bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and properties of polyurethane‐polystyrene‐grafted interpenetrating polymer networks using a microgel process
Authors: Chen Hui , Chen Jiann‐Ming
Published: April 2003

Polyurethane‐polystyrene‐grafted interpenetrating polymer networks (IPNs) were prepared in the presence of a soluble microgel. The objective was to understand the effect of the microgel on the physical and mechanical properties of the IPN systems. Three types of microgels were prepared by the condensation reaction of various amounts of tolylene diisocyanate (TDI) with linear polystyrene containing hydroxyl groups. The structure of the microgel was determined by gel permeation chromatography and intrinsic viscosity measurement. Increasing the amount of TDI resulted in a microgel having a more compact structure. The dynamic mechanical behavior, mechanical properties, densities, and swelling ratios of the IPNs were determined. Only one broad Tg was observed in each of the dynamic mechanical spectra of the IPNs, whether the IPNs were prepared from microgel or not. This is because of increased compatibility of the two networks by the grafting reaction. Using a microgel to prepare IPNs could further improve the degree of network interpenetration. In addition, higher tensile strength and elongation at break were obtained for the IPNs, when the proper structure of the microgel was used. © 1993 John Wiley & Sons, Inc.
Hybrid‐particulate composites based on an epoxy matrix, a reactive rubber, and glass beads: Morphology, viscoelastic, and mechanical properties
Authors: Maazouz A. , Sautereau H. , Gerard J. F.
Published: April 2003

The deformation and fracture behaviors of hybrid‐particulate epoxy composites have been examined. These materials were based on a DGEBA/DDA matrix with various volume fractions of glass beads and different rubber contents. Young's modulus, yield stress, dynamic mechanical spectra, and fracture energy have been determined at room temperature. The Kerner model fits well the Young's modulus for the hybrid complexes with various glass bead contents. The analysis of the relaxation peak recorded from viscoelastic measurements allow us to discuss the influence of the introduction of the glass beads on the mobility of macromolecular chains and the characteristics of the rubber‐separated phase. The fracture energy displays a strong improvement and a synergism effect due to the presence of both kinds of particules. The toughening mechanisms were discussed. © 1993 John Wiley & Sons, Inc.
Synthesis of plasticizing polyesters of dimer acid and propane–diol
Authors: Bajpai U. D. N. , Nivedita Ms.
Published: April 2003

The polyesterification of dimer acid with propane–diol under different experimental conditions has been studied to obtain the optimum conditions for synthesizing the poly(propane–diol) dimerate plasticizers. The effect of varying molar ratio, temperature, and catalyst concentration on the course of the reaction, acid number, intrinsic viscosity, and molecular weight of the resultant polyester has been investigated. p‐Toluene sulfonic acid (PTSA) was found to be an effective catalyst for the polyesterification reaction. The kinetics of polyesterification in the presence and absence of a catalyst has been found to follow the second‐order rate equation in equimolar concentrations of the reactants. © 1993 John Wiley & Sons, Inc.
Epoxidation of natural rubber in latex in the presence of a reducing agent
Authors: Bac Nguyen Viet , Terlemezyan Levon , Mihailov Marin
Published: April 2003

The in situ epoxidation of natural rubber latex was successfully performed in chain‐scissoring conditions. The chain‐scissoring process could be carried out simultaneously or successively to the epoxidation, to a determined extent. The rate and the degree of epoxidation depend on temperature, pH, and H2O2/isoprene units ratio. The chain‐scissoring reaction leads to a limited intrinsic viscosity range and, at pH 2–3, it was practically completed in 24–40 h. The gel content of epoxidized natural rubber (ENR) products are markedly reduced in the presence of reducing agent. Infrared spectra of ENR, thus prepared, are characterized by the presence of a typical weak band at 1550 cm−1, in addition to the other characteristic bands for normal ENR. At low pH and long‐lasting reaction, the epoxide ring undergoes a ring‐opening process, resulting in the formation of new OH, CO, ether groups, and slightly increased gel content. The Huggins constant, for a typical series of ENR obtained in redox conditions, was determined. © 1993 John Wiley & Sons, Inc.
13C NMR analysis method for urea–formaldehyde resin strength and formaldehyde emission
Authors: Ferg E. E. , Pizzi A. , Levendis D. C.
Published: April 2003

A method based on the use of 13C NMR relative peak intensity ratios for different characteristic chemical groups, known or supposed to contribute to urea‐formaldehyde (UF) resin strength and formaldehyde emission is presented. The method relates results obtained by 13C NMR analysis of liquid UF resins with their strength, formaldehyde emission, and percent crystallinity in the resin‐hardened state. Correlation of different peak ratios with experimental results allows the proposal of equations relating the sum of a number of different 13C NMR peak ratios with the three mentioned physical properties of the same resins in their hardened state. Resin strength and percent crystallinity appear to be loosely, inversely related. The equations presented appear to have some applied value in predicting physical properties of hardened industrial‐type UF resins from a single 13C NMR spectrum of the original liquid resins, as well as to render easier comparison between difficult UF resin formulations. This approach has allowed identification of which chemical groups really contribute to the physical properties of the hardened resin, and to what exten. © 1993 John Wiley & Sons, Inc.
Surface activation of polytetrafluoroethylene by bonding of polymeric silicic acid
Authors: Mohammed Mohammed A. , Rossbach Volker
Published: April 2003

