• Fibers and Polymers
• /
• v.2 no.2
• /
• pp.108-115
• /
• 2001

Vinyl acetate was polymerized in ultraviolet-ray initiated bulk system at low temperatures using 2,2-azobis(2,4-dimethylvaleronitrile) (ADMVN) or 2,2-azobis(isobutyronitrile) (AIBN) as the photoinitiator, respectively. High molecular weight (HMW) poly(vinyl alcohol) (PVA) having number-average degree of polymerization ($P_n$) of 3,900-7,800 and syndiotactic diad (S-diad) content of 52.5-54.0% could be prepared by complete saponification of synthesized linear poly(vinyl acetate) (PVAc) having $P_n$ 5,900-9,400 obtained at conversion of below 30%. $P_n$ of PVA using ADMVN was larger than that of PVA using AIBN. On the other hand, conversion of the former was smaller than that of the latter, and it was found that the initiation rate of the ADMVN was lower than that of AIBN. This could be explained by a fact that the rate of photolysis of AIBN is faster than that of ADMVN due to the higher quantum yield or dissociation rate constant of AIBN than that of ADMVN. The $P_n$, syndiotacticity, and whiteness of PVA from PVAc polymerized at lower temperatures were superior to those of PVA from PVAc polymerized at higher temperatures.

• Journal of the Korean Chemical Society
• /
• v.24 no.3
• /
• pp.259-265
• /
• 1980

Poly (styrene-b-methyl methacrylate) (PS-b-PMMA) was synthesized by free radical telomerization: the telomerization of styrene with $CCI_4$ by using AIBN as initiator followed by a second telomerization of methyl methacrylate using $CCI_3$ end group of the resulting polymer as the macrotelogen, with AIBN initiation, gave the styrene-methyl methacrylate block copolymer. The effects of the concentration of the macrotelogen, the concentration of monomer, the molecular weight of the macrotelogen, the reaction temperature and the concentration of the solvent on the formation of the block copolymer were investigated. Block copolymers containing up to 10 weight percent PMMA were obtained by adjusting the reaction conditions.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.5
• /
• pp.284-287
• /
• 1985

Cyanoisopropyl radical derived from azobisisobutyronitrile (AIBN) by either thermolysis or photolysis reacts with oxygen to give cyanoisopropylperoxy radical which then was converted to acetone and cyano radical and/or acetyl cyanide and methyl radical. Of these products, acetone formed was quantitatively determined by the addition of thianthrene cation radical perchlorate to the reaction mixture. The results showed that 55.7 mmol, 16.9 mmol, and 16.0 mmol of acetone were formed for 7 hours from 1 mol of AIBN at $82{\pm}1^{\circ}C$ in acetonitrile, carbon tetrachloride, and benzene, respectively. However, 22.2 mmol of acetone was formed from photolysis of 1 mmol of AIBN in acetonitrile. The value decreased to 13.2 mmol by bubbling argon into the solvent prior to photolysis.

• Macromolecular Research
• /
• v.14 no.4
• /
• pp.466-472
• /
• 2006

The kinetic behavior of emulsion polymerizations of styrene in the presence of sulfonated N-hydroxy ethyl aniline (SHEA) was investigated with two initiators: 2,2'-azobisisobutyronitrile (AIBN) and potassium persulfate (KPS). SHEA was synthesized using a stepwise polyurethane reaction method from 3-hydroxy-1-propane sulfonic acid sodium salt, isophorone diisocyanate (IPDI), and N-(2-hydroxyethyl) aniline. Stable core-shell poly(styrene/sulfonated N-hydroxy ethyl aniline, St/SHEA) latex particles were successfully prepared by using an appropriate amount of AIBN, in which SHEA plays the role of 'surfmer', i.e., acting as both a surfactant in the emulsion polymerization and a monomer in the chemical oxidative polymerization. The kinetic behavior was dissimilar to that of typical emulsion polymerization systems. A long inhibition period and low rate of polymerization were observed due to radical loss by the oxidative polymerization of SHEA. It was concluded, due to the low water-solubility of AIBN and retardation reaction by SHEA, that the initial loci of polymerization were monomer droplets. However, growing polymer particles as polymerization loci became predominant as polymerization proceeded. It was suggested that AIBN was more effective than KPS in the preparation of the core-shell type poly(St/SHEA) latex particles. With KPS, no substantial polymerization was observed in any of the samples.

• Polymer(Korea)
• /
• v.24 no.3
• /
• pp.287-298
• /
• 2000

In preparing micron-sized monodisperse polystyrene beads by dispersion polymerization, the conversion, and the particle size and its distribution were affected by the reaction temperature, concentration of the monomer, solvent and initiator, molecular weight and concentration of the steric stabilizer, amount of oxygen existing in the reactor, and an appropriate combination of these starting materials. Ethanol as a dispersing agent, styrene as a monomer, PVP as a steric stabilizer, AIBN as an initiator, DVB as a cross-linking agent and toluene as a co-solvent were the basic materials for the synthesis. The reaction rate and the conversion were increased with the reaction temperature and the amount of DVB from 1 to 4%, and the conversion was saturated after 10 hours of the reaction time. The optimum reaction recipe for the preparation of the monodisperse PS beads was 25% styrene monomer, 0.5% DVB, 25% toluene, 10-15% PVP, and 2 and 4% AIBN, thereby, 3.9~4 ${\mu}{\textrm}{m}$ and 3.4~9.3 ${\mu}{\textrm}{m}$ of polystyrene beads, respectively, were successfully synthesized.

