• Fibers and Polymers
• /
• v.4 no.4
• /
• pp.182-187
• /
• 2003

Low molecular weight copolymers of maleic anhydride and vinyl acetate were prepared to develop formaldehyde free cross-linking agents. Since lower molecular weight is favorable for efficient penetration of the finishing agent into the cotton fibers in the padding process, the concentration of the initiator, chain transfer agent and the monomer ratios were varied to obtain copolymers of low molecular weights. The prepared polymers were characterized by GPC, $^1{H-NMR}$, FTIR, DSC and TGA. Copolymers of molecular weights of 2 000 to 10 000 were obtained and it was found that the most efficient method of controlling the molecular weight was by varying the monomer ratios. Poly(maleic anhydride-co-vinyl acetate) did not dissolve in water, but the maleic anhydride residue hydrolyzed within a few minutes to form poly(maleic acid-co-vinyl acetate) and dissolved in water. However, the maleic acid units undergo dehydration to form anhydride groups on heating above ${160}^{\circ}C$ to some extent even in the absence of catalysts. The possibility of using the copolymers as durable press finishing agent for cotton fabric was investigated. Lower molecular weight poly(maleic anhydride-co-vinyl acetate) copolymers were more efficient in introducing crease resistance, which appears to be due to the more efficient penetration of the cross-linking agent into cotton fabrics. The wrinkle recovery angles of cotton fabrics treated with poly(maleic anhydride-co-vinyl acetate) copolymers were slightly lower than those treated with DMDHEU and were higher when higher curing temperatures or higher concentrations of copolymer were used, and when catalyst, $NaH_2$$PO_2$, was added. The strength retention of the poly(maleic anhydride-co-vinyl acetate) treated cotton fabrics was excellent.

• Journal of Adhesion and Interface
• /
• v.12 no.1
• /
• pp.1-10
• /
• 2011

An automated reaction calorimeter was used to directly monitor the rate of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) (PVAs) having different degrees of blockiness. By using this technique in conjunction with other off-line measurements of the evolution of particle size distributions, important details of the process were observed. No constant graft rate period was observed for both low and high initial monomer-water ratios. The gel effect was observed for the low monomer-water ratio recipe. The particle size distributions were broad (particle diameter 40~100 nm) and bimodal. Continuous nucleation was observed to be accompanied by 'limited aggregation' and flocculation during the particle growth stages. It was speculated to be due to the occurrence of the extensive 'limited aggregation' and chain transfer to PVA leading to grafting.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.18 no.1
• /
• pp.113-120
• /
• 2000

A previous paper was reported in being sensetized photopolymer, poly(vinyl cinnamoyl acetate) (PVCiA)1) with some squarylium dyes such as 1,3-bis(4 or 6-trifluouomethy1-1,3,3-trimethylindo) squarylium dyes(TFSQ). Here, we synthesized new 1,3-bis(4 or 6-nitro-1,3,3-trimethylindo) squarylium dyes(NISQ) to sensetize photopolymer, such as poly(vinyl cinnamoyl acetate). Absorption's coefficient of (NISQ8) is 8.5x105, the sensitivity of PVCiA added with NISQ8(3%) was highly sensitized 8 times than not added, and 2 times than TFSQ8(3%). Maybe, high absorption'scoefficient and red shift of NISQs with strongly withdrawing group to TFSQs afford to the high sensitivity of PVCiA.

• Polymer(Korea)
• /
• v.32 no.2
• /
• pp.95-102
• /
• 2008

The $\alpha$,$omega$-diacrylate poly(dimethylsiloxane) (DA-PDMS) containing vinyl ester of versatic acid/vinyl acetate (Veova-10/VAc) was prepared by emulsion copolymerization of (DA-PDMS), Veova-10 (with VAc), and auxiliary agents at $85^{\circ}C$ in the presence of ammonium peroxodisulfate (APS) as an initiator. Sodium dodecyl sulfate (SDS) and nonylphenol ethylene oxide-40 units (NP-40) were used as anionic and nonionic emulsifiers, respectively. The resulting copolymers were characterized by using Fourier transform infrared spectroscopy (FT-IR). Thermal properties of the copolymers were studied by using thermogravimetric analysis(TGA) and differential scanning calorimetry (DSC). The morphology of copolymers was also investigated by scanning electron microscopy (SEM) and then the effects of variables such as temperature, agitation speed, surfactant kinds, molecular weights, initiator, and DA-PDMS concentrations on the properties of the silicone-containing Veova-10/VAc emulsions were examined. The calculation of monomer conversion versus time histories indicates that by increasing the DA-PDMS concentration the polymerization rate and the number of polymer particles decrease, respectively.

