bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of thermoset plastics by Lewis acid initiated copolymerization of fish oil ethyl esters and alkenes
Authors: Marks David W. , Li Fengkui , Pacha Chad M. , Larock Richard C. 
Published: October 2004

AbstractThe Lewis acid initiated cationic homopolymerization of Norway fish oil ethyl ester (NFO) or the corresponding conjugated fish oil (CFO) and their copolymerization with various alkene comonomers is investigated. Among the Lewis acids employed, boron trifluoride diethyl etherate (BFE, BF3 · OEt2) is found to be the most effective initiator for cationic polymerization of the NFO and CFO systems. The BFE‐initiated homopolymerization of NFO generally results in low molecular weight viscous oils, while that of CFO leads to a solid elastic gel with a gel time of more than 72 h at room temperature. Copolymerization of the NFO or CFO with some alkene comonomers significantly facilitates gelation. The gel times are largely dependent upon the stoichiometry, the type of fish oil, and the alkene comonomer. After postcuring at elevated temperatures, the cationic copolymerization affords polymers ranging from soft rubbery materials to rigid plastics. These NFO and CFO polymers are composed of highly crosslinked materials and a certain amount of free oils and are found to be fully cured thermosets. Generally, CFO polymers appear to be harder than the corresponding NFO polymers. However, the thermal properties of the bulk polymers are similar to each other, and their insoluble extracts exhibit much higher thermal stability than the bulk thermosets. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2001–2012, 2001
Starch derivatives with high degree of functionalization. III. Influence of reaction conditions and starting materials on molecular structure of carboxymethyl starch
Authors: Heinze TH. , Pfeiffer K. , Lazik W. 
Published: October 2004

AbstractCarboxymethyl starch (CMS) was prepared in a completely heterogeneous procedure in a methanol/water slurry activated with aqueous sodium hydroxide (45%, w/v) using monochloroacetic acid as the etherifying agent. The influence of the reaction conditions and the type of starting starch (amylose content and preactivation) was evaluated in regard to the formation of the main repeating units (i.e., unfunctionalized and mono‐, di‐, tri‐, and tetra‐O‐carboxymethylated) and the pattern of functionalization within the anhydroglucose units (AGU). The reproducible synthesis gave products with a maximal degree of substitution of CM groups (DSCM) of 0.66, which was reached in a one‐step synthesis. Repeated carboxymethylation led to products with a DSCM of 0.88. As revealed by means of HPLC analysis after complete acidic depolymerization, in any sample the mono‐O‐carboxymethylated glucose (mono‐O‐CMglc) was preferably present while the di‐O‐CMglc was formed to a very low extent only. The tri‐O‐CMglc was found in some samples while tetra‐O‐CMglc was not detected. The mole fractions determined did not follow the simple Spurlin statistic as shown for CM cellulose synthesized under comparable conditions. Within the carboxymethylated AGUs a preferred functionalization at position 2 was analyzed by means of 1H‐NMR spectroscopy after hydrolytic chain degradation. Consequently, the CMS samples synthesized contained mainly 2‐mono‐O‐CM‐AGU. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2036–2044, 2001
Surface/interfacial changes during polyurethane crosslinking: A spectroscopic study. V *
Authors: Han Qiwen , Urban Marek W. 
Published: October 2004

AbstractCrosslinking reactions and stratification processes in polyurethane films were investigated using attenuated total reflectance (ATR) FTIR spectroscopy. The HDI trimer levels near the film–substrate (F–S) interface appear to increase at the early stages of reactions, and after reaching a maximum, decrease. This is attributed to solvent depletion and subsequent film shrinkage, thus causing local NCO concentration changes. At the later stages of crosslinking reactions, stratification of the 1,6‐hexamethylene diisocyanate (HDI) trimer occurs, with higher concentration levels at shallower penetration depths from the F–S interface. At the same time, NCO‐containing groups assume preferentially parallel orientation to the F–S interface. On the other hand, H‐bonded carbonyl groups tend to orient themselves in a perpendicular direction. Quantitative analysis indicates that at extended reaction times the amount of H‐bonded CO groups at shallower penetration depths increases and their orientation tends to be more random, which is correlated with migration toward the F–S interface. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2045–2054, 2001
Kinetic and property parameters of poly(ethylene naphthalate) synthesized by solid‐state polycondensation
Authors: Sun Yih‐Min , Shieh Jeng‐Yueh 
Published: October 2004

