bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen‐plasma‐treated polypropylene interfaces with air, water, and epoxy resins: Part I. Air and water
Authors: Occhiello E. , Morra M. , Morini G. , Garbassi F. , Humphrey P.
Published: April 2003

Oxygen plasma treatment of polypropylene (PP) surfaces led to introduction of oxygencontaining functionalities, with consequent improvement of surface wettability. A combination of X‐ray photoelectron spectroscopy (XPS), static secondary ion mass spectroscopy (SSIMS), and contact angle measurements (water‐in‐air and air‐in‐water) allowed us to characterize the behavior of the treated surface in contact with air (low‐energy surface) and water (high‐energy surface).

The treated surface showed the tendency to rearrange itself to minimize its interfacial energy. When contacted with air (low‐energy surface), polar groups were buried away from the polymer/air interface, while in contact with water (high‐energy surface) polar groups remained at the polymer/water interface.

When contacted with air, the polymer surface layer rearranged by macromolecular motions within itself, since interdiffusion with the bulk polymer seems forbidden. These motions are thermally activated and it was possible to obtain an apparent activation energy (58.1 kJ/mol) close to those reported for other vinyl polymers.
Effect of organic amine type on the structure and properties of the complex Zn(II) salts of ethylene–methacrylic acid copolymer with organic amines
Authors: Hirasawa Eisaku , Hamazaki Hirohide , Tadano Kenji , Yano Shinichi
Published: April 2003

The complex Zn(II) salts of ethylene–methacrylic acid copolymer (EMAA) were synthesized by using various organic amines from monoamines to polyamines, from primary amines to tertiary amines, and from molecular amines to polymer amines. Thermal analyses by differential scanning calorimetry (DSC), and the measurement of stiffness, melt flow rate (MFR), and dielectric properties were employed for the complex salts. It was found that the valence, strength of base, rigidity and flexibility, and bulkiness of the organic amines affect the degree of crystalline order of the ionic crystallites, which governs the stiffness of the complex ion ionomers. The stiffness is higher for the complex salts which form the higher orderliness in the ionic aggregates. The organic amines with two or more primary aliphatic amino groups and higher boiling temperatures from more rigid ionic crystallites in the complex ion ionomers leading to the enhanced modulus. Monoamines or polyamines with amino groups attached to flexible chains such as polyether and polysiloxane scarcely develop ionic crystallites and preferentially solvate the amorphous region including ionic groups leading to the decreased modulus. These results provide us with the fundamental information to control the modulus of ionomers.
Characterization of acetylene terminated sulfone (ATS) resin. II. Thermal analysis of the resin
Authors: Stevenson W. T. K. , Goldfarb I. J. , Soloski E. J. , Houtz M. J.
Published: April 2003

The kinetics and thermodynamics of the cure and post‐cure reactions of an acetylene terminated sulfone (ATS) resin mixture and pure fractions from that mixture were studied using differential scanning calorimetry. Thermal stabilities were measured by programmed thermogravimetry under helium, and oxidative stabilities using isothermal thermogravimetry in air. Microstructural changes accompanying the cure reaction were identified using infrared spectroscopy. Early products of thermal degradation were trapped for identification and quantitative analysis using the technique of sub‐ambient thermal volatilization analysis. We found that glass transition temperatures increase with crosslink density in the resin, that oxygen is able to copolymerize or couple with the polyenes to produce peroxides or hydroperoxides (respectively) which subsequently decompose to form terminal alcohols on the polyene, that weight loss in air at 600°F is an oxidative process that is insensitive to resin crosslink density, and that sulfone functionality constitutes the thermal weak link in the ATS resin system.
Epoxy resins based on aromatic glycidylamines. III. Kinetics of intramolecular cyclization of N,N‐bis(2‐hydroxy‐3‐chloropropyl)aniline
Authors: Podzimek Š. , Dobáš I. , Švestka Š. , Eichler J. , Kubín M.
Published: April 2003

The course of intramolecular cyclization of N,N‐bis (2‐hydroxy‐3‐chloropropyl) aniline (DCHA) was followed by HPLC. The rate constants (at 70, 85, 100, and 115°C) and the Arrhenius parameters for individual reaction steps were determined. The resulting product was isolated by semipreparative HPLC and its structure was confirmed by NMR spectroscopy. Attention was also paid to the different reactivity of DCHA diastereoisomers.
Metal ion removal by dyed cellulosic materials
Authors: Shukla S. R. , Sakhardande V. D.
Published: April 2003

Further studies on adsorption of different metal ions by the four dyed and undyed cellulosic substrates namely cotton fibers, bleached bamboo pulp, jute fibers, and sawdust were carried out. Different metal ions adsorbed were Fe2+, Fe3+, Pb2+, and Hg2+. The equilibrium metal adsorption was studied by EDTA method. The control and dyed substrates adsorbed these metal ions to a significant extent, thus providing an effective and cheap method for adsorption of costly but polluting and toxic metals like Pb2+ and Hg2+. The adsorption levels varied up to 95% for various substrate–dye–metal ion combinations.
Viscometric investigation of the poly(acrylic acid)–polyacrylamide interpolymer association
Authors: Staikos G. , Tsitsilianis C.
Published: April 2003

