bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymeric reaction of polymer–monomer system irradiated by low‐energy electron beam. IV. Adhesive properties of pressure sensitive adhesive
Authors: Takiguchi Ryohei , Uryu Toshiyuki 
Published: April 2003

AbstractElectron beam (EB) preparation and properties of pressure sensitive adhesives were investigated. The pressure‐sensitive adhesive was obtained by EB irradiation of a mixture of poly(butyl acrylate) (PBA) modified by acryloyl groups and 2‐[2‐hydrox‐3‐propoxy]ethyl acrylate (HPPA). For the polymer with molecular weight (M̄w) of 10 × 104, the introduction of two acryloyl groups per polymer molecule had the highest peel and dead load strength. On the other hand, for the polymer with M̄w of 3 × 104, five acryloyl groups per polymer gave highest adhesive properties. This difference might be attributed to the entanglement of polymers with high molecular weights. Furthermore, the effect of the addition of polar monomers to the monomer mixture was investigated. Polar groups, such as hydroxyl and carboxyl groups, increased the adhesive properties.
Further characterization of the structure and the thermal transitions of poly(p‐oxybenzoate‐co‐p‐phenylene isophthalate) polymers
Authors: Tsai Hong‐Bing , Lee Chyun , Chang Nien‐Shih , Chen Mei‐Sui , Chang Shinn‐Jen 
Published: April 2003

AbstractA series of poly(p‐oxybenzoate‐co‐p‐phenylene isophthalate)s were prepared by melt polycondensation ofp‐acotoxybenzoic acid,p‐phenylene diacetate, and isophthalic acid followed by solid‐state polymerization. The solid‐state polymerization not only increased the molecular weight, but also annealed the copolyesters. The thermal stability, liquid crystallinity, thermal properties, and solid‐state crystallinity of these copolyesters were investigated by TGA, polarized microscope, DSC, and wide‐angle X‐ray diffraction, respectively. It was found that copolyesters with HBA content of 50, 60, and 70 mol % showed explicit melt birefringence at 370°C and thus exhibited liquid crystalline state. The effect of annealing during solid‐state polymerization on the thermal properties was discussed. The effect of copolymerization on their crystallinity was interpreted with X‐ray diffraction qualitatively.
Kraft lignin in polyurethanes. II. Effects of the molecular weight of kraft lignin on the properties of polyurethanes from a kraft lignin–polyether triol–polymeric MDI system
Authors: Yoshida Hirohisa , Mörck Roland , Kringstad Knut P. , Hatakeyama Hyoe 
Published: April 2003

AbstractPolyurethane films were prepared by solution casting using a three‐component system consisting of polymeric MDI, a propylene oxide‐based polyether triol and kraft lignin fractions of different molecular weights. The polyether triol was used as soft segment. The composition of the polyurethanes was varied whereas the NCO/OH ratio was kept constant. The crosslink density increased with increasing molecular weight of the kraft lignin fraction used, which is a result of an increase in functionality of the kraft lignin with increasing molecular weight. Polyurethanes prepared from low molecular weight kraft lignin were found to be more flexible than those prepared from medium and high molecular weight kraft lignin (at lignin contents below 30%). At kraft lignin contents higher than about 30% (which at the NCO/OH ratio used corresponds to a hard segment content of about 70%), rigid and glassy polyurethanes were obtained regardless of the molecular weight of the kraft lignin fraction used.
Flow behaviour of polyblends of crosslinkable polyethylene and silicone elastomer with and without silane coupling agent
Authors: Mukhopadhyay P. , Chowdhury G. , Das C. K. 
Published: April 2003

AbstractFlow behaviour of melt‐mixed blends of crosslinkable polyethylene (XLPE) and silicone elastomer with and without vinyl silane are studied over the entire composition range. Viscosity and extrudate swelling have been studied as a function of shear rate and processing temperature. The effect of shearing and temperature have pronounced effect as is observed from the data of shear modulus, stored elastic energy, relaxation time, etc. Extrudate surface morphology is studied by scanning electron microscopy. A structure consisting of cross‐linked microgelled silicone elastomer dispersed in continuous XLPE matrix is proposed.
Determination of the composition of post dodecyl benzene by IR spectroscopy
Authors: Beşergil Bilsen , Baysal Bahattin M. 
Published: April 2003

