bluuebunny/crossref_metadata_2025 huggingface dataset:
Acrylic nonaqueous dispersion using butylated melamine‐formaldehyde resin as dispersant
Authors: Miyauchi Noriyuki , Kusahara Masataka , Motomura Toshiro , Akashi Mitsuru
Published: April 2003

A series of acrylic nonaqueous dispersions were prepared by using various kinds of butylated melamine–formaldehyde (BMF) resins as dispersant. The functional group composition of BMF to form stable dispersion was butoxy group more than 13 mol/BMF 1 mol, and methylol group ranged from 1 to 2.5 mol/BMF 1 mol. It is concluded that the anchoring of BMF to acrylic copolymer was due to the formation of covalent bond between methylol group in BMF and hydroxy group in acrylic copolymer.
The effects of annealing and aging in water on the properties of an amorphous copolyester
Authors: Golovoy A. , Cheung M. F.
Published: April 2003

The influence of annealing in a dry oven and aging in water bath at 98°C on the thermal and mechanical properties of an amorphous poly(1,4‐cyclohexandimethylene/ethylene terephthalate) was studied up to 21 days. Oven annealing brought about crystallization, an increase in the tensile modulus and yield strength, and a decrease in elongation and Izod impact strength. The intrinsic viscosity, however, did not change. The samples that were immersed in water embrittled at a faster rate as a result of the combined adverse effects of hydrolysis and crystallization. The intrinsic viscosity decreased from 0.71 to 0.53 after 21 days. Within the limits of this study, the hydrolysis was found to be a zero‐order process with respect to molecular weight. A transition from ductile (> 8% elongation) to brittle failure in tension was observed between 3 and 5 days.
Liquid crystalline acrylic copolymers for high‐solids enamel coatings
Authors: Chen Der‐Shyang , Jones Frank N.
Published: April 2003

Carboxyl functional liquid crystalline (LC) acrylic copolymers were synthesized and were compared with carboxyl functional control copolymers of M̄n about 5000–15,000. Both types were crosslinked with a hexakismethoxymethyl melamine (HMMM) resin at 150°C, a temperature below the clearing points of the LC copolymers. Birefringent phases were visible in the crosslinked films made from LC polymers. FT‐IR indicated the presence of unreacted COOH in all crosslinked materials. Unreacted COOH groups in crosslinked LC copolymers appeared only slightly higher than those in crosslinked amorphous copolymers. The potential utility of these LC copolymers as binders for thermosetting coatings was assessed. Variables studied were HMMM content, the length of PHBA grafts, Tg and M̄n of the acrylic copolymer backbone, and functionality. Optimum LC copolymers have low backbone Tg (<O°C) and low functionality (< 7.5 mol %). Cured films of such copolymers have both high hardness (> 35 KHN), high impact resistance (> 80 in. ib), excellent adhesion, and good solvent resistance.
Functional group efficiency in adhesion between polyethylene and aluminum
Authors: Hjertberg T. , Lakso J.‐E.
Published: April 2003

The effect of different functional groups on the adhesion between polyethylene and aluminum has been studied. Poly(ethylene‐co‐butyl acrylate) (EBA) and poly(ethylene‐co‐vinyl acetate) (EVA) were used as such and provided polyethylene surfaces with two different kinds of ester groups, butyl ester and acetate, respectively. By alkaline hydrolysis in an organic solvent the surface functionality could be changed to carboxylate and hydroxyl, respectively. Finally, acid washing converted the carboxylate groups into carboxylic acid. The effect of the surface treatments were followed by reflection IR. T‐peel tests of laminates made of the original, as well as the surface‐treated polymers, and aluminum allowed an evaluation of the specific contribution to the adhesion for the groups in question. The peel strength increased linearily with the bulk concentration of comonomer in the original EBA and EVA samples. The values increased from about 100 N/m for polyethylene up to 2500 N/m in the case of 3.7 mol % of carboxylic acid. The efficiency of the investigated functional groups increased in the following order: H<OCOCH3 <COOC4H9 <COONa∼OH<COOH.
Structural features of poly(alkylene ether carbonate) diols and intermediates formed during their preparation
Authors: Harris Robert F. , McDonald Lynn A.
Published: April 2003

Capillary vapor‐phase chromatography and carbon‐13 nuclear magnetic resonance (NMR) have been used to elucidate the structure of poly(ethylene ether carbonate) diols and certain intermediates produced by the oligomerization of ethylene carbonate (EC) using monoethylene glycol (MEG) or diethylene glycol (DEG) as initiator and catalyzed by sodium stannate trihydrate. These diols are alternating copolymers of carbon dioxide and DEG which also contain smaller amounts of higher glycols as determined by comparing their 13C NMR spectra to the spectra of model compounds. Diethylene glycol is an important reaction intermediate and is present in steady‐state concentrations. Although both 2‐hydroxyethyl carbonate and 2‐hydroxyethyl ether end groups are present at an intermediate stage in the reaction, only 2‐hydroxyethyl ether end groups are present at high EC conversion. Molecular weight builds as a smooth function of conversion and time.
Preparation of block copolyetheramides and their properties as hot melt adhesives
Authors: Hu Andrew Teh , Tsai Ruey‐Shi , Lee Yu‐Der
Published: April 2003

