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Summary: Cementing is the key factor in releasing ocean oil and gas resources, but more than 70% of marine cementing faces the challenge of hydrates decomposition. Thus, during this study, the micro‐encapsulated phase change material Micro‐P1 was prepared by paraffin wax, urea formaldehyde resin and graphene oxide through in situ polymerization. Firstly, the application performances of Micro‐P1 were studied, and the results show that the performances were significantly improved by graphene oxide. Secondly, a novel cement slurry containing Micro‐P1 was prepared, and the heat evolution was successfully controlled by Micro‐P1. Thirdly, the thermal control mechanism of Micro‐P1 on heat evolution of cement slurry was also investigated, which indicated the heat evolution was controlled through endothermic effect firstly. Simultaneously, the hydration reaction of cement slurry was delayed by Micro‐P1, in this way, the heat evolution was further controlled. The highlights of this study is that the heat evolution was successfully controlled by using Micro‐P1, and provides technical support for exploration and development of ocean oil and gas resources, especially hydrates formation. Furthermore, the thermal control mechanism of Micro‐P1 on the heat evolution was firstly investigated in this study. [ABSTRACT FROM AUTHOR]

Summary: Based on the low hydration heat and temperature rise requirements of cement slurry used in natural gas hydrate layer, two novel microencapsulated phase change materials (MPCM‐1 and MPCM‐2) with different melting point were designed and synthesized; then, the heat evolution of cement slurry was controlled by MPCM‐1 and MPCM‐2 through physical means; the decomposition of hydrates was avoided. Before synthesizing MPCM‐1 and MPCM‐2, the micromorphology, particle size, and distribution of paraffin wax emulsion were studied. Then, the MPCM‐1 and MPCM‐2 containing paraffin wax with urea formaldehyde resin shell was synthesized by in situ polymerization, and the chemical structure and performances were investigated. The melting point of MPCM‐1 and MPCM‐1 is 23.09°C and 35.85°C; the phase change enthalpy is 97.49 and 85.69 J/g. The MPCM‐1 and MPCM‐2 were added into cement slurry, and the controlling effects on heat evolution were studied. As a result, it was found that the hydration heat and temperature rise of cement slurry were successfully reduced by using MCPM‐1 and MPCM‐2. Simultaneously, the investigations of fly ash and slag cement slurry were accomplished. Moreover, the fly ash and slag cement slurry containing microencapsulated phase change materials was prepared. It was shown that the 24 and 48‐hour hydration heat were reduced by 1.10 × 105 and 10.5 × 105 J, respectively. Highlights: A novel microencapsulated phase change material (MPCM) was synthesized.Heat evolution was controlled at different temperature intervals by MPCM.Limiting the temperature rise was achieved by physical and chemical means.Reducing the hydration heat was realized by physical and chemical means.The application of MPCM was significantly increased. [ABSTRACT FROM AUTHOR]

During this study, paraffin wax with low melting point was encapsulated in a urea–formaldehyde resin to prepare a novel microencapsulated phase change material (Micro‐P6) for temperature regulation and thermal energy storage. The structure and properties of Micro‐P6 were characterized by using Fourier transform infrared spectroscopy, differential scanning calorimeter, laser particle size analyzer, thermogravimetric analysis, contact angle analysis, and scanning electron microscope. The results indicated that the chemical structure of Micro‐P6 meets the designed core–shell structure; and the paraffin wax with low melting point was successfully encapsulated by using urea–formaldehyde resin; and the Micro‐P6 shows a spherical structure and rough surface, and the average size is 8.0–10.0 μm. Then, the performances of Micro‐P6, such as core content, mechanical property, thermal conductivity and durability, were tested. Based on above characterization and performance test, it was indicated that the synthesized Micro‐P6 could be used in the field of cementing and construction for temperature regulation and thermal energy storage. The applications of Micro‐P6 in the field of cementing and construction will be completed in our next study. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48578. [ABSTRACT FROM AUTHOR]