AbstractThe purpose of this study is to determine if the chemical coposition of post dodecyl benzene (PDB) which is obtained as the by product during the production of dodecyl benzene (DDB) at PETKIM, Petrochemical Corporation, is a suitable raw material for the production of alkyl benzene sulphonic acids of high molecular weights. In this work, physical and chemical properties of PDB are determined and results are compared with literature values. Chemical composition analysis are done by IR spectroscopy. Thus, the types of alkylates in PDB are determined both qualitatively and quantitatively, the results showed that PDB consist mainly of mono‐and m‐di‐alkyl benzenes, only a small amount of p‐di‐alkyl benzenes are also present.
Influences of the system pressure and the substrate temperature on plasma polymers
Authors: Ohkubo Junichi , Inagaki Norihiro 
Published: April 2003

AbstractPlasma polymerizations of aluminium‐acetylacetone (AlAcAc) complex using a magnetically enhanced plasma reaction system were investigated as functions of the system pressure and the substrate temperature. The system pressure and the substrate temperature rather than the RF power played an important role in plasma polymerization reactions. The high system pressure and the high substrate temperature led to bond scission of monomers to yield plasma polymers rich in aluminium moieties. The chemical composition of plasma polymers prepared from AlAcAc complex was discussed from spectroscopic results with FT‐IR and XPS.
A novel method for graft polymerization onto poly(ethylene terephthalate) film surface by UV irradiation without degassing
Authors: Uchida Emiko , Uyama Yoshikimi , Ikada Yoshito 
Published: April 2003

AbstractA new method omitting oxygen removal procedures from polymerization mixtures was developed for graft polymerization of acrylamide (AAm) onto the surface of poly(ethylene terephthalate) (PET) film with the simultaneous UV irradiation method without photo‐sensitizer. UV irradiation of the PET film with a high pressure mercury lamp under immersion in the 10 wt % aqueous solution of AAm containing an appropriate quantity of periodate (NaIO4) was found to give a highly hydrophilic surface with a water contact angle of about 20°. The original PET film had a contact angle of 75°. In the concentration range of NaIO4 below 1 × 10−4M and above 1 × 10−2 M, polymerization did not take place, whereas polymerization was found to proceed to a significant extent when the NaIO4 concentration ranged between 3 × 10−4 and 5 × 10−3 M. Based on the concentration change of O2 dissolved in the solution during polymerization and the UV spectra of the aqueous AAm solution containing NaIO4 exposed to UV radiation, a reaction mechanism was proposed for the graft polymerization conducted without degassing in the presence of NaIo4.
Rheological behavior of natural rubber latex in the presence of surface‐active agents
Authors: Peethambaran N. R. , Kuriakose Baby , Rajan Manjari , Kuriakose A. P. 
Published: April 2003

AbstractThe rheological behavior of centrifuged and creamed natural rubber latex concentrates and the effect of surface‐active agents such as casein, polyvinyl alcohol (PVA), sodium alginate, and sodium carboxymethylcellulose (NaCMC) were studied at different shear rates and temperatures. The study showed that creamed latex, prepared using tamarind seed powder, is more sensitive to shear rate and temperature than centrifuged latex. The pseudoplasticity and viscosity of the latices can be increased by the addition of surface‐active agents, and the effect varies with the type of surface‐active agents. The behavior of the latices toward temperature is also affected by the addition of surface‐active agents, and maximum effect is observed for polyvinyl alcohol and least for sodium alginate.
Synthesis of organotin polymers from diallyl terephthalate and Bu3SnH
Authors: Moriya Osamu , Endo Takeshi 
Published: April 2003

AbstractCrosslinked polymers containing both ester and organotin moieties were obtained in high yields from diallyl terephthalate (DATP) and tri‐n‐butyltin hydride via radical processes. The tributyltin ester (1) and the hydrostannated derivatives of DATP (2) were prepared and employed for copolymerizations with DATP. The copolymerizations of 1 and 2 proceeded effectively to afford the corresponding organotin polymers, in which the tributyltin group was incorporated through O–Sn and C–Sn bonds, respectively.
Studies of addition type polyimidesulfones and their composites
Authors: Lee Yu‐der , Ting Mao‐i 
Published: April 2003

