摘要:

AbstractA new class of urethane‐acrylic monomers was synthesized from diisocyanates such as toluylene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI), unsaturated alcohols like hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), and saturated alcohols such as stearly alcohol and decanol. The monomers were characterized by IR and NMR spectroscopy. Urethane pendent acrylic polymers, obtained by polymerizing these monomers, were characterized by IR, solubility viscosity, and thermal studies. The thermodynamic parameters for the degradation were calculated and a probable degradation mechanism is propose

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870101

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractA comparative study had been carried out on the behaviour of the degree of polymerization (DP) of sugar cane bagasse during different times of digestion (soda pulping) with and without previous impregnation. Determination of the average DP (DPη) and its distribution show that the impregnated materials undergo degradation during the digestion, what in contrary is not to observe when digestion is carried out without previous impregnation. It is supposed that the impregnation alters the chemical structure of the cellulose, facilitating thus the degradation during digestion. From the distribution curves arises furthermore, independent from impregnation or not and independent from the digestion time, a very pronounced maximum (about 25 wt.‐% of total mass) at DP<150 belonging to a non‐cellulosic polysaccharide present in the sugar cane bagasse, which is removed neither by digestion nor by nitra

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870102

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractEthylene oxide was copolymerized with propylene oxide, epichlorohydrin or styrene oxide at various monomer feed compositions, using partially hydrolyzed organoaluminium compounds as catalysts. The copolymers obtained after doping with NaI form highly conductive polymeric electrolytes. Complex impedance measurements show relaxation semicircles much less depressed than in semicrystalline electrolytes based on Poly(ethylene oxide). The maximum values of the room temperature conductivity for each kind of copolymer containing electrolytes are higher than those for the pristine poly(ethylene oxide)‐Nal system. The highest value, equal to 2.6 · 10−5S/cm at 25°C, was found for poly(ethylene oxide‐co‐propylene oxide) containing 33 mol‐% of propylene oxide mono

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870103

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractPrepolyurethanes were obtained by reacting the hydroxyl functionality of castor oil with diisocyanates, namely toluene‐2,4‐diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 4,4′‐diphenylmethane diisocyanate, respectively. Homogeneous mixtures of prepolyurethanes and epoxy resin (prepared from bisphenol F in alkaline medium) were prepared in acetone containing 1,3‐propanediamine as curring agent. Glass reinforced laminates were prepared by interacting PU/epoxy resin mixtures on glass cloth through compression moulding. The laminates were characterized by chemical resistance to solvents, flexural strength, izod impact strength, and Rockwell hardness. The variation of electrical conductivity σ with temperature was found to confirm with the empirical relation σ = σ

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870104

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractA series of new oligomeric disperse and acid azo‐phenolic dyes were prepared by coupling various aromatic diazonium salts to phenol‐formaldehyde (PF), m‐cresol‐formaldehyde (CF) and resorcinol‐formaldehyde (RF) oligomers. They were characterized in terms of their softening points, colour, solubility, IR and UV‐Vis spectra and thermogravimetric properties. Their dyeing on polyester, nylon and wool resulted in yellow, orange, and brown to red shades with good to excellent light‐fastness and wash‐fast

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870105

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe Photochromic properties by UV and laser irradiation of cationic polyurethanes with viologen groups introducted by Menschutkin reaction were studied and poly(vinylalcohol) was used as matrix.

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870106

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractZur Bestimmung der Teilchengrößenverteilung (TGV) von Polymer‐Dispersionen mit Teilchendurchmessern D<40 nm durch Ultrazentrifugation sind im allgemeinen Konzentrationen erforderlich, bei denen Wechselwirkungen zwischen den Teilchen auftreten. Diese Wechselwirkungen verursachen eine Verschiebung der TGV zu kleineren Durchmessern und bewirken außerdem eine Verengung der TGV. Um niedrige Konzentrationen zu verwenden, bei denen keine Wechselwirkungen auftreten, ist es zweckmaßig, Messungen unter Verwendung weitgehend monochromatischen UV‐Lichtes durchzuführen, da nach der Mieschen Theorie die spezifische Trübung mit der Frequenz des Lichtes zunimmt.Polystyrol‐, Poly (methylmethacrylat)‐, Poly(n‐butylacrylat‐co‐methylmethacrylat)‐und Polyurethan‐Dispersionen, die durch anionische Netzmittel bzw. eingebaute Anionen (Polyurethan) stabilisiert waren, wurden unter Verwendung von Licht der Wellenlänge 546, 436, 365 bzw. 313 nm untersucht. Es zeigte sich, daR insbesondere bei 313 nm niedrige Konzentrationen (≤ 1 g/l) verwendet werden konnten. Die ermittelte TGV war praktisch unabhängig von der Wellenlänge, auch wenn eine vergleichsweise breite unimodale Verteilung vorlag. Der Fehler, den eine konsumptive Absorption im UV‐Bereich hervorruft, kann demnach vernachlässigt werden. Bei Verwendung höherer Konzentrationen ließ sich durch Zugabe von Natrium‐Dodecylsulfat eine Herabsetzung, aber keine völlige Eliminierung der Wechselwirku

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870107

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractIn the present work the impact behaviour at high speed of rubber‐modified epoxy resins has been investigated. Impact‐tension measurements have been performed to evaluate the toughness of different systems. A detailed post‐failure observation of the fracture surfaces has been made through scanning electron microscopy (SEM). A combination of a solid fluorinated rubber with the generally used carboxy‐terminated butadiene‐acrylonitrile rubber (CTBN) was found to be very effective.A correlation was tempted between the observed fracture behaviour and the bulk morphology, examined by transmission electron microsc

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870108

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this work three different techniques were used to determine the crystallinity of polyethylene. After different pretreatment HDPE, LLDPE, and LPDE samples were investigated by density measurements, differential scanning calorimetry, and Raman spectroscopy. The results were compared and relationships were estabilished between the values measured by the different methods.

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870109

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractAm Beispiel von PE‐LD‐Sorten und der durch präparative Fraktionierung gewonnenen Modellsubstanzen (Fraktionen im Molmassenbereich M̄w= 1,2 – 390·104g/mol) wurden umfangreiche Untersuchungen zur Struktur‐Eigenschaftsproblematik durchgeführt.Untersucht wurden die Korrelationen von M̄wmit 15 physikalischen und anwendungstechnischen Parametern unter Berücksichtigung der Reaktionsmechanismen bei der Herstellung von PE‐LD im Rohr‐ und Rührautoklavreaktor, die zur Bildung der sogenannten primären Strukturparameter M̄n,M̄w, Molmassenverteilung, Kurzkettenverzweigung und Langkettenverzweigung führen. Bei der Interpretation der Ergebnisse wurden u. a. auch die morphologischen Gegebenheiten berücksichtigt, die im Zusammenhang mit den molekularen Parametern für bestimmte M̄w‐Bereiche starke Ande‐rungen bzw. Sattigungsbereiche für die physikalischen und anwendungstechnischen

ISSN:0003-3146    

DOI:10.1002/apmc.1991.051870110

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY