spaltung der Trimethylenkette unter Bildung von Methan eintritt. Die Einführung aromatischer Substituenten am Chelatring oder der Ersatz der Trimethylengruppe durch andere Zwischenglieder ist synthetisch schwierig und erbringt keine Erhöhung der thermischen Stabilität der Polymeren. Thermisch beständige Chelate von phenolischen Chelatbildnern ließen sich nicht befriedigend in Siloxane einbauen.
Free radical polymerization of unconjugated dienes III. N‐allylacrylamide in methanol
Authors: Trossarelli L. , Guaita M. , Priola A.
Published: April 2003

The free radical polymerization of N‐allylacrylamide at 60°C. in methanol solution is described. The experimental data show that both, the acrylic and the allylic double bonds of the monomer take part in the intermolecular and intramolecular (cyclization) chain propagation steps. In particular it is shown that the allylic double bond has a greater tendency to participate in cyclization reactions than the acrylic one. These results agree with earlier observations on the free radical polymerization of N‐allymethacrylamide in methanol solution at 60°C. The relative reactivities of the acrylic and the allylic double bonds in N‐allylacrylamide are close to those expected on the basis of copolymerization data for only acrylic and only allylic monomers.
Synthese und eigenschaften copolymer polyharnstoffe mit linearer struktur
Authors: Borner Von P. , Gugel W. , Pasedag R.
Published: April 2003

Es wird über die Syntheses hochmolekularer, thermoplastischer, glasklarer und vorwiegend amorpher Copolyharnstoffe mit periodisch wiederkehrender Harnstoffbindung in der Hauptvalenzkette berichtet. Unverzweigte aliphatische Diamine wurden mit steigenden Mengen von Diaminen cokondensiert, die Ätherbrücken oder verschiedene Seitengruppen besitzen, z.B. Methyl‐, Nonyl‐ oder Fluorengruppen. Der Einfluß dieser Substituenten auf Schmelz‐ und Einfriertemperatur, Kristallisationsverhalten, Wasseraufnahme, Fließ‐spannung, Bruchdehnung, Kerbschlagzähigkeit und E‐Modul wurde untersucht. Die Verarbeitungsmöglichkeiten der neuen Copolyharnstoffe werden kurz angegeben.
Über die reaktivierung der bei der äuthylen/propylen‐copolymerisation verwendeten vanadium‐katalysatoren
Authors: Gumboldt Von A. , Helberg J. , Schleitzer G.
Published: April 2003

Durch Reaktivierung der kurzlebigen Vanadiumkontakte mit Hexachlorcyclopentadien wird eine bessere Katalysatornutzung und damit eine größere Wirtschaftlichkeit bei der Herstellung von Äthylen/Propylen‐Copolymerisaten erzielt.

Hexachlorcyclopentadien wirkt dadurch reaktivierend, daß es das bei der Umsetzung von höherwertigen Vanadium‐ und Al‐organischen Verbindungen entstandene inaktive V (II) zum V (III) oxydiert. V (III) kann dann erneut durch Reaktion mit Al‐organischen Verbindungen zu einem aktiven Katalysator werden.
Neue wege zur modifizierung von ungesättigten polymeren
Authors: Holtschmidt Von H. , Pampus G. , Schön N. , Witte J.
Published: April 2003

Hochpolymere Stoffe mit CC‐Doppelbindungen, die frei von Wasser und H‐aciden Verbindungen als Lösung in unpolaren Lösungsmitteln anfallen, eignen sich für eine nachtrügliche Modifizierung mit Hilfe einfacher, chemisch übersichtlicher Reaktionen. Mit Katalysatoren vom FRIEDEL‐CRAFTS‐Typ lassen sich in Diolefinpolymerisate Langketten‐verzweigungen einbauen. Man erhält gelfreie Produkte mit stark vergrößertem Molekulargewicht.