Block copolyetheramides were prepared by incorporating polyether into polyamide through melt polycondensation of polyetherdiamine, piperazine, dimer acid, and ε‐caprolactam. Bulk properties of block copolyetheramide, such as tensile strength, tensile modulus, elongation at break, hardness, and impact strength, were evaluated with respect to composition. Investigation on the lap shear strength and T‐peel strength of block copolyetheramide hot melt adhesive showed that the lap shear strength was more composition‐dependent. Moisture and elevating test temperature also reduced the lap shear strength significantly.
Pyrolysis‐field ionization mass spectrometry of polyamide copolymers and blends
Authors: Plage Bernd , Schulten Hans‐Rolf
Published: April 2003

Nylon foils of PA 6, PA 66, PA 69, PA 12, the copolymer PA 666, and nine blends based on these polymides have been investigated by in‐source pyrolysis (Py)–field ionization mass spectrometry (FIMS). These polymers and blends can be distinguished by characteristic molecular ions of oligomers, protonated amines and nitriles, and products terminated by olefinic end groups. Series of ions are formed differing in the number of additional monomeric units. Thus, polymers containing different chemical subunits were easily distinguished from each other in the spectra of the blends. Mass signals, only expected for copolymers, were found in the integrated blend spectra, indicating that amide exchange reactions occur under the experimental conditions employed. This observation was confirmed by pyrolysis of mixtures of pure polymers in the same crucible and under the same experimental conditions. Hence, the distinction by Py–MS alone between blends and copolymers with an identical averaged number of identical chemical subunits is not possible.
Effect of comonomers on thermal degradation of polyacrylonitrile
Authors: Gupta D. C. , Agrawal J. P. , Sharma R. C.
Published: April 2003

The thermal degradation of polyacrylonitrile and copolymers of acrylonitrile (AN) with each of vinylacetate (VAC), methallyl sulfonate sodium salt (MASS), and 2‐acrylamido 2‐methyl propane sulfonate sodium salt (2‐AMPSS) i.e., P(AN–VAC), P(AN–MASS), P(AN–AMPSS), and P(AN–VAC–MASS), has been investigated using the technique of thermogravimetry and differential scanning calorimetry (DSC). The initial decomposition temperature (IDT) and integral procedural decomposition temperature (IPDT) for all the copolymers are less than that for polyacrylonitrile irrespective of the nature of the vinyl comonomers. TGA thermograms indicate faster rate of degradation in copolymers compared to polyacrylonitrile. Variation in the glass transition temperature is correlated to the polarity of the functional groups in the polyacrylonitrile copolymers.
Reuse of plastics recovered from solid wastes. Thermal and morphological studies from HDPE/LDPE blends
Authors: Laguna O. , Collar E. P. , Taranco J.
Published: April 2003

In this work a few observations are made about some microstructural aspects from HDPE and LDPE homopolymers and their blends as virgin materials and also from urban plastic wastes. Micrographs were taken by SEM. Micrographs corresponding to the fracture surface from specimens tested in an impact test clearly show different microstructural features due to polymer which is more than 50%. Parts were injection molded. On the other hand, a discussion is given about crystallization behavior of those materials obtained by DSC. For all blends the same results have been found, i.e., two peaks owing to each of the two polymers which are present in the blends.
Mechanism of gas transport in plasma treated glassy polymer films
Authors: Sada E. , Kumazawa H. , Xu P. , Kiyohara T.
Published: April 2003

The effect of oxygen‐ and Ar‐plasma treatment on glassy polysulfone and polyimide films upon the gas diffusion process was investigated in the permeation of CO2 and H2. The plasma treatment apparently induced a reduction of only the diffusivity of Henry's law population, while the diffusion coefficient of the Langmuir population was not altered by plasma treatment. The oxygen‐ and Ar‐plasma treatment on polysulfone films is favorable for permselectivity of H2 relative to CO2. Such a surface modification of polyimide films appears to be ineffective for improvement of permselectivity of H2.
Synthesis of copolymers of N,N‐dimethyl acrylamide and methacrylate esters and their surface tensions
Authors: Weinert Raymond J. , Piirma I.
Published: April 2003

A systematic study of the preparation of N,N‐dimethylacrylamide (NDMA)/methacrylic ester statistical copolymers was conducted. The methacrylic ester comonomers used in the copolymerizations were ethyl, n‐butyl, n‐hexyl, n‐octyl, n‐dodecyl, n‐hexadecyl, and n‐octadecyl methacrylates. It was found that the NDMA copolymers could be prepared in three molecular weight regions 1.0 × 104, 2.0 × 105, and greater than 1.0 × 106 ([η] in water at 30°C of 0.1, 0.6, and greater than 1.5 dL/g, respectively). The molecular weights of the copolymers were dependent on the solvent employed in the polymerizations and on the presence of chain transfer agent (t‐dodecyl mercaptan). All copolymer compositional analyses were made by 400 MHz 1H‐NMR spectroscopy. The NDMA/methacrylic ester copolymers decreased the surface tension of water in the order: C4 = C6 > C8 > C12 > C16 > C2 = C18 > P(NDMA), from lowest surface tension (35 dyn/cm) to highest surface tension (59 dyn/cm).
Determination of Mark–Houwink–Sakurada equation for phenolic resins and estimation of their molecular conformation in acetone solution
Authors: Sue Haruaki , Ueno Eizaburo , Nakamoto Yoshiaki , Ishida Shin‐Ichiro
Published: April 2003

