摘要:

AbstractIn order to study the reactivity of different vinyl monomers, the grafting of different vinyl monomers such as acrylonitrile (AN), methylacrylate (MA), ethylacrylate (EA), methyl methacrylate (MMA), butylacrylate (BA) and vinyl acetate (VAc) onto the sodium salt of partially carboxymethylated amylose (DS= 0.313) has been carried out using ceric ammonium nitrate as an initiator. The following reactivity order of monomers has been found: AN>MA>EA>MMA>BA>VAc.

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100101

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe synthesis of cation exchange resins via the reaction of poly(vinyl alcohol) as a carrier, citric acid as a catalyst and reactive additive to produce resin structures with grafted carboxy groups, along with a melamine‐formaldehyde precondensate, responsible for crosslinking‐reinforcing and insolubilizing the resin structure as well as for fixing and binding the acidic functional groups onto the resin structure, has been investigated using varied molar ratios of reactants and varied time as well as temperature. Reaction conditions were selected to prepare a cation exchange resin based on citric acid. Two other cation exchange resins based on tartaric acid and glycolic acid, were also prepared under the same selected reaction conditions. These three resins were characterized by potentiometric titration, water solubility and swellability, as well as durability to

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100102

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractLow‐pressure discharge treatments were applied to the surface of polypropylene. ESCA analyses, wettability measurements and adhesion tests were carried out to characterize surface modifications as a function of treatment time and nature of gas (air or argon). Advancing and receding contact angles were measured with an automatic dynamical tensiometer. The liquids used were water (very polar liquid) and methylene iodide (apolar liquid). The results show an increase in wettability by the surface treatment. This is due to the creation of high‐energy polar sites. ESCA analysis also shows that the modified surface layer is soluble in methanol and is made up of low‐molecular‐weight material.Adhesion of polypropylene/aluminium is also increased by the low pressure discharge treatment from the few first seconds of the treatment. This adhesion increase is a function of the polar component of the polymer surface

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100103

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of surface treatment of saw dust on the physico‐mechanical properties of saw dust‐filled polypropylene composites was studied. Whereas the elastomer‐pretreated saw dust decreases the strength of composites, in‐situ addition of interface modifiers, such as maleated polypropylene, m‐phenylene bismaleimideSystematic name: N‐(3‐maleimidophenyl)maleimide.‐modified polypropylene, during kneading of polypropylene with untreated or elastomer‐pretreated saw dust improved the mechanical properties with a marginal sacrifice of impact strength. The chemical nature of interphase modifiers played an important role on the mechanical properties of the composites, e.g., maleated polypropylene was most effective among the modifiers used in this study. Halogenated elastomers and phenolic modified polypropylene improved the flame resistant properties of the composites. More over, properties varied with the particle size of wood fiber. The morphological study of the fracture surfaces of composites revealed that interfacial adhesion is improved by adding malea

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100104

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractBlends of poly‐ε‐caprolactone (PCL) and poly(methylmethacrylate) (PMMA) were prepared by a reactive method and characterized by thermal, morphological, dynamic mechanical and mechanical analyses. For comparison, “mechanical” blends, obtained by melt‐mixing of preformed polymers, have been prepared and characterized. The two series of blends are different in phase structure and in mechanical tensile properties, probably due to the formation of grafted species during reactiv

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100105

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractNew oligomeric UV‐stabilizers of the type of 2‐hydroxy‐4‐alkoxy benzophenone‐formaldehyde prepared earlier were incorporated into poly(methyl methacrylate). Accelerated photooxidation as well as oven ageing tests were performed. The stabilizer effectiveness was estimated by IR and UV spectral study, mechanical testing, viscosity measurement, and weight loss measurement. Compared to monomeric stabilizers, the oligomeric compounds show better pe

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100106

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractDurch Photoreaktionen aromatischer Azide sollte die ternwirksame Oberfläche von Ultrafiltrationsmembranen aus Polyarcrylnitril chemisch modifiziert werden, um deren Ultrafiltrations‐Eigenschaften gezielt zu verändern. Neun mit unterschiedlich hydrophilen bzw. hydrophoben Gruppen substituierte Azide wurden eingesetzt. Durch Träanken mit 0,05 molaren Lösungen der Arylazide in Methanol naöhmen die Membranen insgesamt 1,25–1,95 · 10−4mol/g auf. Davon wurden ca. 1 ·10−4mol/g an der Oberfläche der Porenmembran (79 m2/g, mit Hilfe der p‐Nitrophenol‐Adsorptions‐isotherme ermittelt) adsorbiert. Die HPLC‐Analyse der Extrakte von Membranproben gestattete für 4‐Azidobenzoesäuremethylester als Modellverbindung die Ermittlung von Umsatz und Produktverteilung bei der UV‐Photolyse. Die Umsatzgeschwindigkeit nimmt mit der Belichtungsdauer ab, nach 32 min waren 59% Azid photolysiert. Als lösliche Photolyseprodukte wurden 4‐Nitroso‐, 4‐Nitro bzw. 4‐Aminodenzoesäuremethylester in 3%, 13% bzw. 5% Ausbeute gefunden, die Azo‐ bzw. Azoxy‐Verbindungen traten nur in Spuren auf. Mit Hilfe von UV‐Reflexions‐ und FT‐IR‐ATR‐Spektroskopie an PAN‐Membranen konnte eine Funktionalisierung der Membranoberfläche durch sekundäre Amin‐Strukturen als Ergebnis der Photomodifizierung nachgewiesen werden. Die entwickelte Photomodifizierungsvariante sollte durch Einsatz von Arylaziden mit Prinzipiell analoger Photogreaktivität, aber unterschiedlichen funktionellen Gruppen die Herstellung sp

