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The low-carbon transformation of decommissioned offshore oil and gas platforms is an optimal model for intensive resource utilization and for fully exploiting the economic and ecological benefits of decommissioned platforms. It is also an important measure to maintain and enhance the carbon reduction capacity of the marine sector. However, the green and low-carbon development process in China’s marine sector is just beginning, and the low-carbon transformation of decommissioned offshore oil and gas platforms mostly remains at the conceptual stage, urgently requiring practical and feasible comprehensive transformation plans based on low-carbon technologies. This study completes a survey and analysis of the current status of the disposal of decommissioned oil and gas platforms in China and the level of low-carbon technologies. It proposes a main form of transformation for constructing an offshore carbon recycling hub and three low-carbon transformation routes, clarifying key engineering implementation strategies for platform transformation, including platform safety assessment, selection strategies for transformation plans, and full lifecycle environmental protection. In response to practical issues such as the lack of regulations and policies for platform transformation, shortcomings in the application of low-carbon technologies in the marine sector, and unclear cross-industry cooperation mechanisms, it is recommended to improve platform transformation regulations and guiding policies. It is also necessary to focus on the offshore application performance of core technical equipment, optimize theoretical support for technology, and accelerate the transformation of domestic equipment. Priority should be given to carrying out demonstration projects for the transformation of decommissioned platforms to promote the low-carbon transformation process of decommissioned offshore platforms in China.

The crystalline behaviors and micromorphology of polymers have a large impact on the physical and mechanical properties, especially for polypropylene (PP) composites with toughening effect. In this work, the changes of the content ratio for layered double hydroxide (LDH) and [beta]-nucleating agent (CaHA), mechanical properties, and crystallization behaviors of PP/ethylene vinyl acetate copolymer (EVA)/LDH ternary composites are investigated by differential scanning calorimeter (DSC), polarizing optical microscopy (POM), scanning electron microscopy (SEM), and notched impact strength testing. The CaHA is used for synergistic toughening with LDH, and the highest notched impact strength is achieved in the 6PEL2 sample with CaHA of 0.03 phr and LDH of 5.70 phr, which is about 100% higher than that of pure PP. It is found from the crystallization behaviors and SEM images of the composites that 6PEL2 has the highest relative content of [beta]-crystals and the appearance of rougher interface and deformation pullout of the EVA phase in 6PEL2 because of dislocations in the [beta]-crystals and the formation of a large number of cavities absorbing the impact energy. KEYWORDS composites, crystallization, polypropylene, toughness, 1 | INTRODUCTION Polypropylene (PP), one of the general-purpose plastics, is used in large quantities due to its excellent corrosion resistance, processability, and low price. [1] Due to the poor [...]

Deep-sea mineral resource development is an important measure to address China’s long-term dependence on strategic mineral resources. Having a complete and reliable equipment system is a prerequisite for China to promote its deep-sea mineral resource development and realize self-dependence of national strategic resources. This study focuses on the development history and current status of deep-sea mineral resource exploration and mining equipment in China and abroad and analyzes the bottlenecks that restrict China’s equipment development from three aspects: complete mining system, core mining equipment, and basic equipment and components. It also summarizes the scientific problems that need to be solved urgently and proposes development goals and key research directions from the perspectives of industrial integration, improvement of green mining system, and optimization of technical support. China should prioritize core equipment development to support large-scale mining, promote the integration of multiple industries and high-quality development of the entire equipment chain, and launch major projects for the development of deep-sea mineral resource exploitation equipment, focusing on the deep integration of production, education, research, and application of core equipment technologies. In addition, the government should provide various policy support and focus on innovation and upgrade of domestically produced equipment to promote the commercialized mining of deep-sea minerals in China.

This research endeavors to explore the potential of annealing treatment as a viable strategy to optimize the utilization of polypropylene (PP) composites, while preserving their exceptional properties. By incorporating ethylene vinyl acetate (EVA) copolymer and layered double hydroxide (LDH) into PP, this work meticulously analyzes the changes in crystallization behaviors and impact properties under varying annealing conditions. Impact strength is systematically assessed by a digital pendulum impact tester, whereas the crystalline structure is analyzed through polarized light optical microscopy (POM), differential scanning calorimetry (DSC), and x‐ray diffraction (XRD). The notch impact test exhibits a gradual increase in impact strength from 100 to 130°C, followed by a decline at 140°C. The XRD and DSC results elucidate subtle β‐crystal diffraction peaks for PP/EVA and PP/EVA/LDH composites, attributed to the transformative effect of EVA and LDH on PP crystals. POM analysis further unveils a reduction in spherical crystal size and gradual blurring of grain boundaries during the annealing process. Highlights: PP/EVA/LDH composites are effectively regulated by changing the annealing treatment conditions.The crystallization behaviors and crystal structure of PP are induced due to synergistic effect of EVA and LDH under annealing treatment.The toughness of PP is enhanced significantly by synergistic effect of EVA and LDH under annealing treatment. [ABSTRACT FROM AUTHOR]

Driven by global environmental issues, the development of green building materials has become an immediate focus. In this work, n‐pentane was used as an environmentally friendly blowing agent to prepare flame‐retardant rigid polyurethane foam (RPUF) with the addition of expandable graphite (EG) successfully, and the effect of n‐pentane content on flame retardancy and compressive properties of RPUF/EG composites was investigated through limit oxygen index (LOI), vertical burning test (UL‐94), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and compressive properties test. SEM results show that the content of EG and n‐pentane causes a change in the cell structure of RPUF. The change of the n‐pentane content has also an obvious effect on the thermal stability, flame retardancy, and specific compressive strength of RPUF/EG composites. In addition, the cell structure of RPUF matrix has an obvious influence on the distribution of EG in the composites, which indirectly affects the flame‐retardant efficiency of EG. This research explores the conditions for the application of environmentally friendly RPUF and expands its application prospects. [ABSTRACT FROM AUTHOR]

The crystalline behaviors of polymers have a large impact on their physical and mechanical properties, especially as reinforcing and toughening materials in the construction industry. This work investigates the crystallization behaviors of polypropylene (PP) composites with layered double hydroxide (LDH) by using differential scanning calorimeter and a polarizing optical microscope (POM), and analyzed the non‐isothermal crystallization kinetics of PP composites by Avrami model and Mo's method. The results show that the entire process of non‐isothermal crystallization is appropriate for Mo′s method instead of Avrami model due to the offset of the curves in initial nucleation and secondary crystallization stages. The addition of LDH and modified LDH (SLDH) can increase the crystallinity (Xc) of PP despite decreasing the crystallization rate in the non‐isothermal crystallization process. The migration activation energy (∆E) indicates that LDH acts as a heterogeneous nucleating agent, which is consistent with POM results. The values of ∆E and semi‐crystallization time (t1/2) reveal that the nucleation capacity of PP/LDH is greater than that of PP/SLDH, but the crystallization rate of PP/LDH is slower than that of PP/SLDH, resulting in a decrease in Xc. [ABSTRACT FROM AUTHOR]