• Elastomers and Composites
• /
• v.58 no.3
• /
• pp.128-135
• /
• 2023

To improve the adhesive strength of natural rubber (NR) for a seismic isolation damper, citraconic acid-g-NR (CCA-g-NR) was synthesized via the melt grafting of citraconic acid (CCA) onto NR using an azobisisnomerobutyronitrile (AIBN) initiator. Subsequently, the influence of CCA and AIBN concentrations on the graft ratio G/R (%) and graft efficiency G/E (%) of the CCA-g-NR was investigated. The optimum CCA and AIBN concentrations required to achieve the desired G/R (3.49%) and G/E (49.8%) were found to be 7 phr and 0.13 phr, respectively. Additionally, we studied the influence of CCA-g-NR concentration on the mechanical properties (tensile strength, elongation at break, and modulus at 300%), adhesive strength, and cure characteristics of the rubber compound in the seismic isolation damper. As the concentration of CCA-g-NR increased, the elongation at break and adhesive strength of the compound increased, whereas its tensile strength and modulus at 300% decreased. Moreover, as the concentration increased, the maximum torque decreased and the scorch time was delayed to obtain an optimal vulcanization time.

• Journal of the Korean Chemical Society
• /
• v.43 no.1
• /
• pp.74-84
• /
• 1999

Most of the reactions involving benzotriazoles as a synthetic auxiliary have been explained by ionic mechanisms, whereas benzotriazole-mediated radical reactions have received little attention. The reaction of 1-[(aryl)(phenylseleno)methyl]benzotriazole with $Bu_3$SnH in the presence of AIBN in benzene at reflux gave 2-aminodiphenyl selenide (16-29%), 2-aminobiphenyl (9-15%), diphenyl diselenide (30-93%), 1-(arylmethyl) benzotriazole (9-39%) and tributyltin-phenyl selenide (10-36%), whereas the compounds were treated with excess molar amount of $Bu_3$SnH in the absence of AIBN to afford N-(arylmethyl)anilines (44-66%) along with diphenyl diselenide (53-100%), benzotriazole (27-35%) and 1-(arylmethyl)benzotriazole (16-33%). Similarly, treatment of 6-aryl-6-(benzotriazol-1-yl)-1-hexenyl phenyl selenides with $Bu_3$SnH in the presence of AIBN gave 6-aryl-6-phenylamino-1-hexene (9-31%) and 1-aryl-1-oxo-5-pentene (15-44%). A mechanism for the formation of the products is proposed.

• Polymer(Korea)
• /
• v.25 no.5
• /
• pp.754-758
• /
• 2001

In order to use vesicle as a space of polymerization, monomer and cross-linking agent were put into hydrophobic part of vesicle. The vesicle solution of dimethyldioctadecylammonium bromide was formed by ultrasonication. Styrene and divinylbenzene were put into this solution and polymerization was conducted by adding AIBN. The polymer with sphere-shaped structure was obtained by removing all of the surfactant by extraction of ethanol And using methyl methacrylate and ethylene glycol dimethacrylate, this sphere-shaped polymer structure was also formed.

• Journal of Industrial Technology
• /
• v.23 no.A
• /
• pp.187-191
• /
• 2003

A hollow-fiber type polysulfone UF membrane was surface-coated with hydroxyethylmethacrylate (HEMA). The effect of various coating parameters on permeation flux, such as concentration ratio of AIBN/HEMA, solvent(water or methanol), and UV irradiation time, was investigated. The water permeation flux of oil-emulsion increased with concentration ratio of AIBN/HEMA, and increased with UV irradiation time. The flux of the membrane coated in solution using methanol as a solvent was greater than that of the membrane coated in solution using water as a solvent. The flux of both the coated and the uncoated membrane declined with the operation. The flux decline means that the membrane fouling by oil-emulsion occurs. However, the fouling of the coated membrane was much less than that of the uncoated membrane.

• Journal of the Korean Chemical Society
• /
• v.53 no.3
• /
• pp.335-339
• /
• 2009

Polydimethylsiloxane (PDMS) with methacrylate endgroup is used as contact lens material with elasticity and high oxygen permeability. PDMS prepolymer with methacrylate endgroup was prepared by reacting PDMS (polydimethylsiloxane) with HEMA (2-hydroxyethyl methacrylate). The HEMA-substituted PDMS prepolymer was then copolymerized using AIBN (azobisisobutyronitrile) with BMA (butyl methacrylate; to increase elasticity and flexibility). The water content, oxygen permeability, and visible-ray transmissibility of the resulting polymer were measured to be 23%, 83% and Dk/t > 50, indicating that the copolymer can be used as a good contact lens material.