Synthesis of amphiphilic silane coupling agents based on poly(2-ethyl-2-oxazoline) and their reactions with tetraethoxysilane

Summary Ring-opening polymerization of 2-alkyl-2-oxazoline (alkyl=ethyl,n-butyl,n-octyl) was carried out with an initiator of methyl tosylate followed by the treatment with 3-aminopropyltriethoxysilane to produce a novel type of polymeric silane coupling agents. Similary, telechelic triethoxysilyl-terminated poly(2-alkyl-2-oxazoline)s were prepared by using a bifunctional initiator. The molecular weights of the produced polymers could be effectively controlled by the feed ratio of the initiator to the monomer. These end-functionalized polymers were reacted with tetraethoxysilane with an acid catalyst by the solgel method. In the case of poly(2-ethyl-2-oxazoline), a homogeneous and transparent polymer hybrid was obtained. This polymer hybrid absorbed both of water and organic solvents, which showed amphiphilic adsorption property.     

Hydrogen production by the partial oxidation and steam reforming of tar from hot coke oven gas

Hot coke oven gas (COG) with a temperature of about 1050 K was produced from a test unit for coke production, the capacity of which was 80 kg of coal. The COG was introduced into an experimental unit with a tar converter where oxygen and steam were injected. Over 98% of the total carbon in the hot COG was partially oxidized, reformed with steam and converted to hydrogen and CO. About 1 Nm³/h of hydrogen was continuously produced for 5 h in this experiment. The experimental results suggest that three to five times the amount of hydrogen and CO that were present in the original COG could be recovered by this technology, utilizing the heat of the hot COG for the reaction. The feasibility study showed that hydrogen can be produced by this technology at a lower cost and higher efficiency than by the separation of cold COG.     

Synthesis of functional polymers containing distyrylthiophene moiety using the heck reaction

Summary Polymers containing a trans, trans-2,5-thienylenevinylene-1,4-phenylenevinylene moiety were prepared by palladium-catalyzed polycondensation. Couples of 2,5-divinylthiophene derivatives 1 with p-dihalobenzenes 2 successfully produced the expected polymers 5, whereas couples of 2,5-dihalothiophene derivatives 3 with p-divinylbenzene 4 gave only oligomers due to the homo-coupling reaction of 3. Synthesis of a thermotropic liquid crystalline polymer having trans, trans-2,5-distyrylthiophene skeletons as mesogen was also investigated by use of the polyconcensation between 1 and bis(p-iodophenyl) compounds 6 that concurrently have flexible segments.     

Production of Solar-grade Silicon by Halidothermic Reduction of Silicon Tetrachloride

To develop a new production process for solar-grade Si, a fundamental study on halidothermic reduction based on the subhalide reduction of SiCl₄ by Al subchloride reductant was carried out at 1273 K (1000 °C). Aluminum subchloride reductant was produced by reacting AlCl₃ vapor with metallic Al. Silicon tetrachloride was reduced to Si in a gas-phase reaction by vapors of Al subchloride reductant. Silicon deposits produced in the halidothermic reduction were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray fluorescence (XRF). The Al content in the Si deposits was no more than 0.5 at pct. The Si deposits have a fibrous or hexagonal columnar morphology with diameters ranging from 100 nm to several tens of microns. The reaction was discussed by comparison with the results of the conventional aluminothermic reduction of SiCl₄. Moreover, the halidothermic reduction reactions were analyzed from thermodynamical viewpoints. This study demonstrates the feasibility of a halidothermic reduction for producing solar-grade Si with high productivity.     

Intra-arterial ACNU, CDDP chemotherapy for brain metastases from lung cancer: comparison of cases with and without intra-arterial mannitol infusion

To assess whether therapeutic efficacy is related to intra-arterial (IA) mannitol infusion prior to ACNU and cisplatin (CDDP) for brain metastases from lung cancer, clinical results of patients with and without IA mannitol infusion were compared. Thirty-nine patients were randomly assigned to either a mannitol infusion group (group A) or a non-mannitol infusion group (group B). There were 22 patients in group A and 17 in group B. During radiotherapy, ACNU and CDDP, at a dose of 100 mg/body, were given through the common carotid artery at a rate of 20 mg/min. In group A, 50 ml of 20% mannitol was injected intra-arterially at a rate of 50 ml/min immediately prior to the injection of chemotherapeutic agents. Major complications, such as seizure and neurotoxicity, were not observed. Complete response (disappearance of enhanced tumor mass) was obtained in 72% of group A and in 67% of group B. The median time to tumor progression was 40 weeks for group A and 22 weeks for group B. The median survival time (MST) was 45 weeks for group A and 30 weeks for group B. The survival time was significantly longer in group A as compared to group B (p < 0.05). When the patients who died of failure of vital organ systems other than brain complications were excluded in calculating the survival time, the MST was 69 weeks for 11 patients of group A and 34 weeks for 7 patients of group B. These data suggest that an effort to increase drug delivery to the brain tumor may indeed lengthen the survival time of patients with brain metastases from lung cancer.     

