bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of ortho‐methylation on a bis(4‐cyanatocumyl)benezene low‐dielectric resin
Authors: Maya Eva M. , Snow Arthur W. , Buckley Leonard J. 
Published: December 2002

AbstractA synthesis procedure for and characterization of a tetra‐ortho‐methyl substituted three‐ringed cyanate ester monomer, 4,4′‐[1,3‐phenylenebis(1‐methylethylidene)]bis[2,6‐dimethyl]phenylcyanato, and the corresponding cured resin are described with comparative characterization of the resin analogue without the ortho‐methyl substitutents. The othro‐methylation lowered the dielectric from 2.64 to 2.59 at 1 GHz and from 2.64 to 2.48 GHz at 15 GHz, whereas the tan δ was not significantly affected. Other physical properties also affected included a 40 °C decrease in the glass‐transition temperature, an increase in the thermal‐expansion coefficients, and a reduction in thermogravimetric stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 60–67, 2003
Grafting of light‐activated antimicrobial materials to nylon films
Authors: Sherrill Jennifer , Michielsen Stephen , Stojiljkovic Igor 
Published: December 2002

AbstractProtoporphyrin IX and zinc protoporphyrin IX were grafted to the surface of nylon‐6,6 films via an ethylene diamine bridge and a poly(acrylic acid) (PAA) scaffold. X‐ray photoelectron spectroscopy showed that approximately 57% of the nylon surface was covered by PAA and approximately 6% of the carboxylic acid groups in PAA were grafted to the ethylene diamine derivative of protoporphyrin IX or its zinc salt. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 41–47, 2003
Poly(ethylene terephthalate) terpolyesters containing isophthalic and 5‐tert‐butylisophthalic units
Authors: Kint Darwin P. R. , Martínez de Ilarduya Antxon , Alla Abdelilah , Muñoz‐Guerra Sebastián 
Published: December 2002

AbstractPoly(ethylene terephthalate‐co‐isophthalate‐co‐5‐tert‐butylisophthalate) (PETItBI) terpolymers were investigated with reference to poly(ethylene terephthalate) (PET) homopolymer and poly(ethylene terephthalate‐co‐isophthalate) (PETI) copolymers. Three series of PETItBI terpolyesters, characterized by terephthalate contents of 90, 80, and 60 mol %, respectively, with different isophthalate/5‐tert‐butylisophthalate molar ratios, were prepared from ethylene glycol and mixtures of dimethyl terephthalate, dimethyl isophthalate, and 5‐tert‐butylisophthalic acid. The composition of the terpolymers and the composition of the feed agreed. All terpolymers had a random microstructure and number‐average molecular weights ranging from 10,000 to 20,000. The PETItBI terpolyesters displayed a higher glass‐transition temperature and a lower melting temperature than the PETI copolymers having the same content of terephthalic units. Thermal stability appeared essentially unchanged upon the incorporation of the 5‐tert‐butylisophthalic units. The PETItBIs were crystalline for terephthalate contents higher than 80 mol %, and they crystallized at lower rates than PETI. The crystal structure of the crystalline terpolymers was the same as that of PET with the 1,3‐phenylene units being excluded from the crystalline phase. Incorporation of isophthalate comonomers barely affected the tensile modulus and strength of PET, but the brittleness of the terpolymers decreased for higher contents in 5‐tert‐butylisophthalic units. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 124–134, 2003
Reverse atom transfer radical polymerization of methyl methacrylate in room‐temperature ionic liquids
Authors: Ma Hongyang , Wan Xinhua , Chen Xiaofang , Zhou Qi‐Feng 
Published: December 2002

AbstractThe reverse atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was successfully carried out in 1‐butyl‐3‐methylimidazolium hexafluorophosphate with 2,2′‐azobisisobutyronitrile/CuCl2/bipyridine as the initiating system, which had been reported as not able to promote a controlled process of MMA in bulk. The living nature of the polymerization was confirmed by kinetic studies, end‐group analysis, chain extension, and block copolymerization results. The polydispersity of the polymer obtained was quite narrow, with a weight‐average molecular weight/number‐average molecular weight ratio of less than 1.2. In comparison with other reverse ATRPs in bulk or conventional solvents, a much smaller amount of the catalyst was used. After a relatively easy removal of the polymer and residue monomer, the ionic liquid and catalytic system could be reused without further treatment. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 143–151, 2003
Chemical and physical adsorption of polymers containing thiophosphate, amino, or polysiloxane groups at the oil/metal interface under extreme pressure
Authors: Ni Sheng‐Chung , Kuo Ping‐Lin 
Published: December 2002

