bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐soluble polyamides as potential drug carriers. III. Relative main‐chain stabilities of side chain‐functionalized aspartamide polymers on aqueous‐phase dialysis
Authors: Neuse Eberhard W. , Perlwitz Axel G. , Schmitt Siegfried 
Published: April 2003

AbstractA total of 12 water‐soluble N‐substituted polyaspartamides, some of these previously reported, are synthesized from the polysuccinimide 1 by nucleophilic ring opening and are characterized microanalytically and spectroscopically. The relative hydrolytic mainchain stabilities of the product polymers are evaluated in dialysis tests (6000–8000 molecular‐mass cut‐off) performed over periods of 24–48 h in aqueous solution in an effort to assess their suitability as homo‐ or copolymeric carriers for aqueous‐phase coupling to biologically active agents. In agreement with previous work, resistance to main‐chain degradation is found to be very poor with the N‐(2‐aminoethyl)‐ and N‐(3‐aza‐6‐oxahexyl)‐substituted derivatives 2a and 2b (10–20% recovery after 48 h), and moderately poor with the 3,6‐diazahexyl‐substituted 2c (45% recovery). These three representatives, hence, cannot efficaciously be subjected to aqueous‐phase drugcoupling reactions save for short exposure times. Good to excellent stabilities, however, with product recoveries in the 70–95% range, are shown by the remainder of polymers, 2d–21, all of which are characterized by the absence of primary or secondary amino groups in the side chains separated from the amide nitrogen atom by less than three carbon atoms. Polyaspartamides selected from this group for their promising drug coupling potential include the N‐(3‐aminopropyl)‐, N‐(3‐aminohexyl)‐, and N‐(2‐ṕiperazinylethyl)‐substituted types 2e, 2f and 2h possessing primary or secondary amine functions as anchoring sites, and the N‐(2‐(dimethoxy)ethyl) derivative 21, of interest as the precursor to a formyl‐functionalized carrier polymer. Lastly, the units of 2i and 2j, featuring 3‐(dimethylamino)propyl and 3‐(morpholin‐4‐yl)propyl substituents, lend themselves as solubilizing segments in copolymers that comprise additional repeat units equipped with drug‐anchoring sites.
Tensile properties and morphology of injection‐molded poly(1‐butene)
Authors: Lee Mao‐Song , Chen Show‐An 
Published: April 2003

AbstractThe injection‐molded poly(1‐butene) (PB‐1) is found to be more brittle than the compression‐molded PB‐1. The morphologies of these specimens are examined by use of polarized optical microscopy and scanning electron microscopy (SEM). A skin layer and an oblate spherulitic structure extended to the core region are observed in the injection‐molded PB‐1, while typical spherulites exist in the compression‐molded PB‐1. Below the skin layer of the injection‐molded PB‐1, the fracture surface is found to consist of many aligned strip‐like voids with ribbon edges propagating to the center of the specimen and perpendicular to the flow direction of injection‐molding. Based on these observations, it can be inferred that shear stress induced by the melt flow during the injection‐molding does not only cause the formation of skin layer, but also penetrates deeply into the central region of the injection‐molded specimen causing the formation of oblate spherulites. The oblate spherulitic structure is responsible for the aligned voids during elongation of PB‐1, while the existence of the skin layer and the oblate spherulites in core region is responsible for the brittleness of the injection‐molded PB‐1. The elongation of the injection‐molded PB‐1 is found to be lower than that of the compression‐molded. This can be attributed not only to the presence of the skin layer but also to the oblate spherulites in the core region. The elongation can be improved by annealing at a temperature above the melting point of PB‐1.
Gas chromatographic studies on the compatibility of PVC with a migration resistant plasticizer
Authors: Demertzis P. G. , Riganakos K. A. , Akrida‐Demertzi K. , Kontominas M. G. 
Published: April 2003