A viscometric approach to the formation of interpolymer complexes between a polyelectrolyte, polyacrylic acid, and a non‐ionic polymer, polyacrylamide, is investigated. The following method compares the reduced viscosity of the polymer mixture with an “ideal” value which results from the additivity of the reduced viscosities of the two components taking into account the polyelectrolyte effect of polyacrylic acid. This reveals the formation of a compact complex or gel‐like interpolymer association which depends on the polymer mixture composition. Both the influence of the degree of polyacrylic acid neutralization and of the presence of a salt on the interpolymer association are also studied.
Synthesis, characterization, and evaluation of poly[n‐alkyl(oxy)‐n‐hexyl acrylates]
Authors: Pratap G. , Shantha K. L. , Rao D. V. Mohan , Rao V. S. Bhaskar
Published: April 2003

Oxoalkyl acrylates of long‐chain 7‐oxo alcohols were synthesized as intermediate monomers for the preparation of poly[n‐alkyl (oxy) ‐n‐hexyl acrylates] for the first time. These polymers have wide applications as fluidity improvers (pour point depressants) for petroleum crude oils. Characterization of all the intermediate monomers was done by IR, 1H‐NMR, and MS, and that of polymers by IR, 1H‐NMR, and GPC. These polymers were systematically investigated for their efficacy as pour point depressants on three types of high waxy Bombay High (Indian) crudes. In addition to establishing the pour points, relevant rheological parameters of the untreated and the additive‐treated crude oils were determined in the laboratory with a rotational viscometer. Results of the crude oils that were pre‐ and posttreated with these new polymers have shown enhanced activity of flow properties as compared to the crudes that were treated with poly(n‐alkyl acrylate) flow improver.
A simplified degradation model for nylon 6,6 polymerization
Authors: Steppan D. D. , Doherty M. F. , Malone M. F.
Published: April 2003

A simplified reaction scheme for nylon 6,6 degradation that is consistent with all the published data is described. The degradation model has been incorporated into a flowing film polymerizer model with a distribution of residence times in order to predict molecular weight, amount of undegraded (amine and carboxyl) and degraded chain ends, and the extent of crosslinking. The outlet average molecular weight and water concentration come to steady state in about one mean residence time after a change in polymerizer operating conditions, whereas the degradation products continue to change slowly even after four residence times. Also, it is possible to choose the operating conditions of the polymerizer so the same molecular weight is produced at two different temperatures but with very different amounts of degradation products giving rise to products of significantly different quality.
Structural changes during polystyrene orientation: A study of optical birefringence and wide angle X‐ray scattering
Authors: Vancso G. , Snétivy D. , Tomka I.
Published: April 2003

Results of coupled optical birefringence and wide‐angle X‐ray scattering (WAXS) measurements on uniaxially oriented, atactic, glassy polystyrene (PS) samples are reported. Orientations were achieved in tensile test experiments performed slightly above the glass transition temperature. The elongated samples were quenched after orientation. The applied force was kept constant during cooling. The second order moments of the chain orientation distribution function (ODF) were calculated from the azimuthal profile of the scattered X‐ray intensity from measurements made on five PS samples with different degrees of orientation. For ODF calculations the first, equatorial halo was used. The influence of the second, meridional halo was removed by resolving the WAXS patterns into three peaks. The intrinsic azimuthal linewidth of the WAXS profile was estimated and taken into account in the ODF calculations. The magnitude of the intrinsic birefringence Δnint was determined using the linear relationship between the birefringence and the second order moment of the ODF. A value for Δnint of −0.05 was obtained. This result was used to calculate the angle between the normal plane of the benzene ring and the chain axis. A comparison with previously published results indicates that the average relative orientation of the benzene ring with respect to the chain axis was changing in our samples during stretching. This structural difference is attributed to strong deformation of the network and retarded relaxation during sample preparation.
Preparation of Rh‐containing cellulose acetate films and the chemistry of Rh in cellulose acetate
Authors: Park Kwang‐Min , Shim Il‐Wun
Published: April 2003

RhCl [P(C6H5)3]3 complexes have been incorporated in cellulose acetate as a dispersion medium using cosolvent (tetrahydrofuran). The interactions between Rh (I) complexes and cellulose acetate (CA) are examined by infrared spectroscopy and thermal analysis. The chemical reactivities of Rh–CA films have been investigated by reacting Rh sites with CO, H2, O2, and C2H4 in the temperature range 90–150°C and at a pressure of less than 1 atm. Three different Rh‐carbonyls and a Rh‐hydride species formed in CA are characterized by their infrared spectra. Treatment of 10 or 20 wt % Rh–CA films with hydrogen (600 torr) at 150°C produces small Rh metal particles of ca. 10 Å or less in diameter in CA, which show catalytic activities under mild conditions in various reactions such as hydrogenation of C2H4, oxidation of CO, and Fischer–Tropsch type reactions.
Emulsion polymerization of methyl methacrylate using poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)‐graft‐polyoxyethylene as the stabilizer
Authors: Jialanella Gary L. , Piirma Irja
Published: April 2003

