bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly(butyleneterephtalate) photolysis and photooxidation : Identification of the ir‐absorbing products
Authors: Rivaton Agnès
Published: April 2003

Irradiations (λ≥300 nm) of poly(butyleneterphtalate) films were carried out in both vacum and air. Photoproducts were investigated by FTIR spectroscopy, chemical derivatization reactions and physical treatments. The repartition of photoproducts in the polymer was shown to be heterogeneous. A scheme accounting for the main routes of PBT photolysis was found on the basis of photoproducts identification. Most of oxidation products were analogous to vacum photolysis species; the mechanism of photooxidation proposed implied both pure photolytical processes and a photo‐induced oxidation route.
Polymer degradation by elimination of small molecules
Authors: Šimon Peter
Published: April 2003

An outline of a method of deriving the kinetic equations for polymer degradation by the elimination of low molecular weight compounds is presented. The method is based on the stochastic approach. The main ideas are that the degradation occurs via the zip mechanism and that the initiating step, i.e. the formation of an olefinic site in the polymer chain, takes place at random. Three mechanisms have been investigated in this study: (i) ordinary zip mechanism; (ii) autocatalytic mechanism with immediate zip growth and catalyzed initiation; (iii) autocatalytic mechanism with gradual zip growth. The kinetic equations derived have been used in kinetic studies of the dehydrochlorination of PVC in inert, HCl, and oxidative atmospheres, and of the degradation of polyvinyl esters, polyvinyl bromide and polyvinylidene chloride. Kinetic parameters for the degradation of individual polymers have been obtained.
The transformations of organic polymers during the illumination by 147.0 and 123.6 nm light
Authors: Skurat Vladimir E. , Dorofeev Yurij I.
Published: April 2003

The main features of photolysis of organic polymers by the light 147.0 and 123.6 nm (resonance xenon and krypton lamps respectively) were investigated by methods of anaylsis of gaseous products by mass spectrometry, of analysis of polymer transformation by UV and VUV absorption spectroscopy and of measurement of gel does. The quantum yields of main products were measured for photolysis of polyerthylene, polypropylene, polyisobutylene, polyisoprene, polybutadiene, silicone rubbers, polymethylmetacrylate and some other polymers. The quantum yields of products in the VUV photolysis are compared with radiation yields of these products in the radiolysis by gamma‐rays. The main difference between mechanisms of VUV photolysis and radiolysis consists in strong predominance of processes of molecular elimination in VUV photolysis in comparison with free radical processes. In contrast during the radiolysis these processes give approximately equal contributions. This difference is explained by reactions of photo excited singlet states of polymer molecules during photolysis while in the radiolysis the great contribution is given also by excited triplet and ionized states. In experiments with partially deuterated derivatives of polymethylmetacrylate the main channels of formation of formaldehyde, methylformate, methanol and methane were determined.
Photo‐ and radiation‐induced degradation of synthetic polymers: Polymer structure and stability
Authors: Torikai Ayako
Published: April 2003

The effect of polymer density, processing conditions (quenching of annealing), degree of crystallinity, size of crystallite and mobility of polymer chains on the photo‐and radiation‐induced degradation and the polymer stability have been studied by UV, FTIR spectroscopic, viscosity and mechanical property measurements. Four kinds of annealed or quenched polyethylene (PE) films varying densities were used to the studies. Polystyrene (PSt) films were used to investigate the effect of chain mobility on polymer degradation. The following results were obtained.

In linear low density (LLD) PE, greater amounts of crosslinking (irradiated in vacuum) and chain scission (irradiated in air) were noticed than in mediun density (MD) PE and high density (HD) PE samples.

Polyene formation is favored in the case of the irradiation in vacuum for LLDPE.

Polymer stability evaluated by mechanical property such as elongation at break (%) is superior in LLDPE to MDPE and HDPE for annealed and quenched samples.

Segmental motion of polymer chain also affects the polymer stability
Structure and some properties of methacrylonitrile/divinylbenzene macroporous copolymers
Authors: Kolarz Bożena N. , Trochimczuk Andrzej W. , Wojaczyńska Maria , Drewniak Marta
Published: April 2003

Copolymers of methacrylonitrile (MAN) and divinylbenzene (DVB) of different crosslinking degree between 6–50 wt.‐% DVB were obtained by suspension polymerization of monomers in the presence of a diluent (1 : 1, v/v), i.e. a mixture of toluene with tetradecane (9 : 1, v/v). Porosity of the copolymers (MAN/DVB) has been found to fall in the range 48–57.3%. Specific surface area of the copolymers increased in the range of mesopores with the increasing crosslinking degree. Sorption properties of the copolymers towards aqueous phenol solution are similar to those of acrylonitrile‐DVB copolymers. MAN/DVB copolymers display rather poor thermal stability (low residue) what indicates that thermally initiated cyclization of nitrile groups can not take place and the influence of depolymerization may be significant.
Aryl ether‐ketone segmented polypyromellitimides
Authors: Biçak Niyazi , Koza Güneş
Published: April 2003

Aromatic ether‐ketone segments have been incorporated into polyimide backbone to impart the well‐known thermoplastic properties of polyether ketones. For this purpose three aromatic diamines containing ether and ketone connecting groups between aromatic rings have been prepared and polymerized with pyromellitic dianhydride to yield polyimides. The thermal behavior of the polyimide cast films has been investigated.
Polymers with acyloxime ester in the main chain: Synthesis, characterization and initiator properties of an azo‐containing ester initiator
Authors: Onen Aysen , Denizligil Selcuk , Yagci Yusuf
Published: April 2003

For application as initiator, a new polymeric azo‐acyloxime ester (AOE) was synthesized by condensation of 4,4′‐azobis(4‐cyanopentanoic acid chloride) (ACPC) with 1‐(4‐hydroxyphenyl)‐1,2‐propanedione‐2‐oxime (HPO). The initiator structure was confirmed by IR and NMR spectroscopy. The kinetics of the free‐radical polymerization of styrene initiated by AOE was investigated and the kinetic parameters evaluated. The initiation of polymerization of styrene by means of AOE yields polymers with photoactive acyloxime groups in the main chain.
Behaviour of a silica filler surface‐modified with boron‐amine groups
Authors: Elvira M. Rosario , Macias Antonio , Oteo Jose Luis , Royo Joaquin , Rubio Juan
Published: April 2003

The behaviour of silica fillers modified with primary boron‐amine groups has been studied under different reaction conditions. The filler with the best reinforcing properties was used to compare two different vulcanization systems: an efficient vulcanization system, EV, which is the recommended ISO Standards method to study the reinforcing behaviour of new silicas, and a conventional vulcanization system.