The effects of the molecular structure of phenolic resins on the Mark–Houwink–Sakurada (MHS) equation and the conformation in acetone solution were studied. The exponent in the MHS equation was remarkably less than that for linear polymers such as vinyl polymers, cellulose derivatives, and so on. As the cause, the branching and the hydrogen bonding between hydroxyl groups of the neighboring phenolic nuclei were considered. Several kinds of phenol‐p‐cresol and phenol‐p‐tert‐butylphenol cocondensation resins whose composition differs from one another were synthesized. Despite the difference in the degree of branching, the exponent in the MHS equation for each was approximately equal. On the other hand, the exponent for o‐cresol novolak, which was rich in ortho‐para methylene linkages was larger than the all‐ortho novolak and p‐cresol novolak, which were rich in ortho–ortho methylene linkages. Methylation of the phenolic hydroxyl group increased the value of the exponent. From these results, it became obvious that while the hydrogen bonding lowered the exponent in the MHS equation due to molecular conformation compaction in acetone solution, the molecular branching had little effect on the exponent α.
Pulsed NMR study of elastomeric block copolymer under deformation
Authors: Fukumori Kenzo , Kurauchi Toshio , Kamigaito Osami
Published: April 2003

Deformation behavior of an elastomeric styrene–butadiene–styrene block copolymer (SBS) is studied by pulsed NMR techniques, and is related to lifetime distributions and the change of the microstructure in the stress relaxation process. By the measurement of spin–spin relaxation time, it is found that polybutadiene (PB) chains in the vicinity of polystyrene (PS) domains come to be in more constrained conformations with stretching than those remote from the domains mainly through the intramolecular interactions, followed by the enlargement of the constrained regions, which reflects the roles of both crosslinks and filler particles in crosslinked rubbers. In the stress relaxation process, however, the mean lifetime for SBS at the critical strain is longer than that at lower strain in contrast with the results for the crosslinked rubbers. It is estimated that the differences between the failure behaviors of SBS and those of the conventional crosslinked rubbers may be mainly caused by the characteristic change of the microstructure (the disruption of the weak interconnections between the spherical PS domains with high energy dissipation) in SBS on deformation, associated with the limited extensibility of the PB chains between the adjacent PS domains. It becomes clear that the pulsed NMR method complements the mechanical measurements with a more precise information on the heterogeneity in the rubbery polymers under deformation.
Blends of polyamide 6 with bisphenol‐A polycarbonate. I. Thermal properties and compatibility aspects
Authors: Gattiglia Ercole , Turturro Antonio , Pedemonte Enrico
Published: April 2003

Blends of polyamide 6 (PA6) and polycarbonate (PC) have been investigated, over a full range of composition, to check interactions between them. SEM observations show that the mixtures are characterized by domains of clearly segregated homophases and voids between the two polymers. DSC and DMTA data indicate the presence of two Tg' s, corresponding to two separate phases, with the Tg of the PC phase decreasing on increasing the PA6 amount. Moreover, the crystallization kinetics of PA6 is slightly showed down by the PC. Chemical reactions between the two polymers are supposed to give rise to low molar mass compounds, as shown by GPC; these species plasticize the PC and partially dissolve into the molten polyamide, causing decrease of PC Tg and reduction of overall crystallization rate of PA6. Apparent influence of PC on melting temperature and enthalpy of PA6 is also discussed.
Influence of mold filling rate and gate geometry on the modulus of high pressure injection‐molded polyethylene
Authors: Boldizar A. , Kubát J. , Rigdahl M.
Published: April 2003

High pressure injection molding of HDPE with relatively high molecular weight is known to give products with significantly increased modulus and strength. The extent of this improvement is reduced when the thickness of the molded sample increases. The present paper is an account of experiments with varying mold filling rates and gate geometries. After choosing proper gating and then optimizing the filling rate, thick samples with tensile moduli previously characteristic of thinner samples have been obtained. The modulus data are supplemented by measurements of the melting point of the normal and high‐strength HDPE structures at different locations in the molded test bars. Corresponding crystallinity data are also included. The structure of the samples appears to provide some guidance in interpreting the observed modulus variations.
Fractionation of a polydisperse polymer using an antisolvent. Application of continuous thermodynamics
Authors: Wu Albert H. , Prausnitz John M.
Published: April 2003

Continuous thermodynamics is used to calculate liquid‐liquid equilibria in a ternary system containing polydisperse polymer, one good solvent and one poor solvent (antisolvent). The polymer has a semiinfinite molecular‐weight distribution which can be described by a gamma distribution. From Flory‐Huggins theory, the logarithm of the distribution ratio of the polymer is a linear function of the molecular weight. Because the distribution of polymer between the two liquid phases is very sensitive to the choice of binary Flory parameters. The Flory parameters must be fitted to the ternary data. Results are given for the system benzene, ethanol, and polydisperse polystyrene.
Hexavalent chromium interaction with chitosan
Authors: Udaybhaskar P. , Iyengar Leela , Rao A. V. S. Prabhakara
Published: April 2003

Chitosan prepared from fresh water crab shells was used for hexavalent chromium removal. Kinetic studies indicated a rapid removal of chromium from aqueous solutions. The first‐order rate constant for chromium removal was calculated to be 1.92 h−1. Sorption isothermal data could be interpreted by the Langmuir relationship. Drastic decrease in chromium removal was observed with the increase in pH. Sorption was almost 90% at pH 3 at an initial chromium concentration of 5 mg/L and reduced to 10% at pH 7 and above. Presence of electrolytes and chloride significantly affected the chromium removal, indicating the electrostatic attraction as the main removal mechanism. Regeneration of the sorbent with alkali was not very effective as only 60–65% of sorbed chromium could be recovered.
High‐strength poly(L‐lactide) fibers by a dry‐spinning/hot‐drawing process. I. Influence of the ambient temperature on the dry‐spinning process
Authors: Postema A. R. , Luiten A. H. , Pennings A. J.
Published: April 2003

