• Title, Summary, Keyword: cross-linking agent

Search Result 123, Processing Time 0.043 seconds

Encapsulation of Nanomaterials within Intermediary Layer Cross-linked Micelles Using a Photo-Cross-linking Agent

  • Kim, Jin-Sook;Youk, Ji-Ho
    • Macromolecular Research
    • /
    • v.17 no.11
    • /
    • pp.926-930
    • /
    • 2009
  • A new method for encapsulating nanomaterials within intermediary layer cross-linked (ILCL) polymeric micelles using a bifunctional photo-cross-linking agent was developed. For ILCL polymeric micelles, an amphiphilic triblock copolymer of poly(ethylene glycol)-b-poly(2-hydroxyethyl methacrylate)-b-poly(methyl methacrylate) (PEG-PHEMA-PMMA) was synthesized via consecutive atom transfer radical polymerization (ATRP), Di(4-hydroxyl benzophenone) dodecanedioate (BPD) was used as a bifunctional photo-cross-linking agent. The PMMA-tethered Au nanoparticles and BPD, or pyrene and BPD were encapsulated in the PEG-PHEMA-PMMA micelles, and their intermediary layers were photo-cross-linked by UV irradiation for 1 h. The HEMA units donated labile hydrogens to the excited-state benzophenone groups in BPD, and they were subsequently cross-linked by BPD through radical-radical combination. The spherical structures of the PEG-PHEMA-PMMA micelles containing the Au nanoparticles or pyrene were unaffected by the photo-cross-linking process.

Effect of Plasticizer and Cross-Linking Agent on the Physical Properties of Protein Films

  • Lee, Myoung-Suk;Lee, Se-Hee;Ma, Yu-Hyun;Park, Sang-Kyu;Bae, Dong-Ho;Ha, Sang-Do;Song, Kyung-Bin
    • Preventive Nutrition and Food Science
    • /
    • v.10 no.1
    • /
    • pp.88-91
    • /
    • 2005
  • To improve the physical properties of protein films, various plasticizers and cross-linking agents were used in the preparation of the films. For zein film, 3% polypropylene glycol with 3% glycerol was the best plasticizer, while 2.5% glycerol was the most suitable for soy protein isolate (SPI) film in terms of tensile strength (TS), % elongation, and water vapor permeability (WVP). Formaldehyde, glutaraldehyde, glyoxal, and cinnamaldehyde as cross-linking agents of protein films were used to further improve the physical properties of the films. All aldehydes used as cross-linking agent in this study improved TS of zein and SPI films. In particular, cinnamaldehyde was the best cross-linking agent due to its safety in foods. These results suggest that appropriate use of plasticizer and cross-linking agent like cinnamaldehyde should improve the physical properties of protein films for use in food packaging.

Development of Specific organ targeting drug delivery system II : Physico-pharaceutical study on the crose-linked albumin microspheres containing cytarabine

  • Kim, Chong-Kook;Lee, Jin-Kyu;Lah, Woon-Lyong
    • Archives of Pharmacal Research
    • /
    • v.9 no.1
    • /
    • pp.39-43
    • /
    • 1986
  • Bovine serum albumin microspheres containing cytarabine were prepared using cross-linking agent, formaldehyde. The shape and the size distribution of them were observed. The shape of them was spherical and the susrface was compact and smooth. The size distribution of them was affected by dispersion forces during emulsfication. The release of cytarabine from albumin microspheres was dependent upon cross-linking time, amount of cross-linking agent and drug/albumin ratio. However, the difference of drug release by the dispersion forces was not great. After release test, the shape of albumin microspheres was nonspherical and the albumin matrix seemed to be a little relaxed. The degradation tests of albumin microspheres by the proteolytic enzyme showed that albumin microspheres were progressively digested according to the cross-linking degree.