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100107

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractNach einem neuartigen Verfahren mit Hilfe von neun, mit verschieden hydrophilen bzw. hydrophoben Substituenten synthetisierten aromatischen Aziden unterschiedlich photochemisch modifizierten Polyacrylnitril‐Ultrafiltrations‐Membranen wurden in UF‐Versuchen charakterisiert. Dabei sollte der Einfluß der so erzielten Oberflächenfunktionalisierungen (Hydrophilierung, Einführung von Ladungen oder Hydrophobierung) auf das Trennverhalten (Wasserdurchläassigkeit und Selektivitäat für Dextrane, Permeabilität während und nach der UF bzw. nach einfachem Kontakt mit Ovalbuminund mit Lysozym‐Lösungen) studiert werden. Die Modifizierung mit den Arylaziden, die hydrophile Gruppen enthalten (4‐Azidobenzoäure,Ib, (4‐Azidophenyl)‐tri‐methylammoniumiodid,If, Natrium‐4‐azidobenzolsuflfonat,Id), führt zu einer erhöhten Durchlässigkeit der Membranen für Wasser und Dextrane. Alle anderen Azide, darunter besonders stark die deutlich hydrophoben 2‐Naphthoylazid,Ih, und 2‐Naphthoylazid,IX, verringern die Wasserpermeabilität, erhöhen das Rückhaltevermögen für Dextrane und verstärken die Effekte der Wechselwirkungen mit Ovalbumin (pH = 5,0). Das wird in Flußreduzierungen verglichen mit der unmodifizierten PAN‐UF‐Membran sichtbar. Ein positiver Effekt der Photomodifizierung wird besonders deutlich bei der UF von Lyasozym (0,05%, pH = 10,5) mit der mitIdmodifizierten Membran (Jv= 48,1 l/m2h) im Vergleich zur Ausgangs‐Membran (Jv= 13,1 1/m2h). Die Perspektiven und die Grenzen des Modif

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100108

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractThe crosslinking of drawn tapes and fibers from ultra‐high molecular weight polyethylene (UHMW‐PE) initiated by UV‐irradiation has been investigated. Both xanthone and sulphuryl chloride (SO2Cl2) appeared to be rather effective photoinitiators and high gel content was obtained after UV‐exposition in air. The effect of crosslinking on the properties of UHMW‐PE tapes and fibers was examined by tensile tests, dynamic mechanical spectroscopy, and differential scanning calorimetry. High temperature resistance was shown to increase; photocrosslinked fibers retain the storage modulus being about 100 MPa at 200°C whereas uncrosslinked samples break at 135–137°C. No reducation of mechanical properties was found at ambient temperature and hydrophilization of the surface

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100109

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY

摘要:

AbstractBlends of poly‐ε‐caprolactone (PCL) and poly(β‐hydroxybutyrate‐co‐β‐hydroxy‐valerate) (PHBV) containing 4 mol‐% of hydroxyvalerate were prepared by mixing the two polymers in the presence of either dicumylperoxide (DCPO) at 160°C or dibenzoylperoxide (DBPO) at 100°C. Similarly, blends were obtained by mixing the two polymers without any peroxide added. The blends were prepared in to complementary compositions, namely 70 wt.‐% PCL/30 wt.‐% PH BV and 30 wt.‐% PCL/70 wt.‐% PHBV, respectively. Also pure polymers were reacted with DCPO at 160°C in the same way as the blends.Thermal (DSC), mechanical (tensile tests) and SEM analyses were performed on the blends and on the pure polymers.Significant differences were found in the chemical‐physical characteristics of blends with and with out peroxides as well as in blends prepar

ISSN:0003-3146    

DOI:10.1002/apmc.1993.052100110

出版商:Hüthig&Wepf Verlag    

年代:1993

数据来源: WILEY