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Using two catalysts with substantially different monomer

Deformation-Induced Crystallization in Olefin Block Copolymers Benjamin S. Hsiao, SUNY at Stony Brook, DMR 0405432.

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Using two catalysts with substantially different monomer

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  1. Deformation-Induced Crystallization in Olefin Block CopolymersBenjamin S. Hsiao, SUNY at Stony Brook, DMR 0405432 Recently, a novel class of olefin block copolymer (OBC) has been developed using a new chain shuttling technology developed by the Dow Chemical Company. The resulting OBC consists of alternating hard segment with high or medium density and soft segment with low density. In this study, the behaviors of deformation-induced crystallization in OBC and olefin random copolymer with similar overall density were compared using synchrotron in-situ X-ray techniques. It is found that orthorhombic crystals exist in both samples, while only random copolymer contains some monoclinic crystals. During deformation at low temperatures, monoclinic crystals can be induced with the expense of orthorhombic crystals, while at temperatures, the monoclinic phase is thermally less stable than the orthorhombic phase. The deformed random copolymer generally has a higher degree of crystal orientation than OBC. This different behavior can be attributed to the different chain architectures in the block and random copolymers. (Macromolecules, in preparation (2008)) Using two catalysts with substantially different monomer selectivity and a chain shuttling agent in one reactor to produce OBCs from ethylene and alpha-olefin. Science, 2006, 312, 714-719 A B SAXS WAXD 2D SAXS and WAXD patterns of OBC (A) and olefin random copolymer (B) right before fracture during deformation at 60 oC. (Strain = 4.4, and 8.3 for OBC and random copolymers, respectively.)

  2. Deformation-Induced Crystallization in Olefin Block Copolymers Benjamin S. Hsiao, Stony Brook University, DMR 0405432 Education Activities Under the current NSF grant, the following educational accomplishments have been made. • Dr. Jong-Khak Keum has completed his Ph.D. degree in December 2007. Currently, Dr. Keum is a Post-Doc at the Case Western Reserve University • Dr. Pranav Nawani has completed his Ph.D. degree in May 2008. He has just accepted a Post-Doc position at the Center of Functional Materials at the Brookhaven National Laboratory • Three full-time Ph.D. graduate students (Mr., Mr. Feng Zuo, Mr. Yimin Mao and Mr. Xiaowei Li) are currently involved in this project. Mr. Zuo is in the last year of his PhD study, Mr. Mao is a 3nd year graduate student and Mr. Li is a 1st year graduate student. Outreach Activities: All graduate students have participated in collaborative synchrotron experiments with scientists form industry (Dow Chemical scientists: Drs. H. Chen and S.-Y. Lai) and other university (Prof. Eric Baer and Anne Hiltner at Case). They have also been involved in the summer high school student research program sponsored by the Simons Summer Fellowship, REAP program and Stony Brook University 2008 summer high school researchers and their mentors in Hsiao group at Stony Brook

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