AbstractAddition type polyimidesulfone oligomers have been synthesized from 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 3,3′‐bis(aminophenyl) sulfone using three latent crosslinking groups as endcappers. The prepolymers were isolated and characterized for infrared spectra analysis, solubility test in various type solvents, melt flow, and cure properties. The crosslinked polyimides were characterized for thermal stability in a nitrogen atmosphere. The most promising systems, nadimide and maleimide prepolymers, were selected for the detailed study as the matrix for graphite woven cloth reinforced composites for which mechanical and other properties were tested. The differences due to various end‐capped agents, including processibility, the extent of crosslinking of prepolymers, and thermal and mechanical properties of their composites, were compared.
Thermal degradation of functionally terminated polybutadienes: Pyrolysis gas chromatography and thermogravimetric studies
Authors: Rao M. Rama , Radhakrishnan T. S. 
Published: April 2003

AbstractThermal degradation of functionally terminated liquid polybutadiene polymers, carboxy‐terminated polybutadiene (CTPB), hydroxy‐terminated polybutadiene (HTPB), and poly(butadieneacrylonitrile‐acrylic acid) terpolymer (PBAN) and their cured analogues were studied by pyrolysis gas chromatography in the temperature range 500–850°C. It was found that CTPB, HTPB, and PBAN could be distinguished from one another by the variation in the composition of their pyrolyzates. The differences in the product composition were rationalized by the relative importance of unzipping and hydrogen transfer reactions in the mechanisms of their degradation. The presence of the OH group was found to favor hydrogen transfer reactions whereas the COOH group has only marginal effect. The cyclization reactions were found to predominate in the thermal degradation of cured PBAN and the pyrolysis results were substantiated by thermogravimetric studies at several heating rates. The activation energy for the decomposition of cured PBAN was estimated to be 259 ± 16 kJ mol−1 by Ozawa's method.
Effect of thermal contacts between components on thermal conductivity of multicomponent systems
Authors: Piorkowska E. , Galeski A. 
Published: April 2003

AbstractIn the paper the influence of thermal contacts of the interface between the inclusions and matrix on thermal conductivity of a multicomponent system is studied. It is shown that the modification of the interface which improves the adhesion between components causes also the increase of the thermal conductivity of a composition.
Properties of mixtures of silk fibroin/syndiotactic‐rich poly(vinyl alcohol)
Authors: Yamaura Kazuo , Kuranuki Noriyasu , Suzuki Miyako , Tanigami Tetsuya , Matsuzawa Shuji 
Published: April 2003

AbstractThe gelation of mixed solutions of silk fibroin (SF)/syndiotactic‐rich poly(vinyl alcohol) (s‐PVA), the thermal analysis of dry‐gels, and the various properties of blend films were investigated. The rate of gelation of a mixed solution was lower than that of each SF or s‐PVA solution of the same concentration. In the DSC thermograph of mixed dry‐gel (SF/s‐PVA = 2/8–8/2) 2 endothermic peaks corresponding to SF (at 288–299°C: decomposition) and s‐PVA (at 233–241°C: melting) were found. Namely, microphase segregation took place. This was confirmed by optical and electron microscopes. The mechanical properties of blend films did not have additive properties. The degree of swelling in water of blend films was independent on water temperature or methanol treatment. The mechanochemical behaviors were barely observed by the pH exchange between pH 2 and 12 only under lower loads. The addition of SF into s‐PVA films promoted the permeation of neutral salts.
Polymeric resins from renewable resources. II. Synthesis and characterization of flame‐retardant prepolymers from cardanol
Authors: Pillai C. K. S. , Prasad V. S. , Sudha J. D. , Bera S. C. , Menon A. R. R. 
Published: April 2003

