• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.320-320
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• 2006

The authors report the synthesis and radical ring-crossover polymerization of macrocycles with radically exchangeable dynamic covalent bonds. The macrocyclic compounds with alkoxyamine units were designed and synthesized by condensation from alkoxyamine-based diol and the corresponding acid chlorides in the presence of pyridine under high-dilution condition. The macrocycles can thermally polymerize by intermolecular radical crossover reaction. Furthermore, the poly(alkoxyamine)s depolymerized to the monomers principally by the intramolecular radical exchange process under high-dilution conditions.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.267-276
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• 2020

Poly(epichlorohydrin) copolyol series (PECH copolyols) were synthesized via cationic ring-opening copolymerization (ROCP) of oxirane-based monomers and effects of reaction temperature, solvent type, and initiator were studied. As a comonomer, two types of alkylene oxides were used, and polymerization conditions were conducted both with diethylene glycol (DEG) as an initiator in methylene chloride (MC) solvent and tripropylene glycol (TPG) in toluene solvent. In order to induce the active monomer (AM) mechanism in the ring-opening copolymerization reaction, the monomer was injected by an incremental monomer addition (IMA) method using a syringe pump, and the polymerization was performed at -5 ℃. PECH copolyol, a synthesized ephichorohydrin (ECH)-based copolyol, was converted to glycidyl azide-based energy-containing copolyol (GAP copolyol) by azadizing the ECH unit through a substitution reaction. It was confirmed that the synthesized azide copolyol had little effects on changes of the solvent and the initiator. Also, the molecular weight increased 500 after the azide reaction, thereby the GAP copolyol was polymerized as designed. As the content of the comonomer increased, both the T_g and viscosity tended to decrease due to the influence of the alkyl chain length. It is possible to fundamentally prevent CH₃N₃ amount produced in the azide reaction process, and it is expected that a large-scale process could be achievable.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.126-134
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• 2018

Using aqueous solution free radical polymerization with glacial acrylic acid (GAA), maleic anhydride (MA) and sodium methallyl disulfonate (SMADS), a novel linear polycarboxylate dispersant was synthesized for ceramics. Dispersant linear structural characterization was done by FTIR, $^1H$ NMR, HPLC and GPC, and the ratio of monomers was determined using an orthogonal experiment. This research is focused on the effects of polymerization temperature, monomer mole ratios and dosage of initiator on ceramic slurry viscosity with linear polycarboxylate dispersant for ceramic dosage rate of 0.30% (based on dry slurry), all of which were investigated by single factor test. The best polymerization conditions for linear GAA-MA-SMADS are when n(AA) : n(MA) : n(SMADS) equals 3.0 : 1.0 : 0.5, the molecular weight of the polymer is 4600 daltons, the initiator sodium persulfate accounts for 7% of the total mass of polymerized monomers, the polymerization temperature is $90^{\circ}C$ and the reaction time is 2 h. The ceramic body slurry viscosity drops from $820mPa{\cdot}s$ to $46mPa{\cdot}s$ when the concentration of the polycarboxylate dispersant is 0.30%.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.132-138
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• 1977

Anionic polymerization of ${\varepsilon}$-caprolactam via $SO_2$/KOH catalysis was attempted in order to find an optimal reaction condition and physical properties of the polymers. The yield of conversion was relatively low at low temperature and high at high temperature between $150^{\circ}C\;to\;180^{\circ}C$ regardless of $SO_2$/KOH mole ratio in polymerization of ${\varepsilon}$-caprolactam.The inherent viscosity of nylon 6 obtained via $SO_2$/KOH catalysis was 1.2∼2.7. The kinetic equation for the $SO_2$/KOH catalyzed polymerization has been derived and experimentally verified.

