bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and thermal behavior of cotton cellulose graft‐copolymerized using hydroxyethyl methacrylate in presence of triethylene glycol dimethacrylate
Authors: Shukla S. R. , Athalye A. R. 
Published: April 2003

AbstractUV‐radiation‐induced graft‐copolymerization of cotton cellulose was carried out with 2‐hydroxyethyl methacrylate (HEMA) in the presence of small amounts of triethylene glycol dimethacrylate (TEGDMA) using benzoin ethyl ether (BEE), uranyl nitrate (UN), and ceric ammonium nitrate (CAN) as photoinitiators. The presence of very small amounts of (TEGDMA) in the HEMA grafting bath led to great enhancement in the graft add‐on as compared to that obtained on the sodium hydroxide‐preswollen substrate. With increase in the graft add‐on, the breaking load of cotton decreased, whereas its thermal stability improved © 1993 John Wiley & Sons, Inc.
Transport of small molecules in polyolefins. II. Diffusion and solubility of irganox 1076 in ethylene polymers
Authors: Földes Enikő 
Published: April 2003

AbstractDiffusion coefficient and solubility of Irganox 1076 antioxidant in different ethylene polymers (LDPE, LDPE/LLDPE blend, and EVA) were studied between 45 and 80°C. For correct evaluation of the results, physical characteristics of the polymers and the additive were determined as a function of temperature. Good correlation was found between the diffusion rate of the additive and the free volume of the noncrystalline phase in the polymer. Measured solubilities were much higher than reported in the literature. © 1993 John Wiley & Sons, Inc.
Development of polyurethane engineering thermoplastics. I. Preparation and structure
Authors: Frontini Patricia M. , Rink Marta , Pavan Andrea 
Published: April 2003

AbstractRigid, tough thermoplastic copolyurethanes were prepared by a prepolymer technique. The soft‐segment content was varied over the 5–30 wt%. Six stoichiometric formulations based on diphenylmethane 4,4′‐diisocyanate (MDI), one or two different polyetherglycols, and one or two chain extenders of different structure were examined to test the possibilities of varying the degree of crystallinity of the products. Despite their thermoplastic characteristics, the resulting products were insoluble in the solvents normally used for elastomeric polyurethanes. The influence of curing temperature upon crystallinity and degree of polymerization was analyzed. Phase‐structure analysis, performed by differential scanning calorimetry, dynamic‐mechanical thermal analysis, and wide‐angle X‐ray scattering revealed complex phase structures strongly dependent on previous thermal history. In any case, the soft segments appear to constitute a dispersed phase in a rigid amorphous or semicrystalline matrix. Some samples exhibited two hard‐segment glass transitions associated with the existence of a bimodal length hard‐segment distribution. X‐ray diffraction patterns suggested that more than one crystalline form was present in the crystalline phase. © 1993 John Wiley & Sons, Inc.
Preparation and properties of uniform beads based on macroporous glycidyl methacrylate–ethylene dimethacrylate copolymer: Use of chain transfer agent for control of pore‐size distribution
Authors: S̆migol Vladimír , S̆vec Frantis̆ek 
Published: April 2003

AbstractPoly(glycidyl methacrylate‐co‐ethylene dimethacrylate) beads were prepared by both standard suspension polymerization and suspension polymerization in which the suspension of monodispersed droplets of the polymerization mixture was prepared by swelling of the shape‐template polymer particles with porogen diluents and monomers. The effect of bu‐tanethiol, a chain‐transfer agent in radical polymerization, on pore‐size distribution, specific surface area, and chromatographic properties was investigated and the mechanism of its action explained. The synergic effects of the chain transfer, cross‐linking monomer concentration, and content of porogenic diluent were documented. © 1993 John Wiley & Sons, Inc.
The effect of chemical composition of interphase on dispersion of cellulose fibers in polymers. I. PVC‐coated cellulose in polystyrene
Authors: Gatenholm P. , Bertilsson H. , Mathiasson A. 
Published: April 2003