AbstractA low molecular weight prepolymer with reactive end groups was annealed at temperatures between 200 and 245°C to obtain kinetic parameters for solid‐state polymerization of poly(ethylene naphthalate) (PEN). An equation was developed to describe the relationships among time, temperature, and final molecular weight for PEN. The intrinsic viscosity and melting point during polymerization were used to monitor the molecular weight and the thermal stability of the resulting resins. The effect of moisture concentration on solid‐state polymerization was also investigated. Hydrolytic degradation caused initial reductions of the molecular weight if prepolymers were solid‐stated without being dried. With increased exposure to solid‐state conditions, however, the hydrolytically degraded resin dried and repolymerized at rates similar to those samples that had undergone hydrolysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2055–2061, 2001
Synthesis and modification of epoxy‐based divinyl ester resin
Authors: Gawdzik B. , Matynia T. 
Published: October 2004

AbstractSyntheses of epoxy‐based divinyl ester resin and its modification with toluene diisocyanate (TDI) are presented. The resin was obtained from commercially available epoxy resin Epidian 5 and methacrylic acid during graduated heating. Three different resin solutions were obtained by adding 45, 50, and 55% of styrene; then, each solution was modified with TDI at room temperature. Properties of the resins before and after modification were studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2062–2067, 2001
Acoustic analysis of composite soft materials. I. Characterization of the core and boundary layer from compressibility of core/shell particles dispersed in poly(vinyl chloride)
Authors: Koda Shinobu , Tsutsuno Naoki , Yamada Gen , Nomura Hiroyasu 
Published: October 2004

AbstractThe sound velocity of butyl acrylate rubber particles modified by poly(methyl methacrylate) in poly(vinyl chloride) was measured as a function of particle concentration. A model for estimating the adiabatic compressibility of the particle and the boundary layer was proposed. From the model, the partial specific adiabatic compressibility of the particles and the rubber core were evaluated. The adiabatic compressibility of the rubber core was estimated as 3.82 × 10−10 Pa−1. The adiabatic compressibility of the poly(methyl methacrylate) shell is discussed based on the modified model. The study indicates that the shell, including the boundary layer between butyl rubber and poly(methyl methacrylate), is perturbed by the butyl acrylate molecules and is so soft as to be comparable to the rubber. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2089–2094, 2001
An application of micro‐thermal analysis to polymer blends
Authors: Song M. , Hourston D. J. , Grandy D. B. , Reading M. 
Published: October 2004

AbstractMicro‐thermal analysis (micro‐TA) is a new subsurface thermal analysis technology. The average of the DC signal is a function of the thermal conductivity, and the response to the AC modulation signal is a function of the thermal diffusivity of the subsurface. Using this technique, three images based on topography, thermal conductivity, and thermal diffusivity are obtained simultaneously. Specific areas and domains in these images can then be characterized by simply positioning the probe and performing a localized thermal analysis experiment. The technique has been used to study the phase separation process in a 50:50 (by weight) polystyrene (PS)–poly(vinyl methyl ether) (PVME) blend and natural rubber–nitrile rubber blends. For these polymer blends, considerable contrast between phases is obtained, based on thermal conductivity, whereas optical and electron microscopy would show them as being very similar. For example, it is difficult to image the morphology of natural and nitrile rubber blends by means of transmission electron microscopy, because of their similar chemical structures. Micro‐TA gives an excellent image of the morphology of these natural–nitrile rubber blends. This opens a new way for rubber industries to study morphologies of rubber–rubber blends in general. In the 50:50 PS–PVME blend, annealed at 125°C, spinodal decomposition occurred. With increasing time, the domain size and the glass transition temperature of PS‐rich domains increased, indicating that the concentration of PVME in the PS‐rich phases decreases. The results imply that micro‐TA can be used to image the composition in the near‐surface or surface regions in multicomponent materials, if the resolution is high enough. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2136–2141, 2001
Effects of initial structure on the deformation behavior of PP hollow fiber in continuous drawing
Authors: Lee Moo Seok , Kim Sang Yong 
Published: October 2004