This study involved the use of an amphipathic graft copolymer, poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)–graft–polyoxyethylene, as a stabilizer in the emulsion polymerization of methyl methacrylate. The stabilizing effectiveness of this graft copolymer was studied as a function of its chemical structure. It was found that the stabilizing effectiveness of the graft copolymer was independent of the molecular weight of the backbone within the investigated range of 4 × 103 g/mol to 2 × 104 g/mol. In all cases, stable emulsion polymerizations of methyl methacrylate were observed. Effective stabilization also occurred when the graft moieties possessed a molecular weight of either 2 × 103 g/mol or 5 × 103 g/mol. However, the stabilizing effectiveness was found to be dependent on the amount of polyoxyethylene (POE) contained in the graft copolymer. In this case, graft copolymers possessing 67% by weight POE were poor stabilizers, but ones with 85% POE were very good stabilizers. Moreover, the graft copolymers were found to be superior stabilizers as compared to POE homopolymers.
The dynamic mechanical analysis of epoxy–copper powder composites using azole compounds as coupling agents
Authors: Ding Jianfu , Chen Chinmin , Xue Gi
Published: April 2003

The dynamic mechanical properties of cured epoxy resin have been studied in which copper powder treated or untreated with azole compounds was used as fillers. The untreated fillers do not shift the glass transition temperature of the matrix polymer of the composites, whereas the storage modulus rises with increasing content of fillers. The application of azole compounds as coupling agents, which could react with both copper and epoxy resin, extended the polymer–filler interactions. The composite filled with copper powder treated with benzotriazole shows a strong reinforcement effect and high resistance to moisture.
Synthesis and properties of cationic resins derived from aniline‐modified epoxy resins and various amines
Authors: Yang Chin‐Ping , Lee Lung‐Ta , Yu Wen‐Tsong
Published: April 2003

Aniline‐modified epoxy resin which contains tertiary amine in the middle of the polymer chain was synthesized by the reaction of aniline and epoxy resin. The resulting aniline‐modified epoxy resin and two commercial epoxy resins with different epoxy equivalent weights were reacted with 2‐ethylhexanol‐blocked toluene diisocyanate (2‐EH‐blocked TDI) to obtain thermally crosslinkable epoxy resins. These epoxy resins were subsequently reacted with various secondary amines and partially neutralized with acetic acid to give thermally crosslinkable cationic resins. The resulting cationic resins were dissolved in suitable solvents and mixed with deionized water to form emulsions. The crosslinking properties, emulsion, and electrodeposition properties of these resins were studied in some detail. The electro‐deposition yields of the emulsions prepared from aniline‐modified epoxy resins were higher than those of other emulsions. The crosslinked films prepared from aniline‐modified epoxy resins were also glossier than those prepared from commercial epoxy resins. High deposition yield and high glossiness were the characteristic properties of the aniline‐modified epoxy resins. Thermal properties were not affected by aniline‐modified epoxy resins.
Tensile retraction measurements. IV. Determination of loose end pullout in gum vulcanizates
Authors: Hergenrother William L. , Doshak John M.
Published: April 2003

Tensile retraction measurements have been made on unfilled rubbers cured with either sulfur or dicumyl peroxide to different levels of crosslink density. The rubbers chosen were emulsion and solution polymerized anionic SBRs, cis‐polybutadiene, natural rubber, and anionic 1,4‐polybutadienes of different molecular weight. The measured molecular weight between crosslinks (Mc) at each extension gave a smooth curve when plotted against the maximum extension (Λmax) used for the measurement. This curve was separated into three linear regions that characterize the cured rubber. The first region, above about 30% elongation, gave a Λmax = 1 intercept that decreased with either increased polymer Mn or increased level of curatives. Subtracting this calculated crosslink density from the measured crosslink density below about 30% elongation gave another smooth curve when plotted against Λmax. A second linear relationship was described in the general range of 5‐30% elongation. Below about 5% elongation, a third linear relationship was found. This line was determined from the differences between the calculated and the observed crosslink densities in the lowest strain region of the intermediate strain plot. Possible explanations of these three linear regions have been made. Supporting evidence was gained from temperature‐dependent experiments as well as from correlation of experimental results with polymers of different values of Tg.
Internal stress, lattice deformation, and modulus of polymers
Authors: Zhang Anqiu , Jiang Hao , Wu Zongquan , Wu Chenxun , Qian Baojun
Published: April 2003

The relationships among internal stress, lattice deformation, and the moduli of polymers, such as poly(ethylene terephthalate) (PET), polypropylene (PP), polyethylene (PE), polyacryonitrile (PAN), and poly(p‐phenylene terephthalamide) (PPTA), have been studied systematically. Compared to small molecule crystals, polymer crystals have many more defects and their parameters of the crystal unit cells and the density of the crystalline region are easy to vary to a certain extent. During the processing, external stresses were put on the polymer fibers and polymer molecules were drastically deformed, which induced polymer crystallization and preferred orientation. After processing, there are many macromolecules frozen in the nonequilibrium status, which is the cause of internal stress. Heat treatment could give energy to the macromolecules to release the internal stress and to approach thermodynamic equilibrium. For polymer crystals, the higher the annealing temperature, the shorter the lengths of the unit cell axes, the more integral and regular the crystal lattice, and the smaller the unit cell volume. Crystalline modulus changes not only with different kinds of polymer materials, but also with measurement temperature and processing history. Polymer processing, mainly drawing, causes orientation and internal stress which causes lattice deformation and raises tensile modulus of polymer materials.
Synthesis and thermal stability, dielectric and conductivity characteristics of some aromatic anhydride‐modified carbazole polymers
Authors: Biswas Mukul , Mitra Pradyot
Published: April 2003

