Applied Sciences

Research

Jump to: Review

9 pages, 4114 KiB

Open AccessArticle

Effect of Particle Orientation and Porosity on Thermal Conductivity of Petroleum Pitch Polymer-Based Carbon Molded Body

by Jong Hoon Cho, Ji Sun Im and Byong Chol Bai

Appl. Sci. 2020, 10(20), 7281; https://doi.org/10.3390/app10207281 - 17 Oct 2020

Cited by 4 | Viewed by 2004

Abstract

The present study was conducted to investigate changes in the thermal conductivity of petroleum pitch-based carbon molded bodies prepared by anisotropic (uniaxial) molding under different molding pressures. The carbon molded bodies were prepared using needle coke and petroleum-based binder pitch polymers (softening point: [...] Read more.

The present study was conducted to investigate changes in the thermal conductivity of petroleum pitch-based carbon molded bodies prepared by anisotropic (uniaxial) molding under different molding pressures. The carbon molded bodies were prepared using needle coke and petroleum-based binder pitch polymers (softening point: 150 ℃). Green blocks prepared under high molding pressure showed a higher particle orientation value up to 16.4 μm. Graphite blocks, prepared by graphitizing the green blocks at 2800 ℃ showed a similar trend. The pores in the carbon molded body were filled with low boiling point substances, generated by the thermal treatment of the binder pitch polymer or air that could not be discharged during the molding procedure. Therefore, when phonons encountered a pore, phonon scattering, rather than phonon transport, occurred, and thus the heat transport from the hot zone to a cold zone became slow. As a result, although the particle orientation was a little higher in the B_10-G sample than in the B_20-G sample (in the error range), the thermal conductivity was higher in the B_20-G sample, which may be because the B_10-G sample had a higher porosity than the B_20-G sample. Full article

(This article belongs to the Special Issue Polymeric Adhesives for Biomedical Applications)

► Show Figures

Figure 1

10 pages, 2776 KiB

Open AccessArticle

The Control of Volume Expansion and Porosity in Carbon Block by Carbon Black (CB) Addition for Increasing Thermal Conductivity

by Min Il Kim, Jong Hoon Cho, Byong Chol Bai and Ji Sun Im

Appl. Sci. 2020, 10(17), 6068; https://doi.org/10.3390/app10176068 - 01 Sep 2020

Cited by 8 | Viewed by 2672

Abstract

The graphite block as a phase change materials (PCMs) was manufactured by graphitization of a carbon block. Carbon blocks were prepared by filler (cokes or graphite) and binder (pitch). The binder-coated filler was thermally treated for carbonization. The gases generated from the evaporation [...] Read more.

The graphite block as a phase change materials (PCMs) was manufactured by graphitization of a carbon block. Carbon blocks were prepared by filler (cokes or graphite) and binder (pitch). The binder-coated filler was thermally treated for carbonization. The gases generated from the evaporation of low molecular weight components in the binder pitch during the carbonization process were not released to the outside. Consequently, porosity and volume expansion were increased in artificial graphite, and thereby the thermal conductivity decreased. In this study, to prevent the decrease of thermal conductivity in the artificial graphite due to the disadvantages of binder pitch, the carbon block was prepared by the addition of carbon black, which can absorb low molecular weight compounds and release the generated gas. The properties of the prepared carbon blocks were analyzed by SEM, TGA, and thermal conductivity. The addition of carbon black (CB) decreased the porosity and volume expansion of the carbon blocks by 38.3% and 65.9%, respectively, and increased the thermal conductivity by 57.1%. The CB absorbed the low molecular weight compounds of binder pitch and induced the release of generated gases during the carbonization process to decrease porosity, and the thermal conductivity of the carbon block increased. Full article

(This article belongs to the Special Issue Polymeric Adhesives for Biomedical Applications)

► Show Figures

Figure 1

Review

Jump to: Research

14 pages, 2810 KiB

Open AccessFeature PaperReview

Adhesive Catechol-Conjugated Hyaluronic Acid for Biomedical Applications: A Mini Review

by Jongho Kim, Chaemyeong Lee and Ji Hyun Ryu

Appl. Sci. 2021, 11(1), 21; https://doi.org/10.3390/app11010021 - 22 Dec 2020

Cited by 30 | Viewed by 6868

Abstract

Recently, catechol-containing polymers have been extensively developed as promising materials for surgical tissue adhesives, wound dressing, drug delivery depots, and tissue engineering scaffolds. Catechol conjugation to the polymer backbone provides adhesive properties to the tissue and does not significantly affect the intrinsic properties [...] Read more.

Recently, catechol-containing polymers have been extensively developed as promising materials for surgical tissue adhesives, wound dressing, drug delivery depots, and tissue engineering scaffolds. Catechol conjugation to the polymer backbone provides adhesive properties to the tissue and does not significantly affect the intrinsic properties of the polymers. An example of a catecholic polymer is catechol-conjugated hyaluronic acid. In general, hyaluronic acid shows excellent biocompatibility and biodegradability; thus, it is used in various medical applications. However, hyaluronic acid alone has poor mechanical and tissue adhesion properties. Catechol modification considerably increases the mechanical and underwater adhesive properties of hyaluronic acid, while maintaining its biocompatibility and biodegradability and enabling its use in several biomedical applications. In this review, we briefly describe the synthesis and characteristics of catechol-modified hyaluronic acid, with a specific focus on catechol-involving reactions. Finally, we discuss the basic concepts and therapeutic effects of catechol-conjugated hyaluronic acid for biomedical applications. Full article

(This article belongs to the Special Issue Polymeric Adhesives for Biomedical Applications)

► Show Figures