• Macromolecular Research
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• v.16 no.2
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• pp.155-162
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• 2008

We report the successful synthesis of poly(NBECOOH-b-NBEPOSS) copolymers, taking advantage of the sequential, living ring opening metathesis polymerization of NBETMS and NBEPOSS using the $RuCl_2(=CHPh)(PCY_3)_2$/$CH_2Cl_2$/$20^{\circ}C$ system, followed by the hydrolysis of trimethylsilyl groups in poly(NBETMS-b-NBEPOSS) copolymers. The living behavior of ROMP of NBETMS was first investigated using two diagnostic plots, a first order kinetic plot and a $\bar{M}_n$ vs. conversion plot. The plots confirmed that no termination and chain transfer reaction had occurred during polymerization. Poly(NBECOOH-b-NBEPOSS) copolymers were prepared using the sequential monomer addition of NBEPOSS to living poly(NBETMS) chain ends, followed by the hydrolysis of trimethylsilyl groups in the poly(NBETMS-b-NBEPOSS) copolymers. The high structural integrity of poly(NBE-COOH-b-NBEPOSS) copolymers was confirmed by $^1H$-NMR, $^{13}C$-NMR spcctroscopy and GPC.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.214-218
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• 1981

Kinetic studies were carried out on urethane polymerization reaction of hydroxyl-terminated polybutadiene with isophorone diisocyanate under presence of Hexogen as solid additive. The rate was found to increase with the amount of Hexogen added. However the rate acceleration was not a catalytic effect but solely due to an increase of activation entropy. The reaction was a good 2nd order process with nearly constant activation energy of 8.4 kcal/mole.

• Fashion & Textile Research Journal
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• v.6 no.3
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• pp.384-392
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• 2004

The purpose of this study is in development of effective filter-type polymer adsorbent for removal of pollutants from wastewater by UV irradiation graft polymerization. Photografting of acrylic acid (AA) on polypropylene (PP) nonwoven fabric using benzophenone (BP) as a photosensitizer was investigated. Inhibition of homopolymerization was achieved by adding various concentrations of $FeSO_4{\cdot}7H_2O$, $CuSO_4{\cdot}5H_2O$ and Mohr's salt. As AA concentration was increased, the degree of grafting was increased as to a specific value and then decreased, and the effect of BP concentration showed the same tendency. It was also found that the degree of grafting increased with reaction time and reaction temperature. Addition of the polyfunctional monomers and $H_2SO_4$ to the grafting system accelerated the photografting. The melting temperature, molecular weight and breaking stress and breaking strain were decreased with the increase in the degree of grafting.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.418-418
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• 2012

We fabricated a new type of hybrid film using molecular layer deposition (MLD). The MLD is a gas phase process analogous to atomic layer deposition (ALD) and also relies on a saturated surface reaction sequentially which results in the formation of a monolayer in each sequence. In the MLD process, polydiacetylene (PDA) layers were grown by repeated sequential surface reactions of titanium tetrachloride and 2,4-hexadiyne-1,6-diol with ultraviolet (UV) polymerization under a substrate temperature of $100^{\circ}C$. Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of the hybrid films. Polymerization of the hybrid films was confirmed by infrared (IR) spectroscopy and UV-Vis spectroscopy. Composition of the films was confirmed by IR spectroscopy and X-ray photoelectron (XP) spectroscopy. The titanium oxide cross-linked polydiacetylene (TiOPDA) hybrid films exhibited good thermal and mechanical stabilities.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.141-149
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• 2005

We investigated numerically the evolutions of several chemical species which are important for film growth and particle generation in the pulsed $SiH_4$ plasmas. During the plasma-on, the $SiH_x$ concentration increases with time mainly by the generation reaction from $SiH_4$, but, during the plasma-off, decreases because of the hydrogen adsorption reaction. During the plasma-on, the concentrations of negative ions increase with time by the polymerization reactions of negative ions and those become almost zero in the sheath regions because of the electrostatic repulsion. During the plasma-off, the concentrations of negative ions decrease with time by the neutralization reactions with positive ions and some negative ions can diffuse toward the sheath regions because there is no electric field inside the reactor. The polymerized negative ions of higher mass can be reduced successfully by using the pulsed plasma process.

• Textile Coloration and Finishing
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• v.15 no.3
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• pp.154-160
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• 2003

Polypropylene nonwoven fabrics were grafted with acrylic acid by a preirradiation method by using electron beam accelerator. The effect of irradiation dose, storage time, concentration of acrylic acid, reaction temperature, reaction time and Mohr's salt concentration on the degree of grafting were investigated in detail. The grafted Polypropylene nonwoven fabrics were characterized using IR spectroscopy and SEM. The results showed that the degree of grafting increased with increasing absorbed dose and the Mohr's salt in the acrylic acid solution promoted grafting efficiency.