Mit Hilfe von 4‐Isocyanato‐phenyl‐sulfenchlorid lassen sich auf verschiedenen Wegen Langkettenverzweigungen in ungesattigte Polymere einführen. Durch Additionsreaktionen der in das Polymere eingebauten NCO‐Gruppen wird eine Mannigfaltigkeit von Copolymeren zugünglich.

An cis‐1,4‐Polybutadien als Modell werden Wirkungsweise und Anwendungsbereich des 4‐Isocyanato‐phenyl‐sulfenchlorids demonstriert. An NCO‐Gruppen‐haltigem Polybutadien können die Additionsreaktionen der NCO‐Gruppe in sehr starker Verdünnung studiert werden.
Schlagzähe styrolpolymerisate
Authors: Willersinn Von H.
Published: April 2003

Der Zusammenhang zwischen dem Aufbau schlagzäher Styrolpolymerisate und ihren Gebrauchseigenschaften wird eingehend erörtert. Diese Materialien bestehen aus einer Hartkomponente, z.B. Polystyrol, und einer in die Hartkomponente eingebetteten Weichkomponente, die im allgemeinen ein Kautschuk ist. Da diese Systeme aus mehreren Phasen bestehen, bestimmen die Größenverteilung und die Verankerung der Kautschukteilchen wesentlich die Eigenschaften. Auch das mechanisch‐thermische Verhalten des Kautschuks, insbesondere seine Einfriertemperatur, spielt eine große Rolle.

Es wird gezeigt, daß man die Gebrauchseigenschaften durch Änderung der Herstellungsverfahren und durch die Auswahl geeigneter Kautschuke erheblich beeinflussen kann. Bei der Entwicklung von Produkten sind einige physikalisch‐chemische Untersuchungsmethoden von großem Nutzen, da sie eine gewisse Voraussage über die technologischen Gebrauchseigenschaften erlauben.
Bausteinanalyse bei homo‐ und copolymerisaten des trioxans mit hilfe der katalytischen pyrolysegaschromatographie
Authors: Burg Von K. H. , Fischer E. , Weissermel K.
Published: April 2003

Homo‐ und Copolymerisate des Trioxans werden pyrolysegaschromatographisch untersucht. Diese Methode der Kombination einer pyrolytischen Zersetzung mit einer gaschromatographischen Analyse zeigt, daß Polyacetale bei einer Pyrolysetemperatur von 900°C in eine Veilzahl von Bruchstücken aufspalten, die nur schwer chemischen Individuen zuzurodnen sind. Durch Zumischen geeigneter Katalysatoren zum Polymeren kann bei 500°C Pyrolysetemperatur eine katalytische Zerlegung erreicht werden. Hierbei entsehen erheblich weniger Bruchstücke, die leicht identifiziert und auf die Struktur der Polymeren zurückgeführt werden können. Die Methode erlaubt eine quantitative Bestimmung des Comonomerenanteils in Trioxancopolymerisaten. Bei Verwendung von Äthylenoxid als Cokomponente gelingt der Nachweis des Verhältnisses von Mono‐, Di‐ und Trioxyäthyleneinheiten in den Polymeren.
Polyamides containing pendant hydroxyl groups and their derived polyoxazolines
Authors: Iwakura Yoshio , Izawa Shin‐Ichi , Hayano Fusakazu , Kurita Keisuke
Published: April 2003

Bisaminoalcohols were prepared from bisepoxides and ammonia. They were subjected to a polycondensation reaction with dicarboxylic acid chlorides to form polyamides containing hydroxyl groups. These polymers had an inherent viscosity in the range of 0.36 to 1.45 and gave tough, transparent films by solution casting. Polyoxazolines were obtained by treating these polyamides with thionyl chloride.
Zur berechnung der viskositätszahl aus einpunktmessungen
Authors: Solomon Von O. F. , Gotesman B. S.
Published: April 2003