AbstractThe technique of inverse gas chromatography (IGC) was used to investigate the thermodynamic miscibility (compatibility) of low molecular weight PVC‐poly(adipate ester) plasticizer mixtures. The polymer‐plasticizer thermodynamic interaction parameters were determined from chromatographic retention data for various low molecular weight volatile solutes (probes) on stationary phase mixtures which covered the entire composition range for each component. Experiments were carried out in the temperature range of 90 to 110°C. The Flory‐Huggins interaction parameter (χ+23) values were found to be dependent on the chemical nature of the probes, the temperature, and the composition of the mixed phase. The results predict a relatively high polymer‐plasticizer compatibility for a wide range of polymer‐plasticizer mixtures (up to approx. 70 wt.‐% of plasticizer). Results were also compared to our own previous data using high molecular weight PVC.
Synthesis and biological activity of chlorinated polyketone resins
Authors: Patel N. Z. , Patel J. N. , Ray R. M. , Patel R. M. 
Published: April 2003

AbstractSome polyketones were prepared from p‐xylene, chloroacetylchloride, 1,2‐dichloroethane and dichloromethane using anhydrous aluminiumtrichloride and carbon disulfide as solvent. The resins thus obtained have been characterized by IR spectra and number average molecular weight. The thermal properties have been studied by thermogravimetry and differential scanning calorimetry. All the resins were tested for their biological activity against Pseudomonas fluorescens, Bacillus subtilis and Aspergillus niger. The results show that the growth of the tested organisms can be controlled by the polyketone resins.
Preparation and properties of porous particles from trimethylolpropane trimethacrylate
Authors: Reinholdsson Per , Hargitai Tihamér , Isaksson Roland , Törnell Bertil 
Published: April 2003

AbstractSpherical macroporous particles, intended for use as carrier particles in various types of column operations, were prepared by suspension and microsuspension polymerization of trimethylolpropane trimethacrylate (TRIM), in the presence of various amounts of porogenic agents (toluene or mixtures of toluene and isooctane). The texture and properties of the particles varied markedly with the amount and composition of the porogenic agent, and were also affected by the choice of suspension stabilizer. Macroporous particles were prepared, ranging in total pore volume from 0.4 to 3.6 cm3/g, and in specific surface area from 7 to >450 m2/g. All of the particles contained macropores, and except for those with very low specific surface area, contained a certain fraction of micropores (diameter <60 Å). The presence of micropores could be eliminated completely by decreasing the monomer concentration and increasing the isooctane content of the porogenic agent to 50 wt.‐%. Increasing the isooctane content also resulted in an increase in the total pore volume and a decrease in the tendency of the polymer matrix to swell in toluene. The effect on properties of particles by heat treatment at 130°C and by grafting poly(methyl methacrylate) onto the particles was also studied.The amount of unreacted double bonds of the particles could be varied by varying the polymerization temperature. The presence of easily accessible double bonds is important as they can be utilized for functionalization of the rigid macroporous particles.
Miscibility of polyarylate/phenoxy/poly(butyleneterephthalate) ternary blends
Authors: Ahn Tae Oan , Lee Sukmin , Jeong Han Mo , Cho Kilwon 
Published: April 2003

AbstractThe phase and miscibility behavior of binary and ternary blends containing polyarylate (PAR), polyhydroxyether of bisphenol AIUPAC: poly[oxy(2‐hydroxytrimethylene)oxy‐1,4‐phenylene‐isopropylidene‐1,4‐phenylene].
(Phenoxy), and poly(butylene terephthalate) (PBT) were studied. The blends were prepared by solution‐precipitation method and miscibility was examined by DSC and melt transparency. In binary blends, PAR/PBT and Phenoxy/PBT blends show miscibility, while PAR/Phenoxy appeared to be immiscible. However, the miscibility of incompatible PAR/Phenoxy blend was enhanced by addition of PBT. The addition of sufficient amount of PBT caused the ternary blend to have a single glass transition temperature. The shape of miscibility boundary of ternary blend was skewed to the apex of Phenoxy, which was attributed to the better miscibility of PAR/PBT than that of Phenoxy/PBT.
The reaction of pyromellitic dianhydride with 4,4′‐diaminodiphenylmethane
Authors: Marek M. , Bednář B. , Králíček J. 
Published: April 2003

