SiO_2掺杂对Ru-TiO_2催化剂的结构及其对丁二酸湿式氧化活性的影响

在TiO2粉末中掺杂SiO2,制备0—20%的SiO2TiO2载体.利用浸渍法在载体上负载Ru,制备Ru/SiO2TiO2催化剂.结果表明,催化剂的晶相以锐钛矿为主,晶粒尺寸为30—50nm.掺杂的SiO2主要为无定型,以5—15nm分散于催化剂中,比表面积随SiO2掺杂量的增加显著增大,但对TiO2的晶体结构无明显影响,也未形成Si—O—Ti键.Ru因粒径细化及含量过低未产生衍射峰.在300ml间歇式反应釜中,反应温度210—270℃,初始氧分压085MPa条件下,对丁二酸(74g·l-1,COD=7000mg·l-1)的催化湿式氧化结果表明,SiO2掺杂量对COD的去除率有显著影响,掺杂10%SiO2的催化剂对COD的去除率最高.在连续十次运行中,COD的去除率保持在85%左右,活性未见降低.

Effects of Gamma-Ray Irradiation on Dielectric Surface Breakdown of Polybutylene Naphthalate and Polybutylene Terephthalate Under Reduced Pressure

With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becomes necessary to investigate the effects of the radiation and air pressure on insulation materials. This paper describes the effects of gamma-ray irradiation and reduced pressure on dielectric breakdown of polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) by applying a DC pulse voltage. Both PBN and PBT were irradiated in air up to 100 kGy and then up to 1 000 kGy with a dose rate of 10 kGy/h by using a60Co gamma-source. The effects of total dose and reduced pressure on the time to dielectric breakdown and discharge quantity were discussed. Obtained results show that, while increasing the total dose, the discharge quantity decreased with PBN, but increased with PBT. With decreasing the air pressure, the discharge quantity increased with PBN, but decreased with PBT. With increasing the total dose, the time to dielectric breakdown increased with PBN, but decreased with PBT. With decreasing the air pressure, the time to dielectric breakdown increased with both PBN and PBT. The experimental results suggest that the chemical structure of polybutylene polymers plays a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction.

Alkylpolyglycoside inducing poly (butylene terephthalate) non-woven graft copolymerization of chitosan

In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBTNW under alkylpolyglycoside （APG） inducing. The product is thoroughly characterized with the Fourier transform infrared spectroscopy （FrIR）, the electron spectroscopy for chemical analysis （ESCA）, the thermogravimetric （TG） and the scanning electron microscopy （SEM）. It is found that chitosan is successfully grafted onto PBTNW. In addition, the water contact angles, hemolysis tests and cytotoxicity evaluation tests show an improvement in wettability and biocompatihility as a result of graft copolymerization of chitosan. So the CS-grafted PBTNW exhibits greater superiority than the original PBTNW. The CS-grafted PBTNW can be a candidate for blood filter materials and other medical applications.

Nonisothermal Crystallization Kinetics of Poly(butylene adipate-co-terephthalate) Copolyester

Nonisothermal crystallization behavior of poly(butylene adipate-co-terephthalate)(PBAT) synthesized via direct esterification and polycondensation reactions was investigated by the differential scanning calorimetry(DSC).The Avrami equation modified by Jeziorny and the Z.S.Mo equation were employed to describe the non-isothermal crystallization kinetics of copolyester samples.The test results showed that the Avrami equation was successful in describing nonisothermal crystallization process of PBAT copolyesters.PBAT copolyester could give birth to secondary crystallization.The crystallization parameter(Zc) increased with an increasing cooling rate and the Avrami exponent(n) was around 2.3.For a given cooling rate,the value of Zc demonstrated a sagging trend with an increase in adipic acid(AA) content.The equation proposed by Z.S.Mo was successful in describing the nonisothermal crystallization kinetics of PBAT copolyesters.

Preparation and Properties of a New Type of Poly(butylene-terephthalate)with Layered Silicate Nanocomposites

In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPBT samples have apparent viscosity over 0.85, HDT of 30℃ to 50℃ higher than that of poly (butylene-terephthalate) (PBT) for clay load from 1.0% to 10.0% (by mass), and higher capability to accommodate clay than other polymers. The nonisothermal crystallization experiments indicate that the better thermal degradation behavior and crystallization rate of NPBT are 50% higher than PBT, and its injection mould processing temperature is lowered from 110℃ to 55℃. NPBT samples are characterized by several techniques. X-ray shows an original clay interlayer distance enlarged from 1.0 nm to 2.5 nm, while both TBM and AFM indicate an average size from 30nm to lOOnm of exfoliated clay layers, and 3%(by mass) of particle agglomeration being phase separated from PBT matrix, which are factors on some mechanical properties decrease of NPBT. The disappearance of spherulitic morphology in NPBT resulted from layers nucleation is detected. Improving NPBT properties by treating clay with long chain organic reagent and controlling the way to load it is suggested.

Study on Structure and Crystallinity of A New Biodegradable Aliphatic-Aromatic Copolyester

A series of biodegradable aliphatic-aromatic copolyesters, poly(butylene terephthalate-co-butylene adipate-co- ethylene terephthalate-co-ethylene adipate) (PBATE), were synthesized from terephthalic acid (PTA), adipic acid (AA), 1,4-butanediol (BG) and ethylene glycol (EG) through direct esterification and polycondensation. The sequence structure and crystallinity of the copolyester were investigated by 1H NMR spectroscopy and the wide-angle X-ray diffractometry (WAXD). The analytical results showed that the PBATE copolyester was a random copolymer and the composition of PBATE copolyester was almost consistent with the feed molar ratios. The crystal structure of PBATE copolyester belonged to the triclinic crystalline system; The variation in melting point of the synthesized PBATE copolyester agreed well with the estimation obtained by the Flory equation and was applicable to the random copolymer.

Preparation and Characterization of Silica Modified with Calix[4]arene Derivatives

Three new silica gel modified with calix[4]arene derivatives （p-tert-butyl-calix[4]arene （PC4）, calix[4]arene （C4） and calix[4]arene sulfonate （C4S）） have been prepared via modification of activated silica gel with toluene 2,4-di-iso-cyanate （TDI） as linker in tow step. The modified silica were characterized by fourier transform infrared spectroscopy （FT1R）, thermal analysis （TGA） and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalent attached to the silica. Scanning electron microscope SEM and Brunauer-Emmett-Teller BET analysis have been done to get information about the sample＇s surface shape and area. SEM and BET analysis reveal that the modified silica are in the range of microporous adsorbent.

Electrical conductivities of carbon nanotube-filled polycarbonate/polyester blends

Carbon nanotube (CNT)-filled polycarbonate (PC)/poly(butylene terephthalate) (PBT) and polycarbonate (PC)/poly(ethylene terephthalate) (PET) blends containing 1 wt% CNTs over a wide range of blend compositions were prepared by melt mixing in a torque rheometer to investigate the structure-electrical conductivity relationship. Field emission scanning electron microscopy was used to observe the blend morphology and the distribution of CNTs. The latter was compared with the thermodynamic predictions through the calculation of wetting coefficients. It was found that CNTs are selectively localized in the polyester phase and conductive blends can be obtained over the whole composition range (20 wt%, 50 wt% and 80 wt% PBT) for CNT-filled PC/PBT blends, while conductive CNT-filled PC/PET blends can only be obtained when PET is the continuous phase (50 wt%, 80 wt% PET). The dramatic difference in the electrical conductivity between the two types of CNT-filled PC/polyester blends at a low polyester content (20 wt%) was explained by the size difference of the dispersed phases on the basis of the transmission electron microscope micrographs.