Copolycondensates have been prepared from carbazole, poly(N‐vinylcarbazole) and various aromatic anhydrides, e.g., phthalic anhydride, trimellitic acid anhydride, pyromellitic dianhydride, naphthalene tetracarboxylic dianhydride, and benzophenone tetracarboxylic dianhydride in presence of the Friedel–Crafts catalyst anhydrous zinc chloride at high temperature. The polymers have been characterized by elemental analyses and IR spectroscopy. Thermal stabilities, dielectric, and conductivity behaviors of these polymers have also been evaluated and it has been observed that these properties show interesting differences depending upon the nature of the anhydride.
Seeded emulsion polymerization of n‐butyl acrylate utilizing miniemulsions
Authors: Tang P. L. , Sudol E. D. , Adams M. , El‐Aasser M. S. , Asua J. M.
Published: April 2003

Nucleation of polymer particles in the seeded emulsion polymerization of n‐butyl acrylate (BuA) was studied through experiments designed to control the amount of new particles formed. The results show that for the batch and semicontinuous seeded polymerization of BuA, a small amount of new particles was formed in the system in which the monomer was added neat, whereas a singificant amount of new particles was formed when the monomer was added as a miniemulsion. This suggests that new particles formed in the miniemulsion process were from nucleation of the monomer droplets. These experiments also showed that monomer‐droplet nucleation decreased with increasing seed concentration in the reactor. For the seeded semicontinuous polymerizations, monomer‐droplet nucleation decreases with decreasing BuA miniemulsion feed rate. The results also show that monomerdroplet nucleation takes place whenever miniemulsion droplets exist in the reactor. This study suggests that miniemulsions can be used to control the particle size distribution of a polymer latex system.
Quinone amine polymers. IX. Attempts to synthesize polyamine–benzoquinone polymers using air and oxygen as oxidizing agents
Authors: Nithianandam V. S. , Erhan S.
Published: April 2003

Attempts to synthesize Jeffamine D‐400 : p‐benzoquinone = 1 : 1 and later Jeffamine D‐400 : hydroquinone = 1 : 1 oligomers, using air or oxygen as the oxidizing agent, have been only partially successful. Although oligomers that yield nontacky coatings are completely precipitable in water, only about 25% of these products are precipitable in water while 75% remains in suspension. These polymers yield tacky coatings, which suggests that neither air nor oxygen is capable of oxidizing hydroquinone to benzoquinone, which is necessary for the formation of the polymer. Hence, most of the oligomer chains are too short to precipitate in water.
Studies on renewable polyphenol‐based cation exchange resins of moderately high capacity
Authors: Mitra N. C. , Banerjee R. S. , Sarkar A.
Published: April 2003

Most of the commercially available ion exchange resins at present are either styrene–DVB‐based or phenol‐based and these are dependent on petroleum products. In view of the ever increasing demand for ion exchange resins and the petroleum crisis, the cost of these resins is going up in leaps and bounds. Although work on ion exchange resins based on naturally occurring tannins and similar materials have been reported in the literature, their low stability, insufficiently low exchange capacity, and similar other disadvantages come in the way of commercial exploitation of these products. In the present communication, studies on preparation and properties, viz., exchange capacity, hydration, swelling, stability, etc. of some effective cation exchange resins which have been obtained from a renewable natural resource of polyphenolic nature and some small proportion of phenol have been reported. The resins studied are stable and of moderately high exchange capacity (2–3 meq/g). Substituting phenol with low‐priced renewable polyphenolic material, the resultant copolymer matrix after sulfonation gives ion exchange resins which are quite economic. Their properties are comparable with the commercial resins available in the market.
Photoinitiated crosslinking of hydroxypropyl cellulose in the isotropic and liquid crystal states
Authors: Song Cheng Qian , Litt Morton H. , Manas‐Zloczower Ica
Published: April 2003

The influence of temperature, concentration, and shear rate on the formation of liquid crystal solutions of hydroxypropyl cellulose (HPC) in DMAc and the preservation of the structure by photoinitiated crosslinking were investigated. The rate of changes in the relaxation pattern for the characteristic band texture of HPC liquid crystals after cessation of shear is inversely proportional to the extent of the crosslinking. This shows that the liquid crystalline structure is preserved upon crosslinking. The molecular orientation of the crosslinked films as a function of mesophase organization and concentration during crosslinking was studied.
Interfacial polyfunctional condensation: Curing reaction
Authors: Chern Yaw‐Terng , Chen Leo‐Wang
Published: April 2003

Heat treatment of films obtained by interfacial condensation of 4,4′‐methylene dianiline (MDA) or ethylene diamine (EDA) in water and 1,2,4,5‐benzenetetra acyl chloride (BTAC) in dichloromethane were studied by Fourier transform infrared spectroscopy (FTIR), 1H‐and 13C‐nuclear magnetic resonance (NMR), fast atom bombardment mass spectrometry (FABMS), an elemental analyzer, and differential scanning calorimetry (DSC). The reaction scheme for forming the polyimide is presented. Films were synthesized from the aromatic diamine and from the aliphatic diamine system. Both must go through two‐stage thermal treatment to form the structure of the imide. The first stage of this reaction is the imidization of the polyamic acid, and the second is the reaction to imidization of the functional amide group linked to the neighboring carbon on the benzene ring. After thermal treatment, the films will maintain good heat resistance. The difference between the mentioned interfacial synthetic polyimide and the conventional synthetic polyimide is that no isoimide and anhydride groups are found in the former. But the thickness of the film is limited by the nature of interfacial polymerization. In our reaction system, the maximum thickness of the film did not exceed 20 μm.
A new model for the shear viscosity of carbon black–polybutadiene, styrene suspensions
Authors: Chen Chao‐Cheng , Chiu Wen‐Yen
Published: April 2003

