The purpose of this study was to enhance the flame retardancy of cotton fabrics that are largely used for interior textiles including sleepwear, sleeping gear, and curtains by preprocessing untreated cotton fabrics. Mercerization and plasma treatments were used for preprocessing. The variables of mercerization were treatment time (5, 10 min) and temperature (0, 20, $80^{\circ}C$). The variable of plasma is treatment time (5, 10, 15 s). To compare the properties and dynamics between non-treated fibers and preprocessed fibers, SEM, EDAX, weight-gain percentage, transfer characteristics of water, flame retardancy, and a KES-FB system were used. The plasma-treated fabrics exhibited less property change than the mercerization-treated fabrics. The mercerized fabrics had more outstanding features in terms of flame retardancy. The best flame retardancy among the experimental conditions was observed in the condition of processing for 5 min by low-temperature mercerization.

Theoretical equations for quantitative analysis of the effect of fiber swelling on the capillary absorption rate of water-swellable fibers in mixed assemblies were developed. The equation for absorption rate was derived from the Poiseuille equation, whose pressure term was replaced by capillary pressure given as a Laplace equation. The key variables determining the rate were two different capillary sizes of fibrous assembly in dry and wet states. An equation for capillary size was also developed on the basis of the hydraulic radius model. The variables considered in the equation were swelling ratio, cross-sectional shape, fineness, volume density of fiber, and thickness of the assembly. For the experiment, nonwoven webs made of swellable fibers such as cotton, rayon, and superabsorbent fiber blended with hydrophilic polypropylene fiber were prepared. In the experiment, the swelling of the fiber led to a decrease in capillary size, resulting in a decrease in absorption rate. The linear relationship between the rates measured and calculated from the equation shows that the equation could be used to design fibrous assemblies for absorbent products.

Modification of cotton non-woven fabrics through the hydroxyethylation of cellulose using 2-chloroethanol (CE) was carried out in a two-step process of sodium hydroxide pre-treatment and CE reaction in a reaction medium of isopropyl alcohol (IPA) aqueous solution. The effects of sodium hydroxide concentration in the pre-treatment, IPA and CE concentrations, and treatment conditions of the second step were analyzed, along with washing media after treatment on the reacted amounts (add-ons) of CE and property changes of the fabrics. The add-ons of modified samples pre-treated with sodium hydroxide solution of a constant concentration and reacted with CE of different concentrations increased, reached a maximum, and then decreased with increasing CE concentration. The maximum add-on, i.e., the most effective reaction, was obtained when the molar ratio of NaOH/AGU in the pre-treatment and that of CE/AGU in the second treatment was similar. The moisture regain of the modified fabric increased almost linearly with the add-on of CE, indicating increased hydrophilicity. The hydroxyethylated fibers in the modified fabric with high add-ons were damaged severely and stuck together when the modified fabric was washed with water. However, the modified fibers obtained by washing with IPA solutions maintained their fiber shape with increased diameter even at a high add-on of up to 30%. Although the individual fibers might be deteriorated by hydroxyethylation, the tensile strength of the modified non-woven fabric obtained by washing with IPA solution increased compared to the untreated sample, because of the increase in diameter of the fibers, and thus the increased entanglements of the fibers in the fiber assembly of the non-woven fabric. Apparent dye uptake, as measured by the K/S value, of the hydroxyethylated fabric dyed with a reactive dye also increased linearly with increasing add-on amount. The K/S value of a modified fabric with an add-on of 3.5% was four times higher than that of the untreated sample, indicating that the microstructure of the cotton fiber was affected dramatically by hydroxyethylation.

Thermosetting liquid crystalline epoxy is an epoxy polymer that forms a liquid crystalline network structure upon curing. 4,4'-Diglycidyloxybiphenyl with an aromatic rigid-rod part such as a biphenyl group exhibits liquid crystallinity. Biphenol epoxy resin (BP), which is cured by using sulfanilamide, forms a liquid crystalline network by reacting the amine and epoxy ring of sulfanilamide and biphenol. In this experiment, silicon nitride (Si3N4) or aluminum nitride (AlN) was used as a filler. The activation energy required for the decomposition was calculated using the Kissinger method and the Flynn-wall method to confirm the thermal properties of the thermosetting liquid crystalline epoxy with silicon nitride. As a result, the activation energy required for decomposition of the composite increased with increasing silicon nitride content, and it was confirmed that silicon nitride increased the thermal stability of the thermosetting liquid crystalline epoxy.