  • PDF

Synthesis and Characterization of Crosslinked Polyacrylates Containing Cubane and Silyl Groups

  • Mahkam Mehrdad;Assadi Mohammad;Mohammadzadeh Rana
    • Macromolecular Research
    • /
    • v.14 no.1
    • /
    • pp.34-37
    • /
    • 2006
  • Attaching the organosilyl groups to macromolecular chains of 2-hydroxyethyl methacrylate (HEMA) should lead to important modifications of polymer properties. t-$BuMe_{2}Si$ and cubane-l, 4-dicarboxylic acid (CDA) were covalently linked with 2-hydroxyethyl methacrylate (HEMA). The silyl-linked HEMA is abbreviated as TSMA, while cubane-l ,4-dicarboxylic acid (CDA) linked to two HEMA groups is the cross-linking agent (CA). Free radical cross-linking copolymerization of TSMA and HEMA with various ratios of CA as the cross-linking agent was carried out at 60-70$^{circ}C$. The compositions of the cross-linked, three-dimensional polymers were determined by FTIR spectroscopy. The glass transition temperature ($T_{g}$) of the network polymers was determined calorimetrically. The $T_{g}$ of the network polymer increased with increasing cross-linking degree.

Effect of cross-linking agents on the properties of copolyetherester elastomer(II) (코폴리에테르에스테르 고무 탄성체의 물성에 미치는 가교제의 효과(II))

  • Jang, Young-Joo;Kim, Hae-Young;Baik, Doo-Hyun
    • Proceedings of the Korean Fiber Society Conference
    • /
    • /
    • pp.301-304
    • /
    • 2002
  • In the prior work,$\^$l)/ we introduced several chemical cross-linking agents in order to improve elastic recovery of copolyetheresters, but we are confronted by two difficulties. The first is that cross-linking agents interfere with crystal growth which acts as a physical interlocking. The second is that strain at breaking decreases with the amount of cross-linking agent. It is considered that the chemical interlocking parts couldn't be deformed like crystalline phase. (omitted)

  • PDF

Preparation and Characterization of Chitosan Membranes Cross-linked Using Poly(2,6-dimethyl-1,4-phenylene oxide) Polymer and Chitosan (Poly(2,6-dimethyl-1,4-phenylene oxide) 고분자와 키토산을 이용한 가교막 제조 및 특성평가)

  • Son, Tae Yang;Ko, Tae Ho;Jung, Ji Hye;Hong, Jun Ui;Nam, Sang Yong
    • Membrane Journal
    • /
    • v.28 no.3
    • /
    • pp.205-213
    • /
    • 2018
  • In this study, cross-linked membrane were successfully prepared by using brominated PPO (Br-PPO) as the main polymer chain. Chitosan and quaternary ammonium modified chitosan (QA-chitosan) was used as the cross linking agents. The cross linked membranes were post-functionalized by using trimethylamine solution. The degree of cross linking was also controlled by varying the ratio of cross linking agent. The applicability of the cross-linked membrane (A-PPO + chitosan, A-PPO + QA-chitosan) as ion exchange membranes was verified through various characterization techniques. The cross-linked membrane using QA-chitosan as cross linking agent was found to be better in performance than the membrane using pristine chitosan cross linking agent. As the percentage of QA-chitosan increased, the ion exchange capacity from 1.18 meq/g to 1.53 meq/g and water uptake from 21.6% to 42.2% was improved.

Analysis of Starch Properties and Application of Cross-linking Agent for Improving Adhesive Strength of Corrugated Board (골판지 접착 강도 향상을 위한 전분 특성 분석과 가교제의 적용)

  • Jung, Chul-Hun;Park, Jong-Moon;Lee, Jin-Ho
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.44 no.2
    • /
    • pp.67-73
    • /
    • 2012
  • Structural stability and shock absorption are important properties for corrugated board. In order to maintain structural stability, adhesive properties between top/bottom liners and corrugated medium are not only essential but also important for productivity and product quality. Borax has been an essential ingredient in corrugating adhesive solution. Borax increases viscosity, bonding between starchs and green adhesive bond. The objective of this research is to improving adhesive strength and viscosity stability by adding cross-linking agent instead of borax. Rheology and penetration of main starch gelatinization slurry were affected by borax addition level. Borax increased viscosity and decreased viscosity stability, while cross-linking additives increased viscosity stability and adhesive strength by anchoring effect.

