bluuebunny/crossref_metadata_2025_split huggingface dataset:
Miscible blends of poly(styrene‐co‐acrylonitrile) and poly(α‐methyl styrene‐co‐acrylonitrile) with hydroxyl‐containing polymethacrylates
Authors: Goh S. H. , Siow K. S. 
Published: April 2003

AbstractPoly(styrene‐co‐acrylonitrile)(SAN) and poly(α‐methyl styrene‐co‐acrylonitrile)(MSAN) are miscible with poly(2‐hydroxyethyl methacrylate) (PHEMA) and with poly(2‐hydroxypropyl methacrylate) (PHPMA). That SAN and MSAN are immiscible with poly(n‐propyl methacrylate) and with poly(isopropyl methacrylate) but miscible with PHPMA indicates the enhancement of polymer miscibility due to hydroxyl groups. The miscibility of these blends is explained in terms of recent theories for copolymer/homopolymer blends.
Alkalization mechanism of cellulose in hydroxypropylcellulose preparation process
Authors: Yokota H. 
Published: April 2003

AbstractThe role of alkali treatment of cellulose in hydroxypropylcelluloe (HPC) preparation has been studied from the viewpoint of the selective distribution of sodium hydroxide between HPC and cellulose phases. Generally it is considered to be important to prepare uniform alkali cellulose, whose calculated value of composition is C6H10O5NaOH. x H2O, prior to etherification of cellulose. Therefore, enough alkali to obtain alkali cellulose is used by major manufacturers of cellulose ethers. However, HPC having good solution qualities and performance properties can be prepared even from partially alkalized cellulose by using 0.2–0.4 molar sodium hydroxide per anhydroglucose unit. The results obtained from a series of experiments indicate the following mechanism for the formation of HPC. Hydroxypropylation is initiated in the alkalized portion of cellulose if such portion and propylene oxide are present together. As the hydroxypropylation proceeds, the liberated sodium hydroxide in HPC phase migrates into the cellulose phase due to the shift of distribution equilibrium of sodium hydroxide; the above tendency is enhanced by byproducts such as propyleneglycol. Some newly alkalized portions are present and hydroxypropylation follows. These processes are repeated, and then all portions of cellulose are alkalized and hydroxypropylated.
Poly‐1‐hexene, synthesis and solubility in dense carbon dioxide
Authors: Dandge D. K. , Heller J. P. , Wilson K. V. 
Published: April 2003

AbstractSeveral poly‐1‐hexene samples were prepared using different Ziegler‐Natta catalysts, and their solubilities in dense carbon dioxide (CO2) were studied. Despite the varied molecular weight distributions (MWD) in the polymers, a surprising correlation was found between intrinsic viscosity and dense CO2 solubility. Due to the ability of dense CO2 to extract low‐molecular weight fractions preferentially, it is recommended that narrow MWD polymers be used, as far as possible, for dense CO2 solubility determinations.
Removal of polyethylene glycol mono‐p‐nonylphenyl ether and dodecylbenzenesulfonate by chloromethylated polystyrene–polyethylenepolyamines and –polyethyleneimines
Authors: Tashiro Tatsuo 
Published: April 2003

AbstractThe reactions of chloromethylated divinylbenzene crosslinked polystyrene (CMPS) with polyethylenepolyamines (PEPA), polyethyleneimines (PEI), 2‐methyl‐2‐oxazoline (MeOZO), and the hydrolysis of CMPS–MeOZO reaction products were carried out. The abilities of these products for removing a nonionic surfactant, polyethylene glycol mono‐p‐nonylphenyl ether (NP, n = 10), solutes in water were investigated. Removal rates of NP by and the amounts of NP removed by CMPS–PEPA, –PEI, –MeOZO, and hydrolyzate of CMPS–MeOZO were compared. The adaptability of removal behavior of the products to the Freundlich's adsorption isotherm and the amounts of NP removed by unit masses of the products were investigated. The products also removed an anionic surfactant, sodium dodecylbenzene sulfonate (DBS), solutes in water. The mechanisms for removing NP and DBS were discussed.
Phase equilibria and fractionation of linear homopolymers in solution: A thermodynamic numerical interpretation
Authors: Terán C. Chuquilín , Macchi E. M. , Figini R. V. 
Published: April 2003