AbstractCellulose fibers surface‐coated with butyl benzyl phthalate (BBP)‐plasticized PVC were evaluated as a reinforcement in thermoplastic matrices. Coated fibers were agglomerated during compounding with polypropylene (PP) and polyethylene (PE). However, an excellent dispersion and improved processability were achieved in polystyrene (PS). Melt rheology was also seen to be affected by fiber coating, and viscosity was lower for coated fibers. Fiber coatings seem to lubricate the blending process as well as to protect fiber from damage during processing. Fiber length was unaffected during treatment when coated fibers were used, as shown by microscopic investigation of extracted fibers, whereas the length of untreated fibers was reduced during processing. Introducing surface‐coated fibers into PS resulted in an increased elongation at break and improved impact strength of composites. The pullout of the fibers is suggested to be responsible for both improvements. The interphase achieved in PS with PVC/BBP‐coated fibers was simulated with PS/PVC/BBP blends. From DSC and DMTA, it was shown that BBP is a cosolvent for PS and PVC and that a single‐phase material was achieved at the relevant concentrations, which also was confirmed by optical clarity. © 1993 John Wiley & Sons, Inc.
Polyamine‐modified urea–formaldehyde‐bonded wood joints. III. Fracture toughness and cyclic stress and hydrolysis resistance
Authors: Ebewele Robert O. , River Bryan H. , Myers George E. 
Published: April 2003

AbstractThe objective of this study was to improve the durability and stability of urea–formaldehyde‐bonded wood products by decreasing the internal stress developed during the resin cure and by improving the ability of the cured system to withstand cyclic stresses. Urea–formaldehyde resins were modified either by incorporating urea‐capped di‐and trifunctional amines into the resin structure or by using the hydrochloride derivatives of some of these amines as the curing agent, or by both methods. This study supplements our previous work by examining the effects of additional amines and subjecting bonded products to additional testing. Solid wood joints bonded with a variety (7 of 15) of modified adhesives had resistance to cyclic stress superior compared to that of joints bonded with unmodified urea–formaldehyde adhesive; at least three of the modified adhesives approached the behavior of phenol–formaldehyde‐bonded joints. Resistance to moist heat aging, although still inferior to that of phenol–formaldehyde‐bonded joints, was significantly improved for joints bonded with modified adhesives over joints made with unmodified resins. The fracture behavior of joints made with modified adhesives was different from that of joints made with unmodified resins. The fracture energy was greater for joints made with three of four modified adhesives than for joints made with unmodified resins. Modified adhesives produced particleboards made with enhanced cyclic stress resistance. Formaldehyde emission from particleboards made with resins modified with urea‐terminated amines was less than emission from boards made with unmodified resins. However, emissions from particleboards made with amine hydrochlorides were not improved compared to those from boards made with an ammonium chloride curing agent. © 1993 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Difurfuryl diisocyanates: New adhesives derived from renewable resources
Authors: Holfinger Michael S. , Conner Anthony H. , Lorenz Linda F. , Hill Charles G. 
Published: April 2003

AbstractThe syntheses of difurfuryl diisocyanates [e.g., ethylidenebis (2,5‐furandiylmethylene) diisocyanate (EDFI)] have been reported in the literature. Difurfuryl diisocyanates are structurally similar to diphenylmethane diisocyanate (MDI), which has proven to be an excellent adhesive for bonding wood composites. The MDI regin is synthesized from petroleum‐derived chemicals; the EDFI resin is synthesized from biomass‐derived chemicals. In this study, the mechanical properties of aspen flakeboards bonded with MDI and EDFI are compared. In general, results show that the strength properties of flakeboards bonded with MDI are only marginally better than those bonded with EDFI. Because EDFI is more viscous than is MDI less than optimum atomization of the EDFI resin during spraying of the flakes is believed to be largely responsible for the differences in strength property values. The dry internal bond strength values of flakeboards bonded with MDI (1.33 MPa; 193 lb/in.2) at 3% resin content are significantly greater than the 0.41 MPa (60 lb/in.2) required by the American National Standards Institute (ANSI/A208.1) for type‐2 medium‐density particleboard. © 1993 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Study of the dispersion of low‐density polyethylene additive masterbatches in polyolefins
Authors: Ogbobe O. 
Published: April 2003

AbstractLight Microscopy, X‐ray microradiography, and ultraviolet microscopy have been used to examine pigment dispersion in low‐density polyethylene pigment masterbatches and polyolefin/low‐density polyethylene additive masterbatch extrudates. The results obtained show that the dispersion of pigment additives in the low‐density polyethylene masterbatches studied were very poor. Also, the degree of dispersion of low‐density polyethylene pigment and ultraviolet masterbatches depend on the melt‐flow‐index of high‐density polyethylene. Blend is poor because of the two‐phase nature of the mix. © 1993 John Wiley & Sons, Inc.
Improved adhesion strength between aluminum and ethylene copolymers by hydration of the aluminum surface
Authors: Strålin Anders , Hjertbergc Thomas 
Published: April 2003