Die theoretischen Grundlagen eines Verfahrens zur Bestimmung von [η] aus einer einzigen Viskositätsbestimmung werden erörtert. Die folgende Gleichung zur Berechnung von [η] wird abgeleitet:
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Polymerization of methyl methacrylate initiated by the benzoic anhydride/dimethylaniline n‐oxide system and the acceleration by alcohol. Vinyl polymerization. 165
Authors: Sato Tsuneyuki , Takemoto Kiichi , Imoto Minoru
Published: April 2003

In connection with the polymerization of methyl methacrylate initiated by the system benzoic anhydride/dimethylaniline N‐oxide, the reaction of benzoic anhydride with dimethylaniline N‐oxide was studied at 40°c in benzene solution. It was found that alcohol has no effect on this reaction, though the polymerization initiated by this system was accelerated in the presence of alcohol. 14C‐labelled benzoic anhydride was used and, from the results obtained, the initiation mechanism of the polymerization by the system benzoic anhydride/dimethylaniline N‐oxide was discussed.
Environmental effects in free radical polymerizations. Methacrylonitrile and iso‐Butyraldehyde
Authors: Burnett G. M. , Ross F. L. , Hay J. N.
Published: April 2003

The polymerization of methacrylonitrile in an aldehyde environment has been studied. The general kinetic results are consistent with the aldehyde acting only as a very efficient transfer agent. The physical properties of the polymer are directly attributable to the low molecular weight of the polymers. NMR spectroscopy confirmed that there was no increased tacticity in these polymers.

It is considered that the vinyl cyanide units in both acrylonitrile and methacrylonitrile are sufficiently similar to undergo complexing with the aldehyde to similar extents and thus it is concluded that acrylonitrile cannot form complexes with aldehydes which is in agreement with previous observations.
Optical rotatory dispersion studies of poly(l‐α‐methylbenzyl methacrylate) and poly(menthyl methacrylate) in solution
Authors: Liu Kang‐Jen , Lignowski J. S. , Ullman Robert
Published: April 2003

Optical rotatory dispersion studies were carried out on solutions of poly(l‐α‐methylbenzyl methacrylate) and poly (l‐menthyl methacrylate) samples of varying tacticity. Monomeric analogues α‐methylbenzyl pivalate and menthyl pivalate were also investigated in the same way. Ultraviolet spectra of the α‐methylbenzyl series were obtained.

The general shape and form of the optical rotation spectra were similar for the several α‐methylbenzyl polymer samples and monomer analogue. The isotactic polymer showed generally higher optical activity than both the syndiotactic and atactic polymers and the monomeric analogue. This was found to be true in several solvent systems. The ratio of the optical activity of the polymer to that of the monomer increased uniformly with decreasing wave length. The temperature dependence of optical activity was small. The ultraviolet spectra of polymeric and monomeric species were very much the same down to the lowest wave lengths measured, of the order of 210 mμ.

The menthyl polymers and monomer analogue also showed optical rotation spectra which were similar to each other. For this material all polymers had higher optical activity than the monomeric analogue, but in contrast to that which was found for the α‐methylbenzyl systems, the syndiotactic and atactic polymers showed higher optical rotation than the isotactic material.

The relationship of the optical activity of the polymers in solution to the specific conformational structure present is obscured partly by solvent interaction and partly by the fact that the effects of polymer structure on optical activity are small since the asymmetric carbon or carbon atoms are connected by several intermediate bonds to the skeletal backbone of the molecule. The importance of the excited states of the important chromophoric groups of the polymer molecule on the optical activity is discussed.
Über das zustandsdiagramm binärer polymerengemische
Authors: Natov Von M. , Peeva L.
Published: April 2003

