Adaptation of the Direct Reaction Injection Molding Process for Production and Processing of Long FiberReinforced Thermosets (LFD-Injection Molding Process) to the use of carbon fibers instead of glass fibers

用于生产和加工长纤维增强热固性材料的直接反应注塑工艺（LFD 注塑工艺）采用碳纤维代替玻璃纤维

• 批准号: 400343062
• 负责人: Dr.-Ing. Wilfried Liebig, since 9/2022
• 金额: --
• 依托单位: Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/400343062?language=en
• 关键词: Adaptation; Direct; Reaction; Injection; Molding; Adaptation; Direct; Reaction; Injection; Molding

Fiber reinforced phenolic molding resins are among the oldest engineering polymers and are very versatile due to their advantageous properties. In addition to good thermo-mechanical properties, they have excellent media resistance and high dimensional stability. They are typically processed by injection molding. In contrast to thermoplastics, components made from phenolic molding compounds exhibit a low elongation at break and a low impact strength. These disadvantageous material properties restrict the use of fiber-reinforced phenolic resins in numerous applications. The project "LFD injection molding process" investigated the extent to which these disadvantages can be mitigated by increasing the fiber length in the molded part. The scope of the current project is to find out how the property profile of long fiber reinforced phenolic molding compounds can further be improved by using long carbon fibers (LCF) instead of long glass fibers (LGF). This will be realized by a variable feeding of the LCF into the injection molding process. To achieve this, the differences between LGF and LCF in terms of cutting, feeding and homogenization of the fibers are to be determined. In parallel, analysis methods already established for glass fibers will be adapted to carbon fiber-reinforced phenolic resins.Within the scope of the project, suitable carbon fibers and phenolic resins will be selected for the LFD process and compounded to short fiber molding compounds by twin screw extrusion. The moldability of the compounds will be ensured with the aid of calorimetric (DSC), rheological (oscillatory rheology) and typical at-line quality assurance methods (Orifice Flow Test OFT). To reliably evaluate the effects of different material and process parameters on the fiber length distribution, a valid and reproducible measurement method is required. For this reason, a measurement method that was developed for glass fibers will be adapted and validated for carbon fibers as well. The method is based on the pyrolytic removal of the matrix, followed by automated image evaluation of an aqueous fiber suspension. The existing LFD process technology will be adapted to the use of carbon fibers with as little changes as possible , so that the process designs for glass and carbon fibers will be comparable. The incorporation quality of the carbon fibers into the phenolic resin will be characterized by evaluating the opposing effects of (undesired) fiber shortening and (required) fiber dispersion. Fiber length measurements and computer tomographic evaluations will be used for this purpose. Finally, the aim of the project is to draw together the results of the previous work and to derive the process-structure-property relationship for the molding compounds and components produced.

纤维增强的酚类成型树脂是最古老的工程聚合物之一，由于其有利的特性，它们的用途非常广。除了良好的热力学特性外，它们还具有出色的培养基阻力和高维稳定性。它们通常是通过注射成型处理的。与热塑性塑料相比，由酚类成型化合物制成的成分在断裂时表现出低伸长率和低冲击强度。这些不利的材料特性限制了在许多应用中使用纤维增强的酚树脂的使用。该项目“ LFD注射成型过程”研究了通过增加模制部分中的纤维长度来减轻这些缺点的程度。当前项目的范围是找出如何通过使用长碳纤维（LCF）而不是长玻璃纤维（LGF）进一步改善长纤维增强酚类成型化合物的性质曲线。通过将LCF的变量喂养到注射成型过程中，这将实现这一点。为了实现这一目标，应确定LGF和LCF在切割，进食和均质化方面的差异。同时，已经针对玻璃纤维建立的分析方法将适用于碳纤维增强的酚醛树脂。在项目的范围内，合适的碳纤维和酚醛树脂将用于LFD工艺，并通过双螺钉挤出将其复合到短纤维成型化合物中。将借助量热（DSC），流变学（振荡性流变学）和典型的在线质量保证方法（孔口流量测试）来确保化合物的可可。为了可靠地评估不同材料和过程参数对纤维长度分布的影响，需要采用有效且可重现的测量方法。因此，将针对玻璃纤维开发的测量方法也将适应并为碳纤维进行验证。该方法基于矩阵的热解去除，然后对水纤维悬浮液的自动图像评估。现有的LFD工艺技术将适用于使用尽可能少的碳纤维，以使玻璃和碳纤维的工艺设计可比性。碳纤维的掺入质量将以评估（不希望的）纤维缩短和（必需的）纤维分散体的相反作用来表征。光纤长度测量和计算机断层扫描评估将用于此目的。最后，该项目的目的是将先前作品的结果汇总在一起，并为产生的成型化合物和成分提供过程结构 - 特质关系。