AbstractThe effects of the microcrystalline structure of undrawn fibers on the rheological behavior in the process of the polypropylene (PP) hollow fiber formation system were studied by a simple model describing the continuous drawing process. The predicted and observed drawing behaviors were explained in view of a simple approach based on the concept of strain‐rate sensitivity and strain‐hardening parameters. Various parametric studies showing the interactive nature of the strain‐rate sensitivity and strain‐hardening parameters on the drawing behavior were also numerically performed. Strain‐rate sensitivity affects mainly the intensity of the neck, and strain hardening has more effects on the position of the inflection point in continuous drawing. Details of the necking mechanism in the drawing process were studied by observing the deformation behavior of the specimens with different initial microcrystalline structures. The distinctive initial structure of undrawn PP hollow fibers can be formed by controlling the quenching condition in melt spinning. It was shown that the water‐quenched PP fiber exhibited an unstable smectic form, whereas the stable monoclinic phase was observed for the fiber prepared without quenching by forced convection. The experimental results of the drawing behavior indicated that the strain‐rate sensitivity of the fiber with a smectic form was larger than that with the monoclinic form. It was also shown that the hollowness was affected by the quenching condition in melt spinning and the deformation behavior in the drawing process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2170–2182, 2001
Substitution of corn starch with polycaprolactone via chlorination and water resistance of the substituted starch
Authors: Kweon Dong‐Keon , Lim Seung‐Taik 
Published: October 2004

AbstractCorn starch was chlorinated using methanesulfonyl chloride in dimethylformamide (DMF) and then substituted with polycaprolactone (PCL) in various solvents [dimethylsulfoxide (DMSO), water and dimethylacetamide (DMAc)] containing a catalyst [sodium hydroxide (NaOH) or lithium chloride (LiCl)] to improve water resistance. The reaction yield based on the product weight was highest (85%) when DMAc and LiCl were used. Fourier transform infrared (FTIR) spectra showed that starch was monosubstituted with PCL in the aqueous NaOH solution, whereas it was to crosslink by PCL in the case using DMAc and LlCl. The intrinsic viscosity of the products in DMSO supports these trends. By introducing the hydrophobic PCL onto starch, solvent resistance of the substituted starches to water and other aqueous media increased. The crosslinked starch displayed higher water resistance than the monosubstituted starch. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2197–2202, 2001
Surface tailoring of biomedical polymers: An FTIR study
Authors: Stern T. , Cohn D. 
Published: October 2004

AbstractA multistep, surface‐tailoring process of polymeric materials was developed with two consecutive plasma treatments and followed by derivatization reactions. In the first step, tetrafluoroethylene was plasma‐polymerized, generating a highly crosslinked perfluoric surface layer. The next step introduced amine groups into the plasma polymer through exposure of the surface to plasma of ammonia. The reactive amine moieties were then used as anchoring sites for further derivatization. Finally, poly(ethylene glycol) chains were grafted onto the surface via a hexamethylene diisocyanate spacer. This method, aimed at the chemical modification of polymers for biomedical applications, was first demonstrated with poly(ethylene terephthalate) (PET) as a substrate in a previously published study (Cohn, D.; Stern, T. Macromolecules 2000, 33, 137). The aim of this study was to demonstrate the applicability of the method described previously to different polymers: poly(lactic acid), poly(ethylene) (PE), polystyrene (PST), poly(methyl methacrylate), a polybutadiene‐based polyurethane (PEUOXAB‐20), and Lycra. Fourier transform infrared (FTIR) spectroscopy was used to characterize the surface‐modified substrates and the various control treatments. The results obtained were consistent with the derivatization scheme and in full agreement with the FTIR and ESCA results previously obtained for PET. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2203–2209, 2001
Mechanochemical solid‐phase reaction between polyvinylidene fluoride and sodium hydroxide
Authors: Zhang Qiwu , Lu Jinfeng , Saito Fumio , Baron Michel 
Published: October 2004

AbstractGrinding a mixture of polyvinylidene fluoride (PVDF) and NaOH was conducted by a planetary ball mill at atmospheric condition to investigate mechanochemical reaction between the two substances. The grinding stimulates the reaction to form NaF and organic composites. Yield of fluorine converted from PVDF to NaF increases with an increase in grinding time and reaches 90% at 60 min or more. As for the organic phase, oxygen‐bearing compounds are formed due to substitution of fluorine by OH base. The organic compounds are classified into water‐soluble and insoluble ones, depending on their structures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2249–2252, 2001
The rheological and structural behavior of silylcellulosics derivatives
Authors: Bontea D. 
Published: October 2004

