摘要:

AbstractThe synthesis of low‐molecular‐weight poly(acrylamide)s (M̄n= 500 – 1 000) is described. Metal‐activated and non‐activated polymerization in aqueous solution was investigated employing hydrogen peroxide as initiator. Among four transition metal salts considered, Cu2+cations proved to be the most efficient in decomposing H2O2molecules and were used as activator. The experiments were run at three reaction temperatures (60, 80 and 95°C), at three H2O2levels (4, 5 and 6 wt.‐% on monomer), and at four Cu2+levels (900, 600, 300 and 0 ppm by weight of metal on monomer). Thus, ist was possible to prepare acrylamide oligomers with monomer conversions exceeding 95%, and with Mnvalues covering the narrow range indicated above. Within these low limits a molecular weight control is impossible, even with inclusion of the differentiated levels of Cu2+cations. Intrinsic viscosities are very low, too ([η]) = 20 – 50 cm3/g, without any relations of the individual values to variations of the given process parameters. The work provides an industrial route to very‐low‐molecular‐weigh

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140111

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractA study has been carried out on the preparation of some modified imide‐siloxane copolymers. This has been accomplished by means of addition of α,ω‐dihydropoly(di‐methylsiloxane)s to N,N'‐diallyldiimides by hydrosilylation reaction. The copolymers were characterized by IR and NMR spectroscopy methods. Molar mass, molar mass distribution, thermal and mechanical properties of copolymers were determined. These copolymers are used as additives, mixing them in different ratios with a silicone polymer and filler to obtain imide‐silicone rubbers of high temperature vulcanizing (HTV) type. Mechanical properties of the vulcanized rubbers wer

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140112

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractAliphatic polyamides comprising poly(ethylene oxide) chain segments of various lengths, designed for use as drug carriers, are synthesized by interfacial polymerization of succinyl chloride with the two Jeffamine types ED‐900 and ED‐2001, formally described by the supplier as O,O'‐bis(2‐aminopropyl)poly(ethylene glycol) 800 and O,O'‐bis(2‐aminopropyl)poly(ethylene glycol) 1900. Copolyamides comprising both short‐chain diamine and Jeffamine segments are similarly prepared, as are polyamides made up of cystine and diamine segments. The polymerizations are performed in a two‐phase methylene chloride‐water system at temperatures near or below 0°C. The product polymers, crudely fractionated by staged aqueous‐phase dialysis at an ultimate molecular‐mass cut‐off of 25000, are collected after freeze‐drying as water‐soluble resins or solids and are characterized microanalytically and by1H NMR spectroscopy. Inherent viscosities are in the range of 10–20 ml g−1. The drug‐binding potential of a representative target polymer is probed by the covalent anchoring of a ferrocene compound used as a drug model, giving a water

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140113

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe relationship between the miscibility and the physical properties of polymer blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide) and polystyrene (PS), high‐impact polystyrene (IPS) and poly(styrene‐block‐butadiene‐block‐styrene) (SBS), which are blended in different compositions by a twin‐screw extruder is discussed. The three types of SBS that were used are SBS1, SBS2 and SBS3 having different styrene/butadiene ratios. Dynamic mechanical analysis and differential scanning calorimetry were used to study the miscibility. The morphology was examined by SEM. The miscibility of the blends decreases with decreasing PS content. The notch sensitivity is improved by blending. Finally, the micelle model was used to explain the

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140114

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

Abstract2‐Methacryloyloxyethyl phenyl phosphate (MEPP) was synthesized by reacting 2‐hydroxyethyl methacrylate (2‐HEMA) with phenyl dichlorophosphate (PDCP) followed by hydrolysis. This acrylic monomer containing the phosphate group was introduced into a typical UV‐curable acrylated epoxy system as an adhesion promoter. Good adhesion properties and solvent resistance of the films after UV curing were obtained in the presence of MEPP, although there was a decrease in the curing rate. When MEPP was introduced into acrylated epoxy resin, the contact angle remarkably decreased indicating that the wetting ability was improved. When MEPP was applied to the synthesis of the water‐soluble acrylic resins cured with various water‐soluble epoxy resins at 25°C, the adhesion and corrosion resistance of coating films

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140115

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractDas Kristallisationsverhalten sowohl von PBT als auch von PC ist im definiert verarbeiteten Blend infolge intermolekularer Wechselwirkungen zwischen den unterschiedlichen Molekülen in der Schmelze verändert.Die über die Glasübergangstemperaturen gemessene teilweise Mischbarkeit der amorphen Phasen führt bei PBT zu einer Erniedrigung des Kristallinitätsgrades, wenn die kinetischen Bedingungen des Kristallisationsprozesses keine kristallisationsbedingte Entmischung zulassen. Der auf den PBT‐Anteil normierte Kristallinitätsgrad ist bei kleinen Abkühlgeschwindigkeiten vom PC‐Anteil unabhängüg.In der Mischung PBT/PC 40/60 Gew.‐% kommt es bei hohen Kühlraten zu einer fraktionierten Kristallisation. Die Kristallisationstemperatur bei anisothermer Kristallisation ist bei geringen PC‐Gehalten durch Änderung des Keimbildungsmechanismus erhöht. Bei isothermer Kristallisation steigt mit zunehmendem PC‐Anteil die Kristallisationshalbwertszeit des PBT an.Das normalerweise amorphe PC kann in Gegenwart von PBT in den PC‐reichen Mischungen besonders schnell kristallisieren, wobei der Kristallisations‐ bzw. Ordnungsprozeß des PC in situ mittels der Röntgenbeugung gemessen wurde. Kalorimetrische Untersuchungen bestätigen dieses Ergebnis und erlauben eine quantitative Abschätzung des PC‐Kristallinitätsgrades zu ca

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140116

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe photolysis of halogenophenol novolacs is determined by the substitution of halogens by hydrogen and the formation of quinoid groups and intermolecular crosslinks. This is concluded from elemental analysis, NMR, IR and optical absorption measurements. The rate of halogen release depends on the chemical nature of the halogen. It increases in the order F

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140117

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe present paper is concerned with the coating applications of a vinyl ester resin derived from diglycidyl ether of bisphenol‐A and its urethane derivative. The mild steel panels coated with the synthesized resins were evaluated for their gloss on the surface, scratch hardness and chemical resistance. The incorporation of styrene in the resin systems improves the properties of coatings remarkabl

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140118

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0003-3146    

DOI:10.1002/apmc.1994.052140119

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY