Géczy Attila, Piffkó Dániel, Berényi Richárd, Dusek Karel, Xavier Pascal, Cuartielles David
Department of Electronics Technology, Faculty of Electronic Engineering and Informatics, Budapest University of Technology and Economics, Budapest, Hungary.
Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
Nanotechnology. 2024 Aug 5;35(43). doi: 10.1088/1361-6528/ad66d3.
In this paper, we present a novel polylactic-acid/flax-composite substrate and the implementation of a demonstrator: a microcontroller board based on commercial design. The substrate is developed for printed circuit board (PCB) applications. The pre-preg is biodegradable, reinforced, and flame-retarded. The novel material was developed to counter the increasing amount of e-waste and to improve the sustainability of the microelectronics sector. The motivation was to present a working circuit in commercial complexity that can be implemented on a rigid substrate made of natural, bio-based materials with a structure very similar to the widely used Flame Retardant Class 4 (FR4) substrate at an early technological readiness level (2-3). The circuit design is based on the Arduino Nano open-source microcontroller board design so that the demonstration could be programmable and easy to fit into education, IoT applications, and embedded designs. During the work, the design was optimized at the level of layout. The copper-clad pre-preg was then prepared and processed with subtractive printed wiring technology and through hole plating. The traditional surface mounting methodology was applied for assembly. The resulting yield of PCB production was around 50%. Signal analysis was successful with analogue data acquisition (voltage) and low-frequency (4 kHz) tests, indistinguishable from sample FR4 boards. Eventually, the samples were subjected to highly accelerated stress test (HAST). HAST tests revealed limitations compared to traditional FR4 printed circuit materials. After six cycles, the weight loss was around 30% in the case of PLA/Flax, and as three-point bending tests showed, the possible ultimate strength (25 MPa at a flexural state) was reduced by 80%. Finally, the sustainability aspect was assessed, where we found that ∼95 vol% and ∼90 wt% of the traditional substrate can be substituted, significantly easing the load of waste on the environment.
在本文中，我们展示了一种新型聚乳酸/亚麻复合材料基板以及一个演示器的实现：一个基于商业设计的微控制器板。该基板是为印刷电路板（PCB）应用而开发的。预浸料是可生物降解的、增强的且具有阻燃性。开发这种新型材料是为了应对电子垃圾数量的不断增加，并提高微电子行业的可持续性。其动机是在商业复杂度下展示一个能在由天然生物基材料制成的刚性基板上实现的工作电路，该基板结构与广泛使用的4类阻燃（FR4）基板非常相似，且处于早期技术就绪水平（2 - 3）。电路设计基于Arduino Nano开源微控制器板设计，以便演示可编程且易于应用于教育、物联网应用和嵌入式设计。在工作过程中，设计在布局层面进行了优化。然后制备覆铜预浸料，并采用减成印刷布线技术和通孔电镀进行加工。采用传统的表面贴装方法进行组装。PCB生产的成品率约为50%。通过模拟数据采集（电压）和低频（4 kHz）测试成功进行了信号分析，结果与FR4样本板难以区分。最终，对样品进行了高加速应力试验（HAST）。HAST试验揭示了与传统FR4印刷电路材料相比的局限性。六个循环后，聚乳酸/亚麻材料的重量损失约为30%，并且如三点弯曲试验所示，可能的极限强度（弯曲状态下为25 MPa）降低了80%。最后，对可持续性方面进行了评估，我们发现约95体积%和约90重量%的传统基板可以被替代，显著减轻了环境中的废物负担。