The results indicate that the best properties are obtained with silica treated for 3 h at 500°C, reaction conditions which fix most of the primary boron‐amine groups. Using the EV system, the properties of this modified silica are similar to those of silane‐modified silica, and in some cases better than those obtained with a conventional vulcanization system. In all cases, the boron‐amination treatment significantly improves the behaviour of precipitated silica as a reinforcing filler.
Study of the mechanism of the antioxidant action of ethoxyquin
Authors: Taimr Luděk
Published: April 2003

A study has been carried out of the reaction of 6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (ethoxyquin, I) with alkylperoxyls. In the presence of a relatively low concentration of 1‐cyano‐1‐methylethylperoxyl, I reacts to form dimer IV (8‐(6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinolin‐1‐yl)‐6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinoline) as the main product and quinoline derivative III (2,4‐dimethyl‐6‐ethoxyquinoline), as a side product, i.e., substances formed by the conversion of the aminyl II (6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinolin‐1‐yl) alone. Smaller amounts of p‐quinoneimine VI and o‐quinoneimine VIII (2,2,4‐trimethyl‐2,6‐dihydro‐6‐quinolone and 6‐ethoxy‐2,2,4‐trimethyl‐2,8‐dihydro‐8‐quinolone) have been found; these substances are formed by further oxidation of II. In the presence of relatively high concentrations of tert‐butylperoxyls, peroxide IX (6‐tert‐butylperoxy‐6‐ethoxy‐2,2,4‐trimethyl‐2,6‐dihydroquinoline) is formed as the main product. Substance IX thermally decomposes to form VIII, while in the presence of weak acids IX is converted into VI as the main product.

Dimer IV is a medium‐strength antioxidant which is gradually converted into 8‐(6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinolin‐1‐yl)‐2,2,4‐trimethyl‐6‐quinolone (XI) and 8‐(6‐ethoxy‐3‐hydroxy‐2,2‐dimethyl‐4‐methylene‐1,2,3,4‐tetrahydroquinolin‐1‐yl‐)‐2,2,4‐trimethyl‐2,6‐dihydro‐6‐quinolone) (XII). The methyl group in XI actively participates in the antioxidation process.

When formed, nitroxide V (6‐ethoxy‐2,2,4‐trimethyl‐1,2‐dihydroquinolin‐N‐oxyl) acts as an efficient antioxidant which, however, does not participate in the cyclic mechanism that is employed to explain the action of antioxidants of the HALS type.

The antioxidant properties were evaluated on the basis of their effect on the course of the autoxidation of squalene.
Antistatic modification of polyester with carboxyterminated poly(oxyethylene)
Authors: Zhao Yao‐Ming , Chen Junwu , Sano Yoshiyuki , Kimura Yoshiharu
Published: April 2003

Carboxy‐terminated poly(oxyethylenes) (PEO‐acid) with number‐average molecular weights Mn = 8400, 3300, and 1000 were used for antielectrostatic modification of poly(ethylene terephthalate) (PET). The blend PET fibers containing 2.0 and 5.0 wt.‐% of PEO‐acids were melt‐spun at 285°C with an ordinary extruder and then drawn about 4.5‐fold at 80°C. The processabilities of spinning and drawing were excellent at higher molecular weights of PEO‐acid. The anti‐electrostatic properties of the blend fibers became also improved with increasing molecular weight of PEO‐acid. Since little ester interchange reaction took place between PET and PEO‐acid during meltspinning, the blend fibers could retain almost the same mechanical properties as the original PET fiber.
Preparation and characterization of spinning dopes for dry spinning of continuous alumina green fibers
Authors: Clauss Bernd
Published: April 2003

Aqueous spinning dopes for dry spinning of alumina green fibers were prepared by using basic aluminium chloride Al2(OH)5Cl · 2.5 H2O and SiO2 sol as inorganic components and poly(vinyl alcohol) (PVA) as polymeric organic component.

Certain rheological properties of the mixtures are essential to achieve good spinnability at high spinning speeds. The rheology of the dope is influenced by the molecular weight and the degree of hydrolysis of the PVA, as well as by the composition and the concentration of the mixture. For mixtures without SiO2 best results were obtained at a PVA: Al2O3 mass ratio of 18:82 and an Oxide content of about 27 wt.‐%. The PVA used has an average molecular weight of 70000 and a degree of hydrolysis of 89%.