Insulation properties of XLPE by adding Cross-linking Agent and Cross-linking Agent and Cross-linking Co-agent (가교제와 가교조제 함량에 따른 XLPE의 절연특성)

  • 김규식;임기조;손원근;박수길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.715-718
    • /
    • 2000
  • We studied about electrical, chemical and mechanical characteristics of XLPE by dicumyl peroxide(DCP) and trimethylolpropane triacrylate(TMPTA) content ratio. DCP content was changed from 1.0 to 2.Sphr increasing 0.5phr. TMPTA content was changed 0.5 to 1.5phr increasing 0.5phr. Thermal analysis (DSC) was carried out in order to observe tendency of Tg according to DCP and TMPTA content. Tensile strength was measured in order to observe mechanical strength. In experimental results, content DCP 2.0phr and TMPTA 1.0phr has highest breakdown strength. Content DCP 2.0phr and TMPTA 0.5phr has lowest dielectric constant. Tendency of Tg did not affected by DCP and TMPTA content. Breakdown strength and Specific inductive capacity was measured.

  • PDF

Preparation and Characteristics of High Voltage Liquid Silicone Rubber by Modified Cross-linking Agent

  • Jung, Se-Young;Kim, Byung-Kyu
    • Transactions on Electrical and Electronic Materials
    • /
    • v.10 no.1
    • /
    • pp.9-15
    • /
    • 2009
  • There is a growing demand for a high voltage silicone rubber composite with high mechanical property and high electrical property. The effect of modified cross-linking agent on the mechanical, electrical properties, and short-circuit test performance of silicone rubber insulators have been investigated. To use base polymer, the various silicone polymers were prepared by the equilibrium polymerization. Aluminum trihydrate surface was treated by vinyl silane. Liquid silicone rubber nanocomposite was prepared from the compounding of VPMPS, HPDMS, catalyst, and alumina trihydrate modified with 1,3,5-trivinyl-l,3,5-trimethylcyclotrisiloxane. The mechanical property and electrical property for insulation materials were measured, indicating the high tensile strength and the good short-circuit property.

Dexamethasone Release from Glutaraldehyde Cross-Linked Chitosan Microspheres: In Vitro/In Vivo Studies and Non-Clinical Parameters Response in Rat Arthritic Model

  • Dhanaraju, Magharla Dasaratha;Elizabeth, Sheela;Poovi, Ganesan
    • Journal of Pharmaceutical Investigation
    • /
    • v.41 no.5
    • /
    • pp.279-288
    • /
    • 2011
  • The Dexamethasone (DEX) loaded chitosan microspheres were prepared by thermal denaturation and chemical cross-linking method using a dierent concentration of glutaraldehyde as chemical cross-linking agent. The prepared microspheres were evaluated for the percentage of Drug Loading (DL), Encapsulation Efficiency (EE) and surface morphology by Scanning Electron Microscopy (SEM). DL and EE were found to be maximum range of 10.0 to 10.79 % and 58.19 to 64.73 % respectively. The SEM Photographs of the resultant microspheres exhibited fairly smooth surfaces and predominantly spherical in appearance. In addition, Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) shown that there was no interaction between the drug and polymer. In vitro and in vivo release studies revealed that the release of dexamethasone was sustained and extended up to 63 days and effectively controlled by the extent of cross-linking agent. Non-clinical parameters such as paw volume, hematological parameters like Erythrocyte Sedimentation Rate (ESR), Paced Cell Volume (PCV), Total Leucocytes Count (TLC), Hemoglobin (Hb), Differential Cell Count (DCC) were investigated in Fruend's Complete Adjuvant (FCA) induced arthritic rats. Radiology and histopathological studies were also performed in order to evaluate the therapeutic efficacy of the DEX-loaded microspheres in extenuating the rat arthritic model.