高温热塑性复合材料正交铺层热压成型层间结合强度试验研究

Experimental study on interlaminar bond strength of orthogonal laminate hot-press molding in high-temperature thermoplastic composites

  • 摘要: 连续辊压成型技术在制备连续热塑性碳纤维复合材料(CF/PEKK)板材或型材方面,相比传统模压工艺具有生产成本低和易于批量生产的显著优势。然而,受树脂高熔体黏度特性及温度、压力、速度、辊间隙等多参数耦合影响,成型质量调控极具挑战。针对连续生产过程中工艺参数难以在线确定的难题,本文基于“等效重构与过程解耦”思想,搭建了模拟连续辊压局部特征的静态热压装置,制备了不同温度与压力下0°/90°/0°搭接样件,系统研究了热-力历程对层间结合性能及厚度变化的影响。结果表明,层间结合性能对工艺参数呈显著的非单调依赖关系:适宜的参数促进树脂流变浸润与分子链扩散,而过高的温度与压力则导致树脂侧向溢出与层间“贫胶”。在360℃、400 N条件下,界面树脂充分熔融并实现分子链扩散与纠缠,层间结合强度达到峰值16 MPa。由此给出了基于最优压实率区间(24%~27%)的质量判据,为连续辊压成型生产线工艺参数的合理确定提供了可靠的理论依据。

     

    Abstract: Compared to traditional compression molding, continuous roll forming technology offers significant advantages of low production costs and ease of mass production for manufacturing continuous carbon fiber reinforced PEKK plates or profiles. However, controlling forming quality is extremely challenging due to the high melt viscosity of the resin and the coupled effects of multiple parameters, including temperature, pressure, speed, and roll gap. Addressing the difficulty of determining process parameters online during continuous production, this study established a static hot-pressing apparatus based on the concept of “equivalent reconstruction and process decoupling” to simulate the local characteristics of continuous roll forming. 0°/90°/0° lap specimens were prepared under varying temperatures and pressures to systematically investigate the thermo-mechanical coupling effects on interlaminar bond strength and thickness. Results indicate a non-monotonic dependence of bonding properties on process parameters. Appropriate parameters promote resin rheological wetting and molecular chain diffusion, whereas excessively high temperature and pressure lead to lateral resin overflow and interlaminar resin depletion. A peak strength of 16 MPa was achieved at 360℃ and 400 N, where the interfacial resin was fully melted, enabling effective molecular diffusion and entanglement. Based on the results, a quality criterion based on the optimal compaction ratio (24%-27%) is proposed, providing a theoretical basis for parameter optimization and quality control in continuous production lines.

     

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