Polypropylene (PP) composites are widely employed in automotive interior materials but are prone to surface scratches that adversely affect gloss. This study investigated the impact of crystallographic properties on the scratch resistance of PP composites with the incorporation of nucleating agents. The effects were comprehensively analyzed; scratch and mechanical properties are analyzed using techniques such as differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), confocal laser microscopy, glossmetry, and mechanical testing. Isothermal crystallization experiments revealed that beta nucleating agents delayed both crystallization initiation and termination. Avrami constant, n falls within the range of 3 < n < 4, indicating three-dimensional crystal growth. Consequently, the application of beta nucleating agents significantly minimizes changed in gloss properties following scratches, attributed to reduced surface roughness alterations. This study underscored the pivotal role of nucleating agents in enhancing the scratch resistance and preserving the surface quality of PP composites for automotive interiors.

This study focused on manufacturing efficient automobile sound-absorbing materials through alkaline treatment and dimple processing of recycled polyethylene terephthalate (rPET) nonwoven fabric. The rPET nonwoven fabric was produced with a sound-absorbing material through compression molding. It was improved through the development of porous sound-absorbing materials through alkaline treatment and resonant sound-absorbing materials through dimple processing. As a result of morphological analysis, alkaline treatment showed that pore size and air permeability increased according to temperature and concentration increase conditions. On the other hand, dimple processing caused a decrease in air permeability and a decrease in pores due to yarn fusion, and as the dimple diameter increased, the sound-absorbing coefficient increased in the 5000 Hz band. Finally, it was judged that effective sound absorption performance would be improved through a simple process through alkaline treatment and dimple processing, and thus there would be applicability in various industrial fields.

The aging behavior of nitrile butadiene rubber (NBR) was studied by performing a thermo-oxidatively accelerated-aging test in a closed oxygen-rich atmosphere. The oxygen-consumption rates of the aged NBR were measured and correlated with changes in the chemical and physical properties of the rubber. Changes in the morphological, chemical, and mechanical properties of the aged NBR were examined via scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and tensile tests. Morphological observations revealed that the aging conditions severely degraded the surface of the NBR, and additive particles migrated from the inner part of the NBR to the surface at temperatures above 60 °C. XPS indicated that the surface or cross-sectional face of the NBR was oxidized heterogeneously after the thermo-oxidative aging. The oxidation induced cross-linking, which caused the tensile modulus of the NBR to increase with an increase in the aging time and temperature; tensile elongation tended to decrease. The results of the thermo-oxidative accelerated-aging test were analyzed based on the Arrhenius model, using data of the oxygen-consumption rates. Finally, the activation energy of the degradation process was determined and the lifetime of the NBR was calculated. The lifetime of NBR conserved at 25 °C was estimated to be 11.12 years at a 40 % oxygen-consumption rate.

Recently, microwaves have been used for desulfurization because they can selectively dissociate C-S and S-S bonds present in vulcanized rubber. In this study, we investigated the changes in structural and physical properties of EPDM (Ethylene propylene diene monomer) rubber by irradiating it with microwaves for different durations. The surface chemical composition of the irradiated EPDM rubber was analyzed by FT-IR, XPS, and EDS analyses. It was confirmed by XPS that C-S and S-S S2p peak heights greatly decreased when microwave irradiation was performed for more than 5 min. In the EPDM sample irradiated with microwaves for 10 min, the number of S-O bonds significantly increased owing to oxidation. As the microwave irradiation time was increased, SEM images showed cracks and voids on the EPDM surface. The 20% decomposition temperature of the EPDM rubber sample was investigated by TGA, and it was found to be about 435.23 degrees C for the EPDM rubber irradiated for 10 min. The crosslinking density of the EPDM rubber was determined by measuring the degree of swelling, and the highest value was observed for the E5 sample irradiated for 5 min. The degree of swelling of the E10 sample irradiated for 10 min was lower than that of the E5 sample. These results indicate that when irradiated with microwaves for more than a certain time, desulfurization occurs and the side chain of the EPDM rubber dissociates and forms additional crosslinking bonds.

Meta-aramid fabrics were deposited with aluminum to examine the effects of aluminum deposition on the functional properties of meta-aramid fabrics. Various functional properties of the aluminum deposited meta-aramid fabrics were assessed with sputtering processing parameters such as chamber pressure and sputtering power. SEM-EDX was utilized to investigate surface morphology and compositions of the deposited meta-aramid fabrics. The optical, thermal, electric, and abrasive properties of the deposited meta-aramid fabrics were measured by color reader, KES-F7 thermo-Lab 2 system, milliohm meter, and abrasion testing machine. The obtained results indicated the optical, thermal, electric, and abrasive properties of the deposited meta-aramid fabrics were influenced clearly by deposition processing parameters. The light reflectance, thermal conductivity, electric resistance, and abrasion strength of the aluminum deposited meta-aramid fabrics were shown to be a maximum at a chamber pressure and a sputtering pressure, and the optimum deposit condition could be established.