AbstractThiophosphate‐ and amino‐containing polymers—poly[diethyl 2‐(methacryloyloxy) ethyl phosphate‐stearyl acrylate] (PPS) and poly(2‐dimethylaminoethylacrylate‐stearyl acrylate) (PNS)—were synthesized, and their characteristics at an oil/metal interface under a high load and rotary velocity were investigated by the measurement of the temperature of the oil, the frictional coefficient, and the electrical contact resistance between the two metal surfaces. The experimental results indicated that PNS most effectively limited the increase of the oil temperature and the frictional coefficient at low temperatures. However, PNS reduced the oil temperature and frictional coefficient less effectively than the base oil at high temperatures, whereas PPS most effectively reduced the oil temperature and frictional coefficient and increased the electrical resistance at high temperatures. Moreover, the adsorption layers of PPS could be directly observed with scanning electron microscopy (SEM). These adsorption layers were analyzed by energy‐dispersible spectrometry to determine the phosphorus content and by electron spectroscopy for chemical analysis to demonstrate the existence of ferric or ferrous ions of sulfide or sulfate. The results of this study suggested that the adsorption layer of the thiophosphate‐containing polymer resulted in chemisorption by a reaction of the thiophosphate group on a metal surface. In contrast, an amino‐containing polymer was physically adsorbed onto a metal surface at low temperature, although no adsorption layer was observed at a high temperature with SEM. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 106–115, 2003
Use of the Pauson–Khand reaction products as monomers in the palladium(II)‐catalyzed homopolymerization and copolymerization of norbornene derivatives
Authors: Son Seung Uk , Kim Do Han , Jung Il Gu , Chung Young Keung , Lee Sueg‐Geun , Chun Sung‐Ho 
Published: December 2002

AbstractNew norbornene derivatives synthesized from Pauson–Khand reaction products were homopolymerized and copolymerized with norbornene with an allyl–palladium complex as a catalyst. The ketone group was tolerated by the polymerization reaction. Monomers bearing protected alcohols were easily homopolymerized. Most of the homopolymers were soluble in tetrahydrofuran, CH2Cl2, toluene, and cyclohexane. As the steric bulkiness of the substituent increased, the chain length of the homopolymer decreased. Copolymers with a molecular weight of up to 153,800 were formed and were soluble in tetrahydrofuran, CH2Cl2, toluene, and diethyl ether. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 76–83, 2003
Synthesis and characterization of fluorine‐containing polyesters by the polyaddition of bis(epoxide)s with active diesters
Authors: Ito Nobuhito , Kudo Hiroto , Kameyama Atsushi , Nishikubo Tadatomi , Anada Tetsuo 
Published: December 2002

AbstractThe synthesis and optical properties of polyesters with pendant fluorinated phenoxy groups were examined. The polyaddition of bisphenol AF diglycidyl ether (1) with fluorine‐containing terephtalates (2a–f) was carried out with tetrabutylphosphonium chloride (TBPC) as the catalyst in chlorobenzene to afford the corresponding polyesters with number‐average molecular weights (Mn's) ranging from 15,200 to 30,000 in 88–96% yields. Furthermore, the polyaddition of 1 with isophthalate 2g and phthalate 2h also produced high‐molecular‐weight polyesters with Mn's = 22,700 and 22,600 in 88 and 84% yields, respectively. The linear relationship was observed between the fluorine contents and refractive indices of the obtained polyesters. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 213–222, 2003
Using the new in–in method for the synthesis of polyisoprene/polystyrene heteroarm star polymers
Authors: Fazeli N. , Afshar Taromi F. 
Published: December 2002

AbstractThe basis of the two‐step in–in method is as follows: star polymers with poly(divinyl benzene) cores, synthesized by the arm‐first method, include many unreacted double bonds in their core, and these double bonds can be attacked by the carbanions of some monomers such as styrene and dienes. In this work, linear polyisoprene chains were used to attack the double bonds existing in the poly(divinyl benzene) cores of polystyrene star polymers, so that a heteroarm star polymer with polystyrene and polyisoprene arms was synthesized. It was later well characterized with size exclusion chromatography, light scattering, viscometry, UV spectroscopy, dynamic mechanical thermal analysis, and 1H NMR. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 135–142, 2003
Synthesis and solution properties of a new pH‐responsive polymer containing amino propanesulfonic acid residues
Authors: Ali Sk. Asrof , Mazumder Mohammad A. J. , Al‐Muallem Hasan A. 
Published: December 2002

