USY／SAPO-5复合分子筛催化合成长链烷基苯

采用水热合成法制备了一种USY/SAPO-5复合分子筛.通过XRD、IR、TEM等方法进行袁征,分析其晶型结构,证实形成了以USY为核,以SAPO-5为壳的复合分子筛结构.并将USY/SA-PO-5复合分子筛应用于苯和长链烯烃的烷基化反应,在n(苯):n(长链烯烃)=8:1,反应温度200℃,压力3.5 MPa,在此条件下长链烯烃的转化率可达99.2%,选择性也达到最好.     

Thermostimulative shape‐memory effect of reactive compatibilized high‐density polyethylene/poly(ethylene terephthalate) blends by an ethylene–butyl acrylate–glycidyl methacrylate terpolymer

High‐density polyethylene (HDPE)/poly(ethylene terephthalate) (PET) blends were prepared by means of melt extrusion with ethylene–butyl acrylate–glycidyl methacrylate terpolymer (EBAGMA) as a reactive compatibilizer. The effects of the EBAGMA and PET contents, recovery temperature, and stretch ratio on the thermostimulative shape‐memory behavior of the blends were studied. The results show that the addition of EBAGMA to the HDPE/PET blends obviously improved the compatibility and the shape‐memory effects of the blends. The response temperature was determined by the melting point of HDPE, and the shape‐recovery ratio of the 90/10/5 HDPE/PET/EBAGMA blend reached nearly 100%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

水热炭接枝紫脲酸铵对铀(Ⅵ)的吸附性能

选用葡萄糖为炭源,在180℃下反应36h得到水热炭(HTC),后经热处理、胺化和接枝紫脲酸铵合成了一种新的水热炭基吸附剂(Mu-HTC)。通过Boehm滴定分析,热处理后的水热炭表面羧基含量增加近六倍;红外光谱分析证实紫脲酸铵被成功接枝在水热炭上;扫描电镜监测整个合成过程,水热炭球的形貌和粒径没有发生显著变化。根据Langmuir等温吸附方程,该吸附剂对铀(Ⅵ)理论吸附容量为102.05mg/g。在模拟放射性废液的共存离子竞争吸附中,对铀(Ⅵ)的吸附容量占总吸附容量的72.8%,具有较好的选择性。该吸附剂可用于含铀废水的净化处理或从水体中回收铀资源。     

Microencapsulation of APP‐I and influence of microencapsulated APP‐I on microstructure and flame retardancy of PP/APP‐I/PER composites

In this article, the microencapsulated ammonium polyphosphate crystalline with form I (APP‐I) coated with melamine‐formaldehyde (MF) was prepared by in situ polymerization. Results of Fourier transform infrared spectra (FTIR), thermogravimetry (TG) energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) demonstrate that APP‐I is successfully microencapsulated with MF. Compared with APP‐I, the microencapsulated APP‐I with MF (MFAPP‐I) is of much smaller spheroidal particle size and lower solubility in water. In this study, the polypropylene (PP)/APP‐I/penpaerythritol (PER) and PP/MFAPP‐I/PER composites are prepared, and flame retardancy, thermal stability, and microstructure of corresponding composites are carefully investigated by limiting oxygen index (LOI), UL‐94 testing, TG, EDS, and SEM. Experimental results show that PP/MFAPP‐I/PER composites have advantages over PP/APP‐I/PER composites in terms of flame retardant properties and water resistance. Results of TG, SEM, and EDS show that the microencapsulated APP‐I with MF resin is conducive to increase the amount of residual yield and improve thermal stability of PP/MFAPP‐I/PER composites and the compatibility and dispersion of MFAPP‐I. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Surface functionalization of rubber latex nanoparticles with sulfidosilane moieties

Polybutadiene latex particles were functionalized with bis[3‐(triethoxysilyl) propyl] tetrasulfide (TESPT) in the presence of zinc oxide as an activator and ethanol as a co‐solvent. The success of this reaction was confirmed both by the peaks attributed to Si‐O groups at 1085 and 1110 cm^?1 and C‐S bond at 630 cm^?1 which appeared after reaction in Attenuated Fourier Transform Infrared (ATR‐FTIR) Spectra and also by increasing in the particle size diameter of latex particles (from 95 to 127 nm) in Dynamic Light Scattering analysis. X‐ray Diffraction results also showed changes in crystalline structure of the modified particles (as a strong decrease in the intensity of peak at 2θ=19.54). The effect of reactant concentration in a constant amount of TESPT (by varying the water and ethanol content), reaction time, activator size (micro and nanoparticles), and pH (≈7, 8.5) were investigated on degree of grafting (obtained from thermogravimetric analysis and ATR‐FTIR spectra), particle size diameter, cross‐link density, and swelling ratio of the samples. The amounts of silane grafting and cross‐link density of polymer particles were increased by an increase in the reaction time. The highest grafting degree was observed at low concentration of TESPT. Silane functionalization was also improved in a slight basic condition (pH=8.5) rather than neutral pH. The grafting reaction took place such as sulfur pre‐vulcanization and the possible mechanism of this reaction was discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43268.     