• Applied Chemistry for Engineering
• /
• v.10 no.3
• /
• pp.362-366
• /
• 1999

Membranes for biosensor were prepared from poly(vinyl chloride) (PVC)l derivatives using the solution casting method, and their gas permeabilities were studied. The polymer membranes dried slowly in air showed higher permeability coefficients than those dried in vacuum. The permeabilily coefficients of carboxylated poly(vinyl chloride) (CPVC) membranes for $O_2$ and $CO_2$ decreased as the pressure of the feed gas increased. The addition of dioctylphthalate (DOP) enhanced the permeation rates for $O_2$ and $CO_2$. For example, the permeability coefficients of CPVC membranes containing 30 wt. % DOP for $O_2$ and $CO_2$ at 100 psig were 2.03 and 0.96 Barrer, respectively, which were about 4~5 times higher than those of the membranes without DOP. Poly(vinyl chloride-co-vinyl acetate-co-vinyl alcohol) (Syn-PVCAcAl) obtained by hydrolysis of poly(vinyl chloride-co-vinyl acetate (PVCA) showed a higher permeability coefficient for $CO_2$ in the presence of DOP than that for commercial PVCAcAl, but did not show any significant difference in permeability for $O_2$.

• Proceedings of the Korean Fiber Society Conference
• /
• 2000.04a
• /
• pp.265-269
• /
• 2000

• Bulletin of the Korean Chemical Society
• /
• v.22 no.10
• /
• pp.1136-1140
• /
• 2001

• Journal of the Korean Graphic Arts Communication Society
• /
• v.16 no.3
• /
• pp.1-13
• /
• 1998

Some photopolymer, poly(vinyl cinnamoyl acetate)(PVCiA) was synthesized by esterification of polymer(vinyl alcohol(PVA) with monochloroacetic acid, followed by reaction poly(vinyl monochloroacetate)(PVChA) and potassium cinnamate. When esterification of PVA with monochloroacetic acid was reacted in the dimethyl sulfoxide(DMSO), in the synthesis of PVChA, it is very good yield and the successive cinnamoyl acetoxyl esterification of PVCiA can be successfully synthesized. But PVCiA is low photosensitive polymer if not added photosensitizing dyes. Here, we synthesized photosensitizing dyes. trifluoromethylindol squarylium dye derivatives(TFSQ). Indolization of 3-trifluoromethylphenyl-hydrazine formed 4- and 6-substituted indoles, the rate of 4- and 6-substituted indoles is close to unity. Absorption's coefficient of 1,3-bis(4-trifluoromethyl-1,3,3-trimethylindol) squarylium dye(TFSQ) is 7.57$\times$10\ulcorner, PVCiA added with TFSQ(3%) was highly sensitized six times than not added.

• Clean Technology
• /
• v.12 no.4
• /
• pp.191-197
• /
• 2006

Polymerization in supercritical carbon dioxide has been getting attention since it is easier to separate the remaining reactants from product polymer and since it is a cleaner process that produces neither wastewater nor air pollutants, compared to the conventional polymerization processes. In this study, poly(vinyl acetate) (PVAc) that is necessary in producing poly(vinyl alcohol) (PVA) with a lot of industrial applications was manufactured in the presence of supercritical carbon dioxide for the second time in the world. A poly(dimethylsiloxane)(PDMS)-derivative surfactant and three initiators were employed in the polymerization of vinyl acetate (VAc) at 338.15 K and 34.5 MPa. Investigation was carried out to find out the effect of the amounts and types of initiators and surfactants as well as the effect of reaction time on the yield and the molecular weight of PVAc. The weight average molecular weight (Mw) of PVAc was in the range of 60,000 ~ 140,000 g/mol, and the number average molecular weight was in the range of 30,000 ~ 70,000 g/mol. The yield of PVAc was spread over 10 ~ 80%, based on the amount of VAc monomer.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.04a
• /
• pp.319-320
• /
• 2003

압전성과 초전성을 나타내는 고분자인 poly(vinylidene fluoride)(PVDF)는 poly(methyl methacrylate), poly(vinyl acetate), 및 Poly(vinyl methyl ketone)(PVMK) 등과 블렌딩하면 혼화성(miscibility)이 있다. 이들 블렌드물들을 용융온도 이상으로 승온시키면 낮은 온도에서는 균일상으로 존재하지만, 온도가 계속 증가하면 상분리되어 LCST(lower critical solution temperature)를 나타낸다[1]. 이러한 승온에 의한 상분리 거동에서 외부전장을 가하면 전기활성 고분자인 PVDF에 영향을 주어 상분리 거동이 변화될 것으로 예산된다. (중략)