AbstractThe trimethylsilylcellulose (TMSC) samples were characterized in solution by osmometry, viscometry, and gel permeation chromatography. The Mark‐Houwink‐Sakurada (M‐H‐S) equation coefficients were determined in chloroform, 1,1,1‐trichloroethane, and o‐xylene, in all cases the exponent “a” being higher than unit, this indicating a great stiffness of the macromolecules in solution. Also, the temperature dependence of the limiting viscosity number and M‐H‐S coefficients respectively for TMSC in o‐xylene were studied. The exponent from M‐H‐S equation is also higher than unit, and increases linearly with the temperature. The GPC studies indicates a relative high polydispersity of the studied samples; the polydispersity index being situated between 2 and 3. The change of the crystalline structure as the result of silylation reaction was evidenced, the crystallinity of silyl derivatives depending on the substitution degree (DS), and the molecular weight. The viscous flow parameters for dilute solutions of trimethylsilylcellulose in o‐xylene were determined in the temperature range 30–70°C. The temperature dependence of the dynamic viscosity of the solutions obeys an Arrhenius‐type equation in which the apparent activation energy is linearly dependent on both the solution's concentration and molecular weight. For preexponential factor no significant dependence on concentration and molecular weight was found. This behavior was attributed to the very great stiffness of the macromolecular chains. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2277–2285, 2001
Co(III) acetylacetonate‐complex‐initiated grafting of N‐vinyl pyrrolidone on cellulose in aqueous media
Authors: Gupta K. C. , Sahoo Sujata 
Published: October 2004

AbstractThe graft copolymerization of N‐vinyl pyrrolidone (N‐VP) onto cellulose was carried out with a cobalt acetylacetonate complex Co(acac)3 as an initiator under a nitrogen atmosphere at 50 ± 0.1°C. The graft yield percentage (%G) obtained as a function of the concentrations of N‐VP and Co(acac)3 and the temperature was used to calculate various other grafting parameters and the grafting rate dependence on the concentrations of monomer, Co(acac)3 and reaction temperature. The energy of activation (ΔEa) for the grafting of N‐VP onto cellulose was 22.7 kJ/mol within 40–60°C. The molecular weights of the grafted chains and homopolymers were determined viscometrically with a Ubbelohde‐type viscometer. Graft yield (%G) in the presence of various additives such as sodium lauryl sulfate, cetyltrimethylammonium bromide, and methanol was studied, and the results are suitably explained. On the basis of the experimental results, a reaction scheme for graft copolymerization is proposed, and a kinetic rate expression is presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2286–2296, 2001
Properties of polypropylene filled with synthetic sodium aluminum silicate
Authors: Upadhyay R. D. , Kale D. D. 
Published: October 2004

AbstractThe effect of synthetic sodium aluminum silicate (SSAS) on the mechanical, physical, electrical, optical, and rheological properties of two different grades of polypropylene (PP) homopolymer with melt flow indexes (MFIs) of 3 and 11 was studied. Incorporation of SSAS improved the flexural strength and modulus of PP. At a given loading of SSAS, the mechanical properties of MFI 3 PP were better than those of MFI 11 PP. The presence of significant slip at the wall was observed for SSAS filled PP. The addition of a fluoropolymeric processing aid increased the slip effect further. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2297–2303, 2001
Isomerization behavior of aromatic azo chromophores bound to semicrystalline polymer films
Authors: Sarkar Nabin , Sarkar Anjana , Sivaram Swaminathan 
Published: October 2004

AbstractThe cis–trans isomerization of azo chromophores covalently bound to semicrystalline polymer films was investigated. Various azo chromophores were introduced onto the functionalized semicrystalline polymer films by a chemical transformation reaction and their isomerization behavior was investigated by UV‐visible spectroscopy and a contact‐angle goniometer. The thermal Z → E isomerization rate of the azo moiety covalently bound to low‐density polyethylene (LDPE) and polypropylene (PP) films was determined. The rate of thermal isomerization was also compared between amorphous and semicrystalline polymer films bearing azo chromophores. The effect of the intramolecular steric factor and the nature of chromophores was studied on the thermal isomerization rate of the polymer films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2923–2928, 2001
Alkaline depolymerization of poly(trimethylene terephthalate)
Authors: Kim Joon Ho , Lee Joon Jung , Yoon Ji Young , Lyoo Won Seok , Kotek Richard 
Published: October 2004