The effects of e-beam irradiation on water-repellency and washing durability of water-repellent finished chemically-recycled PET(CR-PET) fabrics were investigated. As results, more doses of e-beam irradiation damaged the fabric surface more severely. It was thought because the high densed energy was formed, where the more e-beam was converged. The contact angle measurement showed that as the dose of e-beam irradiation increased, water wettability of the CR-PET fabric increased slightly. It was thought to be due that the surface etching by e-beam irradiation let water droplet permeate into the fabric surface better. The concentration of the water-repellent finishing agent was more important factor than curing temperature as finishing parameter. It was considered because the water-repellent finishing agent used in this study got to cure sufficiently at low temperature. Consequently, e-beam irradiation improved the washing durability of water-repellent finishing on the CR-PET fabrics.

Nonwovens have been proposed as a sound absorber in applications of home interior textile industry for effective noise control. Honeycomb cell blind textiles have been increasingly used in window covering for noise reduction. In this study, the effect of struc- tural parameters of honeycomb cell-structured spunbond nonwoven on the sound absorption property was investigated. Spunbond nonwovens with various thicknesses, areal densities, and porosities were used, and they were joined in the form of a honeycomb cell structure with various cell widths and cell layering. The sound absorption property of the nonwoven improved with increasing thickness. The porosity of the nonwoven was shown to be proportional to the noise reduction coefficient (NRC). An increased air gap between two layers of the nonwoven shifted the maximum sound absorption coefficient toward a lower frequency range. The honeycomb cell structure was confirmed to contrib- ute to an improvement of the sound absorption property. Layering of the honeycomb cell structure was also shown to be a critical factor in controlling the sound absorption prop- erty of the nonwoven.

To investigate the aluminum deposition on the chemically recycled polyethylene terephthalate (CR-PET) fabrics by DC magnetron sputtering, effects of sputtering parameters (sputtering power and deposit time) on the properties of the Al deposited CR-PET fabric were examined. The variations in the properties such as wettability, optical and thermal insulation property of the CR-PET fabric sputtered under various sputtering parameters were discussed. Wettability of the Al deposited CR-PET fabrics decreased with an increase of sputtering power and deposit time, and then they leveled off above a certain condition. The light reflectance of the Al deposited CR-PET fabrics showed a maximum point with proper sputtering power and deposition time. The thermal insulation property of the Al deposited CR-PET fabrics improved with sputtering power and deposit time.

This study investigates the dye ability and fastness of jacquard fabric for blind using low-melting flame retardant polyester. Two types of jacquard fabric were prepared with a low-melting flame retardant polyester and regular polyester. The low-melting flame retardant polyester has a sheath and a core. The core consists of flame retardant polyester and the sheath consists of low-melting polyester. Disperse red 50 (DR 50), disperse blue 56 (DB 56), disperse yellow (DY 54) of E-type dyes and disperse 92 (DR 92), disperse blue60 (DB 60), disperse yellow (DY 79) of S-type dyes were used and dyed on jacquard fabrics dependent of dyeing temperature and time. The fastness, dye exhaustion, color strength (K/S value), and colorimetric properties of jacquard fabrics were evaluated. The dye ability of S-type dyes were higher than E-type dyes. The experiments indicated optimum dye ability that the dyeing temperature was 110℃ for E-type dyes and 120℃ for S-type dyes for 40 minutes. The fastness to washing and light were excellent at a 4-5 grade.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Juniperus Chinensis heartwood has been known to have an excellent antibacterial and anti-inflammatory effect. This study examined the potential of the methanol extract of the Juniperus Chinensis heartwood as a natural dye with an efficacy for the treatment of atopic dermatitis. In an attempt to examine the effect of the Juniperus Chinensis heartwood extract, a skin lesion such as that of AD was induced in the NC/Nga AD mice model by topical administration. DNCB (2.4-dinitrochlorobenzene) was used to induce such AD-like skin lesions. The efficacy of the Juniperus Chinensis heartwood extract in the NC/Nga mice model was assessed by severity of skin lesion (NC mouse score), change in organ weight, serum IgE level, change in epidermal thickness, and mast cell count. The Juniperus Chinensis heartwood extract improved such skin lesions in these NC/Nga mice, and decreased spleen weight and serum IgE level. The results of histopathologic examination revealed that the treatment with the Juniperus Chinensis heartwood extract decreased epidermal thickness and mast cell count. In conclusion, the suppressive effect of local administration of the Juniperus Chinensis heartwood extract verified its potential for application as a natural dye with an efficacy of treatment for atopic dermatitis.

The amphiphilic copolymer by the conjugation of biocompatible chitosan and antioxidant lipoic acid was studied as a drug delivery carrier. The amphiphilic copolymer was self-assembled to form nanoparticles in the aqueous solution. 5-Fluorouracil widely used as an anticancer drug was encapsulated inside the nanoparticles by a solid dispersion method. The degree of branching of lipoic acid on chitosan was controlled to obtain the optimal condition for the drug delivery carrier. The sizes of nanoparticles were about 250 nm by the dynamic light scattering. The encapsulation efficiency of nanoparticles were about 10%. The copolymer with 42% degree of branching showed the best performance as a drug delivery carrier.