Article
  • Preparation and Properties of Thermally Stable Lignin-based Copolymer/PP Blends by Melt Process
  • Kim G, Park IK, Kim SH, Kim Y, Seo HW, Yun JH, Kim SH, Kim DK, Nam JD
  • 열적으로 안정한 리그닌 공중합물과 PP의 용융 블렌드 제조 및 물성
  • 김고은, 박인경, 김성훈, 김영준, 서희원, 윤주호, 김수현, 김동관, 남재도
Abstract
Lignin-based polycaprolactone (LigPCL) copolymer was synthesized by both the ring opening reaction of ε-caprolactone with the hydroxyl groups in the lignin and the concomitant polymerization of ε-caprolactone. FTIR spectra showed C=O (1755 cm-1) and C-O (1202 cm-1) peaks confirming that the esterification reaction took place successfully between lignin and ε-caprolactone. T2, at which the weight loss of 2% occurs, of pristine lignin and LigPCL were measured as 63 and 211 ℃, respectively, and so the synthesized LigPCL had superior thermal stability to the lignin. PP/Lig-PCL blends were prepared at various contents of LigPCL up to 30 wt% by a melt extrusion process. In proportion to the content of the LigPCL, tensile strengths, flexural strengths, and tensile modulus of PP/LigPCL blends greatly decreased, but elongations at break of those greatly increased. To improve the compatibility between PP and LigPCL, maleic anhydride-grafted polypropylene (PP-g-MA) was added. SEM images for the fracture surfaces of the blends showed that the PP-g-MA was effective in reducing the domain size of dispersed phase. Thus, T2, tensile strength, tensile modulus, and elongation at break of a 70/30 blend of PP/LigPCL were enhanced by 6 ℃, 17%, 31%, and 79%, respectively, by the addition of PP-g-MA. This work clearly demonstrates that thermoplastic LigPCL could be desirably synthesized and applied for value added and eco-friendly products through common melt processes used for polymer blend or composites manufacturing.

리그닌과 ε-caprolactone의 고리열림반응과 수반된 ε-caprolactone의 중합을 통해 lignin-based polycaprolactone(LigPCL) 공중합물을 합성하였다. FTIR의 C=O(1755 cm-1) 및 C-O(1202 cm-1) 피크들을 통해 LigPCL이 성공적으로 중합되었음을 확인하였다. 순수한 리그닌과 LigPCL의 T2(열분해로 중량이 2% 감소하는 온도)는 각각 63와 211℃ 로서 LigPCL의 열안정성이 크게 향상된 것을 확인하였다. LigPCL은 용융 압출공정을 통해 PP와 30 wt%까지의 함량비에서 여러 블렌드를 제조하였다. PP/LigPCL 블렌드들은 LigPCL의 함량에 비례하여 인장강도, 굴곡강도 및 인장탄성률은 감소하였으나 파단신율은 크게 증가하였다. PP와 LigPCL 사이의 상용성 증대를 위해 말레산무수물로 그래프트된 폴리프로필렌(PP-g-MA)을 첨가함으로써 분산상의 크기가 감소하는 것이 파단면의 SEM 이미지에서 확인되었다. PP/LigPCL 70/30 블렌드에 PP-g-MA를 첨가하여 T2는 6℃ 증가하였고, 인장강도는 17%, 인장탄성률은 31%, 그리고 파단신율은 79%가 향상되었다. 본 연구를 통해 열가소성의 LigPCL이 성공적으로 합성되었고 고분자블렌드 및 컴포지트 제조에 사용되는 용융공정을 통한 고부가가치의 친환경 제품에 응용될 수 있음을 증명하였다.

Keywords: lignin polymer; bioplastics; compatiblizer; thermal stability; mechanical properties

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2022 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 2016; 40(2): 313-320

    Published online Mar 25, 2016

  • 10.7317/pk.2016.40.2.313
  • Received on Nov 25, 2015
  • Accepted on Feb 3, 2016