When porous polytetrafluoroethylene (PTFE) is treated in a silicon tetrahalide atmosphere and then hydrolysed by means of a water jet, it is possible to achieve surface activation of the PTFE with silicic acid. This results in the surface of the PTFE becoming completely wettable, particularly if SiCl4 is used. This paper provides an account of the physical and chemical investigation into the surface of the activated system. Measurement of the contact angles (with water) and determination of the silanol groups provide evidence of the surface activity. ESCA experiments show that concentrations of silicic acid above 14% w/w result in almost complete coverage of the PTFE surface. Using the BET method to measure the specific surface area, it can be seen that this is not simply a result of adding the areas of the two components, PTFE and silicic acid. © 1993 John Wiley & Sons, Inc.
Grafting of styrene onto polybutadiene: Calculation of the molecular macrostructure
Authors: Estenoz D. A. , Meira G. R.
Published: April 2003

The radical‐induced grafting of styrene onto polybutadiene at 60°C and in dilute solution is theoretically investigated, with the aim of estimating the detailed molecular macrostructure of the evolving polymer mixture. To this effect, the kinetic mechanism proposed by Brydon et al. [J. Polym. Sci. Polym. Chem. Ed., 11, 3255 (1973) and 12, 1011 (1974)] was extended to evaluate the bivariate weight chain‐length distribution (WCLD) for each of different copolymer topologies generated along the polymerization. Each molecular topology is characterized by two integers: the number of grafted styrene chains and the number of incorporated butadiene chains. Apart from the bivariate WCLDs for every topology and for the total copolymer, the molecular weight distributions of the accumulated polystyrene and of the unreacted polybutadiene are calculated. The model predictions of global variables (monomer conversion, polymer production, average molecular weights, grafting efficiencies, and average number of graft sites per reacted polybutadiene molecule) closely match the experimental measurements in the cited publications. © 1993 John Wiley & Sons, Inc.
Surface and interfacial FT‐IR spectroscopic studies of latexes. VII. EA/MAA latex suspension stability and surfactant migration
Authors: Thorstenson Timothy A. , Tebelius Lara K. , Urban Marek W.
Published: April 2003

This article, part VII in a series of latex studies, focuses on the effect of ethyl acrylate/methacrylic acid (EA/MAA) latex stability on the exudation of sodium dioctyl sulfosuccinate (SDOSS) surfactant molecules after coalescence. It is found that “aging” of the latex aqueous suspension causes excessive exudation of the surfactant molecules to the film‐air interface. Upon exudation to the surface, the surfactant SO Na+ hydrophilic heads assemble in preferentially normal‐to‐the‐surface directions, whereas hydrophobic aliphatic tails are randomly burred in the latex surface. ATR FT–IR spectroscopy and a particle size analysis are utilized to elucidate the effects of flocculation and coalescence on the surfactant mobility in latex films. It appears that flocculation, prior to coalescence, enhances exudation and mobility of the surfactant molecules. © 1993 John Wiley & Sons, Inc.
Gas‐transport properties of ethylene/propylene/carbon monoxide polyketone terpolymer
Authors: Del Nobile M. A. , Mensitieri G. , Nicolais L. , Sommazzi A. , Garbassi F.
Published: April 2003

The demand for heat‐stable and easily processable polymeric materials with good gasbarrier properties is becoming more and more important due to the advent of new technological applications in the field of food packaging. A renewed interest has arisen for a polyketone class of polymers, which seems to fulfill these requirements. Our attention has been focused on a polyketone terpolymer (0.93 : 0.07 : 1 ethylene/propylene/carbon monoxide) in order to determine the transport properties and to relate them to the polymer structure. Permeability tests have been performed at three different temperatures (25, 35, and 45°C) with three different gases (helium, oxygen, and carbon dioxide). Permeabilities, diffusivities, and solubilities have been evaluated. Their dependence on temperature was interpreted on the basis of permeation and diffusion apparent activation energies (Ep and Ed) and of heats of solution (ΔHs). The investigated polymer has been found to be rubbery at the test temperature (glass transition temperature is about 17°C), but the detected permeabilities are comparable to those of glassy polymers widely used for packaging applications. The experimentally determined diffusion coefficients have been related to the semicrystalline nature of the polymer and to the different dimensions of the gas adopted in the investigation. The gas‐solubility coefficients determined from permeability measurements were related to the force constant of the gas molecules in the Lennard‐Jones (6–12) potential field equation. © 1993 John Wiley & Sons, Inc.
Development of a new advanced process for manufacturing polyacetal resins. Part I. Development of a new process for manufacturing highly concentrated aqueous formaldehyde solution by methylal oxidation
Authors: Masamoto J. , Iwaisako T. , Chohno M. , Kawamura M. , Ohtake J. , Matsuzaki K.
Published: April 2003

A new technology for the production of highly concentrated aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mol of water per 1 mol of formaldehyde, methylal oxidation produces only 1 mol of water for every 3 mol of formaldehyde. Thus, the output from methylal oxidation is more than 70% formaldehyde compared with 55% from methanol oxidation. For this purpose, basic research for methylal synthesis was tried and the world's first commercial production of methylal was accomplished. Using this methylal, the world's first technology of methylal oxidation for manufacturing highly concentrated aqueous formaldehyde was established by development of a new methylal oxidation catalyst composed of iron, molybdenum, and a third component. This highly concentrated aqueous formaldehyde is then fed to the acetal homopolymer and copolymer plant whose combined capacity is 35,000 tons/years. © 1993 John Wiley & Sons, Inc.
Entanglement fluctuation during phase separation in polymer blends
Authors: Xie Rui , Liang Haojun , Yang Bingxin , Jiang Bingzheng , Zhang Qizhong , Xu Yuanze
Published: April 2003

