• Macromolecular Research
• /
• 제16권8호
• /
• pp.734-740
• /
• 2008

A new crosslinked, poly(acrylic acid)-based, dehydrating agent was synthesized through solution polymerization. The Taguchi method, a robust experimental design, was adopted to optimize the synthetic conditions based on the moisture and water absorbing capacities of the dehydrating agent. The method applied for the experiment was a standard L27 ($3^8$) orthogonal array with eight parameters and three levels. By analyzing the variance of the test results, the most effective parameters to control the moisture absorbing capacity (MAC) and its rate were the kind of alkaline base (LiOH, NaOH, or KOH) used as a neutralizing agent of the acrylic acid monomer and the degree of neutralization: The maximum MAC of 40% was achieved at only 2 hat $32^{\circ}C$ and 50% RH when KOH was used as a base and the degree of neutralization was 90%, respectively. However, the water absorbing capacity (WAC) of the resulting dehydrating agent was very low at 158 g/g, indicating that WAC is unaffected by MAC and its rate in this system. The surface morphologies of the agents were examined using scanning electron microscopy (SEM).

• Journal of Microbiology and Biotechnology
• /
• 제19권6호
• /
• pp.582-587
• /
• 2009

Immobilized cells of Arthrohacter nitroguajacolicus ZJUTB06-99 capable of producing nitrilase were used for biotransformation of acrylonitrile to acrylic acid. Six different entrapment matrixes were chosen to search for a suitable support in terms of nitrilase activity. Ca-alginate proved to be more advantageous over other counterparts in improvement of the biocatalyst activity and bead mechanical strength. The effects of sodium alginate concentration, $CaCl_2$ concentration, bead diameter, and ratio by weight of cells to alginate, on biosynthesis of acrylic acid by immobilized cells were investigated. Maximum activity was obtained under the conditions of 1.5% sodium alginate concentration, 3.0% $CaCl_2$ concentration, and 2-mm bead size. The beads coated with 0.10% polyethylenimine (PEI) and 0.75% glutaraldehyde (GA) could tolerate more phosphate and decrease leakage amounts of cells from the gel. The beads treated with PEI/GA could be reused up to 20 batches without obvious decrease in activities, which increased about 100% compared with the untreated beads with a longevity of 11 batches.

• 접착 및 계면
• /
• 제17권2호
• /
• pp.56-61
• /
• 2016

본 연구에서는 아크릴 접착제의 물성에 대한 주 모노머의 영향을 비교하기 위하여 2-ethylhexyl acrylate 대신에 butyl acrylate를 사용하여 acrylic acid와 2-hydroxyethyl methacrylate의 공중합체를 합성하고 2종의 경화제를 이용하여 접착 물성을 연구하였다. 선형의 측쇄사슬을 가진 butyl acrylate계 점착제는 가지형태의 측쇄를 가진 2-ethylhexyl acrylate계 접착제에 비해 낮은 접착특성을 보였다. 경화제의 경우 가교점이 많고 가교반응을 통해 유연한 ether나 ester그룹을 생성하는 epoxy형 경화제에서 우수한 물성을 보였고 관능기인 산의 농도가 높을수록 접착특성이 향상되는 것을 관찰하였다.

• 방사선산업학회지
• /
• 제9권2호
• /
• pp.77-84
• /
• 2015

The stainless steel mesh coated with poly(acrylic acid) hydrogel was fabricated and applied for the separation of water and oil. The stainless steel mesh was immersed in aqueous poly (acrylic acid) solution, and then irradiated by radiation to introduce poly(acrylic acid) hydrogel on the surface of mesh by crosslinking. It was possible to separate oil and water from mixtures of oil/water effectively using the hydrogel-coated mesh. The effect of irradiation dose, coating thickness, size of mesh on the separation efficiency was examined.

• 방사선산업학회지
• /
• 제5권4호
• /
• pp.377-382
• /
• 2011

Poly(vinyl alcohol) (PVA) is an interesting material with good biocompatibility, high elasticity and hydrophilic chacrateristics. In this study, crosslinked hydrogels based on PVA, and poly(acrylic acid) (PAAc) were prepared by gamma-ray irradiation. PVA and PAAc powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make hydrogels. The hydrogels were then annealed in an oven at $120^{\circ}C$ for 10 min, 30 min and 50 min under nitrogen atmosphere. The properties of a hydrogel such as gel fraction, swelling behavior, thermogravimetric analysis (TGA) and adhesive strength as a function of PAAc content and annealing time were investigated. The gel fraction decreases with decreasing PAAc content and increasing annealing time. The thermal behaviors have shown different patterns according to the annealing time. The adhesive strength increases with increasing PAAc content.