AbstractThe reaction of diallyl amine with 1,3‐propane sultone led to the synthesis of the zwitterionic monomer 3‐(N,N‐diallylammonio)propanesulfonate. The sulfobetaine was cyclopolymerized in water in the presence of sodium chloride with t‐butylhydroperoxide as an initiator to afford a polysulfobetaine (PSB) in very good yield. PSB, upon treatment with sodium hydroxide, was converted into an anionic polyelectrolyte (APE). Although APE was readily soluble in salt‐free water, PSB needed the presence of low‐molecular‐weight salts (e.g., NaCl, KI, etc., in the range of 0.135–1.04 N) for its dissolution. The solution properties of PSB and APE were investigated with potentiometric and viscometric techniques. The basicity constant of the amine was apparent and followed the modified Henderson–Hasselbalch equation; as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogens becomes increasingly more difficult. The composition and phase diagram of the aqueous two‐phase systems of APE/PSB and poly(ethylene glycol) were also explored. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 172–184, 2003
Polymer‐dispersed liquid‐crystal materials fabricated with frontal polymerization
Authors: Gill N. , Pojman J. A. , Willis J. , Whitehead J. B. 
Published: December 2002

AbstractWe report on the morphological and thermal properties of polymer‐dispersed liquid crystals (PDLCs) fabricated with frontal‐polymerization‐induced phase separation (FPIPS). Frontal polymerization is characterized by a rapid‐conversion, high‐temperature, and large‐thermal‐gradient environment. A comparison is made between the morphological and thermal properties of PDLCs fabricated with FPIPS and traditional thermal‐polymerization‐induced phase separation. Characterization includes differential scanning calorimetry to probe the glass and nematic‐to‐isotropic transitions and scanning electron microscopy to evaluate the phase‐separated morphology. In addition, the frontal temperatures and velocities are reported for PDLCs fabricated with frontal polymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 204–212, 2003
Preparation and characterization of macroporous poly(N‐isopropylacrylamide) hydrogels for the controlled release of proteins
Authors: Zhuo Ren‐Xi , Li Wei 
Published: December 2002

AbstractMacroporous, temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPAAm) hydrogels were synthesized with poly(ethylene glycol)s (PEGs; molecular weight = 2000–6000) as the pore‐forming agents. The influence of the molecular weight and PEG content on the responsive kinetics of these macroporous hydrogels was investigated. The PEG‐modified PNIPAAm hydrogels were characterized by the swelling ratio, deswelling–reswelling kinetics, Fourier transform infrared, and differential scanning calorimetry. The morphology of these hydrogels was analyzed with scanning electron microscopy. The prepared macroporous hydrogels exhibited some unique properties in comparison with the gels with low molecular weight PEGs (molecular weight < 2000) as the pore‐forming agents. In addition, a preliminary study on the controlled release of bovine serum albumin from these macroporous hydrogels was carried out. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 152–159, 2003
Controlled cationic ring‐opening polymerization of cyclic thiocarbonates with ester groups
Authors: Nemoto Nobukatsu , Yoshii Kouichi , Kameshima Hisamitsu , Sanda Fumio , Endo Takeshi 
Published: December 2002

AbstractThis work deals with the cationic ring‐opening polymerization of the cyclic thiocarbonates 5‐benzoyloxymethyl‐5‐methyl‐1,3‐dioxane‐2‐thione (1), 5,5‐dimethyl‐1,3‐dioxane‐2‐thione (2), and 4‐benzoyloxymethyl‐1,3‐dioxane‐2‐thione (3). The polymerization was carried out with 2 mol % trifluoromethanesulfonic acid, methyl trifluoromethanesulfonate, boron trifluoride etherate, or triethyloxonium tetrafluoroborate as the initiator to afford the polythiocarbonate with a narrow molecular weight distribution accompanying isomerization of the thiocarbonate group. The molecular weight of the obtained polymer could be controlled by the feed ratio of the monomer to the initiator and increased when the second monomer was added to the polymerization mixture after the quantitative consumption of the monomer in the first stage. The block copolymerization of 2 and 3 was also achieved, and this supported the idea that the cationic ring‐opening polymerization of these monomers proceeded via a living process. The order of the polymerization rate was 3 > 2 > 1. The cationic ring‐opening polymerization of 1 and 3 involved the neighboring group participation of ester groups according to the polymerization rate and molecular orbital calculations with the ab initio method. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 185–195, 2003
Mechanism and kinetics of the imidazolidinone nitroxide‐mediated free‐radical polymerization of styrene
Authors: Dervan Paul , Aldabbagh Fawaz , Zetterlund Per B. , Yamada Bunichiro 
Published: December 2002