In this paper the influence of the ambient temperature of the spinline during dry spinning of PLLA solutions has been discussed. Variation of this ambient temperature induced variation of the extrudate swell of the spinline, affected by the rate of solidification of the PLLA. By way of phase separation, porous filaments were achieved in which the morphology depended on the applied ambient temperature. Hot drawing of these filaments led to tensile strengths varying between 1.1 and 2.2 GPa. An optimal tensile strength of 2.2 GPa was achieved by hot drawing of a filament which was spun into a surrounding of 25°C.
Interfacial adsorption and crystallization of polycarbonate in carbon fiber composites
Authors: Brady Richard L. , Porter Roger S.
Published: April 2003

A polycarbonate (PC)/carbon fiber (CF) composite system has been examined with regard to interfacial adsorption and crystallization by altering times and temperatures of annealing. Times up to 180 min and temperatures of 245, 275, and 300°C have been investigated. Tranverse tensile, tranverse toughness, and scanning electron microscopy results on unidirectional, continuous‐fiber composites indicate improved fiber/matrix adhesion at longer times and higher temperatures of annealing. Improvements in transverse toughness and transverse tensile strength of a factor of two is achieved. The data indicate that primarily adsorption rather than secondary interfacial crystallization is the likely mechanism for increased adhension. Isothermal transverse toughness values have been found to fit well to a Langmuir‐type expression. The temperature dependence of adsorption as measured by transverse toughness is described well by an Arrhenius equation. The dependence of transverse toughness on PC molecular weights from Mw = 26,600 to 39,800 was found to be large, with higher molecular weights adsorbing more effectively.
Reactive extrusion of poly(vinyl chloride) compounds with polyethylene and with ethylene‐vinyl acetate copolymers
Authors: Van Ballegooie Peter , Rudin Alfred
Published: April 2003

The mechanical properties of poly(vinyl chloride)/polyethylene blends can be improved by a reactive extrusion process in the presence of an organic peroxide and a coupling agent. With a judicious loading of dibenzoyl peroxide and triallyl isocyanurate coupling agent, such blends generally exhibit significantly greater ultimate tensile strengths and dynamic moduli. The nature of the sample posttreatment after compression molding is shown to have a major impact upon the relative magnitude of these differences. Evidence is also presented to suggest that such improvements result from a superior physical interlocking between blend components, rather than through the formation of co‐crosslinked graft segments (which would, presumably, impart a compatibilization effect). Similar extrusion trials with a poly(vinyl chloride)/poly(ethylene‐stat‐vinyl acetate) mixture revealed a general worsening of material properties with increasing dibenzoyl peroxide levels. These observations can be rationalized by examination of the degradation reactions that likely occur in these reacting systems.
Grafting of polyacrylamide on to guar gum using K2S2O8 ascorbic acid redox system
Authors: Bajpai U. D. N. , Jain Alka , Rai Sandeep
Published: April 2003

The grafting of polyacrylamide on to guar gum in aqueous medium initiated by the potassium persulfate/ascorbic acid redox system has been studied gravimetrically at the temperature 35 ± 0.2°C in the presence of atmospheric oxygen and Ag+ ions. The rate of grafting was found to increase with temperature, concentration of redox components, acrylamide, and guar gum. But at higher concentration of guar gum, the rate of grafting was found to decrease. A mechanism for grafting and suitable rate expression have been suggested.
Plasma‐modified nylon 4 membranes for reverse osmosis desalination
Authors: Lai J. Y. , Chao Y. C.
Published: April 2003

The effects of maturation time of casting solution and annealing conditions on reverse osmosis (RO) properties of nylon 4 membranes are studied. The effects of plasma treatment conditions, such as supply power, treatment time, and gases used in reactor, on the water contact angle, surface energy, water flux, and salt rejection of nylon 4 membranes are considered. The best results of 4.86 × 10−5 g/cm2 s of water flux with 74.2% of salt rejection for 1 wt % NaCl aqueous feed solution can be obtained in the conditions of plasma treatment for 80 W–3 min in a reactor with O2 on 25 wt % formic acid–4 h annealing nylon 4 membranes. The hydrophilic monomers, such as 1‐vinyl‐2‐pyrrolidone (VP), 2‐hydroxyethyl methacrylate (HEMA), and acrylic acid (AA), are plasma deposited onto the chemical and/or plasma etched nylon 4 membranes to improve the salt rejection without decrease in water flux. The salt rejection of 90.9% and water flux of 3.64 × 10−5 g/cm2 s of the deposited membrane are obtained in the conditions of depositing AA monomer onto the substrate membrane which was previously treated with annealing followed with plasma etching.
Fundamental modeling in anionic polymerization processes
Authors: Chang C. C. , Miller J. W. , Schorr G. R.
Published: April 2003

