“…Shadizadeh et al (2015) reported a novel nonionic surfactant extracted from a plant leaf for inhibiting shale hydration. An et al (2015) evaluated the inhibition of chitosan quaternary ammonium salt (HTCC), and its inhibiting ability was better than polyether amine, but the cost of HTCC was high. The commonly used inhibitors include KCl, CaCl 2 , NH 4 Cl, modified gilsonites, and asphalts (Gholizadeh-Dooechaly et al 2009;Xiong et al 2012).…”
Graphene oxide (GO) nano-sheets were synthesized using a modified Hummers' method from graphite powder. The Raman spectrum of GO displayed a D-band at 1359 cm -1 and a G-band at 1594 cm -1 . The I D /I G value of GO was calculated to be 0.97, suggesting the formation of new sp 2 clusters upon reduction. A method was designed to investigate the assembly of the GO/montmorillonite (MMT) composite. After the addition of GO, the typical peaks of montmorillonite in FT-IR spectra shifted, indicating the assembly between GO and MMT. The D-band and G-band reduced sharply in the GO/MMT composite. More importantly, the D-band (1344 cm -1 ) and G-band (1574 cm -1 ) shifted significantly and the I D / I G value of the GO/MMT composite was calculated to be 1.13, showing a change in the GO structure. In the addition of 0.04 wt% GO to MMT, the value of interlayer space (d) was up to 13.0 Å measured by XRD due to the insertion of GO into MMT. The evident increases in contents of carbon atoms (26.59%) and nitrogen atoms (3.44%) indicate that GO was successfully combined with MMT. The nano-pores and clay sheets were not observed in the SEM image of GO/clay, but obvious wrinkles, while flexible sheets were observed in the typical scanning electron microscopy images of GO. This further proves that GO was combining with clay. The TEM image shows that the GO nano-sheets were tiled on the surface of MMT sheets. This observation suggests that a stable assembly structure was formed between GO sheets and MMT sheets. The change in particle size of MMT with the addition of GO shows that interaction occurred between GO sheets and MMT sheets, which was further confirmed by the results of zeta potential. Adsorption and insertion were the main mechanisms to assemble GO and MMT.
“…Shadizadeh et al (2015) reported a novel nonionic surfactant extracted from a plant leaf for inhibiting shale hydration. An et al (2015) evaluated the inhibition of chitosan quaternary ammonium salt (HTCC), and its inhibiting ability was better than polyether amine, but the cost of HTCC was high. The commonly used inhibitors include KCl, CaCl 2 , NH 4 Cl, modified gilsonites, and asphalts (Gholizadeh-Dooechaly et al 2009;Xiong et al 2012).…”
Graphene oxide (GO) nano-sheets were synthesized using a modified Hummers' method from graphite powder. The Raman spectrum of GO displayed a D-band at 1359 cm -1 and a G-band at 1594 cm -1 . The I D /I G value of GO was calculated to be 0.97, suggesting the formation of new sp 2 clusters upon reduction. A method was designed to investigate the assembly of the GO/montmorillonite (MMT) composite. After the addition of GO, the typical peaks of montmorillonite in FT-IR spectra shifted, indicating the assembly between GO and MMT. The D-band and G-band reduced sharply in the GO/MMT composite. More importantly, the D-band (1344 cm -1 ) and G-band (1574 cm -1 ) shifted significantly and the I D / I G value of the GO/MMT composite was calculated to be 1.13, showing a change in the GO structure. In the addition of 0.04 wt% GO to MMT, the value of interlayer space (d) was up to 13.0 Å measured by XRD due to the insertion of GO into MMT. The evident increases in contents of carbon atoms (26.59%) and nitrogen atoms (3.44%) indicate that GO was successfully combined with MMT. The nano-pores and clay sheets were not observed in the SEM image of GO/clay, but obvious wrinkles, while flexible sheets were observed in the typical scanning electron microscopy images of GO. This further proves that GO was combining with clay. The TEM image shows that the GO nano-sheets were tiled on the surface of MMT sheets. This observation suggests that a stable assembly structure was formed between GO sheets and MMT sheets. The change in particle size of MMT with the addition of GO shows that interaction occurred between GO sheets and MMT sheets, which was further confirmed by the results of zeta potential. Adsorption and insertion were the main mechanisms to assemble GO and MMT.
