Thermal behavior and the determination of the polymer-polymer interaction parameter of polycarbonate and a thermotropic liquid crystalline polymer blends

Summary The surface modification of low-density polyethylene(PE) by liquid phase photograft polymerization with acrylic acid(AA), acrylamide(AM) and glycidyl methacrylate(GMA) was described. The grafting of AA and AM was proved and characterized by electron spectroscopy for chemical analysis(ESCA). It was found that fully hydrophilic surface can be obtained in very short irradiation time. With ESCA and attenuated total reflection infrared spectroscopy(ATR-IR), it can be confirmed that bifunctional monomer GMA was grafted onto the PE film surface. Through further reaction with GMA grafted film, heparin and protamine were immobilized onto the grafted film surface.     

Surface hydrolysis of filaments based on poly(trimethylene terephthalate) spun at high spinning speeds

The surface alkaline hydrolysis of fibers made from poly(trimethylene terephthalate) (PTT) was studied after extruding the polymer at high spinning speeds from 2000 to 6000 m/min and heat setting in the range of temperatures from 100 to 180°C. Fiber weight loss increased with an increasing heat‐setting temperature but it was also dependent on the spinning speed. Some of the partially hydrolyzed fibers had a well‐developed, hydrophilic surface, and pore size in the range of 0.69 to 1.20 μm. The optimum reaction and morphological conditions for increasing porosity in PTT fibers depends on spinning speed and heat‐setting temperature. A temperature of 180°C is the upper limit for heat‐setting PTT filaments but seems to be the most effective for making porous fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1724–1730, 2004     

Upgrading a Granular Computing Based Data Mining Framework to a Relational Case

One of the popular methods to develop an algorithm for mining data stored in a relational structure is to upgrade an existing attribute‐value algorithm to a relational case. Current approaches to this problem have some shortcomings such as (1) a dependence on the upgrading process of the algorithm to be extended, (2) complicated redefinitions of crucial notions (e.g., pattern generality, pattern refinement), and (3) a tolerant limitation of the search space for pattern discovery. In this paper, we propose and evaluate a general methodology for upgrading a data mining framework to a relational case. This methodology is defined in a granular computing environment. Thanks to our relational extension of a granular computing based data mining framework, the three above problems can be overcome.     

Time-slide window join over data streams

The join is an important operator in processing data streams. To produce outputs continuously over unbounded data streams, sliding windows are generally used to limit the scope of the join at a certain time. In the existing join algorithms, only a simple type of windows have been considered, which are updated whenever a new data item arrives on any input stream. On the other hand, a more common type of windows have not been addressed yet, whose intervals are updated periodically, i.e., slid by a predefined time interval. In this paper, we consider the time-slide windows in joining multiple data streams. The algorithm for the time-slide window join can vary according to (i) how frequently the join is evaluated and (ii) which structure is used for windowing. Regarding this, possible algorithms are discussed, and experimental results that compare their performances are provided in this paper.     

Darstellung,Struktur und Reaktivität quartärer Ammoniumcellulosate

Tetraalkylammonium cellulosates were prepared by means of an exchange reaction between cellulose and tetraalkylammonium methoxides in anhydrous methanol and dimethylsulfoxide up to a degree of substitution of about 0,7 without chain degradation. The course of this reaction and the structure of the cellulosates in comparison to lithium and sodium cellulosate has been studied. The reaction rate and the equilibrium substitution decreased with increasing size of the cation in the methoxide. The distribution of the alcoholate groups in equilibrium at C-2, C-3 and C-6 of the glucopyranosyl unit in the cellulosates, which was investigated by methylation, hydrolysis of the methylcelluloses, and analysis of the methylglucoses by gas chromatography, was independent of the nature of the cation. Under the given reaction conditions the hydroxyl group at C-2 was more acidic than those at C-3 and C-6, while for the latter practically no difference was found. The tetraalkylammonium cellulosates are highly reactive intermediates for the preparation of cellulose derivatives. The reactivity of the cellulosates increased with increasing size of the cation, Li^⊕ < Na^⊕ < N(CH₃)₄^⊕ <[(CH₃)₃N? CH₂? C₆H₅]^⊕.     