The shear viscosity of carbon black–polybutadiene, styrene suspensions is studied. The suspensions show strong shear thinning behavior. At very low shear rate, an extrapolated constant shear stress that is designated as the apparent yield stress can be obtained. A model is developed based on the kinetics and energy dissipation of the flocculation process in suspensions of Newtonian liquid. With a mixing rule, the model can also predict the viscosity of suspensions with particle‐size distribution. The applicability of the model can be extended to suspensions of non‐Newtonian liquid if the parameters in the model are regarded as functions of the viscosity of suspending liquid.
Atomic oxygen effects on the prefailure damage processes in highly filled glass/mica/epoxy composites
Authors: Regola M. , Baer E. , Hiltner A.
Published: April 2003

In the present study, the effect of atomic oxygen (AO) exposure, as a simulation of low earth orbit, on the flexural properties and prefailure damage mechanisms of a series of short glass fiber/mica/epoxy composites under three‐point bending were elucidated using acoustic emission (AE) techniques. The incorporation of mica in the composites was shown to increase the resistance to AO as measured by the weight loss, ashing rate, and reaction efficiency. Furthermore, as the mica content increased, the resistance increased such that the all‐mica composite had over one order of magnitude lower ashing rate and reaction efficiency than did the all‐glass‐fiber composite. This increased resistance was caused by the mica particles preferentially orienting parallel to the surface of the composites, creating an inorganic barrier to attack. The AO‐induced erosion was found to have an insignificant effect on both the flexural properties and prefailure damage mechanisms because the erosion was confined to the epoxy surface only and did not affect the bulk.
A DSC study of curative interactions. II. The interaction of 2,2′‐dibenzothiazole with ZnO, sulfur, and stearic acid
Authors: Kruger F. W. H. , McGill W. J.
Published: April 2003

The interaction of combinations of sulfur, 2,2′‐dibenzothiazole (MBTS), ZnO, and stearic acid were studied by differential scanning calorimetry. A MBTS/stearic acid interaction was indicated as evidenced by the effect the MBTS/stearic acid combination had on the melting of sulfur, the Sα → Sβ transition being suppressed in favor of a Sα → Sγ transition. The dissolution/interaction of MBTS in molten sulfur was also delayed by the MBTS/stearic acid interaction, which, it is proposed, involved protonation of the N atom in MBTS by stearic acid. MBTS did not affect the formation of zinc stearate from ZnO and stearic acid, but when sulfure was added to the mixture, the ZnO/stearic acid reaction did not go to completion. No direct evidence for the formation of 2,2′‐dibenzothiazole polysulphides was found, but the absence of the Sγ → Sμ transition in sulfur/MBTS mixes was interpreted as indirect evidence of a reaction between these curatives. There was no evidence for the formation of a sulfur/MBTS/ZnO compound of the type generally attributed the role of an active sulfurating agent in accelerated sulfur vulcanization.
Effect of chemical structure of allyl ethers on polymerization and properties of multifunctional acrylate systems
Authors: Jensen Eirik S. , Gatenholm Paul , Nanguneri Srikanth R. , Mathias Lon J.
Published: April 2003

Allyl ether resins with various chemical structures and degrees of functionality were used as promoters and cross‐linkers for polymerization of acrylic oligomers at room temperature in air. Thin films were prepared to allow monitoring of polymerization via disappearance of acrylate and allylic unsaturation by FTIR. The effect of air upon curing of films was investigated; excluding air from the surface of the film had a much greater effect than did addition of allyl ether. In air, the curing rate and extent of cure were found to be dependent upon molecular weight Mn and degree of functionality of the allyl compounds. At high allyl monomer concentrations, homopolymerization of the allyl groups occurred. The mechanical properties (tensile strength, Young's modulus, and elongation at break) of films were evaluated on an Instron, whereas viscoelastic properties, transition temperatures, and cross‐link densities of polymer bars were studied by dynamic mechanical analysis and relaxation measurements. The study showed that addition of highly functional allyl ethers combines the advantages of an air‐curable system with those of highly cross‐linked materials, allowing ultimate properties to be tailored.
Polycyclic aromatic hydrocarbons (PAHs) in soot produced by combustion of polystyrene, polypropylene, and wood
Authors: Elomaa Matti , Saharinen Erkki
Published: April 2003

The smoke and soot produced by the combustion of plastics or wood in a domestic stove or fireplace contain many poisonous compounds, including the polycyclic aromatic hydrocarbons (PAHs), many of which are carcinogenic. PAHs were selected as the subject of our study to gain a better sense of the hazards of burning plastics. Small samples of polystyrene, polypropylene, and wood underwent combustion in a tubular oven at 700°C; in addition, polystyrene and wood were combusted at room temperature. After their extraction and purification, the PAHs were analyzed by gas chromatography and mass spectrometry. Conditions in the hot oven promoted soot production, whereas combustion at room temperature led to somewhat more complete combustion. The PAH profiles of the examined materials resembled each other to some extent, though the original chemical structure of the polymeric materials varied a great deal. However, clear differences between the materials could be detected from the soot extracts, the soot of polystyrene being especially rich in compounds containing remnants of the polymer structure. Carcinogenic activity caused by the PAHs can be assumed to be of the same order of magnitude as soot from the combustion of wood.
Acid–base surface properties of modified poly(ethylene terephthalate) films and gelatin: Relationship to adhesion
Authors: Lavielle L. , Schultz J. , Nakajima K.
Published: April 2003

