拔制六通管及其连接结构的安全性研究

针对承插式六通管易在承插焊缝附近开裂失效的问题,研制了拔制式六通管。六通管与支管采用对接焊缝,并实施焊前预热,焊后整体消除应力热处理,工艺方法可行,工艺参数合理。通过对试验模型的应力测试和采用ANSYS有限元软件进行数值模拟计算,得出六通管的最大应力点在六通管与横穿其中间部位支管的连接处,制造时此处过渡圆角应尽量大一些。采用第三强度理论做应力分析及评定,认为结构应力强度满足要求。     

耐高温高效泡沫封堵调剖体系的研制与应用

针对胜利油田稠油油藏多轮次吞吐后期蒸汽汽窜、指进以及重力超覆等问题，进行了高温泡沫封堵调剖技术研究。在各种相关机理研究的基础上，对高温泡沫剂的研制、泡沫稳定性影响因素、性能评价以及高温泡沫调剖施工工艺参数进行了探索性研究。研制的泡沫剂TH-I在250℃条件下阻力因子达15．0以上，对蒸汽具有优越的封堵调剖性能，现场应用取得了良好的效果。     

Renewable Resin Precursor and Residual Filler Modified Poly(vinyl chloride) Foam,Investigation of Microcellular Development and Moisture Absorption Behavior

Poly(vinyl chloride) plastisol-based foams were prepared with epoxidized soybean oil and residual low cost fillers. Microstructural characterizations using scanning electron microscopy were carried out to understand the microcellular morphology. Absence of epoxy groups in Fourier transform infrared spectroscopy spectra of epoxidized soybean oil-modified–poly(vinyl chloride) plastisol foams indicated the occurrence of ring opening reaction between poly(vinyl chloride) plastisol and epoxidized soybean oil, signifying epoxidized soybean oil’s role as HCl scavenger. X-ray diffraction study indicated increased crystallinity of filler modified poly(vinyl chloride) plastisol/epoxidized soybean oil foams, suggesting their role as possible nucleating agents. Foams with fillers also showed reduced water uptake, which were in good agreement with other characterizations.     

Natural rubber/leather waste composite foam: A new eco‐friendly material and recycling approach

This article describes a new approach of recycling the leather waste (shavings) using it as filler in natural rubber foams composites. The foams were prepared using different amounts of leather waste (0–60 parts per hundred of rubber) and submitted to morphological (SEM microscopy) and mechanical analyses (cyclic stress–strain compression). The increase of leather shavings on the composite causes an increase of viscosity in the mixture, which reflects in the foaming process. This results in smaller and fairly uniform cells. Furthermore, expanded rubber has the biggest cell size, with more than 70% of cell with 1000 µm, while the composite with the higher concentration of leather has around 80% of total number of cells with 100–400 µm. The mechanical parameters were found to depend on the leather dust concentration. Moreover, the stiffness rises with the increase of leather shavings; consequently, the compression force for expanded rubber was 0.126 MPa as well as the composite with higher concentration of leather was 7.55 MPa. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41636.     

Surface modification of monolithic PolyHIPE Polymers for anionic functionality and their ion exchange behavior

Monolithic PolyHIPE Polymer (PHP), being a highly porous, low density, open cellular material was produced by polymerization of a high internal phase emulsion (HIPE) in which the polymerizable continuous phase consisted of monomers, styrene (STY), and divinyl benzene (DVB). The inner dispersed phase (90 vol %) was an aqueous solution containing 0.4 wt % potassium persulphate as initiator. The resulting porous structure had 12% crosslinking density. Surface chemistry of the monoliths was modified by chloromethylation and amination to impart anionic functionality. Surface modified monoliths had ion exchange capacity of 3.01 meq/g, and had the ability to uptake water about 10 times of its mass. It was used Cr (VI) ion removal from aqueous solution. The experimental results investigated for both the Langmuir and the Dubinin–Radushkevich adsorption models. The maximum Cr (VI) adsorptions are 126.6 mg Cr (VI)/g and 129.3 mg Cr (VI)/g, respectively. The mean free energy E of adsorption is 11.18 kJ/mol according to the Dubinin–Radushkevich adsorption model, indicating that the adsorption occurs through a chemical ion‐exchange process and it is not diffusion limited. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42286.     

Electrical percolation behavior of carbon fiber and carbon nanotube polymer composite foams: Experimental and computational investigations

The effect of foaming on the electrical percolation of polymer composites was simulated by a random sequential additional (RSA) process. Polystyrene composites containing various amounts of carbon fiber (CF) and carbon nanotubes (CNTs) were prepared through melt blending in an internal mixer and subsequently compression‐molded to solid and foam sheets. The electrical conductivity (EC) and percolation threshold (P_c) of both the solid and foam composites were determined to evaluate the simulation results. The experimental results show that the EC of the CF composites decreased with foaming, whereas for the CNT composites, no significant change was observed. The RSA process was used to construct the microstructure of the solid and foam composites and predict their P_cs. Several parameters, including the fiber aspect ratio, bubble volume fraction, and bubble size, were studied by the simulation approach. The P_cs obtained by simulation showed good agreement with the experimental values. When bubbles were excluded to define the volume fraction of the filler, the foam composites with bubbles, close to the fibers in size, had approximately the same P_cs as the solid composites. Better agreement between the experimental and simulation results was found for the foam composites with 30 vol % bubbles rather than those with 15 vol %. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42685.     

