• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.49-58
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• 2011

The maximum drying shrinkage velocity was proposed to verify bulk and stiffness improvement mechanism during drying according to papermaking parameters. It was based on the wet-web shrinkage behavior without the restraint of wet-web during drying, so intact drying impact could be measured. Bulking agent reduced the drying shrinkage and the maximum drying shrinkage velocity, so paper bulk increased and paper strength decreased. When adding cationic starch to stock with the bulking agent for strengthening, the bulk was increased further with additional decreasing of the drying shrinkage and the maximum drying shrinkage velocity. Paper strength also increased except tensile stiffness index with decreasing the drying shrinkage and the maximum drying shrinkage velocity. When using additional strength additives for strengthening of fiber interfaces extended by bulking agent and cationic starch, amphoteric strength additive increased paper stiffness without loss of paper bulk. It was considered that the added amphoteric strength additives were cross-linked to the stretched cationic starch and this cross-linking increased elasticity of fiber-polymer-fiber interfaces without changing the drying behavior. Paper bulk could be increased with decreasing the maximum drying shrinkage velocity. The drying shrinkage of paper also could be controlled by fiber-to-fiber bonding interfaces by the bulking agent. In this case, paper strength including stiffness was decreased by reducing fiber-to-fiber bonding but it could be improved by strengthening fiber-to-fiber interfaces with polymer complex without loss of bulk.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.816-821
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• 2003

This paper deals with a reduction in the setting shrikage of polymer concrete using bentonite as shrinkage reducing agent. This study with polymer concrete using unsaturated polyester(UP) based on recycled PET waste was performed to verify the effect of various shrinkage reducing agent contents and the types of filler which are fly ash and $CaCo_3$. Setting stress induced by setting shrinkage was investigated in temrs of mechanical and chemical combination.

• Polymer(Korea)
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• v.30 no.5
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• pp.407-411
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• 2006

The SiC-based ceramic nanopatterns were prepared by placing polydimethylsiloxane (PDMS) mold from DVD master on the spincoated polyvinylsilaeane (PVS) or allylhydridopolycaybosilane (AHPCS) as ceramic precursors to fabricate line pattern via UV-nanoimprint lithography (UV-NIL), and subsequent pyrolysis at $800^{\circ}C$ in nitrogen atmosphere. As the dimensional change of polymeric and ceramic patterns was comparatively investigated by AFM and SEM, the shrinkage in height was 38.5% for PVS derived pattern and 24.1% for AHPCS derived pattern while the shrinkage in width was 18.8% for PVS and 16.7% for AHPCS. It indicates that higher ceramic yield of the ceramic precursor resulted in less shrinkage, and the strong adhesion between the substrate and the pattern caused anisotropic shrinkage. This preliminary work suggests that NIL is a promissing route for fabricating ceramic MEMS devices, with the development on the shrinkage control.

• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.443-452
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• 2008

Shrinkage crack is a major concern for cement materials, especially for flat structures such as Korean On-Dol floor system, flooring for garages, and wall. One of the methods to reduce the adverse effects of shrinkage cracking is to reinforce cement materials with shot randomly distributed fibers. The efficiency of inorganic fibrous material to arresting cracks in cementitious composites was studied. Cement materials reinforced with five different qualities of inorganic fibrous material were tested. Contents of inorganic fibrous material were 1.0 kg, 1.5 kg, 2.0 kg, 2.5 kg, 3.0 kg by weight of cement mortar and C : S types of cement mortar were 1:3 and 1:4. W/C were 60% and 80%. Cement mortar of inorganic fibrous material reinforcement showed an ability to reduce the crack width and crack length significantly as compared to unreinforced cement mortar. $40%{\sim}60%$ drop in shrinkage crack of 1:4 cement mortar with 1.5 kg over was observed.