AbstractThe homogeneous polyaddition reaction of pyromellitic dianhydride with 4,4′‐diaminodiphenylmethane was investigated. The dependence of the number average molecular weights on time has a maximum; low equilibrium values of M̄n are caused by a disturbed equimolarity of functional groups due to the hydrolysis of dianhydride with water present in the solvent. In the course of establishment of the equilibrium M̄n value, the molecular weight distribution changes to the most probable value.
Zusammenhänge zwischen mechanischem Verhalten und Morphologie von eigenfaserverstärkten Poly(propylen)/Poly(1‐buten)‐Blends, kristallisiert aus der hochorientierten Schmelze
Authors: Wenig Werner , Schöller Thomas 
Published: April 2003

AbstractMechanische Parameter wie Elastizitätsmodul, Fliß‐ und Bruchspannung von aus der hochorientierten Schmelze hergestellten nadelkristallinen Mischungen aus Poly(propylen) und Poly(1‐bute) wurden mit morphologischen Parametern, die aus Röntgenmessungen abgeleitet wurden, korreliert. Es wird gezeigt, daß der Elastizitätsmodul des Verbundes aus den E‐Moduln der Fasern und der Matrix berechnet werden kann (Mischungsregel). Die an der Probe angreifenden Kräfte werden voll auf die Fasern übertragen; der Verbund kann daher als eigenfaserverstärktes System angesehen werden. Die Abschätzung der kritischen Faserlänge ergibt, daß die Festigkeit der FAsern voll ausgenutzt wird; der Bruch des Systems bei Belastung ist daher auf das Versagen der Fasern zurückzuführen. Das mechanische Verhalten des Verbundes wird stark beeinflußt durch die Komponentenzusammensetzung. Die longitudinale Struktur der Nadeln beider Komponenten bleibt unbeeinflußt von der jeweiligen Co‐Komponente.
Studies on rubber bound antioxidants
Authors: Avirah S. , Joseph R. 
Published: April 2003

AbstractAntioxidants were attached to hydroxy‐terminated liquid natural rubber by modified Friedel‐Crafts alkylation reaction using anhydrous zinc chloride as catalyst. The rubber bound antioxidants were found to be less volatile and less extractable compared to conventional antioxidants. The bound antioxidants were tried both in latex compounds and dry rubber compounds. The vulcanizates showed improved ageing resistance compared to vulcanizates based on conventional antioxidants.
Studies on PE‐HD/PE‐LLD blends
Authors: Kurian P. , George K. E. , Francis D. Joseph 
Published: April 2003

AbstractA high density polyethylene grade is blended with two selected grades of linear low density polyethylene and the mechanical and rheological properties of the blends are evaluated over the entire composition range. The blends show sufficient compatibility in the solid phase and in the melt and hence they can be advantageously used to capitalize on their useful properties.
Synthese und Modifizierung polymerer Kationenleiter auf der Basis von Poly(glycerinformal)
Authors: Fritz Heinz P. , Stein Klaus 
Published: April 2003

AbstractDurch ringöffnende Polymerisation von Glycerinformal (GF) mit Alkalimetallen (M) in flüssigem Ammoniak konnten kationisch leitende Polymere (MxPGF) synthetisiert werden. Die Leitfähigkeiten κ hängen vom Alkoholatanteil im Polymeren ab. Na0,1PGF zeigt ein κRT = 3,75 · 10−4 S/cm. Poly(glycerinformal)‐Alkoholate lassen sich mit CO2, CS2, oder SO2 zu entsprechenden Halbestersalzen umsetzen. Das PGF‐O‐Sulfonat (NaSO2)0,1PGF ist bis 100°C thermostabil und hat ein κRT = 6,5 · 10−4 S/cm.
Interpenetrating polymer networks of polyurethanes and epoxy resin, I. Mechanical behavior
Authors: Hsieh K. H. , Chiang Y. C. , Chern Y. C. , Chiu W. Y. , Ma C. C. M. 
Published: April 2003

