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Modification of urea-formaldehyde resin adhesives with blocked isocyanates using sodium bisulfite
Lubis, Muhammad Adly Rahandi,Park, Byung-Dae,Lee, Sang-Min Butterworth-Heinemann Ltd. 2017 International journal of adhesion & adhesives Vol.73 No.-
<P><B>Abstract</B></P> <P>Polymeric 4-4 diphenyl methane diisocyanate (pMDI) was blocked with an aqueous sodium bisulfite solution to obtain water-dispersible blocked pMDI (B-pMDI) resin with different HSO<SUB>3</SUB>/–NCO mole ratios for the modification of urea-formaldehyde (UF) resin. Fourier transform infrared (FTIR) spectra of the B-pMDI resin clearly showed that all isocyanate groups of the pMDI resin were successfully blocked by sodium bisulfite. As the HSO<SUB>3</SUB>/–NCO mole ratio increased, the de-blocking temperature of the B-pMDI resin also increased. Two addition levels (1% and 3%) of the B-pMDI resin with different HSO<SUB>3</SUB>/–NCO mole ratios were mixed with UF resins and used as an adhesive for plywood. The gel time of the UF/B-pMDI resins decreased to a minimum at a mole ratio of 0.9 and then increased with the HSO<SUB>3</SUB>/–NCO mole ratio, and was consistent with the peak temperature (<I>T</I>p). However, as the HSO<SUB>3</SUB>/–NCO mole ratio increased, the viscosity of the modified UF resins by 1% B-pMDI resin addition slightly increased, whereas those of modified resins with 3% B-pMDI resin addition rapidly increased. The adhesion strengths of plywood bonded with the hybrid resins were greater for 1% B-pMDI resin addition than for 3% B-pMDI resin addition. Formaldehyde emission of plywood bonded with the UF/B-pMDI resins significantly decreased up to 34% by the addition of B-pMDI resin at a mole ratio of 1.8. These results suggest that the modification of UF resins by mixing with water-dispersible B-pMDI resin can be a method for improving the water resistance and formaldehyde emission of UF resins for wood-based composites.</P>
LUBIS, Adelina,DALIMUNTHE, Ritha,ABSAH, Yeni,FAWZEEA, Beby Karina Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.3
This study aims to analyze the effect of corporate communication and service quality on loyalty mediating satisfaction. The population of this study is 384 Islamic bank customers in North Sumatra. This research is quantitative research using the survey method. The number of research samples was 384 customers. Characteristics of this research sample were (1) Savings customers who actively carried out transactions in Islamic banks (2) Savings customers who had used bank services for at least 1 year (3) Savings customers who used services directly and individually. The data analysis technique used in this study was the Partial Least Squares-Structural Equation Model (SEM-PLS) analysis technique, using Warp-PLS 3.0 software. This study investigates the largest Islamic banks in North Sumatra, namely Bank Syariah Mandiri, Bank BNI Syariah, and Bank BRI Syariah. The results show that company communication has a positive and significant effect on satisfaction, service quality has a positive and significant effect on satisfaction, company communication has a positive and significant effect on loyalty, service quality has a positive and significant effect on loyalty, satisfaction has a positive and significant effect on loyalty. There is also a significant effect of satisfaction on the relationship between company communication and loyalty, and the relationship between service quality and loyalty. This study contributes to Islamic banking to increase customer loyalty.
Brain Medical Image Retrieval Using Non-Negative Matrix Factorization and Canny Edge Detection
Ali Akbar Lubis,Suharjito 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4
Disease conditions in the human brain can be detected by using medical image analysis. Content Based Image Retrieval of medical images can be used as an alternative to recognize the medical images of the human brain. In CBIR, feature extraction and recognition methods was an important feature because of medical image was different from the general image. In this study medical images that contain clinical information will be used as feature extraction using a canny edge detection and recognition features using non-negative matrix Factorization (NNMF). The purpose of this paper was to describe the use of canny edge detection and NNMF in CBIR. So CBIR could provide information on brain diseases and abnormalities. The results showed that the detection of disease in the human brain can be done by using both methods with good results if done preprocessing using histogram equalization.
