Advancing the Commercial Applications of Graphene

该项目的目的是制造石墨烯功能化纤维增强复合材料，其中通过将等离子体功能化石墨烯的分散体有针对性地喷墨印刷到复合中间体（例如纤维预制件、夹层、组织或织物）上，在需要石墨烯的特定区域上，消除纳米填料分散和分布的可变性。这种方法将提供性能增强或多功能，如结构健康监测（SHM），电气，热和屏障性能，这些都是高端应用所要求的，如太空，航空航天和高科技海洋领域。为了实现这一目标，我们的方法将利用石墨烯的控制引入到复合材料的结构化增强相。石墨烯将被等离子体官能化以确保其保持良好地分散在载体溶剂中，并且因此不会重新聚集，这可能会阻塞喷墨打印头或降低石墨烯的固有性质。拟议的研究将评估石墨烯的两种新的加工方法（等离子体功能化和喷墨打印），这将解决特定的问题，并以合理的成本改善复合结构中石墨烯基材料性能的相对缺点。此外，拟议的申请有可能支持另一个英国优先领域（高价值制造业）。迄今为止，石墨烯在复合材料中的当前使用集中于石墨材料在本体树脂中的混合或原位剥离。这种方法效率低下，因为需要大比例的石墨烯才能具有明显的效果，因此，由于每公斤材料的成本，很难克服成本障碍。喷墨印刷允许小的，但集中的，将大量石墨烯准确且可重复地放置到复合材料的特定区域中，以实现各种不同的潜力。效益在喷墨打印之前对石墨烯进行等离子体功能化有望解决石墨烯形成团聚体的问题，迄今为止，石墨烯在喷墨打印方面的努力有限。该研究将解决石墨烯在航空航天领域的具体应用，以创建定制的多功能复合结构，以形成结构电路，结构传感器用于结构健康监测（SHM）或只是为了获得有针对性的机械性能增加。目前的机载电子系统需要使用PCB电路、嵌入式铜和布线，所有这些都会增加额外的成本和重量，并降低性能。例如，铜插入件通常必须用手层压到复合结构中，然后可以用作层间裂纹萌生的部位。以上面提出的方式使用石墨烯将不会降低性能，因为预期层间韧性将增加并且增加的重量可以忽略不计。由于有针对性的、自动化的和可扩展的制造方法沿着所需的少量材料，即使考虑到石墨烯的当前价格，预计成本也具有竞争力。在该项目中将利用使用石墨烯的多种好处：1）层间韧性增加2）集中石墨烯区域的高导电性，3）印刷嵌入路径的灵活性允许结构内的应变和4）使用喷墨印刷相对容易制造。由于该工艺可用于使干纤维预成型件、预浸料、夹层或固化结构功能化，因此可以应用各种下游复合材料加工方法，因此该联盟预计，除了目标航空航天应用外，在不同领域还将有大量额外的潜在应用。

The purpose of this project is to manufacture a graphene functionalised fibre-reinforced composite material in which the variability of nano-filler dispersion and distribution is eliminated by the targeted inkjet printing of a dispersion of plasma functionalised graphene onto composite intermediates (such as fibre preforms, interleaves, tissues or prepregs), on specific areas where the graphene is required. This approach will deliver property enhancements or multi-functionality such as structural health monitoring (SHM), electrical, thermal and barrier performance that are demanded by high-end applications such as in the space, aerospace, and high-tech marine sectors. To achieve this, our approach will utilise the controlled introduction of graphene to the structured reinforcement phase of the composite. The graphene will be plasma-functionalised to ensure that it remains well dispersed in the carrier solvent and, as such, does not re-agglomerate which could either block the inkjet printheads or reduce the inherent properties of the graphene. The proposed research will evaluate two novel processing methods (plasma functionalisation and inkjet printing) for graphene which will address specific problems and improve on relative shortcomings in the performance of graphene- based materials within composite structures at a reasonable cost. In addition the proposed application has the potential to support another UK priority area (High Value Manufacturing). To date, the current use of graphene within composites has focused on mixing or in-situ exfoliation of graphitic materials within bulk resin. This method is inefficient because large proportions of graphene are required to have a demonstrable effect and consequently, due to the cost per kg of the material, it is difficult to overcome the cost barriers.This proposal takes a different approach: inkjet printing allows small, yet concentrated, quantities of graphene to be placed accurately and reproducibly into specific areas of a composite in order to achieve various different potential benefits. Plasma functionalisation of the graphene prior to inkjet printing is expected to solve the problem of graphene forming agglomerates which so far have limited efforts at inkjet printing it. The research will address specific applications of graphene within the aerospace sector to create multifunctional composite structures tailored to form structural circuits, structural sensors for structural health monitoring (SHM) or simply to gain targeted mechanical property increases. Current on-board electronic systems require the use of PCB circuits, embedded copper and wiring all of which can add additional cost and weight, and reduce performance. Copper inserts for example would typically have to be laminated into the composite structure by hand and could then act as sites for interlaminar crack initiation. The use of graphene in the manner proposed above will not reduce performance as it is expected that interlaminar toughness will increase and the added weight is negligible. Due to the targeted, automated and scalable manufacturing method along with the small amounts of material required the costs are expected to be competitive even considering the current price of graphene. Multiple benefits of using graphene will be exploited within the project: 1) interlaminar toughness increases 2) high electrical conductivity of concentrated graphene regions, 3) the flexibility of the printed embedded paths allowing for strain within the structure and 4) the relative ease of manufacture using inkjet printing. As the process could be used to functionalise dry fibre preforms, prepreg, interleaves or cured structures a wide variety of down-stream composite processing methods can be applied and for this reason the consortium expect that there will be a plethora of additional potential applications in different sectors in addition to the targeted aerospace application.