The dopes were spun to continuous green fibers at speeds up to 500 m/min. The structure and the ageing behaviour of concentrated solutions of basic aluminium chloride has been intensively studied.
Thermal dissociation of urethanes studied by FTIR spectroscopy
Authors: Joel Detlef , Hauser Andre
Published: April 2003

The thermal dissociation of urethane groups has been studied by FTIR spectroscopy depending on the type of diisocyanate, the structure of the hard segment and the composition of polyurethane. Independent of the composition and the structure, the dissociation started between 150 and 160°C. Consequently, the dissociation sets in at temperatures below the melting temperature of the model hard segments, i.e. already in the solid state. The NCO absorption band reaches its maximum intensity between 180 and 190°C. This result opposes the references in literature suggesting a four‐centre reaction for transurethanization.
Effect of styrene content and ZnO‐stearic acid on the mechanical properties of radiation‐vulcanized styrene‐butadiene rubber (SBR)
Authors: Youssef H. A. , Aziz M. M. Abdel , Yoshii F. , Makuuchi K. , El Miligy A. A.
Published: April 2003

The effect of styrene content on the properties of electron irradiation‐vulcanized SBR loaded with carbon black was pronounced only at low irradiation doses where the crosslinking densities were not so high. At high doses, no effect was observed especially for SBR containing ZnO. It was also observed that ZnO (3 phr) increased the tensile strength of SBR containing 23.5 wt.‐% styrene by 20% at 20 kGy irradiation dose, compared to 5% at higher doses for SBR containing 46 wt.‐% styrene. However, the increase in tensile strength by ZnO for loaded SBR (23.5%) was almost 17% at all irradiation doses. Besides, tear strength, abrasion resistance and elongation at break were remarkably improved. The high efficiency of ZnO toward SBR (23.5%) may be attributed to the higher butadiene content. The behavior of SBR (46%) at 20 kGy was surprising, since both tensile strength and elongation at break were almost maximum.
Interpenetrating polymer networks of polyurethane and furfuryl alcohol, IIa. Processability and properties of pultruded fiber‐reinforced composites
Authors: Ma C.‐C. M. , Goang D. Y. , Han J. L. , Hsieh K. H.
Published: April 2003

A feasibility study of pultrusion of fiber‐reinforced polyurethane/furfuryl alcohol (PU/FA) interpenetrating polymer/network IPN composites has been made. From the viscosity study, it was found that the pot life of the PU/FA IPN prepolymers increased with PU content and showed high reactivity at elevated temperature. It was confirmed from the morphological study that the wetting of fibers by the PU/FA IPN resins was improved with PU content. The appearance of the tensile failure surfaces of the pultruded glass fiber‐reinforced PU/FA IPN composites showed “hackle patterns” for PU contents below 15 phr. The mechanical property study shows that the tensile strength of pultruded PU/FA IPN composites is the highest when the PU content is 5 phr. However, the flexural strength, flexural modulus and HDT decreased with PU content. The mechanical properties of various fiber‐reinforced (glass, carbon, and Kevlar 49 aramid fiber) pultruded PU/FA IPN composites increased with fiber volume content.
Rôle des pigments dans une réaction de polymérisation sous lumière UV‐visible
Authors: Catilaz L. , Fouassier J. P.
Published: April 2003

Ce travail sur le rôe des pigments définit le comportement d'un nouveau systeme photosensible qui permet de polymériser des milieux épais et pigmentés selon un procédé en une seule étape. Les différentes interactions présentes en milieu pigmenté sont décrites de façon qualitative, et la part de l'intensité lumineuse absorbée par un photo‐amorceur dans un systéme pigmenté est evaluée. Les propriétés optiques telles que l'absorption et la réflectance des différentes familles chimiques de pigments sont déterminées, et, en paralléle, les propriétés optiques des différentes sources d'irradiation sont étudiées de manière à répondre au mieux aux fenêtres de transmission des pigments. L'effet photocatalytique de certains pigments est mentionné, ceci afin d'amkliorer la réaction de polymérisation.
Synthesis and curing of millable polyurethanes based on castor oil
Authors: Suresh K. I. , Thachil E. T.
Published: April 2003

This paper presents the results of studies on the synthesis and curing of millable polyurethanes based on castor oil. To facilitate the preparation of millable urethanes, the hydroxy number of castor oil was modified to about two by acetylation. It was then used with tolylene diisocyanate (NCO/OH‐ratios 1:0.9, 1:1 and 1:1.1, resp.) for polyurethane preparation. The dynamic curing of the synthesized polyurethanes was studied in a Brabender Plasticorder using various sulfur vulcanizing systems. The effect of stoichiometric ratio and choice of chain extenders on the dynamic curing behaviour was also studied. An NCO/OH ratio of 0.9 and 1,4‐butanediol (30 wt.‐%) as chain extender were found to favour the formation of a crosslinkable polyurethane. It was observed that a cure system containing sulfur, N‐cyclohexyl‐2‐benzothiazole sulfenamide and mecraptobenzothiazole was a possible choice for the preparation of a sulfur‐crosslinked polyurethane.
Molar mass distribution of polybutadiene synthesized with nickel‐based Ziegler‐Natta catalysts, I
Authors: Schröder K. , Schmitz G. , Lechner M. D. , Gehrke K.
Published: April 2003

Cis‐1,4‐polybutadiene was produced by polymerization of 1,3‐butadiene using a catalyst system formed by a two‐step formation, Namely (1) BF3 . O(C2H5)2 and Al(C2H5)3, (2) Ni(OOC8H15)2 and Al(C2H5)3 named in‐situ‐catalyst.

The molar mass distributions (MMD) of the polybutadienes are investigated by means of size exclusion chromatography (SEC). The MMD's were fitted by a sum of Schulz‐Flory‐Functions (SFF). Changed catalyst formation and polymerization conditions influenced the parameters of the SFF. Changed areas and changed molar mass averages indicate a polymerization with more than one peak maximum and kind of active species and lead to a better understanding of the polymerization.
Molar mass distribution of polybutadiene synthesized with nickel‐based Ziegler‐Natta catalysts, II
Authors: Schröder K. , Schmitz G. , Lechner M. D. , Gehrke K.
Published: April 2003

Cis‐1,4‐polybutadiene was produced by polymerization of 1,3‐butadiene using a catalyst system containing Ni(OOC8H15)2 and Al(C2H5)3 and the Lewis acids BF3 · O(C2H5)2 or TiCl4. The molar mass distributions (MMD) of the polybutadienes are investigated by means of size exclusion chromatography (SEC). The MMD's were fitted by a sum of Schulz‐Flory‐Functions (SFF). Taking into account that one kind of active species gives one SFF defined by molar mass averages, one comparable active species in both systems and one different were found. This way it was tried to find a relationship between the grown up of the active species depending on components and reactions conditions.
Synthesis of poly(vinyl alcohol) derivatives containing amidoxime groups
Authors: Arranz F. , Sanchez‐Chaves M. , Gallego M. M.
Published: April 2003