The anionic solution polymerization of butadiene was studied employing both batch and continuous reactor operations with n‐butyllithium (n‐BuLi) initiator, tetramethylethylenediamine (TMEDA) modifier, and hexane solvent. A model was proposed that described the kinetics as a function of both the fully modified and unmodified regressed rate data. Using the proposed kinetic model, the conversion, vinyl structure, and heterogeneity index of polymers produced for a series of continuous runs were successfully predicted. The model was used to simulate several process configurations.
Interpenetrating hydrogel networks. I. The gelatin–polyacrylamide system
Authors: Chatterji Prabha R.
Published: April 2003

In situ polymerization of acrylamide–bisacrylamide mixture in concentrated aqueous gelatin solutions followed by the subsequent crosslinking of gelatin itself with glutaraldehyde yields interpenetrating hydrogel networks. The surface morphology, swelling, and thermal behavior of the samples of different composition were investigated. The swelling characteristics of the hydrogel could be manipulated by varying gelating and acrylamide ratio.
Copolymerization of acrylic esters with ethyl α‐cyanocinnamate
Authors: Angelovici Mose M. , Kohn David H.
Published: April 2003

The copolymers of ethyl α‐cyanocinnamate with methyl, ethyl, and butyl acrylate were prepared in toluene solution with benzoyl peroxide as initiator. The copolymerization parameters were determined and the alfrey–Price Q and e values were calculated. The influence of the comonomer on some of the basic properties of the copolymers, like intrinsic viscosity, solubility, and glass transition temperature, was studied in comparison with the corresponding homopolyacrylates.
Solution viscosities of ethylene–propylene copolymers in oils
Authors: Rubin Isaac D. , Sen Ashish
Published: April 2003

Viscosities were obtained on oil solutions of ethylene‐propylene copolymers with 58‐80 mol% ethylene. For amorphous copolymers, intrinsic viscosities and equivalent hydrodynamic volumes showed little variation from −10 to 50°C. They decreased precipitously at low temperature for a partially crystalline copolymer with 80 mol% ethylene. The data can be explained by postulating that more ethylene and resulting crystallinity lead to ordered domains in solution at low temperatures, giving rise to additional contraction of the copolymer above that expected for a totally amorphous material.
A comparative study on the effect of aging on mechanical properties of LLDPE–glass fiber, mica, and wood fiber composites
Authors: Raj R. G. , Kokta B. V. , Daneault C.
Published: April 2003

Linear low density polyethylene (LLDPE) was reinforced with wood fiber, glass fiber, and mica. The effect of aging on mechanical properties of the composites was examined under different conditions: (i) exposure at 105°C for 7 days; (ii) immersion in boiling water for 4 h. Samples containing glass fibers showed by far the best results with regard to tensile strength, elongation, and fracture energy. LLDPE filled with mica produced poor results compared to wood fiber composites. Dimensional stability of LLDPE–wood fiber composites, after boiling water treatment, was inferior to mica and glass fiber composites.
Characterization of oxidized LDPE by solid state fluorescence spectra
Authors: Konar J. , Ghosh R.
Published: April 2003

The fluoresence excitation and emission spectra of commercial LDPE and oxidized LDPEs using phase transferred permanganate as oxidant have been examined using solid state fluorescence spectra. The luminescent impurity species present in commercial polyethylene is found to be olefinic dione. LDPE has an emmission spectra at 330–345 nm and excitation spectra at 235 and 300–310 nm. The emission spectra of oxidized LDPEs contain two main peaks, one at 290–300 nm and the other at 330–345 nm. A comparison of the emission spectra of LDPE blends with the reference compounds, viz., stearic acid and stearone, with those of the oxidized LDPEs proves the presence of “saturated” keto groups (carbonyl in the main chain not conjugated with C = C) in oxidized LDPEs. This also enables us to find out quantitatively the amount of the keto groups present. The estimates thus obtained tally with the results of FT‐IR measurements and follow the increasing order of the stability constant of the permanganate ionpair in benzene.
Epoxy–amine oligmer production
Authors: Cuadrado T. R. , Macgregor J. F. , Hamielec A. E.
Published: April 2003

The production of an adduct epoxy‐polytheramine with free epoxy groups is anlyzed. Diffrential scanning caloriemetry (DSC), infrared spectroscopy (IR), titration of functional groups, and gel permeation chromatography (GPC) were used to study the reaction of bisphenol A diglycidyl ether (DER 332) with an aliphatic hindered polyether‐amine (Jeffamine D‐2000). The general kinetic model derieved by Riccardi and Williams1 is extended to generate equations for nonstoichiometric epoxy‐amine systems. The parameter N, which gives the reactivity ratio between the secondary and primary amine groups, was obtained from a linear regression obtained at various temperature levels. the activation energies of the epoxy amine reaction catalyzed by OH groups and the noncatalytic one were determined. According to experimental evidence, the etherfication reaction may be neglected. From dynamic experiments in DSC a heat of reaction of 25 kcal/eq was obtained. The weight average molecular weight of different epoxy‐amine oligomers with high ratio of epoxy‐amine were compared with those theoretically predicted using an statistical structural model (SSM). This model utilizes a kinetic scheme and a recursive method to determine statistical parameters and it was applie before to phenolic resins 2,3 epoxy‐amine systems.4 Depending on the required ologomer characteristics, the best production policy can be established using he data supplied in this report.
Aqueous polymerization of methyl methacrylate catalyzed by corundum of different particle sizes
Authors: Moustafa A. B. , Abdel‐Latif Z. H. , Amer L. I.
Published: April 2003

