• Bulletin of the Korean Chemical Society
• /
• 제27권11호
• /
• pp.1819-1824
• /
• 2006

The general objective of the present study was to investigate the potential application of the UV spectroscopic method for determination of the polymeric additives present in papermaking fibrous stock solutions. The study also intended to establish the surface-chemical retention model associated with the adsorption kinetics of additives on fiber surfaces. Polyamide epichlorohydrin (PAE) wet strength resin and imidazolinium quaternary (IZQ) softening agents were selected to evaluate the analytical method. Concentrations of PAE and IZQ in solution were proportional to the UV absorption at 314 and 400 nm, respectively. The time-dependent behavior of polymeric additives obeyed a mono-molecular layer adsorption as characterized in Langmuir-type expression. The kinetic modeling for polymeric adsorption on fiber surfaces was based on a concept that polymeric adsorption on fiber surfaces has two distinguishable stages including initial dynamic adsorption phase and the final near-equilibrium state. The simulation model predicted not only the real-time additive adsorption behavior for polymeric additives at high accuracy once the kinetic parameters were determined, but showed a good agreement with the experimental data. The spectroscopic method examined on the PAE and IZQ adsorption study could potentially be considered as an effective tool for the wet-end retention control as applied to the paper industry.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
• /
• pp.137-140
• /
• 2006

This paper describes a technique combining chemometrics with UV spectroscopy for the determination of the concentra tions of two tissue additives (i.e., wet strength and softening agents) in a cellulose fiber containing solution. In single as ent solutions, the concentration of the additive can be measured by UV spectroscopy at the wavelength where the species having absorption. For a binary (i.e., containing two additives) solution system, the spectral characterization is very complicated. However, if aided by a chemometrical calibration technique, each additive in the binary solution can be quantified simultaneously. The present method is very rapid and simple, it can easily perform a continuous measurement in the changes in the additives' concentration after fiber addition, and therefore this becomes a valuable tool for the adsorption kinetics study of chemical additives onto the cellulose fibers. The time-dependent adsorption behaviors of the wet-strength, softening agent, and their both on fiber were also presented.

• 한국의류학회지
• /
• 제46권4호
• /
• pp.565-582
• /
• 2022

In recent years, Jumchi-Hanji made of mulberry paper is used as a material for fashion items. This study examined the effect of the type of Choji method (Oebal-teugi or Ssangbal-teugi), layer number (one or two layers) and Jumchichigi time (20, 40, or 60 minutes) on the tensile, wet tensile, tearing and bursting strengths of Jumchi-Hanji. Jumchi-Hanjis used as test samples in this study were made from mulbery paper which was manufactured with either bleached or unbleached paper mulberry from Thailand. The results showed that Jumchi-Hanji made with two layers of mulberry papers had higher strength properties than Jumchi-Hanji made with only one layer. The strength properties of Jumchi-Hanji also increased with longer Jumchichigi time. Furthermore, this study confirmed that the effects of Jumchichigi time on Jumchi-Hanji strengths differed based on the type of Choji method, the layer number of mulberry papers used, and the specific strength property measured. Therefore, to guarantee the strength properties required by the application of Jumchi-Hanji paper as a fashion material, it is necessary to carefully consider the adequate Choji method and layer number to apply in the manufacture of Thai mulberry paper and the adequate duration time needed to perform Jumchichigi to Thai mulbery paper.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1989년도 가을 학술발표회 논문집
• /
• pp.9-13
• /
• 1989

The purpose of this paper is to propose a method predetermining the 28-days strength of concrete. In this paper, it was predicted by regression analysis of the relation between 7-days and 28-days strength of fresh concrete and the strength of concrete early cured at $70^{\circ}C$ for rour hours after wet screening and addition of accelerating agent. It is concluded that the formula predeterming the 28-days strength of concrete using 25M/M rubbles from Sam-Cheok and sands from Yon-Gok, by the strength of concrete early cured for 4 hours is Y=-11.45 + 3.686X, where the coefficient of determination of regression-expression is r2=0.938, S=17.94(kg/$\textrm{cm}^2$).

• 펄프종이기술
• /
• 제47권6호
• /
• pp.154-163
• /
• 2015

Because of acute or chronic intoxication by carbon disulfide, viscose rayon industry is strictly subjected to environment regulatory approval. Recently, non-wood fibers are frequently considered as a raw materials for the manufacture of specialty paper for the higher physical strength and functionality. Among the non-wood fibers, hemp bast fiber is one of the most widely used materials in viscose rayon yarn industries. In this study, the handsheet for manufacturing the viscose rayon yarn was prepared with wood pulp fibers and hemp bast fibers. The proper mixing ratio of wood fibers and hemp bast fibers with dry-strength agent and nano-celluloses was analysed in terms of physical and mechanical strength of sheet for viscose rayon yarn. The papermaking conditions for high mechanical strength of sheet were obtained by mixing the SwBKP and HwBKP fibers with freeness level of 200 mL CSF. The dual polymer system by controlling the addition ratio of PVAm and anionic PAM was also important. The addition of nano-cellulose into wet-end furnishes increased the physical strength of sheet, and improved the paper structure for the production of viscose rayon yarn.

