Characterization of morphology and mechanical properties of block copolymers using atomic force microscopy: Effects of processing conditions

Dong Wang, Ken Nakajima, So Fujinami, Yuji Shibasaki, Jun Qiang Wang, Toshio Nishi

    Research output: Contribution to journalArticlepeer-review

    24 Citations (Scopus)

    Abstract

    The effect of preparation methods and processing conditions on morphology and mechanical properties of poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) triblock copolymer were investigated with atomic force microscopy (AFM) tapping mode and nanomechanical mapping, tensile testing, and gel permeation chromatograph (GPC). It was found that the samples prepared by solution casting and melt processing show large difference in morphology and mechanical properties. High shear rate does not induce alignment of lamellar block copolymer melts but leads to serious degradation of SEBS. As increase of rotational speed from 0 to 400 rpm, the molecular weight including Mn and Mw decreases from 67,100 to 26,000 and 70,000 to 43,000, respectively. Such large molecular weight decrease causes greatly decreased tensil strength but there is almost no evident effect on the well-phase separated morphology and Young's modulus of the SEBS. The Young's modulus distribution revealed by nanomechanical mapping becomes narrow as the increase of rotational speed. The amount of SEBS molecular having higher Young's modulus, which play a very important role in tensile strength of SEBS, also decreases.

    Original languageEnglish
    Pages (from-to)1960-1965
    Number of pages6
    JournalPolymer
    Volume53
    Issue number9
    DOIs
    Publication statusPublished - 2012 Apr 17

    Keywords

    • Degradation
    • Nanomechanical mapping
    • Processing

    ASJC Scopus subject areas

    • Organic Chemistry
    • Polymers and Plastics
    • Materials Chemistry

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