bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of copolymers containing (+)‐bornyl methacrylate and their racemate for positive‐tone photoresist
Authors: Liu Jui‐Hsiang , Shih Jen‐Chieh , Shih Chih‐Hung , Chen Wei‐Ting 
Published: August 2002

AbstractThis study investigated the chemical behavior of polymers bearing cycloaliphatic bornyl units along with the steric difference of the chiral (+)‐bornyl methacrylate [(+)‐BMA] and racemic (±)‐BMA, expressed in the physical properties of the copolymers and the resist characteristics. To do this, a series of copolymers containing (+)‐bornyl methacrylate [(+)‐BMA] and (±)‐BMA] units was synthesized. Comonomers of tert‐butyl methacrylate (TBMA), methyl methacrylate (MMA), and maleic anhydride (MA) were used. The thermogravimetric curves, glass‐transition temperature (Tg), and molecular weight (MW) of the copolymers were evaluated. Exposure characteristics of chemical‐amplified positive photoresists comprising various copolymers were investigated. It was found that copolymers bearing (±)‐BMA have higher Tg and better thermostability than those of copolymers containing (+)‐BMA units. The copolymers with (±)‐BMA units, however, revealed an inert photochemical behavior on the positive‐tone photoresist. The patterning properties of the positive photoresist, composed of copolymers bearing (+)‐BMA and (±)‐BMA, and the photoacid generator (PAG) were also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3538–3544, 2001
Copolymerization of carbon monoxide and styrene with the Nd(III)–Cu(II) catalyst
Authors: Yao Fanglian , Deng Liandong , Men Jihong , Feng Yakai , Sun Jingwu 
Published: August 2002

AbstractIn this article, the linear alternating copolymer of carbon monoxide and styrene was obtained using the Nd(III)–Cu(II) catalyst. It was found that the introducing order of the catalyst components can affect the catalytic activity, and the pre‐prepared catalyst had higher catalytic activity than the in situ catalyst. The promoting effect of copper acetate on the catalytic activity was also investigated. The structure of the copolymer was characterized by means of IR, 1H‐NMR, 13C‐NMR, WXRD, and EA methods. The thermal decomposition properties were checked by the way of TGA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 8–13, 2001
Anionic block copolymerization of cyclotetrasiloxanes initiated by 4,4'‐bis(dimethyllithiioxylsilyl)diphenyl ether
Authors: Liu Zonglin , Wu Chunlei , Hu Wenjun 
Published: August 2002

AbstractThe anionic copolymerization of cyclotetrasiloxanes initiated by 4,4′‐bis(dimethyllithiioxylsilyl)diphenyl ether (BDMOLiPE) was carried out for the preparation of poly(diphenyl‐dimethyl‐diphenyl)siloxane block copolymers (PMP). To reduce redistribution reaction, the lithium‐based dianionic initiator (BDMOLiPE) was first used for the copolymerization of the cyclotetrasiloxane monomers without solvent, with dimethyl formamide (DMF) as a promotor. The cyclotetrasiloxanes used involved octamethylcyclotetrasiloxane (D4), octaphenylcyclotetrasiloxane (P4), and tetramethyl‐tetravinylcyclotetrasiloxane (V4). The copolymers obtained were characterized withproton nuclear magnetic resonance spectroscopy, infrared spectroscopy, intrinsic viscosity([η]) determination, transmission electron microscopy, and wide‐angle X‐ray diffraction analysis. The results illustrate that the products should belong to block copolymers but not be too perfect because the block copolymers were scrambled to a certain extent during the copolymerization process. However, we can approximately express them as PMP and PMVP, according to the different order of the feeding in raw materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1203–1210, 2001
Microstructure of HTPB‐based polyurethane membranes and explanation of their low O2/N2 selectivity
Authors: Ruaan Ruoh‐Chyu , Ma Wen‐Chung , Chen Shih‐Hsiung , Lai Juin‐Yih 
Published: August 2002

AbstractPolyurethane (PU) membranes usually have high gas permeability but low selectivity. It was supposed that an increase of the hard‐segment content in PU membranes would enhance the selectivity since the hard segment has a higher oxygen affinity and could reduce the chain mobility. However, an attempt to increase the O2/N2 selectivity by increasing the hard‐segment content failed. It was found that increase of the hard‐segment content did increase the gas solubility but the solubility ratio of oxygen to nitrogen was not increased. Increase of the hard‐segment content also reduced the permeabilities of both oxygen and nitrogen, but no improvement of the O2/N2 diffusivity ratio was observed. The microstructure of polybutadiene‐containing PU was examined by DSC and FTIR measurements. It was found that hydrogen bonding between hard segments was the cause of the failure of selectivity improvement. Avoiding the formation of hydrogen bonds between the hard segments is the key for a successful improvement of the O2/N2 selectivity of the PU membranes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1307–1314, 2001
Preparation and swelling properties of crosslinked sodium polyacrylate
Authors: Liu Mingzhu , Guo Tianhua 
Published: August 2002

