Probing the hard segment phase connectivity and percolation in model segmented poly(urethane urea) copolymers

Jignesh P. Sheth, Garth L. Wilkes, Ann R. Fornof, Timothy Edward Long, Iskender Yilgor

研究成果: Article

48 引用 (Scopus)

抜粋

Soluble model segmented poly(urethane urea)s (PUU) with or without hard segment (HS) branching were utilized to explore the importance of hydrogen bonding and chain architecture in mediating the long-range connectivity of the HS phase. The HS content of all the PUU copolymers was 22 wt%, and the soft segment (MW 970 g/mol) was a heterofed random copolymer of 50:50 ethylene oxide:propylene oxide, which possesses a single terminal hydroxyl group (monol). An 80:20 isomeric mixture of 2,4- and 2,6-toluene diisocyanate, 4,4′,4″-triphenylmethane triisocyanate and water were utilized during the chain extension step of the synthesis to incorporate HS branching. DSC and SAXS results on the final plaques indicated that the samples were still able to establish a microphase morphology even in the presence of the highest extent of HS branching utilized in the study. The tapping-mode AFM phase image of the PUU sample without HS branching exhibited the presence of long ribbonlike hard domains that percolated through the soft matrix. The long-range connectivity of the HS was increasingly disrupted with higher levels of HS branching. Accompanying such disruption was a systematic mechanical softening of the PUU samples. FT-IR indicated that incorporation of HS branching disrupted the hydrogen-bonded network within the hard phase. These results demonstrate the importance of hydrogen bonding and chain architecture in mediating the long-range connectivity and percolation of the HS and achieving dimensional stability.

元の言語English
ページ(範囲)5681-5685
ページ数5
ジャーナルMacromolecules
38
発行部数13
DOI
出版物ステータスPublished - 2005 6 28
外部発表Yes

    フィンガープリント

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

これを引用