“…Meanwhile, the molecular structure and hydrogen bonds of chitosan were broken by acetic acid, which was beneficial for the invasion of water molecules and produced a good swelling behavior. 34,35 Figure 3.Expansion rates of the polyglycolic acid (PGA) group and the polylactic acid (PLA) group. PGA group: PGA1, PGA2, CS-PGA1 and CS-PGA2; PLA group: PLA1, PLA2, CS-PLA1 and CS-PLA2.…”
Section: Resultsmentioning
confidence: 99%
“…Meanwhile, the molecular structure and hydrogen bonds of chitosan were broken by acetic acid, which was beneficial for the invasion of water molecules and produced a good swelling behavior. 34,35 It also can be seen that the expansion rate values of CS-PGA1 were slightly smaller than those of CS-PGA2, while CS-PLA2 showed a significant difference from PLA2 (p < 0.05), and the PGA group had a better swelling behavior than that of the PLA group on the whole. This may be because PLA has a surface hydrophobic property caused by the lack of hydrophilic group, while PGA belongs to hydrophilicity polymers and it was much more likely to attach chitosan molecules in the coating solution than the PLA-based composite monofilaments, and the chitosan coating weight is the main factor in swelling behavior, which has a positive correlation with the expansion rate.…”
With the development of applying acupoint catgut embedding therapy to the treatment of juvenile pseudomyopia, embedding materials are expected to be the perfect for choice by taking advantage of the lasting effect and minimal invasiveness. This work adopted polyglycolic acid (PGA) and polylactic acid (PLA) monofilaments to produce four types of chitosan coated monofilaments with excellent swelling behaviors. For achieving better coating weight gains, a one-dipping-one-rolling coating system was developed. The results showed that both the PGA and PLA monofilaments' swelling behaviors were greatly improved, CS-PGA2 (98.17 ± 3.15%) presented a great difference from CS-PLA1 (47.56 ± 6.15%) and CS-PLA2 (63.31 ± 3.26%), respectively, while CS-PGA1 (87.36 ± 5.16%) had a similar expansion rate to that of CS-PGA2. The resist deformation ability of the monofilament was strengthened and the crystalline zones of PGA and PLA monofilaments were slightly decreased after a chitosan coating process. The CS-PGA group and PGA group were found to degrade completely in 56 days and 70 days, respectively, while the PLA group changed little in the experimental process, offering a new insight into controlled degradation research. In conclusion, all coated monofilaments show potential in acting as embedding materials with good swelling behaviors, and the CS-PGA group is proved to have a higher prospect for clinical applications.
“…The maximum amount of API bentonite inhibited by a single treatment of shale inhibitor could be determined by this test [18]. The volume of 400 mL of fresh water containing 12 g of shale inhibitor was prepared firstly, and 20 g of drilling fluid bentonite was added to the system and stirred at 10000 rpm for 20 min.…”
In order to develop high-performance water-based drilling fluid with the aim of meeting the increasing requirement of drilling industry, highly inhibitive and high-temperature-resistant shale inhibitors are essential. In this study, 4, 4 0 -methylenebis-cyclohexanamine was introduced as a potential shale inhibitor. The inhibitive properties of the amine compound in comparison with currently available polyether diamine inhibitor were evaluated using bentonite inhibition test, shale cuttings hot-rolling dispersion test, linear swelling test, and pressure transmission test. The inhibitive mechanism was investigated with zeta potential measurement, X-ray diffraction analysis, and contact angle measurement. The results indicated that 4, 4 0 -methylenebis-cyclohexanamine can inhibit shale hydration and dispersion effectively, and prevent pressure transmission to a certain extent, performing better than that of polyether diamine. Furthermore, the new diamine provides reliable thermal stability as high as 220°C, preserving the benefits of high-temperature wells application. This novel diamine inhibits shale hydration and dispersion with the combination of chemical inhibition and physical plugging. The intercalation into the interlayer of clay with monolayer collapses the hydrated clay structure and expels the water molecules. After adsorption, clay surface became more hydrophobic, which prevents the imbibition of water. The variation of solubility separates the compound from the solution, which can plug the micro-pores of shale and prevent fluid invasion.
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