AbstractBy immersing aluminum in boiling water, a hydroxyl‐covered pseudoboehmite layer is formed on the aluminum surface. The adhesion strength between aluminum foils, hydrated in boiling water for short times, and ethylene copolymers, with vinyl acetate, n‐butyl acrylate, and acrylic acid, was examined. The laminates were obtained by pressing with 1.2 MPa at 250°C and the peel strengths were measured by a T‐peel test. By hydrating the aluminum foils, the adhesion strength was doubled for the ester copolymers, while a moderate effect was observed for the acrylic acid copolymer. To understand the adhesion mechanism, the chemical and topographic transformations were followed, using FTIR, SEM, TGA, and BET surface‐area analysis. The adhesion mechanism was found to depend on many factors, such as mechanical effects and increased surface area, due to the porosity of the hydrated film formed. The improved adhesion after hydration of the aluminum can also be explained by the fact that new, stronger interactions are formed. A carboxylate formation of carboxylic acid groups and a catalyzed hydrolysis reaction of the ester bond at the interface is also proposed. These reactions change the functionality on the polymer surface and the formation of stronger bonds between the materials is possible. © 1993 John Wiley & Sons, Inc.
Morphology and performance of polysulfone hollow fiber membrane
Authors: Lee Soon Hong , Kim Jae‐Jin , Kim Sung Soo , Kim Un Young 
Published: April 2003

AbstractPolysulfone hollow fiber membranes were prepared via the dry‐wet spinning process from dope solutions comprised of polysulfone, n‐methyl‐2‐pyrrolidone, polyvinyl‐2‐pyrrolidone, and dodecylbenzene sulfonic acid, sodium salt. Morphology and performance of the membranes were affected by the compositions of coagulant and dope solution. Pore size and the water flux of the membrane increased by the addition of dodecylbenzene sulfonic acid, sodium salt to water in the coagulation bath, due to the changes of physicochemical properties of the outer coagulant. Addition of dodecylbenzene sulfonic acid, sodium salt to the dope solution also increased the pore size. The absence of polyvinyl‐2‐pyrrolidone, the pore forming agent, in the dope solution resulted in a remarkable decrease of pore size of the membrane. The distance between the spinneret and coagulation bath affected the membrane structure and performance. The membranes prepared in this study were suitable for hemofiltration in terms of molecular weight cut‐off characteristics. © 1993 John Wiley & Sons, Inc.
The mechanical properties of short fiber‐styrenic block copolymer composites
Authors: Ashida Michio , Guo Wuyun 
Published: April 2003

AbstractThe effect of fiber loading, fiber length, matrix type, and interface adhesion on mechanical properties of PET short fiber‐styrenic block copolymer TPEs, SIS, and SBS, was investigated. A strong bonding between PET fiber and TPE was obtained by surface treatment of TPE with isocyanate in toluene solution. The stress of the composites, filled with treated fiber, increased with increasing strain by two steps; the modulus for the first step was higher than the one for the second step, and the composites yielded obviously at about 50% strain, with higher stress than that of matrix TPE. With increasing fiber loading and fiber length, the modulus for the first step and the yield stress increased, but the yield elongation decreased. It seems that the matrix elastomer underwent most of the deformation and that the filled fiber underwent large internal stress with little deformation during extension of the composite, which may be an important phenomenon to influence short fiber reinforcement. The stress softening of composites showed a somewhat larger decreased rate than that of the matrix with repeated stress‐strain cycles, and the stress softening in the first cycle increased linearly with increasing fiber loading and increased in an S shape with increasing fiber length. In comparison with the SIS elastomer, the hysteresis of the SBS elastomer showed a big residual strain after the first elongation of 30%, and its retraction and subsequent re‐extension curves were obviously different from the extension curve, which was considered to be due to the destruction of parts of the styrene hard domai in SBS. The stress softening of the composites was influenced by the matrix elastomer, as well as by the loading fiber. The interface separation around the end of a fiber under large strain, and the breaking and restructuring of hard domain in the matrix, were considered to be important sources of softening of the composite. © 1993 John Wiley & Sons, Inc.
Synthesis and photoconductivity study of phthalocyanine polymers. III. PVK‐CuPC(NO2)2
Authors: Chen Hong‐Zheng , Wang Mang , Feng Lin‐Xian , Yang Shi‐Lin 
Published: April 2003