The modification reaction of poly(vinyl alcohol) (PVAL) with acrylonitrile in alkaline medium was studied. The structure of the resulting polymers was determined by means of IR, 1H and 13C NMR spectroscopy. The influence of solvent composition, catalyst and temperature was evaluated. 13C NMR spectroscopy was used for the determination of the sequence distribution of cyanoethylated PVAL (considered as a vinyl alcohol (VAL)‐(2‐cyanoethyl) vinyl ether (VCE) copolymer). The 13C NMR spectra of the methylene carbons in the main chain show three split peaks, the intensities of which change with copolymer composition. These peaks can be assigned to the three dyad sequences. The obtained results show that VCE units have an alternating tendency in the copolymer. Nitrile groups in cyanoethylated PVAL were converted to amidoxime groups by reaction with hydroxylamine. The reaction showed second order kinetics. The activation energy was found to be 51.6 kJ/mol. Soluble polymeric chelates between amidoximated PVAL and cupric ions have been prepared. It is noteworthy that not all the amidoxime groups participate in binding cupric ions.
Synthesis and characterization of epoxy resins containing chromium acrylate
Authors: Anand Manjit , Srivastava A. K.
Published: April 2003

Novel epoxy resins containing chromium acrylate have been synthesized by reacting chromium acrylate with bisphenol‐A and excess epichlorohydrin. The quantities such as epoxy equivalent weight, hydroxy content, hydrolyzable chlorine content and viscosity have been determined. The resins have been characterized by IR and 1H NMR spectroscopy. The cured resins were evaluated for thermal properties. The curing of resins was carried out with Ciba Geigy HY 850 (aliphatic amine adduct) at 30°C for 24 h. The cured resins have excellent thermal and chemical resistance, in addition to an excellent electrical conductivity. The reaction follows first order kinetics with an activation energy of 47 kJ mol−1 and 34 kJ mol−1 in the presence and absence of chromium acrylate, respectively. The chromium forms a complex with bisphenol‐A, as indicated by spectroscopic studies, which increases epoxidation.
Auswirkungen von Sterilisationsverfahren auf biologisch abbaubare Kunststoffe
Authors: Bledzki Andrzej K. , Gassan Jochen , Heyne Matthias
Published: April 2003

Für den Einsatz biologisch abbaubarer Kunststoffe in der pharmazeutischen Industrie und Medizintechnik wurden Produkte verschiedener Hersteller, wie Biopol, Biocellat und Mater‐Bi untersucht. Dabei zeigte vor allem Biopol das notwendige Anforderungsprofil, d.h. die Anwendbarkeit aller Sterilisationsverfahren ohne Festigkeitsbzw. Steifigkeitsverluste sowie Temperatur‐ und Alkoholbeständigkeit. Dagegen wiesen die Werkstoffe Mater‐Bi und Biocellat einige Schwachstellen auf. Bei Mater‐Bi lagen diese bei der Wasserdampfsterilisation sowie bei der geringen thermischen und Medienbeständigkeit. Biocellat versprödet dagegen durch die erhöhte Temperatur bei der Dampfsterilisation, d.h. daß ein Einsatz über 60°C nicht möglich wäre.
Interpenetrating polymer networks based on liquid natural rubber. 1. Synthesis and effect of nco/oh ratio on physical and mechanical properties
Authors: Pillai V. Bhoothalingam , Francis D. Joseph
Published: April 2003

Interpenetrating polymer networks (IPNs) of polyurethane based on hydroxyterminated natural rubber with varying NCO/OH ratios and polystyrene were synthesized under different experimental conditions. These IPNs were found to make tough films. The IPNs were characterized by their physical, mechanical and morphological properties like density, Shore‐A hardness, crosslink density, tensile strength and elongation at break. The IPNs exhibited an increasing trend in density, Shore‐A hardness and tensile strength with increasing polystyrene content, while elongation at break decreased with similar variation in polystyrene content. The crosslink density measurements indicated a possible phase inversion process.
Polymers and copolymers based on vinyl tetrazoles, 1. Synthesis of poly(5‐vinyl tetrazole) by polymer‐analogous conversion of polyacrylonitrile
Authors: Gaponik Pavel N. , Ivashkevich Oleg A. , Karavai Vladimir P. , Lesnikovich Anatoly I. , Chernavina Nadejda I. , Sukhanov Gennady T. , Gareev Gegel A.
Published: April 2003

Interaction of polyacrylonitrile with sodium azide and ammonium chloride leading to the formation of poly(5‐vinyl tetrazole) has been studied in detail. The reaction is found to proceed to high conversion extents (up to 94–94.5%) and allows to obtain polymeric products with a wide range of poly(5‐vinyl‐tetrazole) content. Comparative studies of the structures and properties of the obtained polymers and 5‐vinyl tetrazole homopolymer as well as copolymers of 5‐vinyl tetrazole with acrylonitrile have been carried out using IR, 13C NMR and complex thermal analysis data.
Polymers and copolymers based on vinyl tetrazoles, 2. Alkylation of poly(5‐vinyl tetrazole)
Authors: Gaponik Pavel N. , Ivashkevich Oleg A. , Chernavina Nadejda I. , Lesnikovich Anatoly I. , Sukhanov Gennady T. , Gareev Gegel A.
Published: April 2003