AbstractA numerical procedure is described for the quantitative interpretation of experimental fractionations by successive precipitations. The analysis is based on a thermodynamic relationship (mp″/mp′ = A·Bp) between the masses of a polymeric component with degree of polymerization, p, distributed between two liquid phases in equilibrium (mp″ and mp′) and the parameters A and B, which are independent of the degree of polymerization but functions of the thermodynamic variables. An individual pair of A and B parameters corresponds to every individual fraction. The numerical procedure, which is iterative in nature, provides the means for calculating the molecular‐weight distribution of the individual fractions. The procedure requires data from the experimental fractionation (number‐average degree of polymerization and total mass fraction of each fraction) and knowledge of the molecular‐weight distribution function of the whole, starting polymer. The procedure was applied to the analysis of the results of two experimental fractionations of polyamide 11, whereby covergence was quickly reached after a few iterations in the calculations of every set of A and B parameters.
Optimizing polyimide cure using infrared spectroscopy and a factorial design
Authors: Baise A. I. 
Published: April 2003

AbstractThe cure of a polyimide derived from pyromellitic dianhydride (PMDA) and oxydianiline (ODA) has been studied using infrared spectroscopy. A factorial experimental design, combined with regression analysis, was used to find the optimum curing conditions. It was shown that five micron films can be cured by heating at 230–250°C for times of five minutes or longer, while samples cured initially at 150°C did not cure completely when heated to higher temperatures.
Morphological, structural, and interfacial changes produced in composites on the basis of polypropylene and surface‐treated sepiolite with organic acids. III. Isothermal and nonisothermal crystallization
Authors: Acosta J. L. , Ojeda M. C. , Morales E. , Linares A. 
Published: April 2003

AbstractTwo kinetics studies with regard to isothermal and nonisothermal crystallization were conducted on composites samples containing polypropylene and sepiolite surface‐treated with isobutyric acid. Comparison of both studies allows us to demonstrate that isobutyric acid‐treated sepiolite incorporated to the polypropylene at different ratios acts as an effective nucleating agent and, due to its surface activity, generates two different crystalline structures, one of which is attributable to the formation of a mesophase on the periphery of the sepiolite particle.
Sound attenuation of interpenetrating polymer network foams
Authors: Klempner D. , Wang C. L. , Ashtiani M. , Frisch K. C. 
Published: April 2003

AbstractInterpenetrating polymer networks (IPNs) composed of polyurethanes and epoxies were prepared by the simultaneous technique. Modifications of the polymer structures resulted in a series of IPNs exhibiting semimiscible behavior, as evidenced by broad glass transitions in the dynamic mechanical spectra. Since this indicates materials with potentially good sound attenuation properties as a function of temperature and frequency, foams were prepared from these IPN systems. Enhanced sound absorption occurred in these foams when measured using the impedance tube method.
Determination of the density distribution of suspension poly(vinyl chloride) by the density titration method
Authors: Ševčík S. , Kolínský M. 
Published: April 2003

AbstractA dynamic method of density titration for the characterization of powders of suspension poly(vinyl chloride) (PVC) and of their fractions obtained by sieve analysis is described. The method is based on the distribution of PVC particles in variously concentrated aqueous solutions of sodium nitrate according to their specific weight. Separated phases are determinated volumetrically. The method makes possible characterization of various types of PVC powders and of their anomalies.
Tetrachlorophthalic anhydride‐based flame‐retardant chloropolyesters for inhibition of double‐base propellants
Authors: Agrawal J. P. , Kulkarni K. S. 
Published: April 2003

AbstractSeven unsaturated chloropolyesters based on tetrachlorophthalic anhydride (TCPAn) maleic anhydride (MAn), and propylene glycol (PG) (designated as CP‐1) and TCPAn, MAn, and polyethylene glycol molecular weight 200 (PEG‐200) (designated as CP‐2), and TCPAn, MAn, and mixed glycols (PG & PEG‐200 in different molar proportions) and designated as CPM‐2, CPM‐4, CPM‐6, etc. (depending upon molar proportions) have been synthesized. The flameretardant characteristics have been assigned by measuring heat resistance (loss in weight) and flame retardance (burning rate), and it is found that in these chloropolyesters thermal stability increases as chlorine percentage increases. In addition, these chloropolyesters have been characterized for gel time, exotherm peak temperature, tensile strength, percentage elongation and bond strength, nitroglycerine absorption, and cross‐link density. Based on these properties, CPM‐9 with 30% styrene (designated as CPM‐9s) has been selected for inhibition and static evaluation trials, after conditioning at ambient, cold (−40°C), and hot (+50°C) temperatures. The nature of pressure–time profiles indicate the suitability of “CPM‐9s” for the inhibition of double‐base (containing 2‐NDPA) propellants.
Preparation of vinylpyridine irradiation‐grafted poly(4‐methyl‐pentene‐1) membrane for oxygen enrichment
Authors: Lai J. Y. , Wei S. L. 
Published: April 2003

