• Title/Summary/Keyword: effective network chain lengths

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Synthesis and Properties of Polyester System Polyurethane without Solvent (무용제 반응에 의한 폴리에스테르계 폴리우레탄의 합성 및 특성)

  • Kwak Noh-Seok;Yang Yun-Kyu;Jeong Boo-Young;Hwang Taek-Sung
    • Polymer(Korea)
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    • v.29 no.4
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    • pp.344-349
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    • 2005
  • Polyurethanes(PUs) were synthesized by reaction of isophorone diisocyanate, acetylbutyl citrate, and 3 types of polycaprolactone diol. Their structures were confirmed by FT-IR and NMR spectrometer. And, their thermal and mechanical properties were measured by TGA ud UTM. The effective network chain lengths ($\bar{M}_c$), measured by compressive modulus apparatus, were about $8000\~24000$ g/mol. As crosslinking density and amount of hard segment increased, tensile strength increased and elongation decreased. As the crosslinking density of PUs increased, thermal property inproved. When the ratio of NCO/OH is 1.1, maximum crosslinking density was achieved.