AbstractCu‐dinitro‐diamine phthalocyanine was synthesized, the corresponding diazonium salt was reacted with vinylcarbazole (VK), and a novel polyvinylcarbazole (PVK) ‐bonded CuPc(NO2)2 (I) was synthesized. The chemical structure of polymer (I) is identified by elemental analysis and IR and UV / VIS spectroscopy. Polymer (I) contains about 21 mol % CuPc(NO2)2 rings that are covalently bonded to PVK. Polymer (I) shows good pho‐toconductivity, which is much better than that of the corresponding phthalocyanine monomers. The influence of the interface layer and the charge‐transportation material on the photoconductivity of polymer (I) is also discussed. © 1993 John Wiley & Sons, Inc.
Characterization of surface properties of plasma‐polymerized fluorinated hydrocarbon layers: Surface stability as a requirement for permanent water repellency
Authors: Wang H. Z. , Rembold M. W. , Wang J. Q. 
Published: April 2003

AbstractPlasma polymers were deposited on poly (ethylene terephthalate) (PET) substrates using fluorocarbons such as CF4, C2F6, C3F6, C4F8, and mixtures thereof with CH4. The fluoro‐carbons selected were of saturated structure (CF4, C2F6), unsaturated structure (C3F6), and cyclic structure (C4F8). The addition of CH4 to any of the fluorocarbons caused a deposition of plasma polymers. However, the deposition rate strongly depended on the amount of CH4 added. A fluorocarbon‐dominated feed, i.e., fluorocarbons with 17 mol % CH4, was found to lead to an effective deposition of plasma polymers, whereas a CH4‐rich feed, i.e., fluorocarbons with 67 mol % CH4, led to an ineffective polymer deposition. For the same molar composition of fluorocarbon/CH4, polymer deposition depended on the fluorocarbon structure. It decreases in the order C3F6> C4F8> C2F6> CF4. Elemental analysis showed an atomic ratio F/C of 2.2 and 2.3 for C3F6 and C4F8 plasma polymer powder, respectively, whereas the corresponding values obtained from X‐ray photoelectron spectra (XPS) surface analysis of films showed 1.5 and 1.6, respectively. An explanation could lie in bulk and surface differences of the deposited layers. Contact‐angle measurements revealed that among the monomers employed only C3F6 with 17 mol % CH4 resulted in a relatively stable, hydrophobic surface. © 1993 John Wiley & Sons, Inc.
Syntheses and electric conductivities of poly (methyl vinyl ketone–co–maleic anhydride)s reacted with phosphorus oxychloride
Authors: Kim Dae Young , Kim Yoon Seok , Ha Chang Sik , Cho Sung Jin , Park Dong Kyu , Cho Won Jei 
Published: April 2003

AbstractElectric conductivity of poly (methyl vinyl ketone‐co‐maleic anhydride) (poly (MVK‐co‐MAH)) reacted with phosphorus oxychloride was investigated. It was found that conductivities were strongly dependent on the POCl3 treatment time and concentration for poly (MVK‐co‐MAH), but were not appreciably affected by the mol fraction of [MAH] and copolymerization temperature when the precursor copolymer was obtained. The conductivities of the poly (MVK‐co‐MAH)s treated with POCl3 were of the order of 10‐6 to 10‐9S cm‐1. The conductivity of the poly (MVK‐co‐MAH) increased with the treatment time and concentrations of POCl3. © 1993 John Wiley & Sons, Inc.
Multistage melt polymerization of bisphenol‐A and diphenyl carbonate to polycarbonate
Authors: Kim Yangsoo , Choi Kyu Yong 
Published: April 2003