AbstractBy adjusting the casting conditions, the oxygen permeabilities of poly(4‐methyl‐pentene‐1) (TPX) membranes prepared in this study are in the range of 2.91–7.14 × 10−9 cm3(STP) cm/cm2 s cm Hg and permeability ratio of O2/N2 between 2.7 and 4.4. To increase O2N2 selectivity, the vinylpyridine is γ‐ray irradiation‐grafted onto the substrate–TPX membrane. The factors that affect the structure and performance of the grafted membrane considered are: tightness of substrate, kind of solvent for grafting monomers, irradiation conditions, total irradiation dose, and operating temperature and pressure. The O2/N2 selectivities of grafted TPX membranes are significantly improved comparing to that of nongrafted TPX membranes. For example, an O2 permeability of 35.6 × 10−10 cm3(STP) cm/cm2 s cm Hg and an O2/N2 permeability ratio of 7.5 for the grafted membrane can be obtained.
Some aspects of plasticizer migration from poly(vinyl chloride) sheets
Authors: Papaspyrides C. D. 
Published: April 2003

AbstractLong‐term migration data, by radioactivity measurements, are presented for the systems poly(vinyl chloride) (PVC)/labelled dioctyl phthalate (DOP)/methanol, n‐propanol, or n‐butanol. At equilibrium, migration levels determined exceed 85% for methanol and reveal complete removal for the higher alcohols. Migration kinetics failed to be described by the long‐term Fickian approximation with a diffusion coefficient independent of concentration. Nevertheless, qt/q∫, where q∫ the amount migrated at infinite time and qt the amount lost up to time t, increases linearly with (time)1/2/(thickness) during the initial stages of the process and then a linear also relationship appears, but with severely reduced slope. Similar data concerning the systems PVC/DOP/petroleum oils confirm the behavior observed.
An infrared microspectroscopy method for determining deterrent penetration in nitrocellulose‐based propellant grains
Authors: Varriano‐Marston E. 
Published: April 2003

AbstractInfrared microscopy was used to determine di‐n‐butyl phthalate, dinitrotoluene, and methyl centralite diffusion profiles in cross sections of nitrocellulose‐based propellant grains. Absorbance of marker functional groups was determined at 25–50 µm intervals from the edge to the center of the sections. Comparison of IR and light microscopical data indicated that the optically visible boundary does not define the entire depth of deterrent penetration into propellant grains.
Photochemistry of polymeric systems VII. Photo‐cross‐linking of liquid polysiloxanes including cinnamic groups
Authors: Lemaitre Etienne , Coqueret Xavier , Mercier Régis , Lablache‐Combier Alain , Loucheux Claude 
Published: April 2003

AbstractCinnamoyloxymethyl dimethyl vinyl silane was synthesized and bound to a series of commercial polydimethylsiloxane‐type copolymers bearing variable amounts of SiH functions through a hydrosilylation reaction. This reaction was controlled in order to avoid side reactions between the photosensitive unsaturated moiety and the SiH groups.The photosensitivity of polymeric films was studied by a photoresist test described in previous papers. The results emphasize the role of the molecular weight of the starting copolymer and the percentage of pendant photosensitive groups.
Synthesis and characterization of vegetable tannin‐vinyl graft copolymers part I. Cutch‐poly(methyl acrylate) graft copolymers
Authors: Vasantha R. , Rao K. Panduranga , Joseph K. Thomas 
Published: April 2003

AbstractNew graft copolymers were synthesized by grafting methyl acrylate onto cutch, a vegetable tanning agent, in acetic acid medium with hydrogen peroxide as the initiator. The graft copolymers were characterized by infrared spectroscopy and thermogravimetric analysis. The dependence of the percentage of grafting, monomer conversion, efficiency of grafting and rate of grafting on the concentrations of initiator, acetic acid, and cutch were investigated. The optimum experimental conditions for grafting were obtained. A probable mechanism of grafting was also proposed.
Uniaxial compaction behavior of filled polymer powders
Authors: Bhateja S. K. , Gilbert J. R. , Andrews E. H. 
Published: April 2003

