• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.29 no.3
• /
• pp.17-25
• /
• 1997

Natural water-soluble polymers such as starch, casein and carboxy methyl cellulose(CMC) have been limited in their uses. However, the proper water retention of coating colors can not be obtained without addition of these polymers. Furthermore, the coating runnability and the physical properties of coated paper were not also satisfied. Therefore, the objective of this study was to synthesize the water retention and flow modifiers which can improve the water retention and flow properties of coating colors. We have measured physical properties of flow modifiers and coating colors which included flow modifiers. The viscosity of flow modifiers was very low at acid pH, and rapidly increased at about pH 7, and gradually reached to equilibrium at alkali pH. Such an increase comes from the molecular weight of flow modifiers and the amount of acrylic and methacrylic acids. The viscosity of coating color containing the flow modifiers was lower than that containing CMC. However, both of them had little difference in water retention. The water-phase viscosity of synthetic modifier containing coating color was either higher or similar compared to that of CMC containing coating color. The high shear viscosity of coating colors was low. Therefore, it can be concluded that the synthetic flow modifiers are very useful for improvement of flow properties and water retentions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.917-917
• /
• 2003

The auditory experiments based on the subjective annoyance responses were undertaken for the establishment of the adverb modifiers of the heavy-weight impact noises. The standard heavy weight impact noise, impact ball noise and adult walking noise were recorded by dummy head at a newly-built apartment and were presented to the subjects by headphones. The levels of the three impact noises were varied from 30 to 60㏈(A) and the subjects matched one of the adverb modifiers to each level of the noise sources. As a result, seven scale modifiers were established and the intervals between the modifiers were found as equal. In addition, it was found that the lower annoyance noise limits for the heavyweight impact, impact ball and walking were 40-45㏈ (L$\sub$I, Fmax. AW), which is 6㏈ lower than in the previous study. The background noise level was as low as 21㏈(A) in the test booth, therefore, the testing conditions need to be concerned for evaluation of floor impact noise.

• Polymer(Korea)
• /
• v.31 no.1
• /
• pp.68-73
• /
• 2007

This study is on the synthesis of reactive polymer modifiers by emulsion polymerization to improve properties of asphalt for paving. Styrene, methyl methacrylate (MMA), isoprene and glycidyl methacrylate (GMA) which has epoxy ring to react with carboxyl group of asphaltene were used to synthesize polymer modifiers. Modifiers with various composition were tested miscibility with asphalt. Modifiers which showed good miscibility with asphalt were investigated by DSC for $T_g$. Existence of epoxy rings and their reaction with asphaltene wore investigated by FTIR. Molecular structures of synthesized modifiers were confirmed by $^1H-NMR$. The synthesized modifiers which showed good miscibility had their $Tg's$ in the range of $37.5{\sim}56.5^{\circ}C$ and had isoprene contents of 30 wt%. They showed good miscibility in the 1 and 2 wt% concentrations, but not in the 3 wt% concentration.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.21-24
• /
• 2003

In general, to enhance physical properties of PET-layered silicate nanocomposites $(P_{et}LSNs)$, it has been well known that the organic modifiers should introduce into gallery regions. However, the organic modifiers in$(P_{et}LSNs)$ may result in thermal decomposition by melt processing at high temperature, and it necessarily lead to deteriorate various physical properties of final products. Therefore, in this study, $(P_{et}LSNs)$ excluding and including organic modifiers were prepared by solution method $(S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom})$ and we (focused on the effects of the organic modifiers in $P_{et}$ LSNs with exfoliation structure on the crystallization behaviors, the optical transparency, the thermal stability and the mechanical property. The absence and existence of organic modifiers in $S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom}$ were investigated by EA and TGA, and nano-structure of silicate layers in $S-P_{et}LSNs$ was evaluated by using WXRD, SAXS and TEM. $S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom}$ were mixed with neat PET as masterbatches by melt method $(M-P_{et}LSNs_{eom} and M-P_{et}LSNs_{iom})$, and also neat PET was mixed with organically modified layered silicates (OLS) by conventional direct melt method $(D-P_{et}LSNs) at 270^{\circ}C$. As results, it was found that $M-P_{et}LSNs_{eom}, M-P_{et}LSNs_{iom}, and D-P_{et}LSN$ showed a exfoliated structure and exhibited faster crystallization rate, better thermal stability and mechanical property than those of neat PET due to the dispersed and detaminated silicate layers in PET matrix. Whereas, considering organic modifiers effect, $M-P_{et}LSNs_{eom} and D-P_{et}LSN$ exhibited slower crystallization rate, poorer optical, thermal and mechanical properties, in comparison to $M-P_{et}LSNs_{eom}> due to the thermal decomposition of organic modifier in $D-P_{et}LSNs$ during melt method.

