SBS接枝胶的研究

以甲基丙烯酸甲酯和丙烯丁酯对ＳＢＳ进行接枝改性，研究了ＳＢＳ用量，引发剂浓度，单体配比，聚合温度，反应时间，增粘剂用量多种因素对胶液剥离强度的影响，所制得胶液用于粘接ＳＢＳ和皮类材料的９０°剥离强度最刘可达９１Ｎ／ｃｍ，可稳定在７０Ｎ／ｃｍ以上。     

CR-MMA乳液接枝共聚合

用乳液接枝法合成了氯丁橡胶（ＣＲ）－甲基丙烯酸甲酯（ＭＭＡ）接枝共聚物，并用喷雾干燥法制得了粉末状干胶。研究了氯丁二烯转化率、相对分子质量调节剂用量、残留氯丁二烯含量、接枝聚合温度、ＭＭＡ用量等对接枝共聚物溶解性和接枝率的影响。     

高温暴露试验对PBX药柱的影响

对Ｒ８５２。Ｈ７８１、Ｈ８７２、Ｈ８７１８、ＨＭＸ－１５９、８０２１等炸 药进行高温暴露试验，考究其药柱在高温暴露条件下，不可逆尺寸变化和密度变化，并用Ｘ光衍射法研究了试验闪后主体炸药的晶体结构变化。     

Radiation-induced Grafting of Acrylic Acid and Vinyl Acetate Monomers onto Heavy-duty Poly(ethylene–vinyl acetate) Films

The preparation of graft films was carried out by direct radiation-induced graft polymerization of acrylic acid and vinyl acetate comonomer onto heavy-duty poly(ethylene–vinyl acetate) films. The effect of various comonomer compositions on the degree of grafting was investigated. The characterization and some selected properties of the graft copolymers prepared were studied. Thermal stability, mechanical and electrical properties of the films showed great promise for some practical applications. © of SCI.     

Preparation and rheological study of pentaerythritol triacrylate grafted onto polypropylene induced by air plasma

The surface modification of isotactic polypropylene by dielectric barrier discharge of air plasma is studied. The air plasma induces melt grafting of pentaerythritol triacrylate onto polypropylene, which successfully introduces polar long-chain branching (LCB) structure into polymer bulk. The results of X-ray photoelectron spectroscopy show that C─O and CO oxygen-containing functional groups are formed on polypropylene surface, of which the functional groups contents can reach 24.4 and 12.0%, respectively. It is found that there is an optimum plasma treatment time of 4 min to obtain the high peroxides concentration of about 3.38–3.69 × 10⁻⁷ mol cm⁻². The highest grafting degree of this plasma method is 1.79%, which achieves the same level as the chemical grafting method. The molecular structural change of the graft-modified polypropylene, in the form of LCB is investigated by shear rheology. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48054.     

A facile one-pot ultrasound assisted synthesis of 1,8-dioxo-octahydroxanthene derivatives catalyzed by Brønsted acidic ionic liquid (BAIL) under green conditions

A simple and efficient one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthene derivatives in water under ultrasound irradiation is described. These heterocycles were prepared by condensation of dimedone with various aromatic aldehydes in the presence of Brønsted acidic ionic liquids as a convenient, cheap, readily synthesized and eco-friendly catalyst. This procedure has a lot of advantages such as: excellent yields, simplicity of the workup, low cost, short reaction times and green conditions. Ionic liquids could be recycled several times without significant loss of activity and high purity.     

Preparation and characterization of carboxymethyl starch under ultrasound‐microwave synergistic interaction

Using native cassava starch as raw materials, carboxymethyl starch (CMS) was prepared by ethanol solvent method under the ultrasound‐microwave synergistic interaction. And the structure of CMS was characterized employing Fourier transform infrared (FTIR) spectrometer, scanning electron microscopy (SEM), X‐ray diffraction (XRD) and thermogravimetric analyzer. Typically, the optimal synthesis conditions for the preparation process confirmed by orthogonal experiment L₁₈ (6¹ × 3⁶) were shown as follows: the ultrasonic treatment temperature was fixed to 35°C and two steps alkalization was employed; the ultrasonic time was 40 min before alkalizing and the ultrasonic power was 220 W; the amount of sodium hydroxide was 8.8 g, the microwave alkalization time was 2 min; the amount of monochloroacetic acid was 11.34 g; the amount of 95% (v/v) ethanol was 70 mL; the microwave etherification time was 3 min. The degree of substitution of prepared CMS was 1.089 ± 0.041, which was increased 30.4% compared with the prepared sample without ultrasound‐microwave synergistic treatment. FTIR results showed that the strong ? COO? characteristic absorption peaks of the stretching vibration were observed at 1613 and 1421 cm^?1, which proved that the carboxymethylation of cassava starch was occurred. SEM results suggested that there were many cracks and dents on CMS granules; and, XRD results indicated that the carboxymethylation of starch occurred both in amorphous region and crystalline region, the noticeable damage of crystalline region by carboxymethylation was observed. Thermogravimetric analysis (TG) and derivative TG showed that thermal stability of CMS changed better compared with native starch. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40906.     