Die Phasenzustände von folgenden binären Polymerensystemen, die aus je einer kristallisationsfähigen und einer nichtkristallisationsfähigen Komponente bestehen, wurden untersucht: Polyäthylenadipat/Polymethylmethacrylat, Polyäthylensebacinat/Polymethylmethacrylat und Polyäthylenadipat/Polyvinylchlorid. Es ergab sich, daß diese Mischungen homogene Systeme bilden können, die sich durch Zustandsdiagramme charakterisieren lassen, die denjenigen von niedermolekularen Verbindungen ähneln. Im einzelnen wurde die Abhängigkeit der Phasenzustände von den Molekulargewichten der Komponenten, der Temperatur und der Zusammensetzung der Gemische untersucht.
Die copolymerisation des trioxans mit substituierten 1.3‐dioxacycloalkanen
Authors: Weissermel Von K. , Hermann H. D. , Burg K. H.
Published: April 2003

In 2‐Stellung substituierte 1.3‐Dioxacycloalkane sind aus zweiwertigen Alkoholen und Aldehyden oder Ketonen leicht zugänglich. Sie zeigen bei der Copolymerisation mit Trioxan ein ungewöhnliches Verhalten. Es wird zunächst aus Trioxan unter Ringöffnung Formaldehyd abgespalten, der in einer Induktionsperiode mit dem substituierten Dioxacryloalkan unter Bildung von cyclischen Formalen und Freisetzung der Carbonylkomponente reagiert. Erst wenn these Umacetalisierung weitgehend beendet ist, kann sich monomerer Formaldehyd im Reaktionsgemisch bis zur ceiling‐Konzentration anreichern, so daß schließlich eine Copolymerisation von Trioxan mit unsubstituiertem 1.3‐Dioxacycloalkan ausgelöst wird.
Polyamide synthesis via enamines
Authors: Daly W. H. , Kern W.
Published: April 2003

Enamines derived from cyclic ketones behave as difunctional intermediates when treated with phenyl isocyanate to produce dicarboxanilides. Reaction of bis(4‐isocyanatophenyl)‐methane with 1‐N‐morpholino‐1‐cyclopentene in DMSO leads to poly[iminocarbonyl(2‐morpholino‐1‐cyclopenten‐1.3‐ylene)carbonylimino‐p‐phenylenemethylene‐p‐phenylene], a polyamide. The effects of various cyclic enamines and diisocyanates on the polymerization are surveyed. Morpholine and piperidine are more effective than pyrrolidine or dimethylamine when incorporated into cyclopentanone enamines. The molecular weight of the polymer decreases when the ring size of the ketone component is increased. The efficiency of the diisocyanates decreases as follows: bis(4‐isocyanatophenyl)methane > tolylene diisocyanate > naphthylene diisocyanate > hexamethylene diisocyanate > sulfurly diisocyanate. Branched and crosslinked polymers were obtained in the presences of excess diisocyanate. A mechanism is proposed to account for these results.

The polyamides obtained from 1‐N‐amino‐1‐cyclopentene were not thermally stable. The rate of degradation at 60°C was determined by measuring the decrease in viscosity with time. The enamine structural unit of the polyamides can be hydrolyzed with 98% formic acid to the corresponding polyketone, which yields a poly(2.4‐dinitrophenylhydrazone) upon treatment with DNPH in DMSO. Reaction of excess 2‐N‐morpholino‐1‐cyclopentene‐1‐carboxanilide with bis(4‐isocyanatophenyl)methane affords a model compound for the new polyamide. The infrared and NMR spectra of the polymers and their corresponding model systems were compared and found to be consistent with the proposed structures.
Solution properties of copolymer of p‐chlorostyrene and methyl methacrylate
Authors: Mohite R. B. , Gundiah S. , Kapur S. L.
Published: April 2003