AbstractCrosslinked sodium polyacrylate as a superabsorbent was prepared by inverse suspension polymerization with cyclohexane as the continuous phase and sorbite anhydride monostearic acid ester (span‐80) as the dispersant. The crosslinking degree was regulated by NaOH. The distilled water absorbency (WA) of the polymer gel was about 700 times its own weight if the gel was allowed to swell at room temperature for 24 h. WA under various conditions, such as varying pH, temperature, reaction time, neutralization, and cyclohexane concentration, was investigated and optimized. Our results revealed that the optimal reaction conditions were 55°C, 25‐min reaction time, 85% neutralization, and a 7:1 (v/v) cyclohexane/monomer ratio. Our results also showed that such synthesized polymer gels have a high WA and a good water‐retention ability under different pressures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1515–1520, 2001
Studies on the copolymerization of methyl methacrylate with N‐(o/m/p‐chlorophenyl) itaconimides
Authors: Anand Vishal , Choudhary Veena 
Published: August 2002

AbstractThe article describes the synthesis and characterization of N‐aryl itaconimide monomers such as: N‐(p‐chlorophenyl) itaconimide (PI)/N‐(m‐chlorophenyl) itaconimide (MI)/N‐(o‐chlorophenyl) itaconimide (OI) and its copolymerization behavior with MMA. The homopolymers and copolymers of N‐aryl itaconimides and methyl methacrylate (MMA, M2) were synthesized by varying the mol fraction of N‐aryl itaconimides in the initial feed from 0.1 to 0.5 using azobisisobutyronitrile (AIBN) as an initiator and tetrahydrofuran (THF) as the solvent. Copolymer composition was determined using 1H‐NMR spectroscopy [by taking the ratio of intensities of signals due to OCH3 of MMA (δ = 3.59 ppm) and the aromatic proton (δ = 7.2–7.5 ppm) of N‐aryl itaconimides] and percent nitrogen content. The reactivity ratios were found to be r1 = 1.33 and r2 = 0.36 (PI‐MMA) r1 = 1.15 and r2 = 0.32 (MI‐MMA) and r1 = 0.81 and r2 = 0.35 (OI‐MMA). Molecular weight as determined using high‐performance liquid chromatography decreased with increasing mol fraction of itaconimides in copolymers. All the polymers had a polydisperstivity index in the range of 1.5–2.6.Thermal characterization was done using differential scanning calorimetry and dynamic thermogravimetry in nitrogen atmosphere. Incorporation of these N‐aryl itaconimides in PMMA backbone resulted in an improvement in glass transition temperature (Tg) and thermal stability. Percent char increased with the increase of PI/MI/OI content in the copolymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2078–2086, 2001
Effect of metallic oxides on thermal stability of ethylene–propylene terpolymer
Authors: Zaharescu T. , Podina C. , Wurm D. 
Published: August 2002

AbstractThermal stability of ethylene–propylene terpolymer (EPDM) loaded with various metallic oxides (PbO, CuO, NiO, Fe2O3, Cr2O3, TiO2, ZrO2) was assessed by the oxygen uptake method. The effects of 5 phr oxide of thermal aging of elastomer were investigated under isothermal (180°C) and isobaric (air at normal pressure) conditions. The influence of this was pointed out. Some mechanistic considerations on the oxidative degradation of EPDM are presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2155–2158, 2001
Reaction kinetics of liquid crystalline epoxy cured with aromatic diamine: Its synthesis and mechanical and electrical characteristics
Authors: Lee J. Y. , Shim M. J. , Lee H. K. , Kim S. W. 
Published: August 2002