Statistical properties of interparticle/void distance for amorphous plastics toughening

Statistical properties of interparticle/void distance (ID) for various particle/void and dispersion types are studied in relation with toughening of plastics using computer‐generated three‐dimensional models. Particle/void size groups adopted were either of constant diameter or of log‐normal distribution. Particles/voids were dispersed at uniform‐random or flocculated with multiple clusters. It was found that IDs are (a) of approximately Gaussian distribution for particles/voids of either a constant diameter or a log‐normal distribution, when they are dispersed at uniform‐random, but (b) not of Gaussian distribution for particle/void sizes of bimodal log‐normal distribution, nor for flocculated log‐normal distribution of particles/voids dispersed with multiple clusters. It was also found that the degree of ID uniformity for a single group of log‐normally sized particles/voids is not sensitive to standard deviation of particle/void size. Mixing effect on ID properties using two groups of log‐normally distributed particles/voids with similar mean particle/void diameters was simulated. It was found that, when a significant amount (36 vol %) of particles/voids of a small mean and standard deviation of ID was mixed with a group of particles/voids of a large mean and standard deviation of ID, mean and standard deviation of ID for the mixture were not substantially lower than those of the group of particles/voids of the large mean and standard deviation of ID. It was also found that the degree of ID uniformity for the mixture of the two groups was lower than those of individual groups, indicating that the mixing has deleterious effect on toughening. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4256–4262, 2006     

Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran

N‐Vinylcarbazole (VCZ) was solution‐polymerized in tetrahydrofuran (THF) at ?20, 0, and 20°C using the photoinitiation method; the effects of the amount of solvent, polymerization temperature, and photoinitiator concentration were investigated. On the whole, the experimental results corresponded to predicted ones. Low polymerization temperature using photoinitiation proved to be successful in obtaining poly(N‐vinylcarbazole) (PVCZ) of a high molecular weight with a smaller temperature rise during polymerization; nevertheless of free radical polymerization by 2,2′‐azobis(2,4‐dimethylvaleronitrile) (ADMVN). The photo‐solution polymerization rate of VCZ in THF was proportional to the 0.47 power of ADMVN concentration. The molecular weight was higher and the molecular weight distribution was narrower with PVCZ polymerized at lower temperatures. For PVCZ prepared in THF at ?20°C using a photoinitiator concentration of 0.00005 mol/mol of VCZ, a weight‐average molecular weight of 510,000 was obtained, with a polydispersity index of 1.73, and a degree of lightness converged to about 99%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3667–3672, 2002     

Immobilization of a cyclodextrin glucanotransferase (CGTase) onto polyethylene film with a carboxylic acid group and production of cyclodextrins from corn starch using CGTase‐immobilized PE film

Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm² per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002     

Separation of Triacylglycerol Species from Interesterified Oils by High-Performance Liquid Chromatography

Using a 1,3-regioselective lipase as a catalyst, soybean oil and olive oil were interesterified with the short-chain triacylglycerol tributyrin (1,2,3-tributyrylglycerol) to produce mixtures of structured triacylglycerols (SL-TAG). The SL-TAG were purified by column chromatography and analyzed by both normal-phase (silica column; NP_SIL) and reversed-phase [octadecyl silane (ODS) column] high-performance liquid chromatography (HPLC). Individual SL-TAG molecular species were detected by evaporative light-scattering detection, and characterized by mass spectrometry. NP_SIL HPLC successfully separated the newly synthesized SL-TAG into two groups of TAG: one composed of one butyryl group and two long-chain fatty acyl groups (from soybean or olive oil); the second was composed of two butyryl groups and one long-chain fatty acyl group. The SL-TAG species were further analyzed by reversed-phase HPLC which gave a more detailed separation of the TAG species present in the two SL-TAG.     

Hepatic Δ9 and Δ6 desaturase activities during the recovery period following carbon tetrachloride poisoningdesaturase activities during the recovery period following carbon tetrachloride poisoning

The liver microsomal Δ⁹ and Δ⁶ desaturase activities have been studied in rats with carbon tetrachloride-induced hepatitis. Immediately after poisoning, significant decreases were observed for both types of desaturase activity. However, recovery kinetics were slower for the Δ⁶ desaturase than for the Δ⁹ desaturase. The activities of NADH-ferricyanide and NADH-cytochrome C reductases, proteins involved in the electron transfers associated with microsomal desaturation, were also measured. There was a fall in both activities after poisoning, but this decrease was less than that of the desaturase activities.