Alkylation of poly(5‐vinyl tetrazole) with dimethyl sulfate and tert‐butyl alcohol as well as with alkyl halides RHal (RCH3, C2H5, CH2CHCH2, n‐C4H9, t‐C4H9) has been studied under various conditions in order to develop a new method of synthesis of tetrazole‐containing polymers having a complex of valuable properties. The kinetic study of the process and comparison of isomeric compositions and spectroscopic characteristics (IR, 1H NMR and 13C NMR) of poly(N‐alkyl‐5‐vinyl tetrazole)s synthesized by alkylation of poly(5‐vinyl tetrazole) and of those prepared by (co)polymerization of the corresponding vinyl tetrazoles have been carried out. The alkylation is found to proceed to high conversion extents (up to 99.8%) and enables to obtain a wide variety of polymeric products having the composition, structure and properties very similar to those of homo‐ and copolymers.
Determination of 1‐butene distribution in LLDPE by DSC analysis after thermal fractionated crystallization
Authors: Balbontin Giulio , Camurati Isabella , Dall'Occo Tiziano , Finotti Anita , Franzese Rocco , Vecellio Giancarlo
Published: April 2003

The chemical composition distribution (CCD) of LLDPE (1‐butene comonomer) has been studied by thermal analysis. After an opportune thermal treatment of the polymers, thermal fractionated crystallization (TFC), the melting endotherms have been subdivided in areas with fixed temperature ranges. The distribution of the endotherms in different areas gave a semiquantitative idea of the CCD.

The comparison with thermal rising elution fractionation and 13C NMR data of the whole polymers and fractions showed fairly good correlations. An approximate evaluation of the average ethylene sequence length was also obtained.
The influence of inert component composition on the porous structure of glycidyl methacrylate/ethylene glycol dimethacrylate copolymers
Authors: Jovanović Slobodan M. , Nastasović Aleksandra , Jovanović Nadežda N. , Jeremić Katarina , Savić Zorica
Published: April 2003

The influence of the content of inert component in monomer phase on the parameters of porous structure (specific pore volume, Vs, specific surface area, Ss, total porosity, P, pore size distribution and pore diameter dp) of the copolymers of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, obtained by suspension polymerization has been studied. The content of standard inert component (cyclohexanol/dodecanol) was changed by substituting dodecanol with one of the aliphatic alcohols with 4, 8, 10, 14 or 16 C‐atoms and by varying the ratio of aliphatic alcohol in inert component.

The results obtained showed that it was possible by changing type and ratio of aliphatic alcohol in inert component to influence the parameters of pore structure of poly(GMA‐co‐EGDMA) copolymers significantly and that by using tetradecanol or hexadecanol it was possible to obtain these copolymers with pore diameters larger than 200 nm.
Separation of liquid mixtures by using polymer membranes, V. Water‐alcohol separation by pervaporation through poly(vinyl alcohol)‐graft‐poly(styrene‐co‐maleic anhydride) membranes
Authors: Chiang Wen‐Yen , Hsiao Chao‐Yi
Published: April 2003

Graft copolymerization of styrene‐maleic anhydride copolymer (ST‐co‐MA) onto poly(vinyl alcohol) (PVA) was carried out by a condensation‐coupling reaction through esterification. The ST‐co‐MA copolymer was obtained by the copolymerization of MA and ST in dimethyl sulfoxide (DMSO), using azoisobutyronitrile as initiator. The structure of the reaction products was confirmed by infrared analysis. The dependence of composition, viscosity and yield of the graft terpolymers on the concentration of the reactants are presented in detail. Mechanical properties of membranes with different compositions were measured over a wide range of composition. It was found that water was permeated through the membranes preferentially in all ranges of feed compositions. The permeation decreased and the selectivity increased with increasing ethanol concentration in the feed and with increasing PVA content in the membrane. The effect of the molecular size of the permeating species on both permeation and separation is also discussed.
Synthesis and biological activity of chlorine‐containing polyketones
Authors: Patel J. N. , Patel R. K. , Ray R. M. , Patel R. M.
Published: April 2003

Chlorine‐containing polyketones of low molecular weight were synthesized from anisole, chloroacetyl chloride and dichloroalkanes, i. e. dichloromethane and 1,2‐dichloroethane, by the Friedel‐Crafts reaction using carbon disulfide as solvent. The resins were characterized by IR spectra and vapour pressure osmometry. The thermal properties were studied by thermogravimetry and differential scanning calorimetry. The characteristics of the decomposition reactions were evaluated by the Broido and Doyle methods. All the resins were tested for their microbial activity against bacteria, fungi and yeast. The results show that most of the resin can be used as biocides.
Study of some flocculating processes with cationic polyelectrolytes
Authors: Lupaşcu Tudor , Dranca Ion , Sandu Maria , Drăgan Stela , Ghimici Luminiţa
Published: April 2003

The flocculating efficiency of two cationic polyelectrolytes with quaternary ammonium salt groups in the main chain, with different branching degrees, on a bentonitic clay suspension, in comparison with polyacrylamide (PAM) was followed. The cationic polymer with a smaller branching degree operated similar to PAM. In both cases a purification of 100% was achieved. When the cationic polymer with a higher branching degree was used, a stabilization effect on the suspension was observed. The flocculating activity of the mixtures of the cationic polymer and polyacrylamide was also studied.
MgCl2·6H2O‐based titanium catalyst for propylene polymerization: Effect of polymerization parameters
Authors: Gupta Virendra Kumar , Satish Sheo , Bhardwaj Ishwar Singh
Published: April 2003

A supported titanium catalyst was prepared by using MgCl2·6H2O as a precursor for generating an active support. The performance of such catalyst was evaluated for propylene polymerization in conjunction with triethylaluminium as cocatalyst and dimethoxydiphenylsilane as an external Lewis base. The efficiency of the catalyst system is dependent on the polymerization parameters such as time, temperature and monomer pressure. The variation in the concentration of hydrogen used as a chain transfer agent alters the performance of the catalyst system and molecular weight characteristics of polypropylene. The morphology of polymer particles is of globular type and is not affected by the variation in the melt flow characteristics of the polymer.
Hydrolytic stability and mechanical properties of poly(ester urethanes)
Authors: Pegoretti Alessandro , Kolarik Jan , Penati Amabile
Published: April 2003