AbstractThe effect of the molar ratio of diglycidyl ether of 4,4′‐biphenyl (DGEBP) to p‐phenylene diamine (PDA) on the cure reaction rate was studied by the Kissinger and isoconversional equations. The cure mechanism was studied by FTIR analysis and the liquid crystalline phase structure was analyzed by wide angle X‐ray diffraction (WAXD). With an increasing molar ratio of DGEBP/PDA, the preexponential factor was increased by the increasing collision probability between epoxide groups and primary or secondary amine groups in noncataltyic or catalytic modes. The activation energy also increased because of the increasing content of rigid rodlike mesogen and the high crosslink density, which hindered the diffusion of functional groups. The activation energies obtained from the Kissinger equation were in good agreement with average values obtained from the isoconversional equation. The WAXD pattern showed a smectic layer structure with a layer thickness of 15.3 Å and an intermolecular distance of 4.3 Å. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2372–2380, 2001
Miscibility and adhesive properties of EVA‐based hot‐melt adhesives. II. Peel strength
Authors: Takemoto Mototsugu , Kajiyama Mikio , Mizumachi Hiroshi , Takemura Akio , Ono Hirokuni 
Published: August 2002

AbstractA series of ethylene vinyl acetate copolymers (EVA) were blended with some tackifier resins that were made from wood extracts, and possible relations between their miscibility and properties as hot‐melt adhesives (HMA) were investigated. From our previous report on miscibility of various EVA‐based HMAs, we chose some blends that represent some of the typical miscibility types and investigated their peel strengths. When the blends were miscible at testing temperatures, the temperature at which the maximum value of peel strength was recorded tended to move toward higher temperature as tackifier content of blends increased. This result corresponds to the storage modulus of the blends whose curves tended to move toward higher temperature as tackifier content of blends increased when blend components were miscible as well as their maximum values of tan δ, or glass transition temperatures. It was characteristic for peel strength that there existed second peaks on peel strengths curves at ∼ 100°C, which adhesive tensile strengths for the blends did not have. In terms of relationship between miscibility and HMA performances, we suggest that there are several factors other than miscibility that affect absolute values of peel strength more directly than miscibility; this idea has to be investigated further in the a future study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 726–735, 2002
Study of the synthesis and characterization of methacrylate photoresists
Authors: Fu S. C. , Lin H. W. , Chou W. Y. , Wang L. A. , Hsieh K. H. 
Published: August 2002

AbstractPolymethacrylate copolymers used as single‐layer resists (SLR) were investigated in this study. A photoacid generator (PAG) in the chemically amplified resist (CAR) can generate a Brönsted proton after light stimulation, which can catalyze the deprotection reaction of t‐butyl methacrylate during the postexposure baking (PEB) process. Excimer lasers (KrF and ArF) were used as light source to evaluate the lithographic performance of resists. The hydrophobic property of the resist changed to hydrophilic property after the deprotection reaction by light exposure, which made the exposed resist soluble in the base developer. The deprotection reaction was analyzed by using FTIR and the reaction kinetics of the resist is discussed. The effects of the t‐butyl methacrylate and the isobornyl methacrylate in the resists on the light sensitivity, contrast, reactive ion etching (RIE) resistance, and lithographic performance were systematically investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1860–1869, 2002
Poly(dimethylsiloxane)urethane‐co‐poly(methyl methacrylate) with 2,4‐toluene diisocyanate and m‐xylene diisocyanate. I. Compatibility and impact strength of copolymers
Authors: Ma Chen‐Chi M. , Du Yi‐Chang , Wang Feng‐Yih , Wang Hui‐Chung , Yang Jen‐Chang 
Published: August 2002

AbstractIn this study, slightly crosslinked poly(dimethylsiloxane)urethane‐co‐poly(methyl methacrylate) (PDMS urethane‐co‐PMMA) graft copolymers based on two diisocyanates, 2,4‐toluene diisocyanate (2,4‐TDI) and m‐xylene diisocyanate (m‐XDI), were successfully synthesized. Glass‐transition behaviors of the copolymers were investigated. Results confirm that PDMS–urethane and PMMA are miscible in the 2,4‐TDI system, but are only partially miscible in the m‐XDI system. The methylene groups adjoining the isocyanate in the m‐XDI system show increased phase‐separation behavior over the 2,4‐TDI system, in which the benzene ring adjoins the isocyanate. The functional group of PDMS–urethane improves the impact strength of the copolymers. The toughness depends on the compatibility of PDMS–urethane and PMMA segments in the copolymers. In the m‐XDI system, the impact strength of the copolymer containing 3.75 phr macromonomer achieves a maximum value (from 13.02 to 22.21 J/m). The fracture behavior and impact strength of the copolymers in the 2,4‐TDI system are similar to that of PMMA homopolymer, although they are independent of the macromonomer content in the copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1875–1885, 2002
Preparation of cibacron blue F3GA‐attached polyamide hollow fibers for heavy metal removal
Authors: Say Rıdvan , şenel Serap , Denizli Adil 
Published: August 2002