AbstractStyrene radical polymerizations mediated by the imidazolidinone nitroxides 2,5‐bis(spirocyclohexyl)‐3‐methylimidazolidin‐4‐one‐1‐oxyl (NO88Me) and 2,5‐bis(spirocyclohexyl)‐3‐benzylimidazolidin‐4‐one‐1‐oxyl (NO88Bn) were investigated. Polymeric alkoxyamine (PS‐NO88Bn)‐initiated systems exhibited controlled/living characteristics at 100–120 °C but not at 80 °C. All systems exhibited rates of polymerization similar to those of thermal polymerization, with the exception of the PS‐NO88Bn system at 80 °C, which polymerized twice as quickly. The dissociation rate constants (kd) for the PS‐NO88Me and PS‐NO88Bn coupling products were determined by electron spin resonance at 50–100 °C. The equilibrium constants were estimated to be 9.01 × 10−11 and 6.47 × 10−11 mol L−1 at 120 °C for NO88Me and NO88Bn, respectively, resulting in the combination rate constants (kc) 2.77 × 106 (NO88Me) and 2.07 × 106 L mol−1 s−1 (NO88Bn). The similar polymerization results and kinetic parameters for NO88Me and NO88Bn indicated the absence of any 3‐N‐transannular effect by the benzyl substituent relative to the methyl substituent. The values of kd and kc were 4–8 and 25–33 times lower, respectively, than the reported values for PS‐TEMPO at 120 °C, indicating that the 2,5‐spirodicyclohexyl rings have a more profound effect on the combination reaction rather than the dissociation reaction. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 327–334, 2003
Allelic imbalance in hereditary and sporadic prostate cancer
Authors: Verhage Bas A.J. , Houwelingen Kjeld van , Ruijter T. Emiel G. , Kiemeney Lambertus A. , Schalken Jack A. 
Published: December 2002

AbstractBACKGROUNDIn this study, we evaluate the pattern of allelic imbalance (AI) in both sporadic prostate cancer (SPC) and hereditary prostate cancer (HPC) at loci that frequently show allelic imbalance in sporadic prostate cancer, or are believed to have a putative role in the disease.METHODSDNA obtained from 35 sporadic tumors and 46 hereditary tumors were tested for AI, by using a panel of 35 microsatellite markers.RESULTSChromosomal regions that display high frequencies of AI (≥30%) in HPC include 1q, 5q, 7q, 8p, 13q, 16q, 17q, 18q, and 20q. In SPC, high frequencies of AI were found at 5q, 7q, 8p, 10q, 13q. Main differences (Δ ≥ 20%) in AI between HPC and SPC were at 1q, 10q, 17q, 18q, and 20q.CONCLUSIONAI at the prostate cancer susceptibility loci HPC1, PCaP, and HPC20 was seen more often in HPC compared with SPC. It appears that there are marked differences in the pattern of AI between sporadic and hereditary PCa. Prostate 54: 50–57, 2003. © 2002 Wiley‐Liss, Inc.
Seismic isolation of civil buildings in Armenia
Authors: Melkumyan M G 
Published: December 2002

AbstractSince 1994 a total of 24 buildings and structures have been designed in Armenia that incorporate seismic isolation bearings. The number of base‐ and roof‐isolated buildings already constructed in Armenia has reached 14. Currently, several base‐isolated buildings are under construction. Seismic isolation systems and justification of their effectiveness and application in Armenia are given in this paper. Statistics and examples characterizing various types of applications of seismic isolation techniques are described. The development of a design code and design guidelines for seismic isolation of buildings and structures is discussed. A new concept of a dynamic damper to restrict the displacements of seismic isolated buildings is presented, and future applications of seismic isolation techniques are mentioned.
Progress in the application of active vibration control technologies to long‐span bridges in Japan
Authors: Tanida Koji 
Published: December 2002