The monomer reactivity ratios in the free radical copolymerization of methyl methacrylate and p‐chlorostyrene were obtained and an azeotropic copolymer containing the 0.484 mole fraction of methyl methacrylate was prepared. The copolymer was fractionated into nine fractions, which on the basis of their chlorine content and specific refractive index increments, were found to be homogeneous in their chemical composition. The solution behaviour of these fractions was examined by viscosity, osmotic pressure and light‐scattering techniques. The weight‐average molecular weights obtained in dioxane, chloroform and 78:22 v/v mixture of trans‐decalin and trichloro ethylene (Θ solvent at 22.3°C) were found to be identical but those obtained from benzene were as much as 80% higher, depending on the molecular weight. The data were treated by the method of STOCKMAYER and BENOIT and the deviation and square‐deviation of the chemical composition was obtained as zero and proportional to M1.5, respectively. The value of exponent “a” in the KUHN‐HOUWINK equation[η] = KMa obtained by use of the number‐average molecular weight and corrected weight‐average molecular weight, was identical but the apparent weight‐average molecular weights obtained in benzene gave a low value of “a” confirming the applicability of the STOCKMAYER‐BENOIT relationships. The value of the constant K obtained for the copolymer in the theta solvent was 6.4·10−4 compared with 4.9·10−4 and 5.0·10−4 obtained for poly(methyl methacrylate) and poly‐p‐chlorostyrene, respectively, indicating a 10% higher dimension for the copolymer.
Synthesis and reactions of functional polymers. XXIX. Preparation and polymerization of S‐vinyl‐N.N‐dialkyldithiocarbamates
Authors: Nakai T. , Shioya K. , Okawara M.
Published: April 2003

Some S‐vinyl‐N.N‐dialkyldithiocarbamates were prepared in good yields by vacuum pyrolysis of the corresponding ethylene bis(N.N‐dialkyldithiocarbamates). S‐Vinyl‐N.N‐diethyldithiocarbamate was copolymerized with styrene. The ALFREY‐PRICE Q‐ and e‐values were calculated and compared with those of its oxygen analogues.
Über die Synthese und das Redoxverhalten einiger Modellsubstanzen für polymere Hydrochinon‐Chinon‐Redoxsysteme. V1
Authors: Manecke Von G. , Zerpner D.
Published: April 2003

Einige Modellsubstanzen für polymere Hydrochinon‐Chinon‐Redoxsysteme wurden dargestellt, in denen zwei Hydrochinonkerne über eine Methylen‐, Äthylen‐ oder Trimethylenbrücke verknüpft sind. Ihr Redoxverhalten wurde durch potentiometrische Titration untersucht. Die Titrationskurven werden theoretisch gedeutet.
Deformation of extremely thin polyethylene films
Authors: Sakaoku K. , Peterlin A.
Published: April 2003

In order to establish a better correlation between the drawing mechanism of bulk polyethylene (PE) and the observation of plastic deformation of single crystals and the ensuing microfibril formation extremely thin PF films floating on hot water were deformed and studied by electron microscopy. The drawn film consists of about 300 Å wide folded chain blocks arranged in microfibrils. The chains are oriented in the microfibril axis. The lateral coalescence of the blocks into lamellae produces a surface structure of the same type as observed with bulk samples. One hence concludes that also in the latter case the destruction of the original spherulitic structure in the necking zone first produces microfibrils composed of blocks broken off a single lamella. The bundle of microfibrils from a single stack of lamellae with similar draw ratio and draw rate laterally coalesces forming a fibril, i.e., a stack of mosaic type lamellae with rather irregular fold containing surfaces and extending over more or less the whole cross section of the fibril.

In contrast with bulk samples, but in agreement with the single crystal deformation, the long period of the drawn film agrees with that of the starting material. The same situation exists with annealing which increases the long period and the order in lamellar orientation and long period, but does not produce any crystal rotation about an axis in the sample surface and perpendicular to the draw direction which is so conspicuous with drawn bulk PE.
Die chemische heterogenität von copolymerisaten. 2. Die häfigkeitsiverteilung der chemischen zusammensetzung in binären copolymerisaten
Authors: Markert Von G.
Published: April 2003