Coaxial dual electrospun nanofibers were designed for the sustained release of combination drugs. The nanofibers had a sheath-core structure composed of poly(ethylene oxide)/poly(D,L-lactic acid) blend in the sheath and poly(D,L-lactic acid) with drugs in the core. The properties as a carrier in a drug delivery system were analyzed using Fourier transform infrared spectrophotometry, X-ray diffractometry, scanning electron microscopy, and field emission transmission electron microscopy. The release behaviors of the combination drug of methotrexate/probucol were tested. Cumulative release amounts were proportionally increased according to the increased poly(ethylene oxide) ratio in the sheath. The initial release of probucol was approximately half that of methotrexate. In long-term release, the release rate of methotrexate decreased relatively, but that of probucol remained steady. The drug-diffusion milieu in the sheath of the coaxial nanofiber greatly affected the short- and long-term release of the drugs. The possibility of classified release control by components in combination drugs was ascertained.

To improve the acoustic performance of porous fibrous materials, the material thickness should be increased or nonwoven fabrics with a double layered-system should be used as described in the previous paper [2]. In this study, the sound absorption characteristics of nonwoven fabrics with double-layered and triple-layered systems and different density distributions were investigated using an impedance-tube method. In the case of a double-layered system, the results show that a higher face material density increased the sound absorption coefficient in the middle-frequency region. In case of a triple-layered system, when combined with three kinds of materials, under the same condition of face material, a greater density difference with nonwoven in the back resulted in an increased sound absorption coefficient in the middle-frequency region.

Artificial leather has been developed as a substitute for natural leather because of the high demand for high-quality products in automobile interiors and the living leather market. Artificial leather is generally manufactured using microfiber nonwoven fabric. In this study, we analyzed the weight loss behavior of PET/co-PET ultra-microfiber by alkali hydrolysis according to NaOH concentration (10-30% o.w.f.), treatment time (5-60 mins), and treatment temperature ($80-120^{\circ}C$) by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), and mechanical analysis. We found that the optimum condition for alkali hydrolysis is 25% NaOH o.w.f. aqueous solution with a treatment time of 30 min at $100^{\circ}C$.

The interfacial adhesion property between aramid and rubber is a very important factor when aramid is applied as a reinforcing material for automotive heat-resistant hoses. This study examined the improvement of interfacial adhesion between aramid and rubber by applying plasma and a coupling agent to m-aramid. The SEM, AFM, and XPS characteristics were examined based on the plasma treatment conditions. The plasmatreated aramid was then treated with the coupling agent to analyze the interfacial adhesion with silicon, fluorine, and hybrid rubber. The plasma treatment resulted in an increase in the surface roughness of the aramid, and the mechanical properties of the aramid fabric decreased because the surface of the aramid was fibrillated. Moreover, the interfacial adhesion between aramid and rubber increased by 16.2% with the use of the coupling agent and plasma treatment.

In this study, hybrid composites for a door impact beam were manufactured through a stacking sequence and design conditions. Non-crimped fabrics, epoxy resin for prepreg compression molding (PCM), hardener, and reinforcement such as p-Aramid and high strength polypropylene (PP) were used in manufacturing the hybrid composites. Curing behaviors of the PCM epoxy resin were confirmed by analytical methods such as dynamic DSC and FT-IR spectroscopy. The storage modulus, loss modulus, and damping behaviors of these hybrid composites were analyzed by dynamic mechanical analyses. Mechanical properties of the hybrid composites, such as tensile strength, flexure strength, compressive strength, and interlaminar shear strength (ILSS), were measured with a universal testing machine. Dynamic drop impact tests were conducted to measure the impact resistances of the hybrid composites on the stacking sequence. After the drop impact test, fracture shapes of the specimens were observed using a stereoscopic microscope. Based on the fracture shapes developed during the drop impact test, it was concluded that the specimens reinforced either by p-Aramid or PP effectively resisted impact transformations.

In this study, highly releasable phenol films were prepared for simplification of the phenolic composite molding process. Thermoplastic polyvinyl butyral (PVB) was added to the phenolic resin to give the phenol film a high releasability by the hot-melt bonding process. The thermal properties of the prepared phenolic film were analyzed with DSC and TGA, and both degree of cure and active energy were calculated using the DSC data. The rheological properties of the film were analyzed using a rheometer, and the tackiness of the film was assessed by the probe tack test according to the heat treatment time. Curing reaction of the phenolic film occurred at a temperature $20^{\circ}C$ higher than that of the phenolic resin, and its activation energy was also considerably higher. This can be attributed to the gelation caused by the hydrogen bonding between the PVB and phenolic monomer. Thus, the curing of the film is delayed by gelation.