AbstractA multistage melt polycondensation of bisphenol‐A and carbonate has been studied experimentally using LiOH·H2O catalyst. The reaction process consists of batch and semi‐batch periods with different temperature and pressure conditions. It was observed that a small amount of diphenyl carbonate lost from the reaction mixture by vaporization had little effect on the molecular weight in the batch reaction period but the efficiency of subsequent low‐pressure semibatch polycondensation was affected by the change in the mol ratio of the phenyl carbonate group to the hydroxyl end group. A molecular species model developed for the multistage process was used to analyze the kinetics of the polycondensation process. The composition of the reaction mixture was analyzed of HPLC and compared with model simulations. In particular, the effect of evaporative loss of diphenyl carbonate on the progress of reaction is discussed in detail. © 1993 John Wiley & Sons, Inc.
Peroxide modification of linear low‐density polyethylene: A comparison of dialkyl peroxides
Authors: Bremner Tim , Rudin Alfred 
Published: April 2003

AbstractA commercial‐grade LLDPE resin was cross‐linked using three different dialkyl peroxides, at three different concentrations. The peroxides were ranked in order of their Cross‐linking efficiency and their effectiveness at increasing the storage modulus of the virgin resin at the cure temperature. The chemical mechanism by which the cross‐linking occurs is shown to be closely related to the changes in concentrations of reactive vinyl species on the polyethylene molecules, which follows well with proposed mechanisms of previous publications. Finally, a direct relationship is shown to exist between the rate of peroxide decomposition and the rate of increase in storage modulus of the rubbery modified resin during the curing reaction. © 1993 John Wiley & Sons, Inc.
Kinetics and characterization of the process‐zone evolution in polycarbonate
Authors: Kim A. , Garrett L. V. , Bosnyak C. P. , Chudnovsky A. 
Published: April 2003

AbstractThe process‐zone evolution strongly influences the crack growth of polycarbonate. A methodology for determination of the kinetics of the process‐zone evolution by decoupling these two processes was developed. This was achieved using constant displacement (stress‐re‐laxation) conditions under which the crack length remained constant. The morphology of the process zone was characterized using optical microscopy of cross sections and fracture surfaces produced with liquid nitrogen. The kinetics of process‐zone evolution and stress relaxation were monitored and analyzed. The kinetics vary significantly with the level of displacement imposed. Thus, the challenge remains to construct a master curve for the kinetics. © 1993 John Wiley & Sons, Inc.
Molecular changes of PET yarns during stretching measured with rheo‐optical infrared spectroscopy and other techniques
Authors: Van Den Heuvel C. J. M. , Heuvel H. M. , Fassen W. A. , Veurink J. , Lucas L. J. 
Published: April 2003

AbstractA method has been developed for measuring infrared spectra during the mechanical deformation of yarns. This rheooptical technique was applied to study the molecular processes that take place along the stress‐strain curve of PET yarns. The results were combined with data obtained from size exclusion chromatography (SEC) and tensile measurements at elevated temperatures. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncolling by gauche → trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut‐tie molecules causes the modulus to pass through a second maximum. The chain ends of broken molecules recoil by trans → gauche transitions. Local stress accumulation will lead eventually to yarn rupture. © 1993 John Wiley & Sons, Inc.
Preparation of quaternary ammonium resin by epoxy resin and tertiary amine and its electrodeposition properties
Authors: Yang Chin‐Ping , Ting Chih‐Yang 
Published: April 2003

AbstractA quaternary ammonium‐containing cationic resin is prepared by the ring‐opening reaction of epoxy resin and tertiary amine with the presence of a proton donor. Its emulsion can form a uniform polymer film on the cathodic metal by electrodeposition. In this study, the reaction conditions to prepare the quaternary ammonium resin from epoxy resin and tertiary amine, and effects of different proton donors on this reaction, were examined by gel permeation chromatography and infrared. Meanwhile, distinctions of electrodeposition properties between the quaternary ammonium resin and the tertiary amine acid salt resin were considered. Finally, the electrodeposition mechanism of quaternary ammonium resin was also determined. The results show that the quaternary ammonium resin prepared by triethylamine (TEA) and Epon 1004 has better solubility and emulsification than the tertiary amine acid salt resin prepared by diethylamine (DEA) and Epon 1004. Rupture voltage of this quaternary ammonium resin was very low because it was prepared by full‐alkyl group tertiary amine. Therefore, this kind of quaternary ammonium resin was not suitable for use for the electrodeposition resin individually. But when this quaternary ammonium resin was added to the tertiary amine acid salt resin, the deposited yield was much increased. © 1993 John Wiley & Sons, Inc.