Da die Copolymerisationsgleichung unabhängig von bereits vorhandenem Copolymerisat gilt, existiert für jedes Monomerenpaar eine allgemeine, d.h. vom Ausgangsmischungsverhältnis der Monomeren losgelöste, Verteilungsfunktion der chemischen Zusammensetzung. Die beiden Grundtypen der Copolymerisationskurve ohne und mit Azeotrop finden sich entsprechend abgewandelt in den Häufigkeitsverteilungen wieder. Das Azeotrop teilt ein System in zwei voneinander unabhängrige Bereiche, ohne den Kurvenhabitus selbst weiter zu verändern. In Verbindung mit der Copolymerisationskurve ergibt die Häufigkeitsverteilung, eine übersichtliche Informationsquelle über den Aufbau von Copolymerisaten und bietet große Vorteile, wenn man z.B. Sequenzlängenverteilungencoder die Copolymerisation ternärer Gemische erfassen will, d.h. immer dann, wenn eine möglichst genaue und konzentrierte Darstellung der chemischen Verteilung notwendig ist.
Optically active polyamides with regular structural sequences prepared froni α‐amino acid
Authors: Saotome Kazuo , Schulz Rolf C.
Published: April 2003

Optically active polyamides with regular structural sequences have been prepared from L‐lysine and adipic acid. A novel optically active symmetrical diamine, N.N'‐bis(L‐5‐amino‐5‐carboxyl‐amyl)adipamide, was obtained by treating L‐lysine with adipyl chloride in the presence of copper(II) ions. The interfacial polycondensation of this diamine with adipyl chloride afforded a regular polymer, while the polycondensation of L‐lysine with adipyl chloride gave an irregular polymer of the same analytical composition. The melting points, optical rotations and the optical rotatory dispersions of these polymers were investigated.
Polar effects in radical polymerization of vinyl monomers; radical copolymerization of several p‐substituted vinyl benzoates
Authors: Kinoshita Masayoshi , Irie Tsuyoshi , Imoto Minoru
Published: April 2003

The mutual radical copolymerizations of several p‐substituted vinyl benzoates such as vinyl p‐methoxy‐, p‐methyl‐, p‐chloro‐, p‐bromo‐, and p‐cyanobenzoate and vinyl benzoate were carried out at 60°C. The monomer reactivity ratios were determined by the method of FINEMAN and ROSS. The relative reaction rates of p‐substituted vinyl benzoates to a given poly‐vinyl‐p‐substituted benzoate radical plotted against HAMMETT'S σ‐values gave straight lines. The linear relationships and small ρ‐values show in contrary to p‐substituted styrenes that p‐substituents in this case have only a little polar effect on the vinyl group and on the polymer radical which are separated from the aromatic ring through the carboxyl‐group, and on the exaltation of resonance stabilization of polymerizing species at transition state. The observed σ‐values were correlated with the ρ‐values of p‐substituents on the polymer radicals. Polymers and copolymers of these monomers were hydrolysed to give polyvinyl alcohol.
The cationic nature of diethylzinc/water system as polymerization catalyst
Authors: Tsuchiya Shozo , Tsuruta Teiji
Published: April 2003

The nature of the binary system diethylzinc/water as catalyst for the ring opening polymerizations was found to be much influenced by the mole ratio of water to zinc. With mole ratios less than 1, the catalyst system induced the polymerization of tetrahydrofuran, 3.3‐bis(chloromethyl)oxetane and styrene with (or without in some cases) suitable cocatalysts; that points at a cationic character of the zinc catalyst. The 1:1 system, on the other hand, failed to polymerize any of these monomers.