• Elastomers and Composites
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• v.42 no.4
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• pp.201-208
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• 2007

In this study, the thermal shrinkage and expansion stresses of filled NR and SBR vulcanizates were measured to investigate the dimensional stability at an elevated temperature. When a rubber sample was held at constant pre-strain, a thermal stress developed upon heating due to the entropic consideration. The peak shrinkage stress of carbon black or silica filled NR decreased with increasing filler content. In SBR compounds, however, the peak shrinkage stress of SBR with 30 phr filler content was higher than that of unfilled compounds. The expansion stress of carbon black filled NR was changed little, but that of filled SBR increased with increasing the filler content. The peak expansion stress of silica filled NR and SBR vulcanizates increased with increasing silica content.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.151-154
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• 2006

It is generally referred that life cycle of concrete construction is depend on whether durability of concrete is obtained or not. Nevertheless, it has not been yet applied that new material and technology to improve durability of concrete such as seaside concrete construction. In this study, chemical agent which is capable of improving durability added to 2 types seaside concrete mixs and evaluated engineering properties such as slump, air content, setting time and compressive strength. Besides shrinkage crack with an restraint condition and chloride ion penetration tests were executed to measure resistance of concrete added chemical agent and then compared non-added. It was appeared that engineering properties and resistant for chlorides was possible to improved. But resistant for shrinkage crack was not noticeable improvement than non-added. Therefore it is necessary that more consideration and following study to improve durability aspect to shrinkage crack and chlorides resistant.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.853-856
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• 2005

A low water/cement ratio leads to autogenous shrinkage of cement paste at an early age. This autogenous shrinkage is related to the change of relative humidity in the pore structure that is formed during the hydration process. The relationship between autogenous shrinkage and relative humidity change are relatively well defined today, but the effects of temperature on autogenous shrinkage, relative humidity, and pore structures have been studied less systematically. This study focused on correlating alterations of these properties of cement paste hydrated at constant temperatures of 20, 40, and $60^{\circ}C$. The test results clearly indicate that increasing curing temperature resulted in increased porosity, particularly for pores between 5 to 50 nm as measured by MIP, and increased autogenous shrinkages, as a consequence of a reduction of relative humidity at early ages.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.163-164
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• 2020

The purpose of this study was to evaluate the shrinkage properties of a tile reinforced with epoxy resin, which has the advantages of high adhesion and low shrinkage, and causes a hardening reaction by chemical bonding with cement mortar. As a result, since the epoxy resin adhesive suppresses the moisture evaporation of the mortar, the drying shrinkage of the mortar itself is reduced, accordingly, the shrinkage of the tile itself is greatly reduced, and it is thought that it is possible to prevent a decrease in adhesion due to shear stress.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.561-569
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• 2016

Concrete is cheap, easy to deal with, and the quality is satisfactory. Also, it is one of the easiest materials to get because chemical composition of cement is similar to chemical composition of surface. On the other hand, it is so vulnerable to transform because of weak binding capacity and low binding energy that it produces cracks. Cracks decline durability, usability, safety of structures and damage exterior. In order to decline drying shrinkage crack, this study used shrinkage reducing typed Superplasticizer, which is combination of and water-reducing agent for convenience, different with existing study using AE agent, water-reducing agent, shrinkage reducing agent,. Considering SRS field application possibility, this study planned to mix concrete and mortar generally used in ready-mixed concrete company and did basic experiment depending on a change of SRS content ratio and admixture. Based on the experiment result. It is judged that SRS admixture 2% is proper ratio when Given the intensity and length change. Also mass combination will conduct follow-up studies.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3252-3258
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• 2010

In this study, the effects of the various parameters of spinning and drawing processes on the properties of polyester full drawn yarn (FDY) prepared by steam processing during high-speed spinning were investigated using several techniques. The wet shrinkage ratio of the FDY was able to be manipulated by controlling the temperature and draw ratio. The FDY made using the steam high speed spinning technique exhibited identical properties (such as tenacity, elongation, and wet shrinkage ratio) to that of regular FDY, made using the spin-draw process. FDY prepared using the steam process during high-speed spinning showed excellent dyeability. The dye pick-up of the polyester yarn spun at high-speed spinning was found to be improved when dyed under an atmospheric pressure of $100^{\circ}C$. This result was the same as regular FDY dyed under a high pressure of $130^{\circ}C$.