AbstractDye‐affinity adsorption has been used increasingly for heavy metal removal. Synthetic hollow fibers have advantages as support matrices in comparison to conventional bead supports because they are not compressible and they eliminate internal diffusion limitations. The goal of this study was to investigate in detail the performance of hollow fibers composed of modified polyamide to which Cibacron Blue F3GA was attached for the removal of heavy metal ions. The Cibacron Blue F3GA loading was 1.2 mmol/g. The internal matrix was characterized by scanning electron microscopy. No significant changes in the hollow fiber cross‐section or outer layer morphology were observed after dye modification. The effect of the initial concentration of heavy metal ions and medium pH on the adsorption efficiency were studied in a batch reactor. The adsorption capacity of the hollow fibers for the selected metal ions [i.e., Cu(II), Zn(II) and Ni(II)] were investigated in aqueous media with different amounts of these ions (10–400 ppm) and at different pH values (3.0–7.0). The maximum adsorptions of metal ions onto the Cibacron Blue F3GA‐attached hollow fibers were 246.2 mg/g for Cu(II), 133.6 mg/g for Zn(II), and 332.7 mg/g for Ni(II). Furthermore, a Langmuir expression was calculated to extend the adsorption equilibrium. Nitric acid (0.1M) was chosen as the desorption solution. High desorption ratios (up to 97%) were observed in all cases. Consecutive adsorption/desorption operations showed the feasibility of repeated use of this novel sorbent system. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3089–3098, 2002; DOI 10.1002/app.2338
Exhibits facilitate histology laboratory instruction: Student evaluation of learning resources
Authors: McMillan Paul J. 
Published: August 2002

AbstractSome professional schools have replaced microscopes for histology laboratory instruction with printed and electronic media. It is recognized that these media cannot replace experience with the microscope and that there is a cognitive dissonance of completely replacing microscope study. In addition, students believe that their time is not optimally used in the traditional histology laboratory. Therefore, at Loma Linda University, nine weekly microscope exhibits consisting of 10–15 slides each were prepared. For each exhibited slide, a one page “atlas” is provided, consisting of labeled low‐ and high‐power color micrographs taken from that slide and an informative legend. By referring to the atlas, the student can easily identify the exact field and the labeled features with little help from an instructor. A live or taped video demonstration of the microscope exhibit is available on the first day of the exhibit. During the eighth week of the quarter, students were asked to evaluate the various learning resources available to them. No resource was valued significantly more than the microscope exhibits, but the video demonstrations were valued significantly more than the printed black and white atlas or the color atlas on CD. These exhibits have been used for 2 years to instruct a class of 90 dental students. Advantages are (1) students' time is used efficiently, (2) only one slide set and a fourth as many microscopes need be maintained compared with a traditional laboratory, and (3) one‐of‐a‐kind slides derived from research activities provide for high impact learning. Anat Rec (New Anat) 265:222–227, 2001. © 2001 Wiley‐Liss, Inc.
Perturbed turnover of microtubule‐based nutritive tubes in ovarioles of virgin and precocene‐treated Dysdercus fasciatus
Authors: Stebbings Howard 
Published: August 2002

AbstractDuring early oogenesis in Dysdercus fasciatus, anteriorly positioned nurse cells supply each oocyte with mRNA, ribosomes, and proteins via a microtubule‐rich nutritive tube that lengthens as the oocyte is displaced backwards down an ovariole. Nurse cell–dependent development of an oocyte continues until the latter reaches a particular stage of oogenesis after which the nutritive tube supplying it becomes redundant and breaks down. The signal for nutritive tube breakdown is believed to derive from the oocyte, and to be developmental stage‐specific. To explore this, nutritive tube turnover has been investigated following the experimental inhibition of oocyte maturation both by the prevention of mating, and also the topical application of precocene II. In each case, the nutritive tubes with their component microtubules continued to extend and failed to show normal tube redundancy, typified by microtubule rearrangement and then depolymerisation. This provided an in vivo demonstration that the dynamics of a large microtubule aggregate are influenced by the developmental state of the cytoplasm. Arch. Insect Biochem. Physiol. 50:31–40, 2002. © 2002 Wiley‐Liss, Inc.
Isolation and partial characterization of gypsy moth BTR‐270, an anionic brush border membrane glycoconjugate that binds Bacillus thuringiensis Cry1A toxins with high affinity
Authors: Valaitis Algimantas P. , Jenkins Jeremy L. , Lee Mi Kyong , Dean Donald H. , Garner Karen J. 
Published: August 2002