For perhaps the first time, the dynamics of liquid‐liquid phase separation was studied by time‐resolved mechanical spectrometry in order to establish the relationship between blends' properties and the phase structures during spinodal decomposition (SD). The selected system was chlorinated polyethylene (CPE)/ethylene‐vinyl acetate copolymer (EVA). It was found that in the early and intermediate stage of SD, the storage modulus (G′) and the loss modulus (G″) increase with time after the initiation of the isothermal phase separation; in the later stage, G′ and G″ decrease as phase separation proceeds. An entanglement fluctuation model was presented to manifest this phenomenon; it was found that the rheological behavior agrees well with the expections of the model in the early stage. For the later stage, the reduction of G′ and G″ can be attributed to the increment of phase‐domain size. © 1993 John Wiley & Sons, Inc.
High‐temperature dynamic laser light‐scattering characterization of polyethylene in trichlorobenzene
Authors: Wu Chi , Lilge Dieter
Published: April 2003

Polyethylene samples were characterized in trichlorobenzene at 135°C by high‐temperature dynamic laser light scattering (LLS). Precise measurements of the intensity‐intensity time correlation function permit us to make a Laplace inversion to obtain an estimate of the normalized translational diffusion coefficient distribution [G(D)]. After establishing a calibration between the translational diffusion coefficient (D) and molar mass, by using six moderately dispersed polyethylene samples, we were able to transform G(D) to molecular weight distribution (MWD), and to calculate the weight average molecular weight (Mw), which weights were comparable with the ones obtained by using static LLS and size exclusion chromatograph (SEC). The advantages and limitations of using dynamic LLS as a routine method to characterize of polyethylene are discussed. © 1993 John Wiley & Sons, Inc.
Physical properties of silk fibers treated with ethylene glycol diglycidyl ether by the pad/batch method
Authors: Tsukada Masuhiro , Shiozaki Hideki , Goto Yoko , Freddi Giuliano
Published: April 2003

This paper deals with the epoxide treatment of silk fabrics by the pad/batch method. The optimum reaction conditions, i.e., NaOH concentration, and reaction temperature were 2.5 g/L and 30°C, respectively. A weight gain of 8.5% was attained at a reaction time of 6 h. This value slightly increased to 10% after 24 h. The reactivity of tyrosine and basic amino acid residues was dependent on the reaction time and did not significantly differ from the results of epoxide‐treated silk fiber by the conventional method in tetrachloroethylene. The moisture regain slightly decreased at 4% weight gain and then increased with the epoxide content, exceeding the value of the untreated control. The crease recovery of the epoxide‐treated silk fabrics measured in the wet state was significantly improved, whereas that in the dry state was almost unchanged. The rate of photoyellowing of the epoxide‐treated silk fabrics by the pad/batch method was reduced significantly compared with that of the untreated control. Among the mechanical properties, elongation at break and tensile modulus remained unchanged, whereas the tensile strength slightly increased following the epoxide reaction. The thermal properties were evaluated by DSC and TGA and on the basis of the dynamic viscoelastic measurements. The DSC curve of the epoxide‐treated sample showed a slight increase of the decomposition temperature of silk fibroin. The rate of weight loss determined by TGA remained unchanged regardless of the chemical modification, whereas the peak of loss modulus became broader and shifted to lower temperature. The X‐ray diffractograms showed that the crystalline structure of silk fibers was not affected by the reaction with epoxides. © 1993 John Wiley & Sons, Inc.
Photoinitiated oxidation of heterophasic ethylene–propylene copolymers. I. Comparison of oxidation products
Authors: Singh R. P. , Mani R. , Sivaram S. , Lacoste J. , Vaillant D.
Published: April 2003

Detailed photoproducts from photoirradiation of heterophasic ethylene‐propylene copolymers and their fractions have been compared by infrared spectroscopy combined with chemical derivatization. The oxidized films were treated with gaseous NH3, SF4, and NO for the rapid identification and resolution of the various carbonyl species, alcohols, and hydroperoxides. The photoproduct formation depends upon the composition of the sample. The heterogeneities in thin films were also determined by micro FTIR spectroscopy. © 1993 John Wiley & Sons, Inc.
Prediction of gas permeability of nylon from glass‐transition temperature
Authors: Eichler Sigal , Miltz Joseph
Published: April 2003

A method to predict the permeability coefficients of gases in nylons at different relative humidities was proposed. The model was tested for Nylon 6 and 6,6 with oxygen as a permeant. Very good agreement between the predicted and experimentally determined values was found. © 1993 John Wiley & Sons, Inc.
Isolation and identity verification of polyalkylene glycols in fire resistant hydraulic fluids type C and D U
Authors: Van Dam J. , Daenens P. , Busson R.
Published: April 2003

A procedure to verify the identity of hydraulic fluids (HF) type C and D U is described. Different gel filtration systems were tested to separate the constitutive components. After fractionation of the mixture, IR and NMR spectroscopy were tried for their suitability in verifying the identity of the different constituents. The combination of aqueous gel filtration chromatography and IR spectroscopy was found suitable to separate and identify the different components of HFC fluids. For HFD U fluids, a modified gel filtration system was used and NMR spectroscopy was necessary to give a decisive answer about their identity. © 1993 John Wiley & Sons, Inc.
Influence of chain microstructure on thermodegradative behavior of furfuryl methacrylate‐N‐vinylpyrrolidone random copolymers by thermogravimetry
Authors: Peniche Carlos , Zaldívar Dionisio , Bulay Anna , Román Julio San
Published: April 2003