AbstractThe interpenetrating polymer networks (IPNs) prepared from polyurethane (PU) and a glycidyl ether of phenol formaldehyde (GEPF) were synthesized by using a simultaneous polymerization method. The effects of PU molecular weight and amount on the mechanical property are discussed. For the PU/GEPF IPNs based on polyester‐type PU, as the PU content was increased, the tensile strength and fracture energy decreased, but the impact strength increased significantly. However, for the PU/GEPF IPNs based on polyether‐type PU, the extent of heterogeneity was decreased with decreasing molecular weight of polyether polyol in PU and the tensile strength and fracture energy were enhanced. The impact strength increased to a maximum value and then decreased when the PU content was further increased.
Effects of long‐chain alkyl peroxydicarbonates on the properties of PVC produced by suspension polymerization
Authors: Arslanalp Caner , Erbay Erol , Bilgiç Tülin , Savaşçi Ö. Tunç 
Published: April 2003

AbstractCommercially available diethyl, dicetyl, and dimyristyl peroxydicarbonate initiators are investigated in a commercial PVC suspension polymerization receipe. Diethyl peroxydicarbonate, which is formed in situ by the reaction of hydrogen peroxide, lime, and ethylchloroformate, produced PVC with less “fish‐eyes”, whereas it has the disadvantage of being toxic and gives inconsistent polymerization times, therefore the reactor efficiency decreases. Dicetyl and dimyristyl peroxydicarbonates are solid, less toxic materials easy to handle, therefore, when these initiators are used, consistency between batches is obtained. However, PVC with coarse particle sizes containing considerable amounts of “fish‐eyes” is obtained, which eventually causes processing problems. It is found that particle coarsening occurs as a result of water soluble impurities of initiators, and “fish‐eyes” occur as a result of morphological changes. When dicetyl and dimyristyl type initiators are used, the number of non‐porous PVC particles increases. This structure heterogeneity causes formation of ungellified spots, so‐called “fish‐eyes”, during processing. It is found that the non‐porous particles are formed due to accumulation of an excessive amount of initiator in a single vinyl chloride monomer droplet.When the distribution of these solid initiators is homogenized by adding them in solution, the formation of non‐porous particles is inhibited. However, the coarsening effect still remains, which could be eliminated by extraction of initiator solutions with water just before they are fed to the reactor. Extraction also decreases the amount of crust formation.
Die Vernetzung von Perfluoralkenen aus dem strahlenchemischen Abbau von Polytetrafluorethylen zu höhermolekularen Carbonylverbindungen
Authors: Bürger Wolfgang , Lunkwitz Klaus , Platonov Viatscheslav E. 
Published: April 2003

AbstractGrundlage der Untersuchungen waren mittels Elektronenstrahlung aus PTFE‐Abfällen gewinnbare Gemische von Perfluoralkenen. Untersuchungen am Perfluorhept‐1‐en zeigten, daß terminale Perfluoralkene bei der Reaktion mit difunktionellen Partnern bevorzugt ungesättigte Ether‐ bzw. Amidstrukturen ausbilden. Die Reaktion des Perfluoralkengemisches mit Nucleophilen führt zur Vernetzung, wobei primär Additionsprodukte der terminalen Perfluoralkene mit Aminen oder Phenolen/Alkoholän zu Carbonylverbindungen hydrolysieren und Allylstrukturen ausbilden. Innenständige Perfluoralkene des Gemisches bzw. Allylprodukte addieren das Nucleophil and lagern sich teilweise zu stabilen Vinylprodukten um. Es entstehen gemischte Ether‐Esterstrukturen bzw. ungesättigte Polyamide, wobei das Dinucleophil wesentliche Eigenschaften der Fluorverbindung bestimmt. Thermisch und auf chemischem Wege entstehen durch Mehrfachsubstitution hochvernetzte Strukturen, die neue Wege für Fluorcarbonausru‐stüngen eröffnen.
Synthesis and characterization of polymers containing naphthyl‐2H‐benzotriazoles, 2. Polymer synthesis and characterization
Authors: Rasoul F. A. , Shuhaibar K. F. , Attari A. , Pasch H. 
Published: April 2003