The effect of hydrolysis time at 70°C on molar mass and mechanical properties of commercial poly(ester urethanes), i.e., Estanes 54600, 54610, and 54650, was analyzed. Kinetics of hydrolysis is plausibly described in terms of a first‐order reaction with an average induction period of about 7 days. The resulting reduction of molar mass brought about a significant decrease in ultimate properties, particularly in stress at break and tensile energy to break, while elastic properties were affected much less. A quantitative correlation between relative changes in tensile strength and molar mass was attempted. Hydrolysis resistance of Estanes decreasing in the succession 54650 > 54600 > 54610 was related to their chemical composition.
Viscosity behaviour of multivalent metal ion‐containing carboxymethyl cellulose solutions
Authors: Heinze Thomas , Heinze Ute , Klemm Dieter
Published: April 2003

The influence of Ca2+‐and Al3+‐ions, respectively, upon the viscosity behaviour (so‐called salt tolerance) of aqueous solutions of sodium carboxymethyl cellulose (CMC) with different degree of polymerization (DP) and, on the other hand, with both different degree of substitution (DS) and distribution of substituents, was investigated. Viscosimetry by means of a rotational rheometer at a shear rate of 500 s‐1 shows that the relative drop in viscosity as a result of addition of the multivalent metal cations is independent of DP (ranging from 160 to 900) of the CMC samples. Homogeneously synthesized CMCs (2) with a higher content of 2,3,6‐tri‐O‐carboxymethyl glucose units in the polymer chain possess a significantly higher salt tolerance than those (1) prepared under heterogeneous reaction conditions at comparable total DS values.
Adhesion properties and phase separation behavior of glycidyl‐terminated polyurethanes
Authors: Hsia Hung‐Chung , Ma Chen‐Chi M. , Chen Der‐Shyang
Published: April 2003

2,3‐Epoxy‐1‐propanol has been introduced into isocyanate‐terminated polyurethane to form glycidyl‐terminated polyurethane resins. A series of glycidyl‐terminated polyurethanes based on hydroxyterminated poly(oxypropylene) (poly(oxypropylene) glycol, PPG), toluene diisocyanate (TDI), and 1,4‐butanediol (BD) was synthesized with various PPG soft segment lengths (MW 700, 1000 and 2000) and soft segment concentrations (30, 50 and 70 wt.‐%). The effects of glycidyl‐terminated polyurethane on the adhesion properties and the phase separation were investigated. The adhision properties at liquid nitrogen temperature coincide with the phenomenon observed in the phase separation behavior of polyurethane. Differential scanning calorimetry (DSC) and infrared technique (IR) were used to assess the phase separation content. The enthalpy jump at the glass transition temperature (ΔCp) and the unique spectroscopic features in the NH and CO stretching regions were applied to characterized the phase separation behavior. It was found that the modified resins do not only show superior adhesion at liquid nitrogen temperature but also exhibit some unique properties, e.g., room temperature curing and good storage stability.
Air separation characteristics with liquid crystalline alkyl cellulose blend thin‐film composite membranes
Authors: Li Xin‐Gui , Huang Mei‐Rong
Published: April 2003

Composite membranes were made of liquid crystalline triheptyl cellulose (THC)/ethyl cellulose (EC) blends as dense thin films and poly(ether sulfone) (PES) or polysulfone (PSF) as porous support layer. The effects of the composite membrane composition and operating conditions on the air separation characteristics of oxygenenriched air (OEA) permeating through the membranes were studied using a constant pressure‐variable volume method. The flux (OEA) through the membranes decreases slightly and the oxygen concentration in the OEA permeated increases with increasing THC content in the thin film from 4 to 15 wt.‐%. The OEA flux increases significantly with decreasing thin‐film thickness or increasing operating temperature and transmembrane pressure difference. The oxygen concentration in the OEA increases with increasing the thin‐film thickness or the pressure difference but decreases slightly with increasing the operating temperature. There is no regular variation in the air separation properties by changing the support from PES to PSF. In long‐term tests, the air separation properties remained almost constant for as long as 800 h. An OEA flux of 1.0–1.9·10‐3 cm3 (STP)/s·cm2 containing 34.8–39.4 vol.‐% oxygen can be attained at 30–55°C and 0.41–0.49 MPa pressure difference in a single pass through the membranes. The OEA flux is much higher for the thin‐film composite membranes than for the homogeneous dense membranes made of the same materials.
Polyurethane elastomers based on polymer polyols
Authors: Mitzner Elke , Goering Harald , Becker R.
Published: April 2003

Linear polyurethane elastomers based on polymer polyols were synthesized by the one‐shot technique. The hard‐segment content of the polyurethanes, the chain length of the base polyether, and the styrene/acrylonitrile content and/or the ratio of the polymer polyols were varied. The mechanical properties and the results of the dynamic mechanical analysis are discussed and compared with those of equivalent crosslinked polyurethane elastomers.
Surface modification of polypropylene by chromylchloride
Authors: Novák Igor , Pollák Vladimír
Published: April 2003

The changes of the adhesion properties of isotactic polypropylene (iPP) modified by chromylchloride (CrCl) have been studied. The free surface energy (FSE) of the iPP increases with the time of the modification and reaches a constant value after the time which strongly depends on the temperature of the modification. A similar trend has been observed for the dependences of the FSE vs. concentration of carbonyl groups. The molecular weight of the modified iPP decreases with the temperature of modification. The decrease of the FSE with time is negligible. It was found that after modification of iPP with CrCl the increase of mechanical work of adhesion was higher by 36% than that with chromosulfuric acid.
Herstellung und eigenschaften von cellulosebenzoat
Authors: Braun D. , Bahlig K. H.
Published: April 2003