Structure and dielectric properties of polyimide/silica nanocomposite nanofoam prepared by solid‐state foaming

In this article, polyimide (PI)/silica nanocomposite nanofoams were prepared by solid‐state foaming using supercritical CO₂ as foaming agent. To control the cell size and morphology of the PI/silica foam, the silica nanoparticles as nucleating agent were in situ formation from TEOS via sol‐gel process, which make the silica nanoparticles homogeneously dispersed in PI matrix. The resulting PI/silica nanocomposite nanofoams were characterized by scanning electron microscopy (SEM), the image analysis system attached to the SEM and dielectric properties measurements. In PI/silica nanocomposite nanofoams, one type of novel morphology was shown that each cell contained one silica nanoparticle and many smaller holes about 20–50 nm uniformly located in the cell wall. This special structure could visually prove that the nucleation sites during foaming were formed on the surface of nucleating agents. Compared with those of neat PI foam, the cell size of PI/silica nanocomposite nanofoams was smaller and its distribution was narrower. The dielectric constant of PI/silica nanocomposite nanofoams was decreased because of the incorporation of the air voids into the PI/silica nanofoams. While the porosity of PI/silica nanocomposite nanofoam film was 0.45, the dielectric constant of the film (at 1 MHz) was reduced from 3.8 to about 2.6. Furthermore, the dielectric constant of PI/silica nanofoam films remained stable across the frequency range of 1×10²～1×10⁷ H_Z. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42355.     

Nano‐crystalline cellulose,chemical blowing agent,and mold temperature effect on morphological,physical/mechanical properties of polypropylene

Polypropylene (PP)/nano‐crystalline cellulose (NCC) composites and foams were produced through extrusion compounding combined with injection molding. From the samples produced, a complete morphological, physical, and mechanical analysis was performed to study the effect of NCC concentration (0–5wt %), foaming agent content (0 to 2wt %) and mold temperature (30°C and 80°C). NCC was very effective to reduce cell size (42–71%) and increase cell density (5–37 times) of the foams, while slightly increasing the overall density (2–7%). The results showed that NCC addition increased the specific tensile modulus (15–22%), specific tensile strength (1–14%) and specific flexural modulus (13–26%) of PP, but decreased specific impact strength (10–20%) and specific elongation at break (50–96%). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42845.     

Effect of glass transition temperature and saturation temperature on the solid‐state microcellular foaming of cyclic olefin copolymer

Effect of glass transition temperature and saturation temperature on the solid‐state microcellular foaming of cyclic olefin copolymer (COC)—including CO₂ solubility, diffusivity, cell nucleation, and foam morphology—were investigated in this article. COCs of low T_g (78°C) and high T_g (158°C) were studied. Solubilities are 20–50% higher in high T_g COC than in the low T_g COC across the saturation temperature range. Diffusivities are about 15% higher on average in high T_g COC for temperatures up to 50°C. A much faster increase of diffusivity beyond 50°C is observed in low T_g COC due to it being in the rubbery state. Under similar gas concentration, high T_g COC starts foaming at a higher temperature. And the foam density decreases faster in low T_g COC with foaming temperature. Also, high T_g COC foams show about two orders of magnitude higher cell nucleation density than the low T_g COC foams. The effect of saturation temperature on microcellular foaming can be viewed as the effect of CO₂ concentration. Nucleation density increases and cell size decreases exponentially with increasing CO₂ concentration. Uniform ultramicrocellular structure with an average cell size of 380 nm was created in high‐T_g COC. A novel hierarchical structure composed of microcells (2.5 μm) and nanocells (cell size 80 nm) on the cell wall was discovered in the very low‐density high‐T_g COC foams. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42226.     

Degradable polyurethane foams based on disaccharides

New functional elastic polyurethane foams (PUF) degradable under environmental abiotic and biotic factors, retaining all the inherent properties of the conventional foams were synthesized using isocyanate precursors based on disaccharides (DS): lactose, maltose and saccharose. It was shown by the model reactions of monosaccharide glucose, and DS lactose and saccharose, with phenylisocyanate that both the primary and secondary hydroxyls of the carbohydrates reacted to form urethanes. The main properties of DS‐based foams (PUF/DS) were found to be similar to PUF foam (matrix) prepared with conventional polyols. However, the new PUF/DS were found to undergo enhanced acid/alkaline hydrolysis and degradation compared with PUF matrix when incubated in soil. Mass losses of incubated PUF/DSs significantly exceeded the actual carbohydrate content 28.6%, and in 12 months reached 39.58 (PUF‐4), 53.31(PUF‐8), and 47.25 (PUF‐12). In contrast, under the same conditions PUF matrix lost only 2–2.5%, confirming that incorporation of natural compounds into the polymer chain impacted the degradation processes. PUF/DS were characterized by FTIR, ¹H NMR, ebullioscopy, and exclusion chromatography (molecular masses and molecular mass distribution of the oligomeric model), physical and mechanical tests (density, tensile strength, relative elongation, moisture absorption, vapor permeability), morphology, and degradation in the soil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42131.