Abstract2‐(2‐Hydroxy‐7‐(meth)acryloyloxynaphthyl)‐2H‐benzotriazoles were polymerized and copolymerized with styrene and methyl methacrylate in dichloromethane using azoisobutyronitrile as the initiator. The polymer composition was determined by UV spectroscopy and compared with elemental analytical data; the molecular weights were determined by GPC. In homopolymerization, low molecular weight products were obtained due to the bulky naphthyl‐2H‐benzotriazole units. In the case of copolymerization with methyl methacrylate it was found, that the composition of the polymers was very close to the initial ratio of the monomers, whereas in copolymers with styrene the amount of incorporated benzotriazole was higher.
Poly[1‐(2‐hydroxyethyl) aziridine] as polychelatogen for liquid‐phase polymer‐based retention (LPR)
Authors: Geckeler Kurt E. , Rivas Bernabé L. , Zhou Rongnong 
Published: April 2003

AbstractThe metal complexing properties of poly[1‐(2‐hydroxyethyl) aziridine] for the metals Co(II), Zn(II), Ni(II), Cu(II), Cr(III), Fe(III), Cd(II), Pb(II), and Sr(II) in aqueous phase were investigated. The LPR method is based on the retention of inorganic ions by soluble polymers in a membrane filtration cell and subsequent separation of low‐molecular species from the polymer complex formed. The metal interaction with the hydrophilic polymer was determined as a function of pH and filtration factor. According to the interaction pattern obtained, Cu(II) forms the most stable complexes with the polyaziridine within the pH range 3 to 7. At pH 3, it is possible to separate Cu(II) from all other metal ions. Sr(II) is only slightly retained at the pH range investigated. At pH 7, all elements, except Sr(II), did interact with the polymer and were almost quantitatively retained.
Interpenetrating polymer networks of polyurethanes and epoxy resin, II. Compatibility and morphology
Authors: Hsieh K. H. , Chiang Y. C. , Chern Y. C. , Chiu W. Y. , Ma C. C. M. 
Published: April 2003

AbstractThe interpenetrating polymer networks (IPN) of polyurethanes (PU) and a glycidyl ether of phenol formaldehyde (GEPF) were prepared by a simultaneous polymerization method. The dynamic mechanical properties and morphologies of the IPNs were investigated. It was found that multiphased morphology was formed in the PU/GEPF IPNs. With the PU based on polyester‐ or polyether‐type polyols, the dynamic mechanical analysis (DMA) of these IPNs exhibited various shifts in the loss moduli (E″) of the high and low temperature transition domains depending upon the types and molecular weights of the polyols employed in the PU. Three distinct transition domains were observed as the PU content increased up to a certain level.
Extrusion behavior of starch graft copolymers: Starch‐g‐polystyrene and starch‐g‐poly(methyl acrylate)
Authors: Henderson Alex M. , Rudin Alfred 
Published: April 2003

AbstractStarch‐g‐polystyrene and starch‐g‐poly(methyl acrylate) copolymers were synthesized and extruded without separating homopolymer PS or PMA. The extrusion behavior resembled that of thermoplastic melts in that these products were shear thinning and exhibited significant extrudate swelling and entrance pressure losses in capillary flow. These and other observations indicate that the materials comprise deformable polymer‐grafted starch particles suspended in the corresponding homopolymer melt. Flow is apparently by superparticle, rather than continuum melt mechanisms.
Das spezifische volumen geschmolzener polymerer in abhäungigkeit von druck und temperatur
Authors: Busch Bernhard , Lechner Manfred D. , Kleintjens Ludovicus A. 
Published: April 2003

