• Title/Summary/Keyword: polymer synthesis

Search Result 1,422, Processing Time 0.029 seconds

Synthesis and characterization of Star Shape Polycaprolactone containing 4-Arm Polycaprolactone Core (4개의 폴리카프로락톤 가지 코어를 가지는 스타형 폴리카프로락톤의 합성 및 분석)

  • An, Sung-Guk;Cho, Chang-Gi
    • Proceedings of the Korean Fiber Society Conference
    • /
    • 2002.04a
    • /
    • pp.199-202
    • /
    • 2002
  • The synthesis of materials with controlled composition and architectures continues to be a focus of considerable current research. Dendritic multiarm polymers such as dendrimer, hyperbranched polymer, and star polymers are three dimensional macromolecules, in which a large number of linear arms of similar molecular weight and narrow molecular weight distribution emanate from a central core. (omitted)

  • PDF

Studies on Synthesis of Acrylic Water Borne Polymer;Synthesis of Poly(vinyl acetate) and Poly(vinyl acetate-co-2-ethylhexyl acrylate) (Aerylic Water Borne Polymer의 합성 연구;Poly(vinyl acetate)와 poly(vinyl acetate-co-2-ethylhexyl acrylate)의 합성 연구)

  • Kim, Sang-Hern
    • Journal of the Korean Applied Science and Technology
    • /
    • v.13 no.2
    • /
    • pp.77-84
    • /
    • 1996
  • Poly(vinyl acetate)와 poly(vinyl acetate-co-2-ethylhexyl acrylate)를 여러 조건에서 semicontinuous emulsion 중합으로 합성하였다. Overall conversion, emulsion 입자크기, pH, 점도 등을 합성한 두 emulsion polymer에 대해 측정하였다. Vinyl acetate monomer에 2-ethylhexyl acrylate를 도입함으로서 emulsion 입도, 점도, 중합 속도, 유리 전이 속도가 감소함을 확인하였다.

Effect of C/N Ratio on the Production of Poly(3-hydroxyalkanoates) by the Methylotroph Paracoccus denitrificans

  • Kim, Byung-Ki;Yoon, Sung-Chul;Nam, Jae-Do;Lenz, Robert-W.
    • Journal of Microbiology and Biotechnology
    • /
    • v.7 no.6
    • /
    • pp.391-396
    • /
    • 1997
  • Two series of carbon sources, linear primary $C_1$~$C_9$ alcohols and linear $C_2$~$C_{10}$ monocarboxylic acids were tested for PHA synthesis in Paracoccus denitrificans. The results showed that the growth-associated synthesis of PHA could be referred only to the carbon sources with odd number of carbon except methanol. For all carbon sources with even number of carbon, nitrogen limitation was required to induce PHA synthesis in P. denitrificans. Poly(3-hydroxyvalerate)[P(3HV)] homopolymer was synthesized from $C_5$, $C_7$, and $C_9$ while growing in the presence of nitrogen, but the nitrogen depletion in the later growth period incorporated 3-hydroxybutyrate(3HB) unit into the polymer chain. The optimum C/N ratio for P(3HV) homopolymer production was found to be 10 when the strain was grown on 10 ml/l of valeric acid for 96 h. P. denitrificans synthesized P(3HB-co-3HV) copolymers from n-hexanoic and n-octanoic acid. The microstructural characterics of the P(3HB-co-3HV) copolymer from n-propanol was investigated using $^13C$-nuclear magnetic resonance spectroscopy, showing a structural heterogeneity.