AbstractBTR‐270, a gypsy moth (Lymantria dispar) brush border membrane molecule that binds Bacillus thuringiensis (Bt) Cry1A toxins with high affinity, was purified by preparative gel electrophoresis. Rabbit antibodies specific for the Bt toxin‐binding molecule were raised. Attempts to label BTR‐270 by protein‐directed techniques were futile, but it was degraded by proteases with broad specificity indicating the presence of a peptide. Carbohydrate was detected by labeling with digoxigenin hydrazide following periodate oxidation. Mild alkaline hydrolysis destroyed toxin and antibody binding, suggesting O‐linked glycans are involved in the activity. GC/MS composition analysis showed that the predominant sugars were galactose, glucose, and N‐acetyl galactosamine with lesser amounts of N‐acetyl glucosamine, glucuronic acid, xylose, and fucose. The carbohydrate moiety accounted for 73% of its total mass. Amino acid analysis showed a high content of aspartic/asparagine, threonine, and serine residues in the protein moiety. The purified glycoconjugate was not visualized using Coomassie or silver staining procedures, but stained “blue” using the cationic dye Stains‐all. BTR‐270 was labeled with biotin and used as a diagnostic probe for screening and identifying toxins that bind to the receptor. Toxin‐binding kinetics obtained using a biosensor demonstrated that the receptor binds Cry1Aa and Cry1Ab toxins with high affinity, and displays a weaker affinity for Cry1Ac, in correlation with the toxicity of these toxins towards gypsy moth. Arch. Insect Biochem. Physiol. 46:186–200, 2001. © 2001 Wiley‐Liss, Inc.
Sex pheromone levels in pheromone glands and identification of the pheromone and hydrocarbons in the hemolymph of the moth Scoliopteryx libatrix L. (Lepidoptera: Noctuidae)
Authors: Subchev M. , Jurenka R.A. 
Published: August 2002

AbstractThe hydrocarbon sex pheromone (13‐methyl‐Z6‐heneicosene) of Scoliopteryx libatrix L. (Lepidoptera: Noctuidae) was found to reach its highest levels on pheromone glands of 3‐day‐old females. Pheromone levels were not different between the time of maximum calling (end of scotophase) and at the middle of photophase. Overwintering females collected in October had sex pheromone present. Decapitation did not lower the amount of pheromone present, indicating that a head factor is not involved in maintaining pheromone titers. Hemolymph also contained the pheromone, indicating that it is made by oenocytes and transported to the sex pheromone gland. Longer chain length hydrocarbons were also identified from the hemolymph and on the cuticular surface. Quantitative differences in hydrocarbon profiles were found with more methyl‐branched hydrocarbons found in the hemolymph than on the cuticular surface. Arch. Insect Biochem. Physiol. 47:35–43, 2001. © 2001 Wiley‐Liss, Inc.
Effect of nutrient deprivation on ribosomal RNA and ribosomal protein mRNA in cultured mosquito cells
Authors: Liu Jun , Fallon Ann M. 
Published: August 2002

AbstractThe effect of nutrient deprivation on RNA and protein synthesis in cultured Aedes albopictus mosquito cells was investigated by replacing the culture medium with phosphate‐buffered saline. After a 2 h starvation treatment, incorporation of radiolabeled precursor into total RNA was inhibited by 50%, and after 4 h, incorporation of amino acids into protein was inhibited by 50%. To investigate directly the effects of starvation on rRNA synthesis, ribosomal subunits were prepared from treated cells by sucrose density gradient centrifugation. After 4 h in saline, incorporation of [3H]uridine into ribosomal subunits had declined to baseline levels. Even after 8 h starvation, however, the effect was reversed by refeeding with complete medium, in which cells resumed rRNA synthesis and ribosomal subunit assembly. During 8 h starvation, total amounts of rRNA detected by northern blot remained stable. Ribosomal protein mRNA abundance was measured on northern blots, using probes corresponding to L8 and L31 ribosomal protein genes. The content of these ribosomal protein mRNAs was unchanged during starvation, or during treatment with actinomycin D. These results suggest that ribosomal protein mRNAs belong to a long‐lived mRNA population, and suggest that post‐transcriptional regulation of ribosomal protein synthesis is an important regulatory mechanism in growing mosquito cells. Arch. Insect Biochem. Physiol. 37:239–247, 1998. © 1998 Wiley‐Liss, Inc.