• Title/Summary/Keyword: Glass transition temperature (Tg)

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Design and Properties of Laminating Waterborne PSA for Eco-friendly Flexible Food Packaging (식품연포장용 라미네이트 수성 감압점착제의 친환경적 적용에 대한 연구)

  • Lee, Jin-Kyoung;Shim, Myoung-Sik;Chin, In-Joo
    • Journal of Adhesion and Interface
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    • v.17 no.2
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    • pp.49-55
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    • 2016
  • In this study, we designed an environment friendly, water-based adhesive using the acrylic emulsion method as a replacement for solvent-based adhesives, which are most commonly used in layered laminates for flexible food packaging. We designed adhesives with different combinations of anionic, non-ionic, and phosphoric ester surfactants, and with different concentrations of chain transfer agent (CTA). We also examined the effect of the degree of cross-linking by synthesizing and comparing 8 test group adhesives with different types of functional monomers. Additionally, we synthesized 2 other test group pressure-sensitive adhesives (PSA) using styrene/alpha-methyl styrene/acrylic acid (SAA) semipolymer dispersing agents (with molecular weights of 13,000 g/mol and 8,600 g/mol, respectively) to replace the conventional surfactants. We evaluated whether the 10 test group pressure-sensitive adhesives met the basic physical property criteria required for flexible food packaging by carrying out a physical analysis of their glass transition temperature (Tg), particle size, adhesion, and molecular weight. In our test, 2 test group adhesives manufactured with the combination of anionic and non-ionic surfactants, CTA concentration of 0.2%, and functional monomers of hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA) demonstrated molecular weight and flexibility suitable for flexible packaging, with low adhesiveness and small particle size.

Studies on Thermal and Dynamic Viscoelastic Behaviors of Multiwalled Carbon Nanotubes-reinforced Epoxy Matrix Composites (다중벽 탄소나노튜브강화 에폭시 매트릭스 복합재료의 열적 및 동적 점탄성 거동 연구)

  • Seo, Min-Kang;Park, Soo-Jin
    • Korean Chemical Engineering Research
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    • v.43 no.3
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    • pp.401-406
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    • 2005
  • In this work, the effect of chemical treatment of multiwalled carbon nanotubes (MWNTs) on glass transition temperature (Tg), thermal stability, and dynamic viscoelastic behaviors of MWNTs-reinforced epoxy matrix composites has been studied by differencial scanning calorimeter (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) measurements. The MWNTs were chemically treated with 35 wt% $H_3PO_4$ (A-MWNTs) or 35 wt% KOH (B-MWNTs) solutions and the changes of surface properties of chemically treated MWNTs were examined by pH, acid and base values, Fourier transfer-infrared spectroscopy (FT-IR), and x-ray photoelectron spectroscopy (XPS) analyses. The chemical treatments based on acid and base reactions led to a significant change of surface characteristics and chemical compositions of the MWNTs, especially A-MWNTs/epoxy composites had higher thermal stability and dynamic viscoelastic properties than those of B-MWNTs and non-treated MWNTs/epoxy composites. These results were probably due to the improvement of interfacial bonding strength, resulting from the acid-base interaction and hydrogen bonding between the epoxy resins and the MWNT fillers.