Characterization of poly(ethylene terephthalate) (PET) films surfaces through wettability measurements and inverse gas chromatography techniques leads to a better knowledge of the potential interactions with a coating. An important case is the one relative to gelatin coatings for photographic films. In order to favor adhesion on PET, it is of interest to examine the problem in terms of acid–base interactions. PET is found amphoteric and gelatin rather basic. Several surface treatments on PET like orientation on water and flame or plasma treatment in air lead to an increase in surface acidity. Adhesion with gelatin as determined by the peel test is increased through a flame treatment, because of the higher acidity of PET and subsequent chemical bonding at the interface. Determination of acid‐base surface properties of PET and gelatin appears to be an excellent tool for adhesion prediction.
Quinone–amine polymers. VI. Syntheses and solubilities of several cooligomers (paqs) produced by reacting two diamines with p‐benzoquinone
Authors: Nithianandam V. S. , Chertok F. , Erhan S.
Published: April 2003

The solubilities of some polyamine–;quinone oligomers (PAQs) derived from various diamines were found to be incredibly low. Ethylene‐diamine–p‐benzoquinone products were insoluble in all 34 solvents used in assessing solubilities of polymers. Syntheses of copolymers/cooligomers of an amine yielding insoluble product with another that produces highly soluble amine were attempted. The increase in the solubilities of these copolymers/cooligomers as well as their appearances suggest that it is possible to produce PAQs from two different diamines.
Dynamic mechanical properties of quinazolone–imide block copolymer
Authors: Fukami Akira , Iisaka Katsuyoshi , Kubota Shigeru , Etoh Shouhei
Published: April 2003

Dynamic mechanical properties have been investigated over the temperature range of−150–360°C for the quinazolone–imide copolymers, prepared by condensation of the amine‐terminated quinazolone prepolymer with a stoichiometric quantity of pyromellitic dianhydride or 3,3′,4,4′‐benzophenone‐tetracarboxilic dianhydride. Both copolymers have, respectively, the low‐temperature β‐relaxation and the β*‐relaxation, as well as the case of poly(4,4′‐oxydiphenylene–pyromellite‐imide) (Kapton) examined for comparison. These relaxations seem to contribute to toughness of the copolymers. The α‐relaxations for both copolymers occurred at much the same temperature of 320°C, which can be assigned to a large scale segmental motion of the quinazolone chain sequence. The α‐peak temperatures shifted into higher temperatures by heat aging. This can be explained in terms of crosslinking in the copolymers, supported by swelling test in hot m‐cresol and IR spectroscopy.
Phase separation in carboxylated polysulfone/solvent/water systems
Authors: Lau Wayne W. Y. , Guiver Michael D. , Matsuura T.
Published: April 2003

The cloud point curves for the ternary systems carboxylated polysulfones/solvent/water were determined by a titration method. Membrane‐forming solvents used were NMP, DMAc, DMF, DMSO, TMU, and DMPU. Four modified polysulfones containing 0.43, 0.93, 1.38, and 1.93 carboxyl groups per repeat unit were synthesized for this study. Water/solvent theta‐compositions and solubility parameters for these polymers were also estimated.
Plasma graft polymerization of N,N‐dimethylaminoethyl methacrylate and water–ethanol separation by pervaporation through the grafted membranes
Authors: Hirotsu Toshihiro , Arita Akito
Published: April 2003

N,N‐dimethylaminoethyl methacrylate was graft‐polymerized onto the porous polypropylene films of Celgard 2400 and 2500 which have been previously surface‐activated by glow discharge plasmas. The grafting was dependent on various factors both in the plasma pretreatment and the post‐polymerization with the monomer. The reaction was discussed from the aspects of the dependences of graft polymerization on discharge power, plasma pretreatment period, etc. When the grafting exceeded a critical amount depending on the size of pores on the substrate film, pervaporation of water‐ethanol separation functioned through these grafted membranes. The water permselectivity was improved by the ammonium ionization of the pendant N,N‐dimethylamino group using dimethyl sulfate or chloroacetic acid, although the increase of prevaporation performance was not so high as those previously obtained by the grafted poly(sodium acrylate) ‐type membranes. Pervaporation characteristics of these membranes were discussed from the ionized states of the permselective layers analyzed by IR and ESCA.
Hierarchical structure in LCP/PET blends
Authors: Silverstein M. S. , Hiltner A. , Baer E.
Published: April 2003

The structural hierarchy in injection molded blends of poly(ethylene terephthalate) (PET) and a commercial liquid crystal polymer (LCP), two immiscible polymers, was characterized at various blend compositions. The macroscopic core and skin have a gradient structure and are subdivided into ordered and disordered layers. The sublayers consist of rodlike domains at 25% LCP. The domains become thinner, longer, and more fibril‐like with increasing LCP concentration. The interconnection between the LCP domains also becomes more significant at higher LCP concentrations. The highest degree of orientation in the injection direction is at the mold surface and the lowest at the sample center. The LCP orientation reflects the elongational and fountain flow in the mold and increases with increasing LCP concentration. Schematic structural models were used to illustrate the levels of structure in these blends. A minimum exists in the tensile strength, elongation at break, and impact strength with varying blend composition at approximately 50% LCP. The tensile strength of the LCP‐rich blends is significantly lowered by the presence of a weldline or an angle between the stress and orientation directions. The unique mechanical properties of the LCP depend on the formation of a highly oriented and highly connected hierarchical structure that does not exist in blends with 75% or less LCP.
Thermal stability in air of acrylonitrile‐grafted polyethylene by electron beam prior irradiation
Authors: Mori K. , Koshiishi K. , Masuhara K.
Published: April 2003

