• 한국안전학회지
• /
• 제26권5호
• /
• pp.46-53
• /
• 2011

The risk assessment of thermal behavior and runaway reaction cased by an exothermic batch process in manufacture of the vinyl acetate resin are described in the present paper. The aim of the study was to evaluate the risk of runaway reaction with operating parameters such as a reaction inhibitor, reaction temperature and a mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed by a sort of calorimetry with the Multimax reactor system as a screening tool to investigate runaway reaction. From the experimental results, it was found that we could occur the auto acceleration for reaction of raw materials with operating parameters over $65^{\circ}C$ of reaction temperature in the vinyl acetate polymerization process.

• 한국안전학회지
• /
• 제25권3호
• /
• pp.61-65
• /
• 2010

Most of the chemical reactions performed in the chemical industry are exothermic, meaning that thermal energy is released during the reaction. It is also important to understand the thermal hazards such as thermal stabilities and runaway reactions, which are governed by thermodynamics and reaction kinetics of the mixed materials. The paper was described the evaluation of thermal behavior caused by an exothermic batch process in manufacture of the vinyl acetate resin. The aim of the study was to evaluate the thermal stabilities of raw materials with operating conditions such as a reaction inhibitor, heating rate, reaction atmosphere and the mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed in the differential scanning calorimeter(DSC), C 80 calorimeter, and thermal screening unit($TS^u$). It was suggested that we should provide the thermal characteristics for raw materials to present safe precautions with operating conditions in the vinyl acetate polymerization process.

• 접착 및 계면
• /
• 제12권1호
• /
• pp.1-10
• /
• 2011

자동화된 반응 열량계를 이용하여 중합비율을 관찰하면서 blockiness가 다른 PVOH를 이용하여 VAE 에멀젼을 합성하였다. 입자 분포도를 관찰 결과 단량체와 물과 비율에 따른 일정한 그라프트율은 없었다. 초기 단량체-물의 비율이 낮은 곳에서 겔 효과가 관찰되었다. 또한 입자 분포는 넓고 이중 피크가 관찰되었다. 지속적으로 제한적으로 응징집되면서 입자성장이 이루어지는 것이 관찰되었다. 이것은 제한적인 응집현상과 사슬이 PVOH로 그라프팅되어 발생한 결과로 판단된다.

• 청정기술
• /
• 제12권4호
• /
• pp.191-197
• /
• 2006

초임계이산화탄소 내에서의 고분자중합은 생성된 고분자와 미반응물질의 분리가 용이하며, 유기용매나 물을 매체로 사용하는 기존의 고분자합성법에서와는 달리 무독성의 $CO_2$를 사용함으로써 폐수나 공해를 발생시키지 않는 청정공정으로 주목받고 있다. 본 연구에서는 산업적으로 다양한 용도를 가지고 있는 폴리비닐알코올(poly(vinyl alcohol) 또는 PVA)의 제조에 필수적으로 요구되는 폴리비닐아세테이트(poly(vinyl acetate) 또는 PVAc)를 초임계이산화탄소를 용매로 사용하여 세계에서 두 번째로 합성하였다. Silicone계 고분자 계면활성제와 3 가지 개시제를 이용하여 338.15 K와 34.5 MPa에서 vinyl acetate의 분산중합을 실시하고, 개시제와 계면활성제의 함량변화 및 종류에 따라 생성되는 PVAc의 수율과 분자량 변화, 반응시간이 PVAc의 수율과 분자량에 영향을 알아보았다. 반응실험 결과로 얻어진 PVAc의 Mw는 60,000 ~ 140,000 g/mol, Mn은 30,000 ~ 70,000 g/mol이며, 수율은 10 ~ 80%를 기록하였다.

• 한국응용과학기술학회지
• /
• 제15권3호
• /
• pp.55-60
• /
• 1998

The sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers, which are oligomer type surfactants were prepared by polymerization with fatty acid vinyl acetate. The ${\alpha}-sulfonation$ of fatty acid vinyl ester oligomers were carried by direct addition of sulfur trioxide. The dispersing performance of oligomer type anionic surfactants and sodium dodecyl sulfate(SDS) in the aqueous suspension of iron oxide and titanium dioxide particles was evaluated by particle size distribution and zeta-potential measurement. As results, the particles of iron oxide and titanium dioxide were flocculated by addition of small amount of oligomer type anionic surfactants and sodium dodecyl sulfate(SDS), then the flocks redispersed by more addition of oligomer type anionic surfactants and SDS. The flocculation, redispersion process was observed in lower concentration range of oligomer type anionic surfactants than SDS. Especially, the dispersing action of sodium ${\alpha}-sulfo$ palmitic acid vinyl ester oligomer was better than sodium ${\alpha}-sulfo$ lauric acid vinyl ester oligomer.