The 11th Global Conference on Polymer and Composite Materials (PCM 2024)

Abstract: With the gradual depletion of shallow oil and gas resources, deep (>4,500m) and ultra-deep (>6,000m) oil and gas have become the main sources of oil and gas resources in China. With the advancement of technology, the drilling depth has been gradually increased. Two extra-deep wells with a design depth of over 10,000 m are being drilled in China. One of the wells has exceeded 10,000 m. However, the high temperature in the deep formation poses a great challenge to the temperature resistance of drilling fluids. Water-based drilling fluids (WBDF) are multistage dispersion systems of clay, weighting agent and a variety of chemical materials in water. Drilling fluid serves as “drilling blood” and plays a vital role in carrying and suspending drill cuttings, stabilizing wellbores, and lubricating and cooling drill bits during drilling-based engineering. Water-soluble polymers mainly regulate rheology and control filtration in drilling fluids, but their performance fails under high-temperature and high-salt conditions, which is a serious problem for drilling safety and efficiency. This presentation will focus on the topic of high temperature resistant polymers used in the drilling fluid. It will cover the technical challenges of deep well drilling, the challenges for polymers and the current status of research on high temperature resistant polymers. Finally, some research results on high temperature resistant polymers from our team will be presented.

Abstract: Degradable biomaterials have emerged as a viable alternative to permanent materials for regenerative bone medicine. Although Polycaprolactone (PCL) exhibits remarkable extensibility and toughness, its low elastic modulus and strength, hydrophobicity, and excessively slow degradation rate limit its application in orthopedics. Natural silk fibers with macroscopic continuity and highly ordered morphology are selected to reinforce PCL to satisfy the mechanical and biological requirements for bone grafts. In this talk, we discuss the design, fabrication, and bone graft application of fiber silk-PCL biocomposites.
Silk-PCL composites with 20%/40%/60% silk were fabricated via layer-by-layer assembly and hotpressing, allowing facile incorporation of drugs. The fiber silk composites exhibited compatible modulus (1GPa) to the majority of bone tissues, high compressive strength (150MPa), high toughness, hydrophilicity, and water adsorption behavior. The 6-month in vitro degradation experiment showed that passive surface erosion and bulk hydrolysis of the silk-PCL composite by the aqueous environment is negligible, and the fiber-matrix interfaces remained robust. In the in vivo rat subcutaneous model, the degradation of silk composites is significantly accelerated via inflammatory cells mediated PCL dissolution from the surface. Fiber silks are proposed to modulate the inflammatory responses toward synchronized material degradation and tissue reconstruction. A rabbit tibial defect model shows a strong tissue-composite implant bonding, suggesting sufficient mechanical function and the regeneration of new bone.
The silk-PCL composites bring forward exceptional comprehensive mechanical performance and desirable degradation behavior in vivo through the coupled inflammatory modulation effects of silk and PCL. This work may herald the advent of a novel biomaterial for load-bearing bone repair.