• 한국터널지하공간학회 논문집
• /
• 제5권1호
• /
• pp.23-31
• /
• 2003

최근 NATM 터널 현장타설 콘크리트 라이닝의 시공성 향상과 균열에 따른 유지관리비 절감을 위해 양질 암반의 배수형 터널 시공에 있어서는 숏크리트만으로 라이닝을 대체하려는 영구지보 개념의 터널시공 (Single-Shell Tunnel, NMT 등)이 세계적으로 증가하고 있는 추세이다. 이러한 영구지보 개념의 터널 시공을 위해서는 고성능 숏크리트의 개발이 선결되어야 하며, 이러한 목적에서 본 논문에서는 조강시멘트와 최근 주목받고 있는 환경친화적인 alkali-free 급결제의 조합을 통해 고성능 숏크리트의 개발 가능성을 확인하였다. 그 결과, 보통시멘트(OPC)를 사용한 숏크리트보다 약 25%의 높은 초기강도를 확보하였으며, 용수부에서도 뛰어난 부착특성을 확인할 수 있었다.

• The Korean Journal of Ceramics
• /
• 제6권1호
• /
• pp.37-42
• /
• 2000

To reduce shrinkage and the possibility of fracture during ambient pressure drying, it is of great importance to increase the strength and stiffness of the wet gels. In this paper is presented the strengthening and stiffening of wet silica gels prepared from sodium silicate (water glass) as well as properties of the corresponding xerogels. By washing gels containing different initial silica contents in water solutions at elevated pH, a maximum in shear modulus of ~4 MPa was obtained. The maximum stiffness enabled xerogels with bulk density of 0.28g/$\textrm{cm}^3$ to be made regardless of silica content and washing conditions. However, by aging the wet gels in a solution providing fresh monomers to the gel network, a shear modulus of 20 MPa was obtained after 27h. By this method monolithic xerogels with a density down to ~0.2g/$\textrm{cm}^3$ was prepared. The results are compared to alkoxide based gels.

• 한국염색가공학회지
• /
• 제11권1호
• /
• pp.48-60
• /
• 1999

In this paper, a new regenerated celluosic fiber, "Tencel" was treated with cellulase enzyme. Also Tencel fabrics were pretreated with NaOH and dyed with various reactive dyes, and subsequently finished with DMDHEU. $\Delta{E}^*_{ab}$ value was calculated by measuring color difference before and after wet abrasion test to rubbing. The fibrillation propensity was estimated on Tencel by means of weight loss, $\Delta{E}^*_{ab}$ value, and SEM observation. Weight loss of NaOH pretreated Tencel fabric is more lower than that of original fabric. The cellulase treatment decreased tensile strength but improved wet abrasion strength, wrinkle recovery, and bending properties. Tendency of fibrillation for Tencel fabric was reduced by NaOH-pretreatment, dyeing with multifunctional reactive dyes, and afterfinishing by DMDHEU.by DMDHEU.

• 펄프종이기술
• /
• 제35권1호
• /
• pp.1-6
• /
• 2003

This study was carried out to investigate the effect of internal fibrillation on the pulp and paper properties. The internal fibrillation was introduced into the SwBKP and recycled SwBKP by the mechanical treatment with Hobart mixer. WRV and physical properties of SwBKP were improved by the internal fibrillation. However the mechanical treatment of recycled SwBKP resulted in the decrease of strength properties of paper except for the tear index, although it was observed that WRV was somewhat increased by the mechanical treatment. The decrease of strength properties of recycled SwBKP might be caused by the hornification of fiber and the decrease of fiber strength.

• 펄프종이기술
• /
• 제41권1호
• /
• pp.17-23
• /
• 2009

The influence of different forming elements on the local paper structure and the related paper properties was investigated in this study. Specifically, a conventional papermaking foil system and a velocity induced drainage (VID) system were compared. The study involved the analysis of the product samples obtained from the commercial machine trials. The paper samples produced with VID forming systems showed better formation. The deterministic patter in the local structural profile map of the Foil samples indicated the structure of foil samples was more supple after forming process and then easier to be marked by various fabrics such as wet pressing fabric. The higher bulk was observed in the VID samples, which resulted in higher scattering coefficient, lower ZDT strength, and higher bending stiffness.