The thermal behaviour of random copolymers of furfuryl methacrylate (F) and N‐vinylpyrrolidone (P) was studied by means of dynamic thermogravimetric analysis (TGA) in the range 100–600°C. The dynamic experiments show that these copolymers exhibit two degradation steps in the intervals 260–320°C and 350–520°C, respectively. The normalized weight loss in the low temperature interval increases as the mole fraction of F in the copolymer mF increases, whereas an inverted trend in the high temperature interval is observed. The apparent activation energy Ea of the first degradation step for copolymers prepared with different composition, was obtained according to the treatment suggested by Broido. A plot of the values of Ea versus the F diad molar fraction in the copolymer chains mFF gave a straight line that indicates that there is a direct relationship between the thermogravimetric behaviour of these systems and their corresponding microstructure, that is, the distribution of comonomeric units along the copolymers chains. The first decomposition step was also studied by isothermal TGA and a good linearity for the variation of the weight loss percentage ΔW versus mF at least during the first 30 min of treatment was obtained. These results also indicate that from a kinetic point of view the isothermal degradation in these conditions follows a first order behaviour and the corresponding reaction rate constants increase linearly with mFF. © 1993 John Wiley & Sons, Inc.
Sequential‐interpenetrating polymer networks from castor oil‐based polyesters. XXVI.
Authors: Suthar Bhikhu , Dave Mayank , Jadav Kanak
Published: April 2003

Polyesters were obtained from castor oil and dibasic acids for example, malonic, succinic, glutaric, adipic, suberic, and sebacic acids. These prepolyesters were characterized by infrared spectrometry, viscosimetric measurements, and molecular weight determinations (GPC). These prepolyesters were mixed with methyl methacrylate and were subsequently polymerized by free radical polymerization by benzoyl peroxide in the presence of the crosslinker ethylene glycol dimethacrylate. Polyester/poly(methyl methacrylate)‐interpenetrating polymer networks, PPE/PMMA IPNs, were obtained as soft and opaque elastomers by the transfer molding technique. These IPNs were characterized by static mechanical properties, differential scanning calorimetry (DSC), and thermogravimetry. © 1993 John Wiley & Sons, Inc.
Stress relaxation behavior of polyacetal–thermoplastic polyurethane elastomer blends
Authors: Kumar G. , Arindam Mr. , Neelakantan N. R. , Subramanian N.
Published: April 2003

The yield stress of polyacetal (POM) decreases monotonically with the incorporation of thermoplastic polyurethane (TPU) elastomer in POM/TPU blends as would be anticipated. However, the impact strength of the resultant POM/TPU blends increases initially up to 30% TPU and thereafter decreases with the addition of TPU. Stress relaxation measurements in simple extension were carried out for POM and its blends with 10, 20, and 30% TPU at a constant temperature (30°C). Rate of loss of the relaxation modulus was found to be a nonlinear function of time. It has been demonstrated that the stress relaxation modulus values measured at different strains can be superimposed by a shift along the logarithmic time axis to yield master curves of modulus over an extended time period. It has also been found that while it is possible to determine, at any strain, relaxation curves covering an appreciable time range, the demarcation of linear and nonlinear behavior ranges of stress could not be done for these materials as all the strain values chosen in our experiments were in the region of linear behavior. © 1993 John Wiley & Sons, Inc.
Mechanical properties of thermoplastic elastomers of poly(butylene terephthalate) and poly(ethylene glycol) in a bending deformation
Authors: Wang Shuhong , Mark J. E. , Erman B. , Fakirov S.
Published: April 2003

Thermoplastic elastomers based on poly(butylene terephthalate) (PBT) and poly(ethylene glycol) (PEG) were studied by bending‐creep measurements. The dependence of the creep compliance on the composition of the block copolymer was determined, and the experimental results were compared with calculated results to obtain a better understanding of structure‐property relationships for this class of materials. The hard PBT domains in the rubbery PEG matrix make a large contribution to the mechanical strength and hardness, presumably serving as reinforcing fillers as well as cross‐links. Relaxation effects were found to decrease significantly with increase in hard‐segment content. © 1994 John Wiley & Sons, Inc.
The thermal decomposition of sulfenamide accelerators
Authors: Gradwell M. H. S. , Mcgill W. J.
Published: April 2003

The thermal decomposition of three sulfenamide accelerators N‐cyclohexylbenzothiazole sulfenamide (CBS), 2‐(4‐morpholinothio) benzothiazole (MOR) and 2‐t‐butylaminobenzothiazole sulfenamide (TBBS) were investigated by differential scanning calorimetry. The sulfenamides decompose rapidly at 210–220°C, yielding a number of products, including reactive polysulfidic complexes. Thus, CBS gives N‐cyclohexylamino‐2‐benzothiazole polysulfides (CBP), 2‐bisbenzothiazole‐2,2′‐disulfide (MBTS), 2‐bisbenzothiazole‐2,2′‐polysulfides (MBTP), 2‐bisbenzothiazole‐2,2′‐monosulfide (MBTM), 2‐mercaptobenzothiazole (MBT), and 2‐N‐cyclohexylaminobenzothiazole (CB). The polysulfides are unstable, and on prolonged heating, only MBT and CB remain. The amine fragment of the accelerator is present as the amine salt of MBT. At lower temperatures, the sulfenamides are relatively stable. MOR forms an analogous product spectrum. The decomposition of TBBS is endothermic, in contrast to the exothermic reaction observed with CBS and MOR, and the concentrations of the various polysulfides do not decrease on prolonged heating. Reaction mechanisms are proposed to account for the formation of the products. © 1994 John Wiley & Sons, Inc.
Gamma‐sterilization effects and influence of the molecular weight distribution on the postirradiation resistance of polypropylene for medical devices
Authors: Martakis Nick , Niaounakis Michael , Pissimissis Dimitris
Published: April 2003