Studies were made of the thermal softening and degradation behavior in air of low‐ and high‐density polyethylene (PE) grafted with acrylonitrile (AN) by electron beam prior irradiation in nitrogen. It was found that both LDPE and HDPE were made to exhibit higher softening points by grafting and that this tendency increased with increasing percent graft. The starting temperatures of the thermal degradation and thermogravimetric curves were also found to shift to higher temperatures. On the other hand, in marked contrast to the thermal softening and degradation behavior of grafted PE in air, its behavior in nitrogen showed substantial dependance on oxidative degradation, suggesting that the oxidation of PE was inhibited by polyacrylonitrile (PAN), which forms graft chains. It was considered that the oxidation‐inhibiting mechanism of PAN produced in the amorphous regions prevents oxygen from dissolving and diffusing into the amorphous phase, thus inhibiting the oxidative degradation of PE, and that, when heated, PAN undergoes nitrile oligomerization and the nitrile oligomer end radicals act to trap those radicals which participate in PE oxidative degradation.
Glycidyl methacrylate and N‐vinyl‐2‐pyrrolidone copolymers: Synthesis, characterization, and reactivity ratios
Authors: Soundararajan S. , Reddy B. S. R.
Published: April 2003

Free radical copolymerization of glycidyl methacrylate (GMA) and N‐vinyl‐2‐pyrrolidone (VPD) was carried out using 2,2′‐azobisisobutyronitrile (AIBN), in chloroform at 60°C. The polymers were characterized by IR and 13C‐NMR spectroscopic methods. The percentage composition of the copolymers were established by microelemental analysis and by 13C‐NMR spectroscopy. The copolymerization reactivity ratios were computed using the Fineman‐Ross method, the Kelen‐Tudos method, and the extended Kelen‐Tudos method. The molecular weights of the copolymers were obtained by GPC measurements. Thermal properties of the homo‐ and copolymers were also studied by thermogravimetric analysis. The copolymers were tested as adhesives for leather‐to‐leather and leather‐torubber bonding.
Investigation of the relationship between conductivity and protein‐binding properties of polypyrrole
Authors: Smith Abraham B. , Knowles Christopher J.
Published: April 2003

Polypyrrole was synthesized using two different methods of chemical synthesis to obtain a product with different electrical conductivity values. The two products were found to possess about the same ability to bind protein. After prolonged exposure to aqueous solutions of different ionic composition and at different pH values, the polymer was tested for electrical conductivity and protein‐binding ability. Electrical conductivity was found to vary with the conditions under which the polymer was stored, and of these, the pH of the medium was found to be the most important. On the other hand, the ability to bind protein did not show any such variation and only chemical reduction of the polymer produced a significant reduction in the level of protein binding.
Glow‐discharge‐induced graft polymerization of acrylic acid onto poly[1‐(trimethylsilyl)‐1‐propyne] film
Authors: Masuda Toshio , Kotoura Masaaki , Tsuchihara Kenji , Higashimura Toshinobu
Published: April 2003

Graft polymerization of acrylic acid onto poly[1‐(trimethylsilyl)‐1‐propyne] [poly(TMSP)] film was examined. The water contact angle of poly(TMSP) film decreased remarkably from 90 to 15° by plasma treatment, which gradually increased up to 40° after several days. When the film exposed to a glow discharge was heated in an aqueous solution of acrylic acid at 80°C for 24 h, graft polymerization proceeded on the film surface, which was confirmed by ATR‐IR and ESCA spectra. Graft polymerization effectively occurred above a threshold temperature (80°C). The water contact angle of the grafted film was about 30°, and did not change with time. In contrast, when a poly(TMSP) film exposed to UV irradiation was heated in an aqueous solution of acrylic acid, graft polymerization took place not only on the film surface but also inside the film.
A study using 13C CP/MAS NMR of microstructural changes in acrylate copolymers due to photolytic/SO2 degradation
Authors: Schadt R. J. , Gilbert R. D. , Fornes R. E.
Published: April 2003

Photolytic degradation (350 nm) of acrylate‐type copolymer films in the presence of SO2 and H2O has been examined using 13C CP/MAS NMR. Copolymers in this study are used as binders in the paint and adhesives industry. The compositions contain butyl acrylate, vinyl acetate, vinyl chloride, and methyl methacrylate units in various combinations. Elemental analyses of the samples allow comparisons and confirmations of structural changes observed in the NMR spectra. A significant result is identification of pendant sulfate group incorporation in UV/SO2/or UV/SO2/H2O‐exposed VAc/BA‐type copolymers which has been attributed to a co‐unit interaction between BA and VAc units. It is suggested that effects on Tg, the glass transition temperature, may account in part for this co‐unit effect on photodegradation.
Transient length dilation vs. transient increase in permeability of natural rubber films
Authors: Pope D. S. , Koros W. J. , Jagur‐Grodzinski J.
Published: April 2003