AbstractPhosphorylated cardanol prepolymers (PCP) are obtained by simultaneous phosphorylation and oligomerization of cardanol, an unsaturated pentadecylphenol extracted from the nuts of the plant Anacardium occidentale L. Although GPC showed the presence of only oligomeric species in the system, the high viscosity of 0.35–0.45 million cps was found to be due to involvement of hydrogen bonding. IR spectra of PCP gave bands at 1030 and 1240 cm−1, indicating P—O—C linkages. The decrease in iodine value and the absence of vinyl IR bands at 895 and 907 cm−1 indicated oligomerization. NMR spectra of PCP showed partial loss of unsaturation. A carbonium ion initiated mechanism is indicated for the oligomerization. PCP was found to be highly reactive with aldehydes, amines, and isocyanates. Highly insoluble and infusible thermoset products could be obtained. TGA studies showed a two‐stage decomposition with improved thermal stability above 500°C for PCP compared to cardanol‐formaldehyde (novolac)‐type resins. Completely cured PCP was highly resistant to hydrolysis by water. Studies on mechanical properties showed that the PCP cured with HMTA gave a tensile strength of 16.9–21.5 MN/m2 and an impact strength of 1.63–2.04 J. compared to 24–48 MN/m2 and 1.35 J, respectively, for phenol formaldehyde (novolac) resin prepared under similar conditions. The lap shear strength of PCP‐bonded wood pieces showed a value of 400 ± 10 N/cm2 in comparison to 60 ± 10 N/cm2 of cardanol formaldehyde (novolac) resin, indicating that phosphorylation improves the bonding characteristics. With a phosphorus content of 7.9%, PCP showed good fire‐retardant properties. Vertical burning studies did not show any propagation of fire or any afterglow. PCP cured with HMTA gave a limiting oxygen index value of 35, which on bromination increased to 42.0. PCP could find application as polymeric fire‐retardant additive for plastics and elastomers or as filled or unfilled fire‐resistant plastics/composite products.
The effect of γ–irradiation on poly(methyl methacrylate) using an ultrasonic technique
Authors: Aziz A. W. , Abd‐El‐Malak N. A. 
Published: April 2003

AbstractUltrasonic absorption measurements were made at 3.14 MHz on poly(methyl methacrylate) as a function of temperature and after various doses of γ‐irradiation. The measurements showed a relaxation phenomenon. The activation energy of the various doses was determined and the smallest doses that affected the specimen was found to be 4 Mrad.
Permeability through cellulose membranes grafted with vinyl monomers in a homogeneous system. VII. Acrylamide grafted cellulose membranes
Authors: Nishioka Noboru , Uno Masakuni , Kosai Kouichi 
Published: April 2003

AbstractThe homogeneous grafting of acrylamide (AAm) onto cellulose was carried out in a dimethyl sulfoxide/paraformaldehyde (DMSO/PF) solvent system. The diffusive permeabilities of solutes through the AAm‐grafted cellulose membranes, apparent activation energy for solute permeation through them, states of water in them, and their microphase separated structures were investigated. The permeability through the grafted membranes was superior to that through the cellulose membrane cast from the DMSO/PF solution of cellulose. The total water contents of the grafted membranes were larger than that of the cellulose membrane. The state of intermediate water in the grafted membranes with fine microphase separated structures was influenced remarkably. A higher activation energy was observed for the solutes with poor permeability through the membranes.
Starch‐derived glycol and glycerol glucosides prepared by reactive extrusion processing
Authors: Carr M. E. 
Published: April 2003

AbstractPreviously, starch‐derived glycol and glycerol glucosides were prepared by batch‐reaction processes and had excellent potential as chemical intermediates for a wide range of products. However, more efficient processes for preparation of these derivatives are needed. In this present work, a modern corotating, intermeshing, twin‐screw extruder with a barrel length/screw diameter (L/D) ratio of 43: 1 was used to study the reaction of starch with ethylene glycol and glycerol in the presence of sulfuric acid catalyst at elevated temperatures. A fully continuous process was used. Variables that were investigated included temperature (140–180°C), glycol or glycerol/starch AGU mol ratio (1.5–4.0), starch feed rate (5–30 lb/h), screw speed (100–475 rpm), residence time, specific energy, and several types of commercial cornstarch and corn flour products. Rates and extents of reaction that occurred in the barrel were determined by analyzing samples that were quenched just prior to extrusion. The major glucosides were quentitated by high‐performance liquid chromatography. Results of this study show that starch can be continuously, rapidly, and efficiently converted to glucosides in 90% yield at high production rates. Such processing is expected to be technically feasible for the reaction of a wide range of polyhydroxy alcohols with various starch substrates.
Interaction of poly(methyl methacrylate) and nafions
Authors: Wilkie Charles A. , Thomsen Jeffry R. , Mittleman Martin L. 
Published: April 2003