In the present study, the dose‐rate effects of γ‐irradiation in air on two isotactic polypropylene grades of different molecular weight distribution, used for medical devices, were investigated. The thermal, mechanical, rheological, and photometric properties of these materials were examined using DSC, stress–strain measurements, MFI, and a yellow index. At low dose rates (0.12 Mrad/h), the oxygen diffusion parameter prevailed. At high dose rates (2.84 Mrad/h), the thermal degradation became dominant. However, at high dose rates, an increase in sample temperature was monitored. This temperature rise is thought to increase the oxygen diffusion rate, peroxide decomposition, and radical migration. As a result, intermediate dose rates (in the region of 0.72 Mrad/h) gave the lowest changes in physical properties in both samples. Furthermore, it was found that the polypropylene grade of broader molecular weight distribution and lower Mn had a higher γ‐irradiation and postirradiation resistance. © 1994 John Wiley & Sons, Inc.
Cure behavior of paper–phenolic composite systems: Kinetic modeling
Authors: Kiran Erdogan , Iyer Rajan
Published: April 2003

Cure reactions in paper–phenolic composite systems were studied by differential scanning calorimetry. A phenomenological approach was used to characterize the cure kinetics. Various kinetic models including homogeneous reaction, diffusion‐controlled reactions, surface reaction and phase boundary movement, and nucleation and growth‐type kinetic models have been tested. Kinetic analyses using integral and derivative procedures on dynamic and isothermal data indicate that the cure reaction data can be described well with the homogeneous first‐order reaction model or the Jander three‐dimensional diffusion model. The activation energies are found to be in the range 20–40 kj/mol. © 1994 John Wiley & Sons, Inc.
Reactivity ratios and microstructure of vinyl acetate–butyl methacrylate copolymers: NMR study
Authors: Brar A. S. , Charan Shiv
Published: April 2003

Vinyl acetate/butyl methacrylate (V/B) copolymers were prepared by free‐radical solution polymerization in benzene. Compositions of the copolymers have been obtained from 1H‐NMR spectroscopy. Kelen–Tüdös (KT), the nonlinear error in variables method (EVM), and 13C{1H}‐NMR spectra of the copolymers were utilized to calculate the comonomer reactivity ratios. The reactivity from different methods are rV = 0.06 ± 0.02, rB = 26.34 ± 8.49 (KT); rV = 0.06 ± 0.01, rB = 26.88 ± 3.59 (EVM); and rV = 0.06, rB = 18.20 (13C‐NMR spectroscopy). The microstructure in terms of V‐ and B‐centered triad fractions was obtained using 13C{1H}‐NMR spectra of copolymers. The copolymerization behavior of V/B copolymers as a function of conversion was also studied. © 1994 John Wiley & Sons, Inc.
Decomposition of polyurethane foams by alkanolamines
Authors: Kanaya Kouji , Takahashi Shizuo
Published: April 2003

Methylene diphenyl isocyanate (MDI)‐based polyurethane flexible foams were decomposed by alkanolamines without a catalyst at 150°C. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, and the lower liquid layer was methylene diphenyl amine (MDA) and alkanolamine derivatives. These layers were analyzed using gel permeation chromatography (GPC) and 13C‐NMR. The upper layer was obtained as a relatively pure polyether. The lower layer was observed to be MDA and 2‐hydroxyethyl carbamic acid ester prepared from alcoholysis products during the decomposition reaction. It was thought that the decomposition process of polyurethane foam by alkanolamines was not aminolysis but alcoholysis. © 1994 John Wiley & Sons, Inc.
Polymer–filler interaction in polyurethane kraft lignin polyblends
Authors: Feldman D. , Lacasse M. A.
Published: April 2003

Kraft lignin fillers have been shown to enhance the mechanical characteristics of different types of polymeric‐based sealants; however, the mechanism for reinforcement and the degree of interaction was not well understood. In this study, interactions between a polyurethane‐based elastomer and various Kraft lignin fillers as well as kaolin and titanium dioxide filler combinations were investigated in an effort to determine the most useful elastomer–filler combination for use as a construction joint sealant. A relationship that describes and relates the characteristics of polymer–filler interaction requires that the surface‐energy properties of both the polymer matrix and the filler be determined. Measurements using the sessile drop method are used to evaluate the critical surface energy of the polymer matrix, whereas the rate of rise of a liquid through a bed of filler provides the means to evaluate the surface energetics of the various fillers. Results obtained from this study show that the tensile modulus of the different elastomer formulations are proportional to the equilibrium work of adhesion, as described by the relationship derived by Lee that relates the degree of interaction of the formulation components and the mechanical properties of the blends. © 1994 John Wiley & Sons, Inc.
A phenomenology based equation of state for polymer melts
Authors: Arends C. B.
Published: April 2003