AbstractThe purpose of this study was to investigate the effects of reaction media, composition, and temperature on the rate of the alkaline depolymerization of poly(trimethylene terephthalate) (PTT). The alkaline depolymerization of PTT was carried out at 160–190°C in ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), ethylene glycol monobutyl ether (EGMBE), diethylene glycol monoethyl ether (DEGMEE), and a mixture of these solvents. During the reaction, PTT was quantitatively converted to disodium terephthalate and 1,3‐propanediol. The alkaline depolymerization reaction rate constants were calculated based on the concentration of sodium carboxylate, which was equivalent to the molar amount of sodium hydroxide. The depolymerization rate of PTT was increased by increasing the reaction temperature and by adding ethereal solvents. Moreover, the depolymerization rate was significantly accelerated in the order of EG < DEG < TEG < EGMBE < DEGMEE. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 99–107, 2001
Cellulose furoate. III. Properties and applications
Authors: Yan Hui , Hon David N.‐S. 
Published: October 2004

AbstractCellulose furoates synthesized by a homogeneous reaction was used to make film and fiber. Either colorless or light yellow, transparent cellulose furoate film can be made by solvent cast. Cellulose furoate film with a DS of 2.56 and 20% PEG‐400 as the plasticizer displayed 5441 psi maximum tenacity and 21.5% maximum strain. The film without plasticizer has a water vapor permeability of 0.124 ng · m/m2 · s · Pa. DMTA study identified the Tg of cellulose furoate with a DS of 2.77 was 225°C. As the DS decreased, the Tg shifted toward higher temperature. The success of wet‐spun fibers from LiCl/DMAc solution of cellulose and cellulose furoate substantiated cellulose furoate is compatible with cellulose. Unfortunately, the wet‐spun fibers lost their mechanical and surface properties, and bioresistant property against Myrothecium verrucaria, Cheatomium globosum, and Aspergillus terreus. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 253–257, 2001
Effects of plasma treatment and metal‐ion chelation on lightfastness of dyed polyester/cotton fabric
Authors: Jahagirdar C. J. , Srivastava Yasmin 
Published: October 2004

AbstractPolyester/cotton blend fabric was dyed with Chemistron dye—a mixture of reactive/disperse dyes. Dyed fabrics were subjected to radiofrequency (RF) plasma treatment of different duration and were subsequently treated with metal salts. The effect of surface modification by plasma and dye–metal complex on colorfastness to light is discussed. Evaluation of the improvement in lightfastness was made using the CIE system of color measurement with a standard illuminant D65 and 10° standard observer. The color parameters and color deviations were obtained by Data flash–100 color measurement spectrophotometer with chroma QC 3.0 color quality control software. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 292–299, 2001
Formation of antibiotic, biodegradable polymers by processing with Irgasan DP300R (triclosan) and its inclusion compound with β‐cyclodextrin
Authors: Lu Jin , Hill Marcus A. , Hood Miriam , Greeson Dale F. , Horton John R. , Orndorff Paul E. , Herndon April S. , Tonelli Alan E. 
Published: October 2004

AbstractThe inclusion compound (IC) between the FDA‐approved antibacterial Irgasan DP300 (Trichlosan), and β‐cyclodextrin (CD) has been formed. When the Irgasan–β‐CD–IC is embedded in biodegradeable/bioabsorbable films of poly(ϵ‐caprolactone) (PCL) at low levels (a few wt %), they are rendered resistant to the growth of E. coli bacteria. When these same PCL films embedded with Irgasan–β‐CD–IC are used as the adhesive for laminating cotton fabrics, we observe the resulting cotton laminates to also be resistant to the growth of E. coli bacteria. These results hold promise for the fabrication of bacteria‐resistant polymer films and fibers, as well as antibacterial fabrics, by means of simple melt processing with Irgasan–β‐CD–IC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 300–309, 2001