Discussions are presented on the characters of the two catalyst systems on the basis of these results together with those for D(+)‐propylene oxide polymerization.
Die herstellung molekulareinheitlicher leiteroligomerer und einer molekulareinheitlichen hexaacrylsäure. IV. Mitt.: Modelle für matrizenreaktionen
Authors: von Kämmerer H. , Önder N.
Published: April 2003

Die phenolischen Hydroxylgruppen molekulareinheitlicher Mehrkernverbindungen mit vier und fünf pKresolbausteinen je Molekül konnten vollständig mit Acrylsäurechlorid in Gegenwart von Triäthylamin verestert werden. Ließ man auf die in siedendem Benzol stark verdünnten mehrafachen Acrylsäureester einen Überschuß an Radikalen aus α.α′‐Azoisobutyrodinitril einwirken, so bildeten sich mit guter Ausbeute molekulareinheitliche, dünnschichtchromatographisch reine Leiteroligomere. Die alkalische Verseifung des Leiteroilgomeren mit vier p‐Kresolbausteinen gab eine molekulareinheitliche Hexaacrylsäure, die als Hexamethylester durch Elementaranalyse und Molekulargewicht charakterisiert wurde; die gefundenen Werte stimmten innerhalb der üblichen Fehlerstreuung mit den berechneten überein. Die durchgeführte Reaktionsfolge ist eine synthetische Matrizenreaktion und vegleichbar mit einer natürlichen Matrizenreaktion.
Komplexbildung von acrylnitril mit AgNO3 und initiierung der lichtsensibilisierten polymerisation. Zur polymerisation von acrylnitril mit AgNO3, 4. Mitt.
Authors: Schnecko Von H.
Published: April 2003

Es wird über die Komplexbildung von Acrylnitril (AN) mit AgNO3 berichtet, und die experimentellen Ergebnisse werden kinetisch ausgewertet; die Annahme, daß im Falle des AN die Initiierung aus einem Komplex des Monomeren mit dem Salz erfolgt, wird enhärtet. Daräber hinaus hängt die Polymerisationsgeschwindigkeit von der Wellenläange des eingestrahlten Lichts ab. für den Initiierungsmechanismus wird eine Reduktion des Metallions mit gleichzeitiger Bildung eines NO3‐Radikals vorgeschlagen, das den eigentlichen Initiator darstellt.
The stability of the helix of amylose and amylopectin in DMSO and water solutions
Authors: Erlander Stig R. , Tobin R.
Published: April 2003

The DMSO molecule behaves as a zwitterion having an electrostatic charge density on its oxygen atom comparable to that of the fluoride ion. Therefore the DMSO anion interacts with water to form an A‐region having two water molecules, i.e., a DMSO 2H2O complex at 66% DMSO. Studies on amylose and amylopectin show that DMSO 2H2O as well as anhydrous DMSO help to stabilize the helix structure of amylose and amylopectin. Because this helix structure is absent in dextran and hydroxyethyl cellulose, their properties in DMSO/water solutions are different from those of starch. The proposed model for the interaction of DMSO or hydrated DMSO with the starch helix shows how these molecules stabilize the helix by interacting with only one hydroxyl group of the C‐2 and C′‐3 hydrogen bonded hydroxyl groups. The α‐helix of amylose and amylopectin is more stable at acid pH values of 90 and 100% DMSO solutions than alkaline values because of the formation of the (CH3)2S+‐OH cation. The hydroxyl group of this cation salts‐out the hydrogen bonds just as the case of the hydrated A‐regions of Li+ and Na+ cations. Optical rotation studies show that the addition of hydrated Na+ ions also stabilizes the α‐helix just as a decrease in apparent pH. The greater stability of the helix in these DMSO solutions predicts that its average segment length will also increase. The decrease in the corrected specific rotation of amylose in going from water to DMSO solutions is most likely due to an increase in the thermal motion of the amylose rather than any decrease in the helix stability. The DMSO disperses starch because, unlike the hydrogen bonds in the helix, both of the hydroxyl groups involved in intermolecular hydrogen bonds can become complexed to DMSO anions. The lower pK of such Intermolecular hydrogen bonds also allows alkali in DMSO to increase the dispersion power of DMSO. Salt (NaCI) decreases the dispersion power of DMSO because of the formation of interchain linkages through the unhydrated Cl− ion. The (CH3)2S+‐OH cation increases the dispersion power of DMSO by favoring the formation of those hydrogen bonds involved in the helix.