AbstractBei der industriellen Herstellung von polymeren Werkstoffen ist eine möglichst genaue Kenntnis des spezifischen Volumens v in Abhängigkeit vom Druck p und von der Temperatur T erforderlich. Dafür ist ein sogenannter „Biegeschwinger”︁ entwickelt worden, mit dem man v im Bereich von 1 bis 800 bar und von 20 bis 200°C ermitteln kann. Dieses wird an Testmessungen mit destilliertem Wasser bewiesen. Am Beispiel von fünf flüssigen Polymeren und Copolymeren wird die Brauchbarkeit sowohl empirischer als auch theoretisch fundierter Zustandsgleichungen überprüft. Dabei zeigt sich, daß die rein empirische Tait‐Gleichung und die zum Teil theoretisch fundierte Simha‐Somcynsky‐Gleichung mit sechs bzw. fünf anpasbaren Parametern die Meßwerte am besten beschreiben.
Optimal monomer addition policies for composition control of emulsion terpolymers
Authors: Arzamendi Gurutze , De la Cal José C. , Asua José M. 
Published: April 2003

AbstractAn approach for the calculation of the optimal monomer addition policies for polymer composition control in emulsion terpolymerization is presented. The model allows the calculation of the composition of the initial charge of the reactor and the time dependent monomer addition rates. Monomer addition strategies for reactors with limited capacity for heat removal were obtained. A heat removal rate dependent on the latex solids content was considered. Simulation showed that the present approach leads to the production of homogeneous terpolymers in process times which are significantly shorter than that required by the classical starved process to produce a terpolymer of similar homogeneity.
Synthesis and characterization of polymers containing naphthyl‐2H‐benzotriazoles, 3. Hydrogen bonding in monomers and polymers containing naphthyl‐2H‐benzotriazole
Authors: Pasch H. , Shuhaibar K. F. , Rasoul F. A. 
Published: April 2003

AbstractThe UV absorption characteristics of a number of dihydroxynaphthyl‐2H‐benzotriazoles, their (meth)acryloyloxy derivatives and the corresponding polymers have been studied in a range of solvents of different polarity. It was shown that the formation of hydrogen bonds in these compounds strongly depends on the polarity of the solvent and an equilibrium exists between intramolecular and intermolecular hydrogenbonded states. The stability of the intramolecular hydrogen bond was determined quantitatively. The equilibrium between the intramolecular and the intermolecular hydrogen‐bonded state of the molecule was strongly affected by the chemical structure of the naphthyl‐2H‐benzotriazole. The stability of the intramolecular hydrogen bond increased when electron‐donating substituents were introduced into the benzotriazole or when the naphthyl‐2‐benzotriazole was fixed to a polymer backbone.
Characterization of ultra low density polyethylenes (PE‐ULD)
Authors: Kim Byung Kyu , Kim Myun Soo , Jeong Han Mo , Kim Kook Joong , Jang Jae Kwon 
Published: April 2003

AbstractUltra low density polyethylene (PE‐ULD), the newest and most recently commercialized member of polyethylene family, has been characterized in terms of structure, thermal and rheological properties, and molecular parameters. Since the prime use of PE‐ULD is polyolefin modifier, emphasis is put on the melt rheology of the samples to provide data base for blending with other resins.
Studies on new non‐shrinking, thermally stable, araldite‐type photopolymers with pendent arylacryloyl groups III. Photopolymers with pendent cinnamic acid ester and furan acrylic ester groups and their reactions with low molar mass modifiers
Authors: Budde Klaus , Quella Ferdinand , Mathes Alfred , Melchior Walter , Müller Harald , Nuyken Oskar , Spiegel Sabine 
Published: April 2003

AbstractCommercially available Araldite™‐type polymers have been modified with cinnamic and furan acrylic acid chlorides. The polymers were photochemically crosslinked via a [2 + 2] cycloaddition. The resulting polymers show glass transition temperatures up to 130°C and dielectrical constants of ϵr = 3.0. Therefore, these polymers can be applied as permanent resists in multi‐layered wiring structures. Numerous well‐defined multifunctional modifiers have been synthesized. The effect of those modifiers on the polymerization and properties of the araldite‐type polymers has been studied in some detail.