An equation of state for polymer melts has been devised from observation on pressure–volume–temperature data for several thermoplastics. The final equation has the form (P + Π − mT ln (cV*)) ln (cV*) = gT, where P is pressure; T, absolute temperature, V*, the volume normalized by van der Waal's volume, and Π, m, g, and c, parameters. Pertinent ancillary relationships include a “universal” bulk modulus vs. a normalized volume function and an observation that the thermal expansion coefficient is solely dependent on pressure. We find that the parameter “Π” is precisely the first derivative of internal energy with respect to volume and is evaluated from the thermal expansion coefficient and bulk modulus. It appears that “Π” is constant over a wide range of conditions. The parameters “m” and “g” are related through the bulk modulus relation. Finally, “c” has been found to be nearly a constant whose action is to change the volume reference state to the melt volume when extrapolated to absolute zero. The “universal” nature of the temperature‐reduced bulk modulus and the constancy of Π suggest that the melt state is controlled by entropy rather than by potential energy. © 1994 John Wiley & Sons, Inc.
Lower critical solution temperature (LCST) polymer solution for clear/cloud glazing applications
Authors: Gundlach D. P. , Burdett K. A.
Published: April 2003

An aqueous‐based clear/cloud solution was developed using poly(vinyl methyl ether) and an antifreeze mixture of ethylene and propylene glycols. The solution has a controllable cloud point from 15 to 90°C, freeze protection to −46°C, and a density that prevents the precipitated polymer from settling and is fairly stable to UV degradation. A significantly smaller heat gain is achieved through the clear/cloud glazing when compared to a normal double‐pane window. © 1994 John Wiley & Sons, Inc.
Photoinitiated graft copolymerization of glycidyl methacrylate and 2‐hydroxyethyl methacrylate onto polyacrylonitrile and application of the synthesized graft copolymers in penicillin–amidase immobilization
Authors: Pashova V. S. , Georgiev G. S. , Dakov V. A.
Published: April 2003

The photoinitiated graft copolymerization of hydroxyethyl methacrylate and/or glycidyl methacrylate onto polyacrylonitrile (PAN) and the applicability of the matrices synthesized in this way for penicillin–amidase immobilization are discussed. The copolymers are prepared by putting irradiated PAN fibers with preliminary adsorbed benzophenone on them into the polymerization feed that includes hydroxyethyl methacrylate and/or glycidyl methacrylate dissolved in a water–methyl ethyl ketone mixture. The degree of grafting varies between 11.7 and 46.0%, and its efficiency, between 27.8 and 78.9%. The concentration of epoxy groups in the synthesized copolymers is in the range between 210 and 2220 μmol/g. The reactivity ratios of the two comonomers are determined to be rGM = 0.70 ± 0.15 and rHEMA = 2.73 ± 0.14. The grafted copolymers containing HEMA units provide milder conditions for penicillin–amidase covalent binding. The optimum pH and temperature values of penicillin–amidase immobilized on these matrices are 7.5 and 45°C, respectively. © 1994 John Wiley & Sons, Inc.
Dynamics of solvent diffusion in an aromatic polyimide
Authors: Moon Yoon Duk , Lee Young Moo
Published: April 2003

Diffusion behaviors of two polyimides (PIs) synthesized from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), 4,4′‐oxydianiline (ODA), and 4,4′‐diaminodiphenylsulfone (DDS) were investigated by the gravimetric method. The weight uptake of penetrants (solvents) was nearly proportional to the exposure time in solvent. This phenomenon was considered as the Case II diffusion (non‐Fickian) mechanism. Two PI films had an affinity to N‐methyl‐2‐pyrrolidinone (NMP) rather than to dimethylsulfoxide (DMSO). The solubility parameter differences between two polyimides and NMP are less than 5, whereas that between polyimides and DMSO are greater than 5, as calculated by Hoy's group contribution method. The solvent uptake of anisotropic films contributed to an increase in the thickness. The swollen amount of anisotropic films increased with the swelling temperature but tended to decrease with the imide content and the thickness of the anisotropic films. Isotropic films of two PIs did not swell in both NMP and DMSO. © 1994 John Wiley & Sons, Inc.
Copolyesters. VII. Thermal transitions of poly(butylene terephthalate‐co‐isophthalate‐co‐adipate)s
Authors: Chang Shinn‐Jen , Tsai Hong‐Bing
Published: April 2003

The copolyesters of 1,4‐butanediol, terephthalic acid, isophthalic acid, and adipic acid with different compositions were prepared by melt polycondensation. The intrinisic viscosity of the copolyesters was controlled to be about 0.7–1.0 dL/g. Their second‐run thermal properties were determined by DSC. The composition was found to be a major factor in the determination of the thermal transitions. The effect of the composition on the glass transition temperature and melt transition temperature was interesting. The glass transition temperature was found to be dependent mainly on the content of adipic acid. As the content of adipic acid increased, the glass transition decreased. When the content of terephthalic acid was not less than 35 mol % based on the total diacid monomers, the melting temperature was dependent mainly on the content of terephtalic acid and increased with incrase of the content of terephthalic acid. When the content of terephthalic acid was less than 35 mol %, the melt temperature of the copolyesters did not follow a simple rule. However, the effect of the composition on their melting enthalpy showed no simple trend. © 1994 John Wiley & Sons, Inc.
Specialty polymeric membranes 3. Pervaporation separation of acetic acid/water mixtures through polymeric membranes having a pyridine moiety as a side group
Authors: Yoshikawa Masakazu , Kuno Shin‐Ichi , Kitao Toshio
Published: April 2003