The aqueous polymerization of MMA in the absence and presence of corundum of different particle sizes was studied, and the effect of corundum on the conversion of monomer to polymer, as well as on the obtained average molecular weights, rate of flow (Rf) values, and activation energy, was also given.
Evaluation of disbondings and measurement of Poisson's ratio for plastic composites using holographic interferometry
Authors: Kimoto Masaki , Nagata Itsuo , Minowa Akio , Moriwaki Kousuke , Watanabe Toshiaki
Published: April 2003

Disbondings and Poisson's ratio were examined for several plastics composite plates using holographic interferometry. The displacement at the disbondings could be detected below submicrometer order. The value of Poisson's ratio strongly depended upon orientation and type of fiber and laminate construction.
Copolymerization of cis‐butenedioic acid with sodium methallylsulfonate in an aqueous solution
Authors: Kejun Yao , Zenquan Qin , Chuanyao Ye
Published: April 2003

Water‐soluble copolymers of cis‐butenedioic acid (MA) with sodium methallylsulfonate (SMAS) were prepared in aqueous solution using potassium persulfate (KPS) as the initiator. The effects of reaction conditions (e.g., monomer concentration, initiator concentration, monomer fractions and pH, reaction temperature and times, etc.) on the copolymerization were also studied. The results showed that higher conversion could be obtained under suitable conditions (see Figs. 1–5). The copolymers were characterized by IR and NMR spectroscopy. The ratios of infrared absorbances at 1585 cm−1 (carboxyl absorption) and 1048 cm−1 (sulfonic group absorption) were used to de‐termine the composition of poly(MA‐co‐SMAS). The reactivity ratios were calculated by Kelen–Tudos method and Fineman–Ross method. Both the chemical analysis and the scanning electron micrographs showed that the copolymer has an excellent antiscaling effect on calcium carbonate.
A dynamic‐mechanical study of polycarbonate‐polyester blends
Authors: Li Yuan , Williams H. Leverne
Published: April 2003

Bisphenol‐A polycarbonate and an aromatic linear copolyester were melt blended for dynamic mechanical tests using a Dynastat. Corresponding powders were used in thermal analysis by differential scanning calorimetry. The deduced glass transition temperatures of the pure polymers and blends were compared to estimate the miscibility of the two polymers.
The effect of sulfur‐ and nitrogen‐containing fire retardants on reducing the flammability of a polychloroprene composition used for cables
Authors: Karaivanova M. , Mihailova N. , Gjurova K.
Published: April 2003

The influence of ammonium sulfamate (AS) independently or in a combination with antimony trioxide (AO) and chloroparaffin (ChP)–70% chlorine, on the oxygen index (OI) values as a flammability indicator, as well as on some physicomechanical and thermal characteristics of filled and unfilled compositions for cables based on chloroprene rubber (ChR), is studied here. It is found out that, at definite concentrations, AS and AO reveal an additive effect as fire retardants, decreasing the rate of heat rlease on heating. AS reveals a plasticizing effect as well.
Synthesis and characterization of new aromatic polyamides, polyimides, and polyureas containing 1,3,5‐triazine rings
Authors: Lin Jui‐Kun , Yuki Yasuo , Kunisada Hideo , Kondo Shuji
Published: April 2003

Novel aromatic polyamides, polyimides, and polyureas containing 1,3,5‐triazine rings were pre‐pared by the reaction of 2‐anilino‐4‐aminoanilino‐6‐aminophenyl‐1,3,5‐triazines with aromatic dicarboxylic acid chlorides, pyromellitic dianhydride, and diisocyantes, respectively. All polymers were soluble in polar aprotic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, and pyridine. The glass transition temperatures of polymers were in the range of 220–260°C. The thermal stabilities of polymers were evaluated by thermogravimetric analysis in air. These polymers were stable up to 420°C for polyamides, 470°C for polyimides, and 300°C for polyureas.
Stress relaxation of reptating chains of acrylonitrile–butadiene copolymer in end‐linked acrylonitrile–butadiene copolymer networks
Authors: Liu Weilian , He Tianbai
Published: April 2003

Stress relaxation of unattached chains of acrylonitrile–butadiene copolymer in TDI end‐linked acrylonitrile–butadiene copolymer has been studied. The advantage of this system is that the polar nature of the TDI crosslinking agent in end‐linked acrylonitrile–butadiene copolymer can be compensated if an unattached acrylonitrile–butadiene copolymer with moderate acrylonitrile content is selected. It was found that with increasing unattached chain content, the position of the relaxation spectra transitions shifted to shorter times. The frictional resistance for the relaxation of networks containing unattached chains was proportional to the amount of crosslinked components. This means that crosslinked components not only bear load but also resist the relaxation of unattached chains. The relaxation moduli contribution from unattached chains first increased and then decreased with increasing amount of crosslinked components. This can be explained by the presence of two kinds of entanglements, i.e., those between unattached chains themselves and those between unattached chains and crosslinked components, which in turn depend on the amount of unattached chains. At lower concentrations of unattached chains, relaxation of unattached chains requires that molecules pass only through obstacles formed by one kind of entanglement; this results in lower relaxation modulus. With increasing unattached chain content, the relaxation of those chains require molecules reptation through both kinds of entanglements, which results in higher relaxation modulus. Therefore, the enhancement of mechanical properties for networks containing unattached chains originates not only from load‐bearing of crosslinked components but also from the relaxation of unattached chains.
A semiempiric model for establishing the drawability of solution‐spun linear polyamides and other flexible chain polymers
Authors: Smook J. , Vos G. J. H. , Doppert H. L.
Published: April 2003