AbstractA simple method is described to obtain rheological data on filled polymeric materials in the form of powders. The powder is compacted in a cylindrical chamber by a plunger driven by the cross‐head in an Instron testing machine and the load‐displacement curve is recorded. Further information is obtained by compressing the powder to a fixed load and measuring the load decay with time (stress‐relaxation). The tests are illustrated by application to “monocomponent toner” powders used in dry copying or nonimpact printing processes. It is shown that compaction and stress‐relaxation data are able to differentiate between different toners and facilitate the prediction of their relative performances in terms of pressure fusing. A mechanical spring‐dashpot‐slider model is effective in describing the rheological behavior of these powders and its dependence on the loading of a hard filler (magnetic pigment). The latter affects the “slider” yield stress in the model but has no influence on the relaxation times.
Electron beam effects on polymers: Structure–property behavior of radiation‐cured bis‐GMA
Authors: Thompson Danny , Song Joo Hae , Wilkes Garth L. 
Published: April 2003

AbstractStructure–property relationships were investigated for the diglycidly methacrylate derivative of bisphenol‐A crosslinked by electron beam irradiation. This material, commonly called bis‐GMA, is a viscous liquid at room temperature which crosslinks to form a glassy network. The major parameters which were systematically varied in this study were radiation dosage, dose rate, aging time after irradiation, and post‐cure annealing at higher temperatures. Measurements were conducted to quantify the crosslinking reaction and to characterize the physical properties of the resulting networks. Solvent extraction was done to determine the relative degree of network formation through the equilibrium swelling and the gel weight fraction after drying. Another method utilized FTIR to monitor the disappearance of double bonds as the crosslinking reaction proceeded. To characterize the thermal and physical properties, differential scanning calorimetry (DSC) and dynamic mechanical spectroscopy were utilized. Network density was found proportional to the irradiation dosage, with an upper limit reached above some critical dosage. Over the range of dose rate studied, this variable was not found to influence the degree of cure greatly. The crosslinking reaction became diffusion limited as vitrification occurred. These phenomena were discussed in terms of the well‐known time–temperature–transformation diagram. Free radicals trapped in these reacting networks due to vitrification exhibited a finite lifetime. Post‐curing could be achieved by annealing at a temperature above the Tg of the initially cured network, as shown by the increase of the glass transition temperature from both DSC and dynamic mechanical results.
Accelerated heat age testing of phenolics: Morphological changes
Authors: Stransky Paul D. , Johnson Julian F. , Yates W. Ross 
Published: April 2003

AbstractThe morphological changes that occur in molded phenolic specimens during long‐term heat aging tests have been observed in optical and scanning electron microscopy. The changes in morphology include shrinking and the formation of both cracks and charred zones in the phenolic matrix. The relationship of these morphological changes to weight losses and flexural strength losses was demonstrated.
Changes of non‐Newtonian behavior of carboxylated acrylate dispersions during alkalinization
Authors: Quadrat Otakar 
Published: April 2003

AbstractChanges of flow curves of the carboxylated acrylate latex dispersions during alkalinization were described in terms of parameters of the Cross theory of aggregation of disperse particles. It was found that the dependence of viscosity on pH has a maximum at pH ≃ 9.3 where a yield stress appears.
Study of the curing process giving the rigid polyurethane foam by dynamic viscoelastic method
Authors: Nabata Yoshiyuki , Mamada Akira , Yamasaki Harumasa 
Published: April 2003

AbstractDynamic viscoelastic properties of the rigid polyurethane foam, which is used in Japan as a thermal insulator for refrigerators were studied during the curing process using the RDS‐7700 Dynamic Spectrometer. The curing process, in which large volume expansion and heat evolution occurred, was easily analyzed by this method. The apparent storage modulus (G′app), the apparent loss modulus (G″app), and the apparent loss tangent (tan δapp) were measured as a function of cure time. The effects of the curing temperature and the amine catalyst on the curing process were investigated. It was found that the curing process proceeded through three stages: logarithm of G″app (log G″app) increased with increasing cure time in the first stage, log G″app increased with increasing logarithm of cure time in the second, and the change of G″app cannot be expressed simply in the final. Curing behavior can be estimated from changes of rheological parameters during the curing. The fluidity of reaction mixture can be also predicted from the peak time of tan δapp.
Viscoelastic properties of (cellulose oligo‐oxymethylene ether) acylates with bulky side chain
Authors: Morooka Toshiro , Norimoto Misato , Yamada Tadashi , Takuma Satoshi , Okamura Keizo 
Published: April 2003