Pervaporation of an acetic acid/water mixture was studied through synthetic polymeric membranes made from poly(1‐butyl methacrylate), poly(2‐ethylhexyl methacrylate), polystyrene, and copolymers of 4‐vinylpyridine and styrene, whose mole fraction of 4‐vinylpyridine was 0.028 or 0.050. Permselectivities through polystyrene and poly(4‐vinylpyridine‐co‐styrene) (mole fraction of 4‐vinylpyridine, 0.050) are discussed based on the solution‐diffusion theory. © 1994 John Wiley & Sons, Inc.
Electrical behavior of carbon black‐filled polymer composites: Effect of interaction between filler and matrix
Authors: Tang H. , Liu Z. Y. , Piao J. H. , Chen X. F. , Lou Y. X. , Li S. H.
Published: April 2003

The effect of interaction between carbon black and polymer on electrical behavior was studied using the ESR method. The polymer matrices used were HDPE, LDPE, and ethylene/vinyl acetate (EVA). Two kinds of carbon blacks (CB), high structure CSF‐III and low structure FEF, were used as a conductive filler. Compared to that of the HDPE/FEF compound, the positive temperature coefficient (PTC) intensity is lower and electrical reproducibility is worse for the HDPE/CSF‐III compound; however, it can be improved significantly by radiation cross‐linking. On the other hand, the cross‐linking has no practical effect on the PTC intensity of the LDPE/CSF‐III compound while it can be achieved by mixing the compound for a longer time. The great PTC intensity was obtained in the HDPE/EVA/CSF‐III compound, and it is greater than that of HDPE/CSF‐III or EVA/CSF‐III. We explain these results using the concept of interaction between the filler and matrix. The absorption of the polymer on the carbon black surface may be physical or chemical; the latter is caused by the free‐radical reaction between the polymer and carbon black, and it can occur during the radiation or preparation process of the compound. These “bound polymers” are essentially important for materials to have a great PTC intensity and good reproducibility. © 1994 John Wiley & Sons, Inc.
Preparation and properties of transparent and conducting nylon 6‐based composite films
Authors: Im Sung Soon , Byun Sung Weon
Published: April 2003

Highly transparent and conducting polypyrrole–(PPy–N) and polyaniline–nylon 6 (PAN) composite films could be easily obtained by immersing nylon 6 films containing pyrrole or aniline into an oxidant solution such as aqueous FeCl3 solution or aqueous (NH4)2S2O8 solution containing HCl. The conductivity, transmittance, and mechanical properties of these composite films were affected by the preparative conditions. The maximum conductivity and transmittance of the PPy–N composite films were 10−3 S/cm and about 75% at 550 nm, and in the case of the PA–N composite films, 10−2 S/cm and 75%, respectively. The morphology of PPy–N and PA–N composite films depended on the polymerization conditions, which might be due to the difference in the polymerization speed of pyrrole or aniline in polymer matrices. These PPy–N and PA–N composite films exhibited good environmental stability and excellent mechanical properties. © 1994 John Wiley & Sons, Inc.
Polarized internal reflectance spectroscopic studies of oriented poly(ethylene terephthalate)
Authors: Lofgren E. A. , Jabarin S. A.
Published: April 2003

Polarized internal reflectance spectroscopy (IRS) has been used to evaluate molecular orientation and crystallinity of poly(ethylene terephthalate) film surfaces. Measurements were taken using samples stretched in both uniaxial and biaxial modes. All bands of interest were normalized with a reference band near 1410 cm−1, resulting from phenylene ring vibrations. Normalization was performed in order to overcome problems with sample contact and effective thickness. Results obtained using bands representing trans and gauche rotational isomers, present, respectively, at 1340 and 1370 cm−1, have been related to data acquired using density and birefringence techniques. The polarized IRS technique discussed is well suited for investigations of polymer orientation and crystallinity, since it avoids limitations related to sample thickness and clarity imposed by polarized transmission infrared spectroscopy. Parameters such as orientation functions, attenuation indices, dichroic ratios, and structural factors have been determined from data collected in each of the three spatial directions. Results are correlated with corresponding density, birefringence, and refractive index values and are found to give good agreement with these methods. © 1994 John Wiley & Sons, Inc.
Cold‐setting wood adhesives from kraft hardwood lignin
Authors: Truter P. , Pizzi A. , Vermaas H.
Published: April 2003

The model compound used in this study, for hardwood kraft lignin, 3,5‐dimethoxy‐4‐hydroxyphenyl ethane, was successfully hydroxymethylated at the position meta to the aromatic hydroxy group. The consequent expectation that kraft hardwood lignin syringyl units can, under optimum conditions, also be hydroxymethylated to a substantial extent was confirmed in the present work and made it possible to cross‐link the kraft hardwood lignin to yield polymeric products that could be used as adhesives. © 1994 John Wiley & Sons, Inc.
Transport of small molecules in polyolefins. III. Diffusion of topanol CA in ethylene polymers
Authors: Földes Enikó
Published: April 2003

Transport properties of Topanol CA, [1,1,3‐tris(2‐methyl‐4‐hydroxy‐5‐tert‐butyl‐phenyl)‐butane], were studied in low‐density polyethylene (LDPE), in a blend of low‐density and linear low‐density polyethylenes (LDPE/LLDPE) and in ethylene vinyl acetate copolymer (EVA). The rate of diffusion (D) was evaluated on the free‐volume theory basis. A linear relationship was obtained between In D and the reciprocal fractional free volume of the noncrystalline phase of the polymers. Solubility of the additive is higher in EVA than in polyethylene. Compatibility of Topanol CA with ethylene polymers is poor, the measured solubility values depend on the experimental conditions and thermal history of the additive source. © 1994 John Wiley & Sons, Inc.
A study of coating properties of novel poly(amino‐quinone)s prepared from 2‐methylbenzoquinone and 2‐phenylbenzoquinone
Authors: Reddy T. Ashok , Erhan S.
Published: April 2003

