LT: Models and Instruction for Life Cycle Material Content Decisions

点击翻译按钮获取中文摘要

9727209 Stuart This proposal focuses on engineering approaches for sustainability and design for materials reuse through the development of polymer degradation models, product characterization models, and life cycle material content decision models. Because these challenges are multidisciplinary, collaboration between Chemical Engineering (polymer processing), Industrial Engineering (manufacturing processes), Operations Research (applied mathematical modeling), and Mechanical Engineering (product design) are described. An important element of this proposal is the integration of environmentally conscious engineering approaches into undergraduate and graduate engineering curriculum. As the demand for plastics by the transportation, aerospace, and durable goods industries is increasing, the disposal of plastics is also increasing. The analysis of life cycle trade-offs between use of recycled plastics, recyclability, reduction of process wastes, energy consumption, yields, and product performance are complex. To date, most companies process either 100% virgin material or virgin material with small percentages of regrind. Sources of pure regrind may be internal or from another industrial processor(s). Companies embracing product stewardship are struggling to develop viable approaches to economically process and recycle returned products. Post-consumer polymers have been exposed to various thermal and mechanical conditions. In addition, post-consumer products contain polymer blends as well as additives such as reinforcements, paint, or flame retardants. Thus, post-consumer plastics introduce additional raw material uncertainties into the manufacturing process. To achieve corporate sustainability goals for cradle to cradle products, companies producing advanced polymers and composites need polymer degradation models, product characterization models, and decision tools for recycled material content choices as well as engineers who understand sustainability issues and approaches. Several materials, manufacturing, design, and decision modeling issues as well as curriculum integration must be addressed. First, we must be able to identify the measure of degradation for incoming recycled materials. Previous studies have demonstrated the relationship between the molecular weight distribution (MWD) and polymer degradation properties such as viscosity and melt index. We will investigate the feasibility of measuring the MWD for common material mixes where mixes refer to various recycling generations (virgin through fifth generation) as well as polymer blends. We must also characterize the product complexities and the corresponding material properties required. Next, we will investigate the relationship between the product complexities and the material degradation properties. Typical industrial processing parameters for temperature and pressure will be used. The goal is to characterize the relationship between the ratio of recycled content to virgin content and the mold geometry, mechanical properties, and rheological properties. The materials degradation models will provide valuable input for the life cycle material content decision model. The objective of the life cycle material content decision model is to select material content ratios in order to minimize costs subject to constraints on regrind, post-consumer, and virgin material supply, energy consumption, cycle time, and quality. In five different undergraduate and graduate classes, the principal investigators will motivate future engineers to grapple with environmental materials selection challenges. Industrial ecology principles as well as analytical methods for life cycle material content decisions will be integrated into the engineering curriculum. ***