• Macromolecular Research
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• v.11 no.6
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• pp.495-500
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• 2003

UV-induced graft polymerization of glycidyl methacrylate (GMA) to a polypropylene (PP) membrane was carried out in the vapor phase with benzophenone (BP) as a photoinitiator. Attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) were utilized to characterize the copolymer. The degree of grafting increased with increasing reaction time, increased UV irradiation source intensity, and increased immersion concentration of the BP solution. The optimum synthetic condition for the PP-g-GMA membrane was obtained with a reaction time of 2 hrs, a UV irradiation source intensity of 450 W, and an immersion concentration of the BP solution of 0.5 mol/L. The pure water flux decreased upon increasing the degree of grafting and increasing the amount of diethylamino functional group introduced. The analysis of AFM and SEM images shows that the graft chains and diethylamino groups of PP-g-GMA grew on the PP membrane surface, resulting in a change in surface morphology.

• Textile Coloration and Finishing
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• v.20 no.5
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• pp.28-34
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• 2008

PET fabrics were photografted under continuous UV irradiation with vinyl pyrrolidone (VP) and acryloylmorpholine(ACMO) as monomers and benzophenone as a hydrogen-abstractable photoinitiator. ACMO can be grafted onto the PET fabrics more efficiently than VP. The grafted PET surfaces were characterized by ATR, ESCA, SEM and zeta potential measurement. ATR and ESCA analysis indicated significant alterations on chemical structure and atomic composition on the surface of the grafted fabrics, where nitrogen content increased with increasing grafting yield. SEM images showed that the fabric surface was covered with the grafted polymers. The zeta potentials and the water wettability of the grafted PET increased with grafting. Also the photografted fabrics showed an increased dyeablity to reactive dyes and increased affinity to various iodine species which imparted anti-bacterial properties.

• Membrane and Water Treatment
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• v.6 no.5
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• pp.411-422
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• 2015

Membrane modification by different concentrations of acrylic acid has been described. Grafting of acrylic acid to the surface of a polypropylene membrane was obtained by a Fenton-type reaction. Membrane permeability seemed to have been dependent on the value of pH in the solution. To explain tendency, a simple theoretical model was developed. The model incorporates explicitly statistical conformations of a polyacid chain grafted onto the pore surface. The charged capillary model with a varying diameter for porous membranes was then used to evaluate the permeability of the membrane. It has been shown both theoretically and experimentally that the permeability of a grafted membrane depends on the pH of the solution.

• Textile Coloration and Finishing
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• v.7 no.1
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• pp.43-50
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• 1995

The grafting of methacrylonitrile(MAN) onto Kevlar 49 filament surface was carried out by anionic polymerization using sodium methylsulfinylcarbanion formed from sodium hydride and dimethyl sulfoxide(DMSO). The effects of reaction conditions on the grafting percentage(GP) and on the tensile strength of the fiber were investgated. GP marktedly increased with increasing metalation time, and NaH concentration, polymerization temperature and time. The tensile strength of fiber decrased with increasing metalation time, and NaH concentration, polymerization temperature and time. The optimum conditions to increase over 40% of GP with below 10% reduction rate of tensile strength of fiber : NaH concentration ; 30.6 mmol/l/0.5g Kevlar, metalation time : 10min, polymerization tempera- ture : 5$0^{\circ}C$, polymerization time: 20 sec, monomer concentration : 1.12mol/l/0.5g Kevlar.

• Fibers and Polymers
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• v.7 no.3
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• pp.235-240
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• 2006

Polyacrylonitrile (PAN) fiber was grafted with casein after alkaline hydrolysis and chlorination reactions of the original fiber. The structures and morphologies of the casein grafted fiber were characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), and scanning electron microscope (SEM). Moisture absorption, specific electric resistance, water retention value, and mechanical properties were also investigated. The results showed that casein was grafted onto the surface of the PAN fiber and the grafted PAN fiber presented better hygroscopicity compared with the untreated fiber. With proper tensile strength, the modified fiber could still meet the requirement for wearing. A mechanism was proposed to explain the deposit of casein on the synthetic acrylic fiber.

• Textile Coloration and Finishing
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• v.23 no.3
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• pp.155-162
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• 2011

para-Aramid has limited dyeability because of its highly crystalline structure and compactness. To improve the dyeability of the para-aramid to reactive dyes of bright color in deep shade, the fabrics were photografted under continuous UV irradiation with dimethylaminopropyl methacrylamide and 4-benzoyl benzoic acid as a monomer and a hydrogen -abstractable photoinitiator respectively. A UV energy of 35J/$cm^2$ and a photoinitiator concentration of ten percent or more with respect to the monomer in the formulation was required for optimal photografting. Grafting yield increased with higher monomer application level. Surface analysis indicated significant alterations in the atomic composition of the photografted fabric surface and the fabric surface was covered with the grafted polymers. While the pristine para-aramid fabrics showed no appreciable dyeability to the ${\alpha}$-bromoacrylamide reactive dyes, the grafted para-aramid fabrics enhanced the dyeability to the reactive dyes substantially. In case of C.I. Reactive Blue 50, a K/S value of 8.7 can be obtained with the grafted para-aramid fabrics with a grafting yield of 2.3 %. Also the color fastness properties of the dyed fabrics was excellent in the conditions of washing, rubbing and light irradiation.