Cellulosebenzoate mit Substitutionsgraden von 2,8–2,9 wurden in einer einstufigen Reaktion durch Umsetzung von Cellulose mit Benzoylchlorid in Gegenwart von Pyridin als Base hergestellt. Die Molekulargewichte der Cellulosebenzoate lagen zwischen 140000 und 100000; die mittels DSC gemessene Glastemperatur Tg betrug 155°C, die Schmelztemperatur TS 274°C. Die Ester sind gut löslich in organischen Lösungsmitteln wie N,N‐Dimethylformamid, Chloroform und Dichlormethan und besitzen ferner eine gute thermische Beständigkeit bis ca. 250°C. Filme und nacharbeitbare Preßlinge aus Cellulosebenzoat lassen sich aufgrund der hohen Sprödigkeit nur durch Zumischen eines Weichmachers (Diethylphthalat) herstellen. Dabei bleibt das hart‐spröde Verhalten, wie Zug‐Dehnungs‐Versuche und Schlagzähigkeitsmessungen zeigten, bis zu einem Weichmacheranteil von 20 Gew.‐% bestehen.
Copolymers of methyl methacrylate and N‐cyclohexyl maleimide: Preparation and properties
Authors: Usha V. , Varma I. K. , Bhayani G. G. , Sinha T. J. M.
Published: April 2003

Copolymers of methyl methacrylate (MMA) and N‐cyclohexyl maleimide (NCM) with low intrinsic viscosity were obtained when free‐radical copolymerization was carried out in benzene solution. Copolymers containing 0–30 wt.‐% NCM were also prepared by bulk polymerization as cast acrylic sheets and had much higher intrinsic viscosity. An increase in NCM content in copolymers resulted in an increase in thermal stability and modulues and a decrease in tensile strength, strain at break, impact strength of unnotched specimen and light transmittance. The increase in haze was marginal up to 15 wt.‐% of NCM. A decrease in water absorption was observed with an increase in NCM content.
An example of free radical graft polymerization where the mechanism from‐to applies
Authors: Casinos Ismael
Published: April 2003

Free‐radical grafting on natural and synthetic polymers is a method widely used to modify these polymers chemically. A number of these chemical systems show an unexpected behaviour of the polymerization rate when the monomer concentration is sufficiently high: it decreases and sometimes it increases afterwards. Here, the effect of varying the monomer concentration on the graft yield when grafting methyl acrylate, vinyl acetate and a mixture of both monomers onto cellulose initiated by ceric ions is discussed, considering a three‐component mechanism of grafting (mechanisms from, onto and from‐to). It is suggested that the unexpected behaviour indicated above is accounted for by the presence of the grafting mechanism from‐to. Some knowledge about the copolymer structure can be reached by using this mechanistic approach.
Investigations on thermal properties of triazinestilbene optical brightening agents and their copolymers with styrene and acrylonitrile
Authors: Konstantinova T. , Grabchev I. , Konstantinov H.
Published: April 2003

The effect of four optical brightening agents, chemically incorporated into polystyrene and polyacrylonitrile, on the molecular weight and polydispersity of the polymers has been investigated. Thermal analysis of the 1,3,5‐triazine‐stilbene brighteners has been carried out and the effect on the thermal and thermooxidative destruction of their copolymers with styrene and acrylonitrile has been studied.
Preparation of polymeric diketones and their conversion to polymeric hydroxy acids in crosslinked polymeric matrices
Authors: Kuriakose Sunny , Rajasekharan Pillai V. N.
Published: April 2003

Supports of polystyrene (PS) crosslinked with divinylbenzene (DVB) with varying crosslink densities were prepared and furnished with 1,2‐diketo functions through a series of polymer‐analogous reactions. Crossed benzoin condensation between polymeric aldehyde (formylated polystyrene) and substituted low‐molecular aldehydes gives a set of mixed α‐hydroxy ketones. These polymeric benzoin analogues were converted to α‐diketones by oxidation. The polymeric systems containing α‐diketo functions were subjected to rearrangement under basic conditions into hydroxy acids. The products were characterized by IR and 13C CP‐MAS NMR spectroscopy and by chemical methods. The rearrangement was observed to be facile in these highly crosslinked networks in spite of the environmental constraints imposed by the rigid and high‐molecular‐weight polymeric backbone.
Damping materials based on simultaneously grafted interpenetrating polymer networks from castor oil
Authors: Xie Hong‐Quan , Wang Gui‐Gui , Guo Jun‐She
Published: April 2003

Four kinds of grafted interpenetrating polymer networks (IPNs) were synthesized from castor oil (CAS), toluene diisocyanate (TDI), monohydroxy terminated acrylic (or methacrylic) prepolymer and/or acrylic (or methacrylic) monomer in the presence of dibutyltin dilaurate and redox initiators. Formation rates of soluble and insoluble polymers were investigated in the course of synthesis of the grafted IPN from NCO‐terminated CAS precursor, butyl acrylate prepolymer, CAS and ethyl methacrylate monomer. Mechanical properties of the IPNs were studied as well. Studies of the dynamic mechanical properties of the various grafted IPNs showed that certain IPNs (from CAS/TDI/butyl methacrylate and butyl acrylate prepolymers, CAS/TDI/butyl acrylate monomer/ethyl methacrylate prepolymer, CAS/TDI/ethyl methacrylate monomer/butyl methacrylate prepolymer) exhibit high damping behavior over wide temperature ranges for tan δ ≥ 0.3 (ΔThd from 88°C up to 133°C) and maximum tan δ values higher than 1.1.
Electroinitiated polymerization of some new monomers with schiff's base structure and pyrrole moieties
Authors: Simionescu C. I. , Grovu‐Ivanoiu M. , Grigoras M. , Cianga I.
Published: April 2003