AbstractThe thermal degradation of Nafion–H, Nafion–K, and the mixture of each of these with poly(methyl methacrylate) (PMMA) has been studied. A mechanism is proposed for the thermal degradation of Nafion–H that involves an initial cleavage of the carbon–sulfur bond leading to SO2 and OH radical and a carbon‐based radical. This carbon‐based radical then undergoes further degradation. The addition of PMMA to Nafion–H inhibits further degradation of the Nafion carbon‐based radical and instead radical recombination reactions between PMMA fragments and this Nafion radical dominate the reaction scheme. The replacement of the hydrogen in Nafion–H with a potassium (i.e., Nafion–K) produces a much more robust material that does not degrade under conditions similar to those used for Nafion–H. Nafion–K has little effect on the degradation of PMMA.
Complexes of starch polysaccharides and poly(ethylene co‐acrylic acid): Structure and stability in solution
Authors: Shogren R. L. , Greene R. V. , Wu Y. V. 
Published: April 2003

AbstractChiroptical methods have been used to study the conformation and interactions of amylose and amylopectin with poly(ethylene co‐acrylic acid) (EAA) in aqueous solution. These studies, along with X‐ray diffraction and solid‐state NMR data, show that amylose and EAA, as well as amylopectin and EAA, form helical V‐type inclusion complexes when mixed in aqueous suspension. This structure apparently accounts for the partial compatibility observed in films containing starch and EAA. About 2/3 by weight of EAA does not interact with amylose and probably represents the ethylene‐rich central core of the EAA micelle. EAA/amylose complexes in 10 mM NaOH were stable to temperatures > 90°C, whereas EAA/amylopectin complexes in the same solvent were largely disrupted at this temperature. Urea, at a concentration of 8 M, further destabilized both EAA/amylopectin and EAA/amylose complexes. Solutions with an alkaline pH (> 9.5) dispersed EAA optimally and allowed maximum complexing with amylose. At pH values > 13, the EAA/amylose complexes were weaker, most likely due to electrostatic repulsion between ionized hydroxyl groups of amylose and carboxyl groups of EAA.
Mechanism of degradation and crosslinking of polyurethane when irradiated by gamma‐rays
Authors: Shintani Hideharu , Nakamura Akitada 
Published: April 2003

AbstractWe conducted a study to clarify the mechanism of crosslinking and degradation of thermoplastic polyurethane (PU) when irradiated with gamma‐rays. Changes in molecular weights as a result of gamma‐ray irradiation, the UV absorption, the amount of PUs with amino groups, and the elution of oligomers to an organic solvent were determined to estimate characteristic changes in PU caused by irradiation. The amount of PUs with primary amino groups as a degradated PU products at p,p′‐methylenediphenyl diisocyanate–1,4‐butanediol (MDI–BU) hard segments increased linearly with increasing irradiation level. The amount of this products by gamma‐ray irradiation was approximately 10–20% of the calculated amount, indicating that predominant degradation occurred at polytetramethyleneglycol (PTMG) soft segments (about 80–90% of the degradation). Characteristic differences were seen in crosslinking between non‐chain‐extended thermoplastic PUs based on the molecular weights of PTMG, (Mw of PTMG = 640–2800). The crosslinking ratio is linearly proportional to the molecular weights of PTMG, indicating that crosslinking at PTMG soft segments was major (the ratio of crosslinking at PTMG was more than 90%). Methanol extract of PU indicated elution of PU oligomers ranging from 13 to 1 as a polymerization degree.
Modification of the dynamic swelling behavior of poly(2‐hydroxyethyl methacrylate) in water
Authors: Kabra B. G. , Gehrke S. H. , Hwang S. T. , Ritschel W. A. 
Published: April 2003

AbstractThe equilibrium and dynamic swelling behavior of glassy polymers immersed in solvents can be modified by controlling the history of the polymer sample, which includes prior swelling and the drying method, or by copolymerization with other monomers. In this paper, the swelling kinetics in water of ionic hydrogels of 2‐hydroxyethyl methacrylate copolymerized with potassium 3‐sulfopropylmethacrylate and/or ethylene glycol dimethacrylate have been studied at 23°C. The dimensional changes of a swelling polymer sheet can be controlled through incorporation of anisotropic stresses in the initially dry, glassy polymer. These anisotropic stresses do not affect the swelling kinetics as long as the sample is partially glassy. However, differences in the initial stresses cause sharply different swelling kinetics once the polymer becomes entirely rubbery, due to differences in dimensional changes. Increasing the percentage of ionic comonomer in the polymer increases the equilibrium degree of swelling and the water sorption rate without changing the time for equilibration or the swelling transport mechanism. In contrast, increasing the percentage of cross‐linker in the polymer not only reduces the degree of swelling and water sorption rate, but also increases the equilibration time and shifts the water transport mechanism from Fickian diffusion to anomalous transport.