A series of high molecular weight, linear polyamide samples have been subjected to various solution spinning techniques, such as gel, wet, and dry spinning, in an attempt to produce high‐tenacity filaments. The spinning experiments involved polyamide 6, polyamide 12, and copolymers thereof, with a molecular weight Mw in the range of 105−106 kg/kmol. Filaments with a tenacity of 100 cN/tex have been obtained. Their draw ratio never surpassed a value of six, which may also be reached after conventional melt spinning. Apparently, the drawability of polyamides cannot be improved via solution spinning techniques, although a favorable molecular topology for accomplishing high draw ratios has most likely been realized. This behavior is in sharp contrast with the highly increased drawability after solution spinning of less polar polymers, such as polyethylene or polyvinyl alcohol. A semiempirical equation is now proposed that relates the maximum drawability of flexible chain polymers with their polarity, being expressed in terms of cohesive energy. A preassumption underlying this equation is that drawability is not limited by a high entanglement density as is, e.g., the case after melt processing.
Room temperature curing of CTBN‐toughened epoxy adhesive with elevated temperature service capability
Authors: Achary P. Sasidharan , Latha P. B. , Ramaswamy R.
Published: April 2003

The adhesive joint strengths at room temperature (25°C) and at 120°C for an epoxy resin cured at room temperature with tris (N,N‐dimethylaminomethyl) phenol and containing varying amounts of a carboxyl‐terminated polybutadiene‐acrylonitrile copolymer (CTBN) were investigated and reported. It was observed that as CTBN content increased, lap shear strength and T‐peel strength increased significantly and passed through a maximum at about 10 parts CTBN content per 100 parts epoxy resin and then decreased. To explain the observed results, the effect of CTBN content on the bulk tensile strength, impact energy, glass transition temperature (ETg), and morphology were also evaluated. SEM observations showed microphase separation between CTBN and epoxy matrix for the composition containing 10 parts CTBN per 100 parts epoxy resin, and this composition exhibited maximum bulk tensile strength and impact energy. The enhancement of bulk mechanical properties, hence the adhesive joint strength, was attributed to the higher toughness produced by the dispersed rubber particles. At higher CTBN content, the rubber phase became continuous, and the system exhibited a fall in mechanical properties, hence in adhesive joint strength, which was attributed to the flexibilization effect. The glass transition temperature of the cured epoxy resin was little influenced by CTBN incorporation up to 10 parts per 100 epoxy resin. Higher levels of CTBN content due to the flexibilization effect, decreased the ETg, hence the elevated temperature capability. The results of this study demonstrate that epoxy resins containing low levels of CTBN, cured at room temperature with tris (N,N‐dimethylaminomethyl) phenol can be used to formulate structural adhesives for use in elevated temperature environments.
The pyrolytic characterization of a surfactant/polymer/ceramic composite system using combined thermogravimetric analysis‐mass spectrometry
Authors: Nelson K. M. , Manson J‐A. E. , Seferis J. C. , Prime R. B.
Published: April 2003

An experimental technique of combined thermogravimetric analysis (TGA)‐mass spectrometry (MS) was used to study the pyrolysis process during binder removal from a ceramic/binder system. The effect of a fluorocarbon surfactant on the pyrolysis process was also investigated and it was discovered that the surfactant had no significant effect on pyrolysis. A simple paraffin binder system was implemented so as to enhance the effects of the surfactant. The identification of the fragments created during pyrolysis is also discussed.
Infrared spectra of alkali treated jute stick
Authors: Reddy S. S. , Bhaduri S. K. , Sen S. K.
Published: April 2003

The infrared spectra of alkaline jute stick have been discussed and compared to that of untreated and control sample. A higher shift in the OH and lower shift in the CH stretching frequencies were observed in alkaline sample. The presence of a strong band at 1440–1430 cm−1 may be due to the coupling of COO− frequency with CH2 deformation frequency. The CO stretching mode at 1240 cm−1 disappears on alkaline treatment with the formation of new peaks at 1265 and 1225 cm−1. The β−glucosidic band at 895 cm−1 is shifted to 880 cm−1 with doubled intensity in alkaline jute stick.
Retention of polyvinylpyrrolidone swelling agent in the poly(ether p‐phenylenesulfone) ultrafiltration membrane
Authors: Miyano Tadaaki , Matsuura Takeshi , Carlsson D. J. , Sourirajan S.
Published: April 2003

The detection and quantification of polyvinylpyrrolidone (PVP) polymer in the top skin layer of the poly(ether p‐phenylenesulfone) (PES, Victrex) ultrafiltration membrane was attempted by applying the technique of internal reflection Fourier transform infrared spectroscopy (FTIR‐IRS). The effects of the PVP concentration in the casting solution and that of the PVP molecular weight on the residual quantity of PVP were investigated in detail. The PVP content in the membrane was further correlated to the ultrafiltration performance data of PES membranes.
Further studies on the moisture‐related properties of hydrolyzed poly(ethylene terephthalate)
Authors: Zeronian S. Haig , Wang Hui‐Zhen , Alger Kenneth W.
Published: April 2003

