More recently, this has been streamlined by performing the polymerization with multisite catalysis or with cascade reactors 2. This simple approach requires synthesizing a large number of batches to reduce the multimodality of the final MWD (Fig. Thus, achieving high precision tailored MWDs remains a topic of high interest for studying material properties, as well as tailoring materials for specific applications.Įarly approaches to engineered MWDs relied on blending distinct batches of polymers with known MW 1, 2, 5, 14, 15, 16, 17, 18. While coarse MWD tuning is common practice, independent control over MW, MWD breadth, and MWD shape remains challenging. In addition, emerging areas of applications for thermoplastics (e.g., 3d printing) demand high mechanical performance while maintaining ease of processing, which can be achieved through tuning of the MWD 12, 13. Moreover, the latest improvements to polyolefins have been the tailoring MWDs for specific applications 2. For example, polyethylene produced by the Philipps catalyst has a dispersity >10, as this provides the ideal balance of fast processability and high mechanical strength 2, 11. In fact, broad distributions remain a staple in industry 2, 10. Controlled polymerizations have revolutionized the synthesis of advance materials, however, the control they offer does not directly provide tunability for broad MWDs which are advantageous for many applications 9. Much of the work regarding MWDs, has primarily focused on the development of polymerization methods to access polymers with narrow MWDs (referred to as controlled polymerization) 7, 8. This correlation is general across all polymers and has motivated the development of many synthetic and process techniques. A polymer’s molecular weight distribution (MWD) impacts material properties such as processability, mechanical strength, and morphological phase behavior 1, 2, 3, 4, 5, 6.
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