Pyrrole‐2‐aldehyd azine, N,N'‐bis(2‐pyrrolylmethylene)‐1,4‐diaminobenzene and N,N'‐bis(2‐pyrrolylmethylene)‐4,4′‐diaminobiphenyl were polymerized by electro‐chemical precipitating oxidation reaction in 1,2‐dichloroethane and acetonitrile, respectively, in the presence of electrolytes like tetrabutylammonium perchlorate, tetrabutylammonium tetrafluoroborate and sodium p‐toluene sulfonate. The doped resulted polymers were characterized by elemental analysis, IR spectroscopy and thermal analysis.
Polymerization of ethylene and 1‐hexene with Cp2ZrCl2‐methylaluminoxane catalyst in a heat balance reaction calorimeter
Authors: Koivumäki Jari , Lahti Mikko , Seppälä Jukka V.
Published: April 2003

A heat balance reaction calorimeter was used to obtain information about the typical process parameters such as viscosity and heat transfer properties in polymerizations carried out with Cp2ZrCl2‐methylaluminoxane catalyst. The rate enhancement upon comonomer addition was of particular interest. The viscosity of the reaction mixture was found to increase dramatically during the homopolymerization of ethylene but to increase only a little in the copolymerization of ethylene and 1‐hexene even though the final slurry concentration was six times as high as in the homopolymerization. The explanation offered for this unexpected result is the much smaller particle size in the copolymerization. In part, this might also explain the higher activity in the copolymerization.
Polyelectrolyte complexes of binary and ternary systems containing poly(sodium styrene sulfonate), poly(sodium styrene sulfonate), poly(sodium phosphate), and poly(N‐ethyl‐4‐vinylpyridinium bromide)
Authors: Trinh Cam Khon , Schnabel Wolfram
Published: April 2003

Polyelectrolyte complexes (PECs) were prepared by precipitation upon mixing solutions of poly(N‐ethyl‐4‐vinylpyridinium bromide), PVPE, and poly(sodium styrene sulfonate), PSS, and/or poly(sodium phosphate), PP. The chemical composition of the PECs was determined as a function of the initial polyelectrolyte (PE) concentration ratio. With binary systems water‐insoluble PECs being 1:1 stoichiometrically composed were formed in the case of the system PP/PVPE at ϕPP = [PP]0/ = 0.8 to 4.0. In the case of the system PSS / PVPE, water‐insoluble PECs were formed at all ϕPSS = [PVPE]0 ratios. Up to ϕPSS = 1.0 the PEC composition was stoichiometric. At ϕPSS = 1.0–8.0 non‐stoichiometric PECs containing surplus PSS were formed. With ternary systems, water‐insoluble PECs were formed regardless of the initial PE concentration ratio. The PEC composition was stoichiometric up to ϕPSS = 1.0, but preferntial binding of PSS became increasingly important with rising ϕPSS. At ϕPSS 2.5, PP was totally replaced by PSS and non‐stoichiometric PECs containing surplus PSS were formed.
Styrol‐maleinsäure‐copolymere als korrosionsinhibitoren für aluminiumpigmente in wäußrigen medien
Authors: Müller Bodo , Mebarek Denise
Published: April 2003

Styrol‐Maleinsäure‐Copolymere (Molmassen 1600‐2500 g mol‐1) inhibieren die Korrosion von Aluminiumpigmenten in Wasser/Butylglykol‐Gemischen bei pH 10 sehr effektiv (Schutzwerte bis 99%), wie durch gasvolumetrische Bestimmung des Korrosionsproduktes Wasserstoff nachgewiesen wurde. Es existiert ein Zusammenhang zwischen der Zusammensetzung der Copolymeren und ihrer Wirkung: Je geringer die Säurezahl des Styrol‐Maleinsäure‐Copolymeren ist, desto besser ist ihre korrosionsinhibierende Wirkung. Dieser Zusammenhang gilt allerdings nur innerhalb der hier untersuchten Gruppe von Styrol‐Maleinsäure‐Copolymeren. Ein zum Vergleich geprüftes Styrol‐Acrylsäure‐Copolymeres mit vergleichbarer Molmasse und Säurezahl erwies sich dagegen als deutlich deutlich schlechterer Korrosionsinhibitor.

Aus Messungen der Konzentration von gelöstem Aluminium(III) mit Hilfe der Atomabsorptionsspektroskopie wurde auf die Bildung von (zumindest teilweise) löslichen Polymer‐Aluminium(III)‐Komplexen geschlossen.
Triazine‐based polymers, 2. Synthesis and characterization of polyethers
Authors: Braun D. , Most D. , Ziser T.
Published: April 2003

Triazine‐based polyethers can be synthesized by phase transfer catalysed interfacial polycondensation at room temperature and reaction times of about 1 to 3 h. In this way, more than 20 polyethers were synthesized and solubilities, glass transition temperatures, thermogravimetric data, elongations at break, tensil strengths, elasticity moduli and impact strengths were determined. In addition, the degree of crystallinity was investigated for the polymer obtained from of 2,4‐dichloro‐6‐diethylamino‐s‐triazine and bisphenol A by wide angle X‐ray diffraction. The increment of the 1,3,5‐triazinetriyl ring was determined, which made it possible to calculate the glass transition temperatures of some polyethers according to van Krevelen.
Ionic polymers, I. Poly(vinyltoluene‐co‐divinylbenzene) networks and some chemical transformations
Authors: Luca Cornelia , Neagu Violeta , Poinescu Ignat , Simionescu Bogdan C.
Published: April 2003

Different poly(vinyltoluene‐co‐divinylbenzene) networks, precursors for ionic polymers, were synthesized and characterized. The influence of diluent nature and divinylbenzene (DVB) content on copolymer properties is discussed. Both expanded and porous structures can be easily prepared. Expanded structures are formed when good or poor diluents are used for low DVB content, i. e. less than 20 wt.‐% with respect to vinyltoluene. Higher DVB content yields macroporous structures. Also, the possibility of obtaining strong base anion exchangers from poly(vinyltoluene‐co‐divinylbenzene) networks as precursors was investigated. Therefore, the above‐mentioned networks were transformed by the chlorination reaction with NaOCI/phase transfer catalyst system, followed by the amination reaction with trimethylamine or N,N‐dimethyl‐2‐hydroxyethylamine.