Novel poly(amino‐quinone)s were quantitatively prepared from in situ produced 2‐methylbenzoquinone and 2‐phenylbenzoquinone with Jeffamine D‐400® in the presence of calcium hypochlorite as the oxidizing agent. These polymers were readily soluble in most of the organic solvents such as ethanol, acetone, tetrahydrofuran, chloroform, N,N‐dimethylformamide (DMF), N‐methyl‐2‐pyrrolidone (NMP), and N,N‐dimethylacetamide (DMAc). The coatings prepared from these polymers showed very good adhesion to metals, hardness, and flexibility even after curing at 110°C for 5 h. Particularly, coatings formulated with epoxy‐novalac resin D.E.N‐438 showed excellent corrosion resistance in artificial sea water and did not form any blisters. © 1994 John Wiley & Sons, Inc.
Curl‐free high‐adhesion polyimide/copper laminate
Authors: Chen H. L. , Ho S. H. , Wang T. H. , Chen K. M. , Pan J. P. , Liang S. M. , Hung Aina
Published: April 2003

6‐Amino‐2‐(p‐aminophenyl) benzimidazole (BIA) was synthesized and empolyed as a diamine component in the preparation of polyamic acid. The mechanical and thermal properties of polyimides made from BIA as a diamine component were investigated. A highadhesion, curl‐free polyimide/copper laminate has been obtained by using BIA as a diamine component. © 1994 John Wiley & Sons, Inc.
Interaction of dyes used for foods with food packaging polyester fibers
Authors: Arvanitoyannis I. , Tsatsaroni E. , Psomiadou E. , Blanshard J. M. V.
Published: April 2003

The effect of pH, temperature, dye concentration, and additives on the absorption of the dyes FD & C (Food, Drugs and Cosmetics) Blue 1 and Blue 2 upon poly(ethylene terephalate) (PET) and poly(butylene terephthalate) (PBT) subjected to different draw ratios (and, thus, resulting in different percentage crystallinities determined with DSC and wide‐angle X‐ray diffraction patterns) was investigated and a correlation between these parameters and the dye uptake was suggested. The absorption kinetics of the dyes on the polyesters were studied and a mechanism based upon the development of hydrogen bonds between the dyes and the end groups (COOH,OH) of the polyesters and the swelling of the network was proposed. Finally, an indirect measurement of the Tg values of the polyesters was suggested based upon the different dyeing diffusion rates. © 1994 John Wiley & Sons, Inc.
Improved methods for solving monomer partitioning in emulsion copolymer systems
Authors: Armitage Philip D. , De La Cal José C. , Asua José M.
Published: April 2003

A new algorithm for the calculation of monomer partitioning in emulsion copolymer systems is presented. The algorithm can be applied both to monodisperse and polydisperse systems and the outputs of the algorithm include the distribution of the volume fractions of the monomers according to the particle size distribution, the volume fractions of the monomers in the monomer droplets, and the aqueous phase and the total volumes of all the phases in the system. The algorithm can handle both Interval II and Interval III conditions, using the same set of equations. This results in substantial computer time savings during the simulation of emulsion copolymerization systems. Examples of applications are given. © 1994 John Wiley & Sons, Inc.
Preparation of porous membranes grafted with poly(spiropyran‐containing methacrylate) and photocontrol of permeability
Authors: Chung Dong‐June , Ito Yoshihiro , Imanishi Yukio
Published: April 2003

Graft copolymerization of spiropyran‐containing methacrylate (SPMMA) and acrylamide (AM) onto the surface of a porous polymer membrane was carried out. The permeability of the graft membrane varied with ultraviolet (UV) ‐ or visible‐light irradiation. It was found that the change by UV‐light irradiation of the permeability of the H2O/CH3OH mixture through the SPMMA/AM‐grafted membrane is related to the change by UV‐light irradiation of the solubility, i.e., the chain extension, of the graft copolymer in the mixed solvent. When the free SPMMA/AM copolymer becomes insoluble in the H2O/CH3OH mixture by UV‐light irradiation, the permeability of the H2O/CH3OH mixture through the SPMMA/AM‐grafted membrane is increased. © 1994 John Wiley & Sons, Inc.
Various properties of diimide–diacid‐modified saturated polysters
Authors: Lee Wen‐Fu , Chen Ienwhei , Chang Chi‐Hong
Published: April 2003

Polyesterdiimide prepolymers containing synthesized diimide–diacid monomer (DIDAn) were synthesized under conditions previously under conditions previously reported. One‐component varnishes were obtained by mixing the synthesized prepolymers with phenol‐blocked toluene diisocyanate (TDI) and/or hexamethylene diisocyanate (HMDI). The solubility parameter of diimidemodified polyester prepolymer was investigated using an intrinsic viscosity measurement. Thermal behavior and pyrolysis activation energy were also investigated using thermogravimetric analysis. The thermal stability increased with an increase in the content of DIDA. The diimide‐modified polyester one‐component varnishes coated onto an aluminum panel were found to be acceptable, according to the specification of ASTM D‐3794. © 1994 John Wiley & Sons, Inc.