• Applied Chemistry for Engineering
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• v.2 no.2
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• pp.175-184
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• 1991

Ultraviolet curable coatings are often used to protect the surface of polymer materials exposed to the ultraviolet radiation. However, the adhesion of epoxy acrylate on poly(vinyl chloride) and the UV curable coating on polystyren are poor. The objective of this work was to improve the adhesion of coating according to various formulations of the reactive diluents and finishing methods using the photografting of multifunctional acrylate and the surface activation on polymer surface impregnated a phtoinitiator. The addition of Tripropylene glycole diacrlate in the formulation of coating results in the improvement of adhesion of coating due to the flexibility. But the increase of the crosslinking density which results from the oxidation of surface during the exposure of UV radiation caused the loss of adhesion of coating exept the photografting method. In the trimethylolpropane triacrylate the improvement of adhesion are considerable due to the chemical bond between multifundtional acrylate and surface. From this work we expect to achieve the varity and functionality in the formulation of coating according to the photografting and surface activating of polymer.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.322-327
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• 2019

This study was conducted to improve the performance of automatic grafting robot using image recognition technique. The stem diameters of tomatoes and cucumber at the time of grafting were $2.5{\pm}0.3mm$ and $2.2{\pm}0.2mm$ for scions and $3.1{\pm}0.7mm$ and $3.6{\pm}0.3mm$ for rootstocks, respectively. The grafting failure was occurred when the different height between scions and rootstocks were over 4 mm and below 2 mm due to the small contact area of both cutting surface. Therefore, it was found that the height difference at the cutting surface of 3 mm is appropriate. This study also found that grafting failure was occurred when the stem diameters of both scions and rootstocks were thin. Therefore, it was suggested to use at least one stem with thicker than the average stem diameter. Field survey on the cutting angle of stems by hand were ranged from 13 to 55 degree for scions and 15 to 67 degree for rootstocks, respectively, which indicates that this could cause the grafting failure problem. However, the automatic grafting robot developed in this study rotates the seedlings 90 degree and then the stems are cut using a cutting blade. The control part of robot use all images taken from grafting process to determine the distance between a center of both ends of stem and a gripper center and then control the rotation angle of a gripper. Overall, this study found that The performance of automatic grafting robot using image recognition technique was superior with the grafting success rates of cucumber and tomato as $96{\pm}3.2%$ and $95{\pm}4%$, respectively.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.343-348
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• 2010

The surface of low density polyethylene (LDPE) film was oxyfluorinated under different reaction conditions to introduce hydroperoxide groups and change surface characteristics. Hydroperoxide functional groups created by oxyfluorination were used as active sites for graft polymerization with hydrophobic monomer, acryl amide (AM), and hydrophilic monomer, methyl methacrylate (MMA) to carry out the second modification of the LDPE film surface. The surface properties of the OFPE films and grafted OFPE films were characterized by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method, ATR-IR, contact angle measurement and DSC. From the results of DPPH method, the amount of hydroperoxide groups on the oxyfluorinated LDPE film continuously increased as the total pressure in the oxyfluorination and the partial pressure of fluorine gas increased. The water contact angle and surface free energy measurements showed that hydrophilic liquid (water) contact angle on LDPE film surface decreased with hydrophilic AM grafting and hydrophobic liquid (methylene diiodide) contact angle on LDPE film surface decreased with hydrophobic MMA grafting. These were attributed to AM or MMA monomer grafting and the wettability of LDPE filmsurface to hydrophilic and hydrophobic liquids were improved.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.395-405
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• 1994

The various functional groups, such as hydroxyl(-OH), carboxyl(-COOH) and quinonic oxygen(OC<) on the carbon black(abbreviated to CB) surface were activated with n-butyl lithium solution in n-hexane and then acrylate and methacrylate monomers were graft polymerized onto these activated anionic sites and CB-grafted polymers were obtained. To separate homopolymers from reaction mixture, non-solvent precipitation method or centrifugal separating method were applied. Subsequently, conversion, grafting ratio and efficiency were determined at various reaction temperatures and times. In case of acrylates, the grafting ratio showed 20~30% but methacrylates showed 150~200%. Also the anion polymerizations between CB and monomers were nearly reached to equilibrium state within one or two hours under each reaction temperatures but conversion and grafting ratio were increased a little with reaction temperature increase. In colloidal dispersion stability test, before heat-drying, the all CB-grafted polymers showed good dispersed stability in good solvents for acrylic and methacrylic homopolymers. Futhermore, CB-polymethacrylates were found to show excellent collidal properties for good solvents of methacrylic homopolymer even after heat-drying. Identification of the grafted polyacrylates and polymethacrylates onto the CB surface was performed by FT-IR spectroscopy. In addition, electric resistance values of CB-grafted polymers were measured by Four-probe method, and the increase of the grafting ratio showed the increase of the surface resistance.