دانلود رایگان مقاله شیشه الیاف خود ترمیم/ کامپوزیت اپوکسی با لوله پلی پروپیلن

Abstract

To improve flowability of the healing agent released from micropipelines without manual intervention, this work prepared a proof-of-concept self-healing glass fiber/epoxy composite, in which plastic (polypropylene (PP)) tubes were embedded and used as containers of epoxy/mercaptan healing agent and foaming agent. Decomposition of the foaming agent at 70 °C created inflated gas in the sealed PP tubes in advance, which increased the internal pressure. Upon damage of the composite, the pressurized healing fluid burst out covering larger cracked plane and enhanced mixing of the liberated epoxy monomer and hardener. As a result, higher healing efficiency was observed as compared to the case without pressurization. The factors that influence healing performance of the system (e.g., tube spacing, content of the foaming agent, foaming time, etc.) were discussed in detail. The proposed approach is believed to have adequate expansibility and can be applied in other self-healing composites with micropipelines.

4. Conclusions

The present work shows the feasibility of a self-pressurized healing system for self-healing glass fiber/epoxy composites. The core issue lies in the introduction of foaming agent into healing agent-loaded thermoplastic PP tubes. Decomposition of the foaming agent generates gas inside the sealed tubes and pressurizes the included healing fluid. Upon damage of the composites, the released healing agent is driven by the high internal pressure and spreads out over larger cracked planes, as compared with the unpressurized version. As a result, higher healing efficiency is detected. The factors that influence healing performance of the composites are interconnected. Polymerization speed of the healing agent had better to be lower than its diffusion rate, allowing complete mixing of the components during long-distance delivery [35,36]. This is true, especially in the case of large damages. Additionally, impermeability of the PP tubes should be improved for reducing gas leakage. Although the processing and materials parameters have not yet been optimized, the results of this preliminary exploration have shown that our idea works, which might have broad applicability to other microvascular self-healing composites.