  • PDF

Synthesis of Star like Random Copolymers from Resorcinarene-based Alkoxyamine Initiator via Nitroxide Mediated Free Radical Polymerization

  • Abraham, Sinoj;Choi, Jae-Ho;Ha, Chang-Sik;Kim, Il
    • Proceedings of the Polymer Society of Korea Conference
    • /
    • 2006.10a
    • /
    • pp.337-337
    • /
    • 2006
  • The synthesis of an octafunctional resorcinarene based initiator for nitroxide mediated polymerization and its ability to yield random star copolymers of styrene and methyl methacrylate is studied. The effect of the initiator conformations towards its activity and the conditions that permit the formation of well-defined star block copolymers is also investigated in detail. The characterization of the initiator and the polymers were carried out by various spectro-analytical techniques. Well-defined random copolymers were obtained with controlled molecular weight and low PDI depending on the monomer feed.

  • PDF

Peptide Synthesis with Polymer Bound Active Ester. I. Rapid Synthesis of Peptides Using Polymer Bound 1-Phenyl-3-methyl-4-oximinopyrazole

  • Lee, Ki-Wha;Lee, Yoon-Sik
    • Bulletin of the Korean Chemical Society
    • /
    • v.10 no.4
    • /
    • pp.331-335
    • /
    • 1989
  • Polymer bound 1-phenyl-3-methyl-4-oximinopyrazoles were prepared through a series of chemical modifications of Merrifield's resin (chloromethylpolystyrene-$1{\%}$ DVB-copolymer). Several polymer active esters of N-blocked amino acids were prepared from the polymer bound 1-phenyl-3-methyl-4-oximinopyrazoles. Polymer bound active esters were found to be highly reactive in N-acylation reaction. The resins were tested for the preparation of several dipeptides. The peptides were obtained in high yields within 10 minutes and the progress of the reactions could be easily followed up by the color change of the resin. The resulting peptides were characterized by NMR and other physical methods.

Polymers and Nanosized Particles: A Happy Marriage?

  • Wegner, Gerhard
    • Proceedings of the Polymer Society of Korea Conference
    • /
    • 2006.10a
    • /
    • pp.7-8
    • /
    • 2006
  • Interest in "nanotechnology" has triggered the question whether new materials can be obtained blending nanosized particles with polymers. This contribution considers modification of polymer properties by nanoscale particles, stabilization of polymer properties by nanoscale particles, stabilization of nanoscale particles against Ostwald-ripening and agglomeration, synthesis of nanoscale particles assisted by polymers and effects of such particles on polymerization mechanisms.

  • PDF

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
    • /
    • v.17 no.12
    • /
    • pp.976-986
    • /
    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

Solid Phase Synthesis of Lysine-exposed Peptide-Polymer Hybrids by Atom Transfer Radical Polymerization (ATRP를 이용한 Lysine 말단기를 가진 펩타이드-고분자 하이브리드 합성)

  • Ha, Eun-Ju;Kim, Mijin;Kim, Jinku;An, Seong Soo A.;Paik, Hyun-Jong
    • Polymer(Korea)
    • /
    • v.38 no.4
    • /
    • pp.550-556
    • /
    • 2014
  • Recently, the peptide(or protein)-polymer hybrid materials (PPs) were sought in many research areas as potential building blocks for assembling nanostructures in selective solvents. In PPs, the facile routes of preparing well-defined peptide-polymer bio-conjugates and their specific activities in various applications are important issues. Our strategy to prepare the peptide-polymer hybrid materials was to combine atom transfer radical polymerization (ATRP) method with solid phase peptide synthesis. The standard solid phase peptide synthesis method was employed to prepare the PYGK (proline-tyrosine-glycine-lysine) peptide. PYGK is an analogue peptide, PFGK (proline-phenylalanine-glycine-lysine), which interacted with plasminogen in fibrinolysis. The peptide and the peptide-initiator were characterized with MALDI-TOF mass spectrometry and $^1H$ NMR spectrometer. The peptide-polymer, pSt-PYGK was characterized by GPC, IR, $^1H$ NMR spectrometer and TLC. Spherical micellar aggregates were determined by TEM and SEM. Current synthesis methodology suggested opportunities to create the well-defined peptide-polymer hybrid materials with specific binding activity.