Contact angle measurements with water indicate that the hydrophilicity of poly(ethylene terephthalate) (PET) film decreased in the order PET treated with aqueous sodium hydroxide > untreated PET > PET treated with methanolic sodium methoxide. When the sodium‐methoxidetreated polyester was hydrolyzed with caustic soda, its contact angle fell, indicating that the methyl ester groups formed during the sodium methoxide reaction by a base‐catalyzed ester interchange had been the cause of the high contact angles. Thus it appears that carboxyl groups at the surface of hydrolyzed PET play an important role in determining its hydrophilicity. It appears from adsorption experiments that there is a marked increase in the surface area of PET fibers on treatment with aqueous sodium hydroxide. The increase is attributed to the presence of the pits produced by the hydrolysis. It is suggested the higher surface area leads to increased numbers of hydrophilic groups on the fiber surface causing the greater wettability observed in the caustic hydrolyzed samples.
Aromatic polyamide–hydrazides for water desalination. I. Syntheses and RO membrane performance
Authors: Satre M. D. , Ghatge N. D. , Ramani M. P. S.
Published: April 2003

Wholly aromatic polyamide–hydrazides (PAH) were synthesized by low‐temperature solution polycondensation of m‐amino benzhydrazide (MABH)/p‐amino benzhydrazide (PABH) with isophthaloyl chloride (ICL)/terephthaloylchloride (TCl) in N,N‐dimethyl acetamide (DMAC)/N‐methyl‐2‐pyrrolidone (NMP). The polymers were characterized for their properties. Membranes were prepared from these (PAH) polymers under different casting conditions by varying the casting solution composition, evaporation time, post‐annealing treatment, etc. The reverse osmosis (RO) tests for these membranes were performed with 5000 ppm aqueous sodium chloride feeds at 40 and 70 kg/cm2 operating pressures. Addition of lithium chloride to casting solutions and annealing in hot water conferred optimum selectivity to RO membranes. Membranes showed rejections up to 98.5% at flux > 20 cm/day.
Measurement method and apparatus for monitoring the kinetics of polymerization and crosslinking reactions by microwave dielectrometry
Authors: Carlini C. , Rolla P. A. , Tombari E.
Published: April 2003

The experimental apparatus employed for monitoring fast polymerizing and crosslinking processes is described in detail. The measurement method for the particular application is widely discussed and the resulting performances of the measurement technique are reported. As an example, the experimental results for polymerization and crosslinking reactions of n‐butyl acrylate and 1,6‐hexandiol‐diacrylate are shown and the accuracy of the data acquisition is demonstrated.
Synthesis and characterization of 1,6‐and 1,7‐dihydroxy alkanes and their acrylic esters. I
Authors: Shantha K. L. , Pratap G. , Rao V. S. Bhaskar , Krishnamurti N.
Published: April 2003

The 1,6‐ and 1,7‐dihydroxy alkanes having chain lengths C13–C24 were synthesized in high purity by lithium aluminum hydride reduction of corresponding 6‐oxo and 7‐oxoalkanoic acids. These were then converted to 6‐hydroxy and 7‐hydroxy acrylic esters, respectively, and were characterized by infrared, 1H nuclear magnetic resonance, and mass spectroscopic methods.
High conversion polymerization of methyl methacrylate in the presence of n‐dodecylmercaptan
Authors: Madruga E. L. , Román J. San , Benedi P.
Published: April 2003

The kinetics of free‐radical homopolymerization of methyl methacrylate in the presence of different amounts of n‐dodecylmercaptan has been studied at 70°C. The introduction of n‐dodecylmercaptan in the reaction mixture modifies not only the onset and magnitude of the gel effect but also the limiting conversion with respect to the corresponding parameters for the homopolymerization of pure methyl methacrylate. The results obtained are qualitatively correlated with the current theories on the free radical polymerization at high conversion degrees.
Blends and interpenetrating networks of phenolic resins and polyamides
Authors: Yang T. P. , Kwei T. K. , Pearce E. M.
Published: April 2003

Blends and interpenetrating networks of phenolic resins and polyamides were prepared. Control of miscibility was achieved by modifying nylon 6I through copolymerization and N‐alkylation. The phenolic resin was also modified by partial conversion of the hydroxy groups to cinnamyloxy groups. The phase behaviors of these blends and semi‐IPNs were investigated.
Phase behavior of blends of polycarbonate with partially miscible polymers
Authors: Kim Woo Nyon , Burns Charles M.
Published: April 2003

Phase behavior of blends of bisphenol A polycarbonate (PC) with polystyrene (PS), poly(styrene‐co‐acrylonitrile) (SAN), poly(acrylonitrile‐butadiene‐styrene) (ABS), poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate) (PET), and poly(butylene terephthalate) (PBT) has been investigated. Blends were prepared by screw extrusion and solution casting with weight fractions of PC in the blends varying from 0.90 to 0.10. From the phase diagram of the blends, it appears that PS, SAN, ABS, PMMA, PET, and PBT dissolve more in the PC‐rich phase than does PC in the PS‐, SAN‐, ABS‐, PMMA‐, PET‐, and PBT‐rich phases. Also, from the measured glass transition temperature (Tg) of the screw‐extruded blends and the solution‐cast blends, it appears that compatibility increases more in the PS‐, SAN‐, ABS‐, PMMA, PET‐, and PBT‐rich compositions than in the PC‐rich compositions. Composition‐dependent values of the polymer‐polymer interaction parameters (g12) of various blends were calculated and found to be from 0.034 to 0.053 for equal weights of each of the polymers with PC.