AbstractVibration of long‐span bridges can be caused by various types of dynamic excitation, wind‐induced vibration may be the most critical for long‐span bridges such as suspension bridges and cable‐stayed bridges. Typical example are pylons, and wind induced vibration of these during erection affects the safety serviceability of the structure. Formerly, sliding‐block dampers using wires were installed to reduce wind‐induced vibration of pylons, but these had the defects of requiring large space for installation, and there were difficulties with evaluation of damping effects. For the past 15 years, passive‐type tuned mass dampers or tuned liquid dampers have become popular in Japan, but as natural frequencies of pylons vary widely according to the height of pylons during erection, several sets of mass dampers of different natural frequencies have to be prepared. To overcome these drawbacks of passive type mass dampers, actively controlled mass dampers have been developed to reduce the vibration of various modes of structures. The pylons of the Rainbow Suspension Bridge in Tokyo incorporated the first application of the active control system in the world in 1991. The results of active control were found to be very effective, and its technologies have already been applied to more than 10 pylons of long‐span bridges in Japan. This paper reviews progress in the application of active vibration control technologies to long‐span bridges in Japan.
Progress of applications of active vibration control for buildings in Japan
Authors: Fujita Takafumi 
Published: December 2002

AbstractIn Japan, applications of active/hybrid mass dampers have steadily progressed since the first application in 1989. Particularly, applications of hybrid mass dampers with convertible active and passive modes have recently progressed because their effectiveness has been gradually recognized by many structural engineers. This paper overviews the progress of applications of active/hybrid mass dampers, and describes merits of the hybrid mass dampers.
Status of structural health monitoring of long‐span bridges in the United States
Authors: Pines Darryll , Aktan A Emin 
Published: December 2002

AbstractThis paper gives an overview of ongoing research and development in the field of structural health monitoring technologies in the US, with application to long‐span bridges. Specifically, this paper attempts to review various key structural health monitoring technologies, including sensor development, data processing, damage detection algorithms, data analysis and information processing. Several examples are cited from the aerospace, civil and mechanical communities. Monitoring of constructed systems are of considerable interest since the consequences of failure can have a significant effect on the society at large. For instance, consider the 1100 major long‐span bridges in the USA (those with spans of 100 m or longer), many are over 50 years old, and several notable ones are over 100 years old. These bridges fall outside the Standard Specifications issued by AASHTO (1998), and there is little generic experience related to maintaining their performance, especially after they age and/or following any damage. More than 800 of the long‐span bridges in the National Bridge Inventory are classified as fracture‐critical. It follows that structural health monitoring techniques may prove to be useful for maintaining and preserving this population of aging civil infrastructure. It is hoped that the following will stimulate additional discussion regarding the importance of structural health monitoring as an emerging research area for a variety of aerospace, civil and mechanical applications.
Dynamic response of structures to thunderstorm winds
Authors: Choi Edmund CC , Hidayat Ferry A 
Published: December 2002

AbstractA study of the dynamic response of structure to different types of wind is reported in this paper. Response to large‐scale (monsoon wind) and small‐scale winds (thunderstorm) of a SDOF structure is investigated. The monsoon wind is observed to be relatively stationary, and structure response predicted by the gust response factor (GRF) method is reasonably accurate. However, for thunderstorm events, the wind processes are observed to be non‐stationary, and predictions using GRF method very much under‐estimate the actual response.A modification to the GRF method is proposed for thunderstorm winds whereby a running‐mean procedure is introduced. The fluctuation about the running‐mean is observed to be more stationary. The result obtained from the running‐mean GRF method is more accurate. For the thunderstorm events studied, the best predictions are obtained for a running‐mean period of around 60 s.
Three‐dimensional continuum finite element models for plate/shell analysis
Authors: Sze K Y 
Published: December 2002

AbstractIn the last one and a half decades, a considerable amount of three‐dimensional continuum finite element models have been proposed for plate/shell analysis. These continuum elements possess no rotational degree of freedom and are sometimes known as solid‐shell elements. Development of solid‐shell elements is not straightforward. To be applicable to thin‐ and curved‐shell analysis, element deficiencies known as shear, membrane, trapezoidal and thickness lockings must be envisioned. To alleviate or resolve them, advanced finite element techniques, including reduced integration, stabilization, assumed natural strain, enhanced assumed strain, hybrid strain and hybrid stress methods, have been resorted to. This article aims to provide a review of past efforts at formulating reliable solid‐shell elements.