N-acetylpolyethylenimine

Summary This paper describes a blending agent N-acetylpolyethylenimine(AcPEI) for polyamide fiber. Two types of AcPEI were examined; the branched one which was the acetylated product of commercial polyethylenimine(PEI) and the linear one prepared by the ring-opening polymerization of 2-methyl-2-oxazoline. Polyamide fibers(nylon 6) blended with a 2–10 wt % ratio of AcPEI were prepared by the melt-spinning technic. The processability of spinning was very high because and were very compatible with polyamide. In addition, the polyblend fibers obtained displayed good antistatic and dyeing properties, in which containing tertiary amino groups was more effective than. The mechanical properties were also disccussed.     

Ring-opening copolymerization of 2,4-bisphenyl-1,3,2,4-dioxadiphosphetane-2,4-dioxide with oxetane via zwitterion intermediates

Summary Copolymerization of 2,4-bisphenyl-1,3,2,4-dioxadiphosphetane-2,4-dioxide (DPO) with oxetane, a cyclic ether, was found to take place at 90 and 120°C without initiator. Copolymers obtained have a structure of phosphonate-ether units (1), which was determined by ³¹P, ¹H and ¹³C NMR, IR and elemental analysis. Oxetane was incorporated into 1 in a slight excess in all runs(m value in 1=1.5–2.1). A small amount(<15%) of a by-product (2) was always formed. Other cyclic ethers such as ethylene oxide and propylene oxide did not afford copolymers but gave 11 addition products, 10 and 11, quantitatively. The copolymerization is reasonably explained by a mechanism in which DPO behaves as an electrophilic monomer and oxetane as a nuicleophilic one. A pyrophosphonate species is considered to be a key intermediate to lead to copolymer 1 and the whole reaction course is discussed in detail.     

Polymerization via zwitterion. 24. Copolymerization of a cyclic acyl phosphonite with aromatic aldehydes

Summary Spontaneous copolymerizations of 2-phenyl-4-oxo-5, 6-benzo-1,3,2-dioxaphosphorinane, a new cyclic acyl phosphonite, (M_N) with p- and o-substituted aromatic aldehydes (M_E) gave 1∶2 (M_N ∶ M_E) alternating copolymers. This copolymerization took place without added catalyst affording copolymers via zwitterion . The intermediate of spiro acyloxyphosphorane was detected in situ by 31p NMR. The formation of a stabilized intermediate was taken as an important factor to control the 1∶2 composition. The scheme of the copolymerization involving a zwitterion was presented. For the comparison with the above system, copolymerizations of ethylene phenyl phosphonite with aromatic aldehydes were also examined.     

Grain boundary void nucleation in astroloy produced by room temperature deformation and anneal

Dyson and co-workers have shown that the creep life of a nickel base superalloy can be greatly shortened if the material is strained at room temperature before the creep test is carried out. They found that a prestrain followed by a short annealing time produces small grain boundary cavities, and it is the presence of these prenucleated voids which so seriously degrades service life at elevated temperatures. The present work explores the relationship between microstructure and prestrain void nucleation. Samples of the nickel base superalloy astroloy were given various heat treatments which led to significantly different microstructures. It was found that voids resulting from a prestrain-anneal treatment form preferentially at the ends of carbides on grain boundaries oriented roughly parallel to the prestrain tensile axis or rolling direction. Void spacing in the various microstructures is proportional to (but larger than) carbide spacing. The growth of these cavities during annealing is attributed to the presence of tensile residual stresses arising from the difference in deformability between grain boundary regions and the relatively soft matrix. Formerly Postdoctoral Fellow with the Department of Materials Science and Engineering, Northwestern University, Evanston, IL Formerly Postdoctoral Fellow with the Department of Materials Science and Engineering, Northwestern University, Evanston, IL