Polyurethane/organic vermiculite composites with enhanced mechanical properties

In this article, a series of polyurethane (PU)/organic vermiculite (OVMT) composites are prepared by intercalating polymerization. 1,4‐cyclohexane diisocyanate (CHDI) as hard segment of PU is designed to improve the decomposition temperature of composites. Vermiculite (VMT) is modified by method of cation exchange with octadecyl trimethyl ammonium bromide (OTAB); the resulting product OVMT with the function of physical cross‐linking disperses well in soft segment of PU polycarbonate polyol (PCDL), which improves the mechanical properties of composites obviously. This modification further enlarged the interlayer of OVMT and improved the properties of composites. The structure and properties of OVMT and PU/OVMT composites are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, scanning electron microscope, and tensile strength test. The results showed that the layer spacing of OVMT increased 1.41 nm compared with that of VMT (the value of layer spacing of VMT is 0.96 nm) and further enlarged to 2.92 nm by the loading of PCDL. The tensile strength and the strain at break of PUCPB/OVMT (3.0%) composites reached 26.8 MPa and 443%, respectively. The temperature resistance of PUCPB/OVMT (3.0%) composites is above 300°C, which is more suitable for the steam channeling plugging of heavy oil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43219.     

Pluronics as crosslinking agents for collagen: novel amphiphilic hydrogels

A series of Pluronic samples (L61, L121, F68, F108) were investigated as collagen crosslinking agents to determine their ability to improve the Young's modulus of a collagen hydrogel, while simultaneously serving as surfactants for single‐walled carbon nanotubes (SWNTs). The crosslinked collagen matrices were prepared by blending type I bovine collagen with either Pluronics or SWNTs dispersed in an aqueous Pluronic solution and crosslinked utilizing carbodiimide chemistry. The resulting material was a crosslinked collagen hydrogel with sufficient mechanical strength to be manipulated and transferred without damaging the matrix. Differential scanning calorimetry confirmed a change in the denaturation temperature for hydrogels prepared using Pluronic or Pluronic/SWNT solutions. Water uptake analysis confirmed the crosslinked matrices to be hydrogels. These collagen hydrogels produced with Pluronics as the crosslinking agents exhibited a Young's modulus 3 to 9 times greater than collagen hydrogels produced in the absence of any crosslinking agent, regardless of polymer molecular weight. However, non‐covalent incorporation of SWNTs was not found to affect the Young's modulus of the resulting collagen hydrogels at the incorporation levels achieved with the Pluronics surfactants. Copyright © 2010 Society of Chemical Industry     

Preparation and characterization of covalently functionalized graphene using vinyl‐terminated benzoxazine monomer and associated nanocomposites with low coefficient of thermal expansion

We describe the preparation of vinyl‐terminated benzoxazine‐functionalized graphene using free radical grafting. The resulting functionalized graphene (f‐graphene) was incorporated into bis(3‐allyl‐3,4‐dihydro‐2H‐1,3‐benzoxazinyl)methane (V‐BF‐a) monomer in order that nanocomposites could be prepared. Results of scanning electron microscopy and transmission electron microscopy revealed that the sheets of f‐graphene were well dispersed throughout the matrix, and there was a strong interfacial interaction between the f‐graphene and polyV‐BF‐a. The inclusion of f‐graphene into the nanocomposites resulted in a material with a high thermal stability and a low coefficient of thermal expansion (CTE); increasing the content of f‐graphene reduced the CTE significantly more. A reduction in the CTE of up to 48% was produced by adding just 1 wt% of f‐graphene; this corresponded to an increase of 12 °C in the glass transition temperature. These results suggest that f‐graphene nanocomposites can be ‘tuned’ to give materials with both a low CTE and a high thermal stability, and that graphene composites of this type can thus be manufactured to withstand a wider range of temperatures.     

Facile synthesis of amphiphilic chitosan‐g‐poly(lactic acid) derivatives and the study of their controlled drug release

We report here a simple and green procedure for the synthesis of amphiphilic chitosan (CS) derivatives with poly(lactic acid) (PLA) side chains, without the use of high pure lactide, high temperatures, or large amounts of organic solvent. The chemical structure and physical properties of these CS derivatives were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, thermogravimetric analysis, and X‐ray diffraction. The formation and characteristics of polymeric micelles based on these CS derivatives were studied by fluorescence spectroscopy and dynamic light scattering. The critical aggregation concentration in water varied from 0.048 to 0.021 mg/mL, and the mean diameter was in the range 169.8–260.7 nm in aqueous solution at 25°C when the PLA grafting percentage increased from 92 to 132%. Transmission electron microscopy showed that the micelles exhibited a nanospheric morphology within a size range of 60–120 nm. For the resulting micellar aggregates, the drug loading and in vitro drug‐release characteristics were studied with indomethacin as the model drug. We found that such micellar aggregates could be potentially used as nanocarriers for drug delivery. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 908‐915, 2013