• Journal of Adhesion and Interface
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• v.19 no.2
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• pp.74-82
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• 2018

Many methods for cross-linking acrylic PSAs have been discussed previously. For high cross-linking density, epoxy functionalized monomer and methyl aziridines as cross-linking agents were used in this study. Additionally, photopolymerization using different UV doses was investigated to synthesize a binder because of its rapid productivity. FT-IR analysis, curing behaviours and adhesion performance were examined for the relationship between UV doses and temperature as curing conditions. According to the results, the gel fraction was over 50% even at $120^{\circ}C$ after UV curing at a dose of $800mJ/cm^2$. On the other hand, while gel fractions of all samples reached approximately 80% only at $180^{\circ}C$ in thermal curing for 1 hour, gel fractions of the samples after thermal curing for 3 hours increased rapidly above $120^{\circ}C$ regardless of UV doses and reached approximately 100% at $180^{\circ}C$. This means that the second cross-linking reaction, esterification, is mainly dependent on the curing temperature.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.355-358
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• 2001

Copolyetheresters are us,ed as an engineering thermoplastic elastomer due to their excellent mechanical properties, thermooxidative stability up to high temperatures and a good resistance against many chemicals. However, fibers made from the copolyetheresters exhibited elastic recovery of about 80-85％ after being stretched 200％, while spandex fibers usually showed 90-95％ recovery. (omitted)

• KSBB Journal
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• v.18 no.2
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• pp.161-164
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• 2003

Oral drug delivery system using pectin gel was developed for colon-targeting of peptide drug. BSA(bovine serum albumin)-loaded pectin and pectin-alginate beads were prepared for drug release properties in vitro. Morphological studies by electron microscopy indicated that pectin and pectin-alginate beads were spherical in shape and approximately 1.0 mm. In order to find the suitable beads, effects of cross-linking agents (calcium chloride or zinc acetate) and drying temperature of beads were investigated. Drug release decreased with concentration of cross-linking agents and drying temperature. For colonic drug delivery from pectin and pectin-alginate beads, pectin degradable enzymes were added at 5 hrs from the beginning of drug release. After addition of enzymes, drug release was suddenly increased against free enzymes. Therefore, pectin and pectin-alginate beads can be promised as useful drug release carriers for colon-targeted delivery.

• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.134-140
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• 2006

The effect of surface treatment of fillers on the mechanical, electrical properties, and tracking performance of silicone rubber insulators have been investigated. For base polymer, $\alpha,\;\omega$) vinyl poly(dimethyl-methylphenyl) siloxane(VPMPS) containing dimethyl siloxane and methylphenyl siloxane was prepared by the equilibrium polymerization. High voltage silicone rubber composites(HVSRC) were prepared from VPMPS, nano-silica, and alumina trihydrate (ATH) modified by various coupling agents. Bound rubber of uncured silicone rubber, cross-linking density of the vulcanizate as well as the mechanical, electrical properties, and tracking performance were measured.

• Elastomers and Composites
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• v.53 no.3
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• pp.136-140
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• 2018

In this study, research was conducted into the manufacture of thermally expandable microspheres for automotive underbody coatings and applications in industry. In particular, the relationship between heat resistance and the ratio of crosslinking agents and initiators in the manufacture of the thermally expandable microspheres was investigated. We focused on the results with various cross-linking agents; our aim was to make the walls of the microspheres thicker to solve the problem of reductions in size caused by shrinkage when the microspheres are heated to $T_m$ ($T_{max}$). We observed the sectional thickness and surface of the samples with thicker walls. The thick thermally expandable microspheres showed reduced shrinkage and excellent stability in spite of prolonged exposure to heat.

• Korea Journal of Cosmetic Science
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• v.2 no.1
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• pp.11-19
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• 2020

