PREMISE: Exploratory Research: An Alternative Process Model for Printed Circuit Board Recycling

本产品实现与环境制造创新系统(Premise)探索性研究项目的目标是：(1)对基于多氯联苯低温分解的替代印刷电路板回收工艺的可行性进行探索性研究；(2)建立一个跨学科研究团队，能够在本项目所达成的理解的基础上开展长期合作；(3)从回收利用率、能源消耗和环境性能方面评估拟议的回收工艺与传统的印刷电路板回收工艺相比；(4)研究在建议的回收工艺中重复使用塑料的可行性。这一过程利用了这样一个事实，即在非常低的温度下，聚合物材料变得非常脆。此外，由于聚合物和印刷电路板上的其他材料之间的热膨胀失配而在印刷电路板树脂中建立的残余应力预计将导致比单纯由于塑料脆化而可能产生的更好的分离。实际的实验室实验将使用低温测试系统进行。电子设备的广泛传播和产品生命周期的缩短带来了一个严重的问题：如何处理大量报废或过时的电子设备。虽然电子产品回收和循环利用面临各种技术挑战，但本研究的重点是印刷电路板(PCB)或印刷线路板(PWBS)。印刷电路板是许多军用和商用电子产品的主要部件。由于其复杂的结构和随之而来的复杂的材料混合物，印刷电路板回收对当今的行业构成了严重的挑战。贵金属的丰富含量为材料回收和循环利用提供了强有力的经济理由。另一方面，大量的有毒成分和纤维增强聚合物给回收带来困难，并对环境造成不利影响。

The objectives of this Product Realization and Environmental Manufacturing Innovative Systems (PREMISE) Exploratory Research project are: (1) To conduct exploratory research into the feasibility of an alternative PCB recycling process based on cryogenic decomposition of the PCBs; (2) To establish an interdisciplinary research team that can develop a long-term collaboration that builds on the understanding developed in this project; (3) To evaluate the proposed recycling process against traditional PCB recycling processes in terms of recycle rate economics, energy consumption, and environmental performance; and (4) To examine the feasibility of reusing plastics in the proposed recycling process.The proposed recycling process is cryogenic decomposition of the PCBs. The process takes advantage of the fact that at very low temperatures, polymeric materials become highly brittle. In addition, the residual stresses set-up in the PCB resins due to thermal expansion mismatch between the polymers and other materials on the PCB is expected to lead to a better separation than might otherwise be possible simply due to the embrittlement of the plastics. Actual laboratory experiments will be performed using a cryogenic test system.Wide diffusion of electronic equipment and shortening of product lifecycles have caused a serious problem: how to deal with large quantities of end-of-life or obsolete electronic equipment. While there are various technical challenges for electronic product recovery and recycling, this research focuses on printed circuit boards (PCBs) or printed wiring boards (PWBs). PCBs are primary components in many electronic products built for both military and commercial applications. Due to their complex construction and the consequent complicated mixture of materials, PCB recycling presents a serious challenge to today's industry. The rich content of precious metals provides a strong economic justification for materials recovery and recycling. On the other hand, large amounts of toxic components and fiber-reinforced polymers create difficulties for recycling and adverse environmental impact.