AbstractA series of (cellulose oligo‐oxymethylene ether) acylates (COAs) are characterized by the presence of the micro‐Brownian motion of the side chain (β process) which appears separately from that of the main chain (α process). Both the alpha; and β processes are largely affected by the kind of acyl groups introduced in the side chain. To clarify the effect of the acyl group on these processes, we investigated the dynamic mechanical properties of newly prepared COAs with acyl side chain, bulky in chemical structure (iso‐butyrate, privalate, and benzoate) in relation to those for COAs with linear acyl side chain (acetate, butyrate, and valerate). By substituting bulky acyl isomer for linear acyl group in COAs, we observed that the temperature region of both the α and β processes moved to higher temperature. Furthermore, with an increase in molecular size of bulky acyl group, the β region shifts were much larger than the α region, indicating that the mobility of the side chain became comparable to that of the main chain. Finally, when such a large bulky group, for example, benzoate was introduced, the micro‐Brownian motion of the side chain prior to that of the main chain ceased. The apparent activation energy for a third process (γ) due to the motion of the oligo‐oxymethylene parts in the side chain was estimated to be 10.3 kcal/mol.
Surface tension of polytrifluoropropylmethylsiloxane
Authors: Owen Michael J. 
Published: April 2003

AbstractSurface tension studies of the most common fluorosilicone, poly(3,3,3‐trifluoropropylmethylsiloxane) (PTFPMS), give unexpected results. Compared to polydimethylsiloxane (PDMS), the liquid surface tension is higher, the critical surface tension of wetting similar, and the solid surface tension, determined by water and methylene iodide contact angles and the method of Owens and Wendt, considerably lower. As the outermost surface of the lowest energy materials are comprised of close‐packed perfluoromethyl groups and as a flexible polymer backbone should aid in the adoption of the lowest surface energy configuration, fluorosilicones could in principle be the lowest surface energy polymers. In practice, other groups such as the ethylene link between the perfluoromethyl group and the siloxane backbone in PTFPMS are required to produce a stable material. This introduces factors such as bulkiness of side chains, unresolved fluorocarbon/hydrocarbon dipoles, and fluorine/silicon coordination effects. The results are discussed in these terms and compared with PDMS and two fluoropolymers, polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE). PTFE shows similar trends to PTFPMS whereas PCTFE behaves rather like PDMS.
Synthesis and properties of bismaleimide resins containing ether bonds
Authors: Takeda Shinji , Akiyama Hiromi , Kakiuchi Hiroshi 
Published: April 2003

AbstractNew bismaleimides containing ether bonds were prepared. The thermal properties of the bismaleimides were investigated by differential scanning calorimetry (DSC). The effects of structure of the bismaleimides and curing conditions on the thermal and mechanical properties of the cured resins such as initial decomposition temperature (Td), glass transition temperature (Tg), and flexural strength were studied. The introduction of ether bonds to bismaleimide resins decreased the brittleness of the resins without reductions in their heat‐resistant properties.
Linear polyesters products of interfacial polycondensation of bis(4‐hydroxyphenyl)ether with some aliphatic acid dichlorides
Authors: Podkościelny Wawrzyniec , Wdowicka Danuta 
Published: April 2003

AbstractNew polyesters were obtained by interfacial polycondensation of bis(4‐hydroxyphenyl)ether with succinyl, adipolyl, suberoyl, or sebacoyl chlorides. To define the optimal conditions of the process, the polyesters of diol and adipoyl or sebacoyl chlorides were chosen as a model system. Yield for all reaction products and reduced viscosity were found. The following factors were studied: organic phase, contribution of catalyst, concentration and molar ratio of reagents, rate of addition of acid chloride, temperature of reaction and concentration of hydrochloride acceptor. The structure of all polyesters was determined by means of elementary analysis, infrared spectra, and X‐ray. Initial decomposition and initial intensive decomposition temperatures were defined by the curves of thermogravimetric analysis. Thermal and electrical properties of polyesters from diol and adipoyl or sebacoyl chlorides were studied. The molecular weights for these polymers were also determined by gel chromatography.