Development of Selective Inhibitors for Human Aldehyde Dehydrogenase 3A1 (ALDH3A1) for the Enhancement of Cyclophosphamide Cytotoxicity

Aldehyde dehydrogenase 3A1 (ALDH3A1) plays an important role in many cellular oxidative processes, including cancer chemoresistance, by metabolizing activated forms of oxazaphosphorine drugs such as cyclophosphamide (CP) and its analogues, such as mafosfamide (MF), ifosfamide (IFM), and 4‐hydroperoxycyclophosphamide (4‐HPCP). Compounds that can selectively target ALDH3A1 could permit delineation of its roles in these processes and could restore chemosensitivity in cancer cells that express this isoenzyme. Here we report the detailed kinetic and structural characterization of an ALDH3A1‐selective inhibitor, CB29, previously identified in a high‐throughput screen. Kinetic and crystallographic studies demonstrate that CB29 binds within the aldehyde substrate‐binding site of ALDH3A1. Cellular proliferation of ALDH3A1‐expressing lung adenocarcinoma (A549) and glioblastoma (SF767) cell lines, as well as ALDH3A1 non‐expressing lung fibroblast (CCD‐13Lu) cells, is unaffected by treatment with CB29 and its analogues alone. However, sensitivity toward the anti‐proliferative effects of mafosfamide is enhanced by treatment with CB29 and its analogue in the tumor cells. In contrast, the sensitivity of CCD‐13Lu cells toward mafosfamide was unaffected by the addition of these same compounds. CB29 is chemically distinct from the previously reported small‐molecule inhibitors of ALDH isoenzymes and does not inhibit ALDH1A1, ALDH1A2, ALDH1A3, ALDH1B1, or ALDH2 isoenzymes at concentrations up to 250 μM . Thus, CB29 is a novel small molecule inhibitor of ALDH3A1, which might be useful as a chemical tool to delineate the role of ALDH3A1 in numerous metabolic pathways, including sensitizing ALDH3A1‐positive cancer cells to oxazaphosphorines.     

Influence of carboxyl and amide groups on in vitro hemocompatibility of sulfonated polypropylene non‐woven fabric

The sulfonated polypropylene non‐woven fabric (PP_NWF) was successfully fabricated via γ‐ray simultaneous radiation‐induced graft polymerization of acrylic acid (AA)/sodium styrenesulfonate (NaSS) and acrylamide (AAm)/NaSS. The existence of graft chains in both PP‐g‐P(AA‐co‐NaSS) and PP‐g‐P(AAm‐co‐NaSS) was proved by attenuated total reflection Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. Water contact angle measurement illustrated the sulfonated PP_NWF owning good hydrophilicity. The in vitro hemocompatibility evaluation showed that both PP‐g‐P(AA‐co‐NaSS) and PP‐g‐P(AAm‐co‐NaSS) inhibited effectively the adhesion of platelets and were significantly compatible with erythrocytes. Moreover, no obvious difference was confirmed in the prevention of platelet adhesion and hemolysis ratio between carboxyl and amide groups. However, as compared with that of PP‐g‐P(AAm‐co‐NaSS), PP‐g‐P(AA‐co‐NaSS) exhibited outstanding anticoagulant activity via increased activated partial thromboplastin time and thrombin time. This result indicated that the carboxyl group but not amide group featured strong synergistic effect on the anticoagulant activity of sulfonated PP_NWF. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45915.     

Facile synthesis of nanocrystalline hexagonal tungsten trioxide from metallic tungsten powder and hydrogen peroxide

A hexagonal form of tungsten trioxide (h‐WO₃, particle size: 15.9‐57.1 nm) was found to be formed by a direct reaction between metallic tungsten powder (W, particle size: 0.45‐0.59 μm) and 15%‐30% hydrogen peroxide (H₂O₂) aq solution. Oxide film on the powder surface having the similar crystal structure as h‐WO₃ was essential for the formation, and the surface oxide film was formed by aging the powder in air at 45°C, a relative humidity of 100% (P_H2O 96 hPa) for 3‐28 days or in ambient atmosphere at room temperature for 12 years. The Rietveld analysis performed in the space group P6₃/mcm (Z = 6) indicated the crystal structures were the same as those of the reported h‐WO₃ and that the crystallographic characteristic was as follows: a = 0.74219 nm, c = 0.77198 nm for h‐WO₃ from the 28‐day aged powder, and a = 0.74538 nm, c = 0.77194 nm for h‐WO₃ from the 12‐year aged powder.