< 구두-E-03 > Modified Urea-Formaldehyde Resin Adhesives with Oxidized Starch for Plywood
( Muhammad Adly Rahandi Lubis ),( Byung-dae Park ) 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1
Incorporation of oxidized starch (OS) into urea-formaldehyde (UF) resins has been made to reduce formaldehyde emission of panel bonded with UF resins. The addition effects of OS on basic and thermal properties of modified UF resins was studied. Therefore, this work characterizes the properties of modified UF resins at two different formaldehyde/urea (F/U) mole ratios and different contents of OS. The performance of UF/OS adhesives was also evaluated by making plywood panel. The OS was synthesized using hydrogen peroxide oxidation. Fourier-transform infrared analysis showed that both carbonyl and carboxyl groups at 1710-1720 cm<sup>-1</sup> were detected in the OS. The UF/OS adhesives then were prepared by adding 0, 5, 10, and 15% of OS based on UF resins solids content. Blocked isocyanate was added at 1% level based on OS weight as a cross-linker in the UF/OS adhesives. Regardless of F/U mole ratio, both solids content and viscosity of UF resins decreased while the gel time increased as the OS content increased. Differential scanning calorimetry analysis showed that the activation energy of 1.0 F/U mole ratio UF resins were higher than those of 1.2 F/U mole ratio as the OS content increased. It was found that plywood properties could be improved by adding OS into UF resins and the FE values of plywood could meet the E1 standard. Statistical analysis suggested that the performance of UF resins in plywood could be improved by adding 10% OS based on resins solids content for two F/U mole ratio resins.
< 구두-E-11 > Tuneable Oxidized Starch Adhesives for Recycling of Medium Density Fiberboards
( Muhammad Adly Rahandi Lubis ),( Byung-dae Park ),( Min-kug Hong ) 한국목재공학회 2019 한국목재공학회 학술발표논문집 Vol.2019 No.1
Medium density fiberboard (MDF) is an important wood product and is being globally used in the world. MDFs bonded with urea-formaldehyde (UF) resin adhesives are mainly used for furniture manufacturing, but they are difficult to be recycled after their end-life. As a way of recycling MDFs, this study prepared oxidized starch (OS) adhesives to have a balance between the adhesion and disintegration of MDF by controlling the degree of oxidation and types of cross-linker. Four mole ratios of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)/starch and two types of cross-linkers, i.e., blocked-pMDI (B-pMDI) and citric acid (CA), were employed to tune the performance of OS adhesives. For cross-linking, the OS reacted with the isocyanate groups from B-pMDI by forming amide bonds while it formed ester bonds by reacting with CA. As a result, the B-pMDI/OS-bonded MDF had better physical and mechanical properties than those bonded with the CA/OS. In addition, the B-pMDI/OS-bonded MDF possessed comparable internal bonding strength with UF resin-MDF at 0.34 MPa. Recyclability of OS-bonded MDFs were greater than that of UF resin panel, as indicated by higher mass loss and greater degree of fiber disintegration. The results showed that OS adhesives with 7.5% B-pMDI at 0.5 H<sub>2</sub>O<sub>2</sub>/starch mole ratio provided a balance between adhesion and disintegration, suggesting that the OS adhesives could replace UF resin for MDF with zero formaldehyde emission and easy recyclability in future.
< 전시-P-38 > Bond-Line Features of Melamine-Urea-Formaldehyde Resin Adhesives in Plywood
( Muhammad Adly Rahandi Lubis ),( Bora Jeong ),( Byung-dae Park ) 한국목재공학회 2019 한국목재공학회 학술발표논문집 Vol.2019 No.1
Melamine-urea-formaldehyde (MUF) resins have been widely used for the production of wood-based panels, such as plywood. However, the addition of melamine to MUF resins tend to produce higher molecular weight resins, to increase the viscosity, and to decrease the resin penetration, leading to poor a adhesion strength. Here, this study investigated the effect of addition of melamine on bond-line features of MUF resin adhesives in plywood. Three different contents of melamine (5, 10, 20 %) and two synthesis methods were employed to prepare two types of resins, namely MUF and MFU. 3-ply plywood panels were produced using those resins, and bond-line thickness and resin penetration of the resins were investigated by imaging thin samples (70 μm) of cross-section of plywood using a light microscope. As expected, higher melamine content increased viscosity of MUF and MFU resins. Depending on the resin types, resin penetration of MUF resins decreased by 48% while the penetration increased by 16% for MFU resins at higher melamine content. As a result, MUF resins had higher bond-line thickness than that of MFU resins as a function of melamine content. Regardless of the resin synthesis method, tensile shear strength of plywood increased as the melamine content increased. Further, higher melamine content significantly reduced formaldehyde emission of plywood by 24% for both resins.