The aim of this study is to investigate the effect of various pentapeptides on hair repair depending on the characteristics of comprising amino acids using crosslinking agents in hair. Total ten peptides were synthesized with two kinds of amino acids respectively, of which were previously categorized according to R group of the amino acids contributing to the characteristic of each peptide: STTSS (Ser-Thr-Thr-Ser-Ser), LIILL (Leu-Ile-Ile-Leu-Leu), CMMCC (Cys-Met-Met-Cys-Cys), DEEDD (Asp-Glu-Glu-Asp-Asp), RKKRR (Arg-Lys-Lys-Arg-Arg), TAMRA-STTSS, TAMRA-LIILL, TAMRA-CMMCC, TAMRA-DEEDD, and TAMRA-RKKRR. Pentapeptide alone, or pentapeptides with crosslinking agents such as polymeric carbodiimide (PCI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were treated to chemically damaged hair. Hair diameter and break strength (N = 40/case) were measured to calculate tensile strength of hair for computing hair repair ratio, and fluorescence yields (N = 20/case) were collected for hair treated with TAMRA-peptides. The tensile strength of hair treated with pentapeptides alone, or pentapeptides with cross-linking agents is consistent with the fluorescence yield from the microscope images of the cross-sectioned hair in vision and in numerical values. Pentapeptides consisting of hydrophobic amino acids (LIILL), amino acids with sulfur (CMMCC), and basic amino acids (RKKRR) increased the tensile strength in perm-damaged hair. Pentapeptides with no extra carboxyl/amine groups in R group of amino acids resulted in no significant differences in hair strength and fluorescence yield among hairs treated with alone and with crosslinkers. Pentapeptides with extra carboxyl groups or amine groups enabled further strengthening of hair due to increased bonds within the hair after carbodiimide coupling reaction. The hair repairs of pentapeptides with various amino acid sequences were studied using crosslinking. Depending on the physical characteristics of comprising amino acids, the restoration of damaged hair was observed with tensile strength of hair and fluorescence signals upon cross-sectioned hair in parallel to possibly understand the binding tendency of each pentapeptide within the hair.

• Membrane Journal
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• v.10 no.3
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• pp.148-154
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• 2000

Poly(vinyl alcohol)(PVA)/sulfur-siccinic acid(SSA) membrane performances have been studied for the vapor permeation separation of methyl tort-butyl ether(MTBE)/methanol mixtures with varying operation temperatures, amount of cross-linking agents, and feed compositions. 1'here are two factors, the membrane network and the hydrogen bonding, in the swelling measurements of PVA/SSA membranes. These two factors act interdependently on the membrane swelling. The sulfuric acid group in SSA took an important role in the membrane performance. The cross-linking effect might be more dominant than the hydrogen bonding effect due to the sulfuric acid group at 7% SSA membrane. Hydrogen bonding effect was more important for 5% SSA membrane. In vapor permeation, density or concentration of methanol in vapor feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membrane shows the highest separation factor of 2187 with the flux of 4.84g/$m^2$hr for MTBE/methanol=80/20 mixtures at 3$0^{\circ}C$.

• Membrane Journal
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• v.14 no.1
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• pp.44-52
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• 2004

This paper concerns the development of a cationic polymeric membranes for direct methanol fuel cell. The crosslinked poly(vinyl alcohol) (PVA) membranes with poly(acrylic acid-co-maleic acid) (PAM) and hydroquinonesulfonic acid (HQSA) as the crosslinking agents were prepared according to the amount of crosslinking agents. The resulting membranes were characterized in terms of methanol permeability, proton conductivity, water content and ion exchange capacity. The methanol permeability and proton conductivity increased with increasing PAM content up to 9 wt% and then decreased. This trend is considered the effect of the cross linking rather than the introduction of hydrophilic groups. When the HQSA contents were varied, no interesting increases of proton conductivity, water content and ion exchange capacity were found.

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.320-326
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• 2021

This study investigated the effect of the structure of the crosslinking agent used in contact lens polymerization on the physical properties and drug dissolution of contact lenses.es Contact lenses were manufactured using 0.3% and 3% of 4 types of crosslinking agents, respectively, and ofloxacin was used as the drug. Contact lenses using hydrophilic crosslinking agents improved water contents and wettability, and the more hydrophilic functional groups, the greater the effect. Contact lenses with a high concentration of crosslinking agent had a low concentration of eluted drug and a longer release time. The cross-linking agent structure of contact lenses had an effect on improving the performance of contact lenses and controlling drug release.

• Macromolecular Research
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• v.12 no.6
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• pp.564-572
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• 2004

Modem applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal, or mechanical properties, especially when coupled with locally controlled distribution of the directional response. Such materials are difficult to engineer by conventional methods, but the electric field-aided technology presented herein is able to locally tailor electroactive composites. Applying an electric field to a polymer in its liquid state allows the orientation of chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixtures of pre-polymers and cross-linking agents. Upon curing, a 'created composite' results; it consists of these 'pseudofibers' embedded in a matrix. One can also create oriented composites from embedded spheres, flakes, or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of the field-aided self-assembled composites. The strength and duration of exposure of the electric field control the degree of anisotropy created. Results of electromechanical testing of these modified materials, which are relevant to sensing and actuation applications, are presented. The materials' micro/nanostructures were analyzed using microscopy and X-ray diffraction techniques.