Air dissolved under pressure in a film, made from natural rubber, causes its slight dilation. Sudden decompression of this film leads to its large transient dilation that afterwards vanishes within less than a minute (τ ≈ 20 s). Such transient expansion is apparently caused by internal stresses due to oversaturation. This behavior is analogous to the previously reported transient increase in the permeability to gases of the suddenly decompressed polymeric membranes. A clear correlation between results derived from the dilation and the permeability measurements seems to be evident.
The sol/gel contribution to the behavior of γ‐irradiated poly(vinylidene fluoride)
Authors: Rosenberg Y. , Siegmann A. , Narkis M. , Shkolnik S.
Published: April 2003

Poly(vinylidene fluoride) films were γ‐irradiated in the dose range of 1–20 Mrad, resulting in up to 74% gel. The irradiated polymer undergoes both crosslinking and chain scission, about 5 : 3 events, respectively. Swelling measurements indicate an increasing crosslink density with the gel content, already at the lower doses. Thermal analysis of the gel fraction and the unextracted irradiated samples shows that although crosslinking affects the crystallization, degree of crystallinity, and the melting characteristics, the behavior of the crosslinked material is predominantly controlled by the extractable sol fraction which consists of the more mobile original chains, branched chains, and degraded ones. The crosslinks, already at low density, retard the development of ordinary crystalline polymer morphology.
Thermal degradation studies of perchlorate‐doped conductive polymers
Authors: Neoh K. G. , Kang E. T. , Tan K. L.
Published: April 2003

The thermogravimetric behavior of polypyrrole (PPY), polybithiophene (PBT), and poly‐aniline (PAN) perchlorate complexes and their corresponding base polymers have been studied. The PBT–perchlorate complex and base polymer decompose at significantly lower temperatures than do the PPY and PAN counterparts. All three perchlorate complexes retain half or more of their original conductivities with no changes in the doping levels after one cycle of heating to 150°C in air and cooling to room temperature. However, after heating at 150°C for 24 h, only the PAN–perchlorate complex shows no significant change in the doping level, although its conductivity decreases by more than two orders of magnitude. X‐ray photoelectron spectroscopy analyses of the perchlorate complexes reveal the presence of at least two distinct chlorine species. The thermal decomposition of the perchlorate anions results in the formation of volatile chlorine species as well in chlorine covalently bonded to the polymer. The thermal decomposition of the PPY–perchlorate complex also results in the conversion of positively charged nitrogens to iminelike structures.
Relation between low‐frequency dielectric behavior of cellulosic materials and their inorganic contaminations
Authors: Moteleb M. M. Abdel , Shinouda H. G.
Published: April 2003

Results are given for dielectric constant and loss factor of some cellulosic materials of different fine structure free of and contaminated with water‐soluble inorganic salts in the frequency range 0.1–100 kc/s and at temperatures 283.15–333.15 K. The analysis of the results reveals that the dielectric dispersion and loss peak found before with medicated cotton and viscose rayon, of ash contents of 0.3 and 1.4% respectively, disappear when these fibers have been “cleaned up” from inorganic impurities by acid washes. These anomalous dielectric behaviours reappear again with “cellulose‐inorganic salts” admixtures. Based on these findings, it has been concluded that the secondary relaxation process observed in the low‐frequency region 0.1–1 kc/s with cellulosic materials contaminated with inorganic impurities is not intrinsic but extrinsic in nature due to the displacement of ions adsorbed in the inner surfaces of such interstitial conduction system.
Segmental orientation behavior of flexible water‐blown polyurethane foams
Authors: Moreland J. C. , Wilkes G. L. , Turner Robert B.
Published: April 2003

The ambient temperature structure–property orientation behavior in two different polyureaurethane polymers (one cross‐linked and one linear) was measured by using infrared dichroism along with mechanical response. Thin films (plaques) thermally compression‐molded from TDI‐polypropylene (PO) flexible water‐blown polyurea‐urethane foams and solution‐cast TDI–PO polyurea–urethane elastomers were studied. Segmental orientation was measured as a function of elongation and relaxation, as well as of hysteresis behavior. The level of strain was 50–70% for the plaques and up to 240% for the elastomer. The soft segments for both materials exhibited a low state of orientation with elongation. Small changes in orientation with time and upon cyclic straining were also observed for the soft segments. Significant transverse orientation upon stretching was observed in the hard segments of the plaques and up to elongations of 100% for the elastomer. The transverse behavior of the hard segments in the plaques pressed from the foams was attributed to both the smaller hard domains as well as to the polyurea aggregates that have been reported to be present in flexible foams. This transverse behavior also suggested that the smaller hard domains and the polyurea aggregates possess a lamellarlike structure. At low strain levels (up to 50%), only small amounts of orientation hysteresis as well as mechanical hysteresis were observed for the hard segments of the plaques as well as for the elastomer. No significant relaxation in orientation was detected for the hard segments of both materials at a 30% strain level.
Preparation, morphology, and deformation behavior of polyoxypropylene‐co‐nylon 6 thermoplastic elastomers
Authors: Sikkema D. J.
Published: April 2003

Segmented block copolymers consisting of nylon 6 and polyoxypropylene blocks were prepared and characterized. Pronounced phase separation in the solid phase was deduced from differential calorimetry and from small‐angle X‐ray scattering, as well as from dynamic mechanical measurements. The morphology (from X‐ray diffraction) and anisotropy in mechanical properties strongly suggest phase separation in the melt (which is optically clear). Elastomerlike properties are described and discussed.