• Journal of Korea Foundry Society
• /
• v.11 no.4
• /
• pp.314-322
• /
• 1991

In this study, Na, Li, Sb, Sr were added as the modifiers to improve the mechanical proper ties of Al-Si alloys and their effects were compared one another Thermal analysis was carried out to measure the degree of undercooling, that is, the basic mechanism of modifying effect. The measurements of holding time and analyses of components of Al-Si alloys were carried out to compare the fading of the modifiers. Greater degree of undercooling was measured from the modified alloy than the normal alloys. In the modified alloy, the shape of Si was changed into a fine fiber phase or a lamellar phase from the coarse plate phase. There are not modifying effect of Sb below the $1.5^{\circ}C$ /sec of cooling rate. As the cooling rate increases, similar effects appears in the non-modified alloys like the modified alloys. Na and Li were faded in short time and were difficult to control on the melt, but Sb and Sr were scarcely faded for 6 hours of holding and were easy to control on the melt. Na and Sr are the good modifiers in terms of microstructure. Sb is the best modifier, but Na, Li are the inadequate modifiers in terms of fading.

• Archives of Pharmacal Research
• /
• v.23 no.2
• /
• pp.163-166
• /
• 2000

The effects of modifiers such as methanol, water diethylamine in methanol (10 v/v %), and diethylamine in water (10 v/v %) were investigated at three different concentrations (1, 5, and 10 v/v %) of the modifiers in supercritical $CO_2$ (SC-$CO_2$) in order to enhance the supercritical fluid extraction (SFE) efficiency of cephalotaxine from Cephalotaxus wilsoniana Leaves. Among the modifiers employed, methanol basified with diethylamine was found to greatly enhance the extraction efficiency relative to any other modifiers employed. The results suggest that cephalotaxine in plant matrices may be readily changed from SC-$CO_2$-insoluble salt to SC-$CO_2$-soluble free base by basified modifiers. In addition, SC-$CO_2$modified with basified methanol could enhance the extraction efficiency of cephalotaxine more than 30% when compared to the conventional organic solvent extraction.

• Polymer(Korea)
• /
• v.27 no.6
• /
• pp.589-595
• /
• 2003

Unsaturated polyester (UP) nanocomposite with montmorillonite (MMT) which contains different types of organic modifiers far nano-filler have been prepared to investigate the effect of chemical structure of organic modifiers and mixing time of all components on properties of products. It was found that the morphology and various physical properties of UP/MMT nanocomposites were influenced by properties of organic modifiers of MMTs. It was also confirmed that the content of MMT does not significantly affect properties of UP/MMT nanocomposites.

• Tribology and Lubricants
• /
• v.8 no.2
• /
• pp.7-13
• /
• 1992

Wear experiments were conducted using the SRV machine on the lubricated conditions of the several temperature and load. Oil samples were prepared by adding several friction modifiers into both paraffinic base oil and engine oil. Friction and wear characteristics of the oils were determined and are discussed in connection with the friction modifiers contained, the testing temperature and the load applied. From the study, it was found the MoDTC and the MoDTP, added into the engine oil, caused drastic increase in wear and had a tendendy to lose the friction-reducing property on some specific conditions of temperature and/or load, though they had the good property on other conditions. Ashless friction modifiers and dispersed $MoS_2$ investigated showed the good friction-reducing property, but the loads, where they became active, were different.

• Earthquakes and Structures
• /
• v.22 no.1
• /
• pp.83-94
• /
• 2022

In recent years, some studies have identified and quantified factors that can increase or decrease the seismic vulnerability of buildings. These modifier factors, related to the building characteristics and condition, are taken into account in the vulnerability assessment, by means of a numerical estimation resulting from the quantification of these modifiers through vulnerability indexes. However, views have differed on the definition and the quantification of modifiers. In this study, modifier parameters and scores of the Risk-UE Level 1 method are adjusted based on the Algerian seismic code recommendations and the reviews proposed in the literature. The adjusted modifiers and scores are applied to reinforced concrete (RC) buildings in Boumerdes city, in order to assess probable seismic damage. Comparison between estimated damage and observed damage caused by the 2003 Boumerdes earthquake is done, with the objective to (i) validate the model involving influence of the modifier parameters on the seismic vulnerability, and (ii) to define the relationship between modifiers and damage. This research may help planners in improving seismic regulations and reducing vulnerability of existing buildings.

• Elastomers and Composites
• /
• v.57 no.4
• /
• pp.215-221
• /
• 2022

In this study, high-penetration asphalt with low greenhouse gas emissions was used in the asphalt mixing process to reduce the carbon emissions during the reaction due to its capacity to be produced even at low temperatures. In effect, cationic, anionic, and non-ionic dispersants were added and mixed in different feeding ratios, seeking an effective dispersion of the modifiers (SIS, PS, TPEE, and SEBS) into the high-penetration asphalt matrix and forming an asphalt binder with a melting point of 120 ℃. The compatibility of the modifiers and the high-penetration asphalt was examined using SEM and DSC techniques, and the role of NDP-1 as a dispersant was carefully investigated with respect to dissolution time. The analyses showed that: (1) the dispersibility of the asphalt binder is good when the non-ionic dispersant is used; (2) as the concentration of the non-ionic dispersant increases, the dissolution time decreases and the domain size contracts; (3) the ND70-PS has the shortest dissolution time, the lowest agglomeration rate, and a single Tg value.