STTR Phase I: Advanced compatibilization for mixed plastic recycling

这一小型企业创新研究第一阶段项目的更广泛影响是促进增加回收，并使混合废物流中最常见的两种聚合物：聚乙烯（PE）和全同立构聚丙烯（iPP）的升级循环成为可能。虽然塑料回收可以帮助减少大量且不断增长的塑料废物，但混合塑料流（特别是含有PE和IPP的塑料流）带来了许多挑战。 这些聚合物是不混溶的，但密度相似，使它们不适合简单的熔融共混，但难以分离。尽管已经开发了添加剂来克服不可吸收性问题，但是这些添加剂通常需要以高负载量添加并且产生具有差的机械性能的树脂。本项目致力于开发能够以低浓度导入的高级添加剂（相容剂），生产具有与均聚物相媲美或优于均聚物的上级耐久性、延展性和工业实用性的PE/iPP树脂。这种技术有可能为混合回收过程带来上级效率，推动该领域朝着更循环的塑料经济发展。通过从废物流中提供高价值产品，该技术的广泛采用将推动塑料废物收集、回收和再制造的改进，支持这些领域和相关领域的工作。该项目涉及创造非反应性多元接枝共聚物，能够支持高质量的iPP/PE共混物，与现有树脂相比，该共混物具有上级拉伸强度特性，耐冲击性和刚性。所提出的方法利用互锁分子缠结和共结晶来提供对iPP和PE的更强粘附。该技术旨在使用低至1重量%的添加剂来生产高价值的共混材料，从而在PE中实现高达30%的iPP污染。第一阶段开发将涉及：1）优化聚乙烯-接枝-iPP共聚物增容添加剂，2）扩大优化的聚乙烯-接枝-iPP共聚物的规模，3）测试大规模批次的最终聚合物质量，以及4）测试增容剂与不同等级的实际消费后塑料废物的组合。该技术可能有助于增强对特定共聚物结构如何影响相容效率的理解，同时也满足了对用于混合回收应用的PE和iPP相容技术的需求。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact of this Small Business Innovation Research Phase I project is to promote increased recycling and to enable the upcycling of two of the most common polymers found in mixed waste streams: polyethylene (PE) and isotactic polypropylene (iPP). While plastic recycling can assist in mitigating the vast and continuously growing volume of plastic waste, mixed plastic streams—notably those with PE and iPP—introduce many challenges. These polymers are immiscible but of similar density, making them unsuitable for simple melt-blending yet difficult to separate. Although additives have been developed to overcome the immiscibility issue, these additives typically need to be added at high loadings and produce resins with poor mechanical properties. This project focuses on the development of advanced additives (compatibilizers) that can be introduced in low concentrations to produce PE/iPP resins with superior durability, ductility, and industrial utility that rivals or outperforms homopolymers. Such a technology has the potential to bring superior efficiency to the mixed recycling process, advancing the field toward a more circular plastics economy. By delivering high-value products from waste streams, widespread adoption of this technology would drive improvements in plastic waste collection, recycling, and re-manufacturing, supporting jobs in these and adjacent fields.This project involves the creation of non-reactive, multi-graft copolymers capable of supporting high-quality iPP/PE blends with superior tensile strength characteristics, impact resistance, and rigidity compared to current resins. The proposed approach leverages interlocked molecular entanglements and co-crystallization to provide stronger adhesion to iPP and PE. This technology seeks capability of up to 30% iPP contamination in PE using as little as 1 wt% additive to generate high-value blended materials. Phase I development will involve: 1) optimization of polyethylene-graft-iPP copolymer compatibilization additives, 2) scale-up of optimized polyethylene-graft-iPP copolymers, 3) testing of larger scale batches for end polymer qualities, and 4) testing of compatibilizers with combinations of different grades of actual post-consumer plastic waste. The technology may contribute to an enhanced understanding of how specific copolymer architectures influence compatibilization efficiency, while also meeting the need for technologies to support compatibilization of PE and iPP for blended recycling applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.