• 대한화학회지
• /
• 제56권1호
• /
• pp.92-101
• /
• 2012

The degradation of one of the commercially important hydrogel based on acrylic acid and acryl amide, (acrylic acid-co-acryl amide) hydrogels, by means of ultrasound irradiation and its combination with heterogeneous ($TiO_2$) was investigated. 24 kHz of ultrasound irradiation was provided by a sonicator, while an ultraviolet source of 16 W was used for UV irradiation. The extent of sonolytic degradation increased with increasing ultrasound power (in the range 30-80 W). $TiO_2$ sonophotocatalysis led to complete (acrylic acid-co-acryl amide) hydrogels degradation with increasing catalyst loading, while, the presence of $TiO_2$ in the dark generally had little effect on degradation. Therefore, emphasis was totally on the sonolytic and sonophotocatalytic degradation of hydrogels and a synergy effect was calculated for combined degradation procedures (Ultrasound and Ultraviolet) in the presence of $TiO_2$ nanoparticles. $TiO_2$ sonophotocatalysis was always faster than the respective individual processes due to the enhanced formation of reactive radicals as well as the possible ultrasound-induced increase of the active surface area of the catalyst. A kinetics model based on viscosity data was used for estimation of degradation rate constants at different conditions and a negative order for the dependence of the reaction rate on total molar concentration of (acrylic acid-co-acryl amide) hydrogels solution within the degradation process was suggested.

• 공업화학
• /
• 제9권4호
• /
• pp.516-522
• /
• 1998

아크릴산과 가교제로서 1,2-propandiol dimethacrylate (PDDMA) 및 1,1,1-trimethylolethane triacrylate (TMETA)를 셀룰로오스에 방사선 그라프트 중합시킨 후 5% 수산화나트륨 수용액으로 처리하여 흡수성 재료를 제조한 다음, 순수한 물과 염화나트륨 수용액에 대한 흡수성에 대하여 고찰하였다. 가교제로서 다관능성 단량체가 포함된 아크릴산 그라프트 셀룰로오스의 흡수력은 PDDMA는 0.75부피%에서 TMETA는 1.0부피%에서 최대점을 나타내었다. 방사선 그라프트 중합법에 의하여 제조한 흡수성 셀룰로오스와 상용화된 여성용 생리용품과의 물 및 염화나트륨 수용액에 대한 흡수율을 비교해 본 결과 여성용 생리용품의 경우 물에 대한 흡수율은 21 g/g이고 염화나트륨 수용액에 대한 흡수율은 22 g/g을 나타내었으나, 본 방사선 그라프트 중합법에 의하여 제조한 셀룰로오스는 물과 염화나트륨 수용액에 대하여 최대 298 g/g, 54 g/g의 우수한 흡수능을 나타내었다.

• 한국응용과학기술학회지
• /
• 제37권6호
• /
• pp.1627-1634
• /
• 2020

본 연구에서는 수성 아크릴계 점착제의 물성에 대한 주 단량체의 측쇄 사슬의 영향을 비교하기 위해 주 단량체로 각각 ethyl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate를 사용하여 acrylic acid, 2-hydroxyethyl acrylate와 공중합체를 합성하여 수성 아크릴 점착제를 제조하였다. 제조한 수성 아크릴 점착제의 고형분, 평균입도분포, 초기점착력, 최대점착력, 박리강도, 내열점착력 등의 물리적 특성을 비교하였다.

• 멤브레인
• /
• 제13권2호
• /
• pp.118-124
• /
• 2003

막소재는 투과증발 막공정에서 메탄을 저항체로 잘 알려진 Poly(vinyl alcohol, PVA)과 술폰기가 있는 가교제 sulfo-succinic acid(SSA)를 PVA에 대해 17 wt.%로 고정시켜 제조하였다. 이에 이온교환능력을 향상시키기 위해 양이온교환기가 포함된 poly(acrylic acid, PAA)를 첨가하여 함량변화에 따라 메탄올투과도 (methanol permeability) 특성과 이온전도도(ion conductivity)를 측정하였으며, 기본적인 이온교환막의 특성인 함수율 (water content), 이온교환용량 (ion exchange capacity, IEC) 등을 측정하였다. PAA함량에 따른 메탄을 투과도와 이온전도도 결과는 SSA만을 사용했을 때 보다 전체적으로 감소하는 경향을 나타났는데 이는 PAA의 함량 증가를 통하여 가교도의 증가로 인한 자유부피감소가 카르복실기인 양이온교환기 도입 영향보다 더 크게 작용한 것으로 판단된다 이온전도도와 메탄올투과도의 결과로부터 'vehicle mechanism'이 본 실험에서 제조된 PVA/SSA/PAA막에서 더 우세한 영향을 미쳤을 것이라 사료된다.

• 폴리머
• /
• 제33권4호
• /
• pp.319-325
• /
• 2009

편광필름용 점착제를 합성하기 위해 아크릴 단량체를 사용하여 용액중합이 수행되었다. 사용된 아크릴 단량체는 2-ethylhexylacrylate, butylacrylate, acrylic acid였으며, 비율은 점착제의 유리전이온도 $-40^{\circ}C$에 맞추어 2-ethylhexylacrylate: butylacrylate: acrylic acid=25:50:3.5로 하였다. 중합된 점착제에 커플링제를 1 wt% 첨가하였을 때 점착제의 광투과율이 매우 증가하였다. 이러한 현상은 커플링제의 Si-O 결합이 액정셀에 대한 점착력을 향상시킨 결과임을 알 수 있었다. 가교제를 단량체 대비 0.5, 1.0, 1.5 wt% 첨가하였을 매 가교제의 함량이 증가할수록 초기점착력은 감소하고 응집력은 증가하였다. 접촉각 분석에서 가교제의 함량이 증가할수록 표면에너지가 커져 접촉각이 감소하였다. 내열성 측정에서 가교제의 증가나 온도변화에 관계없이 아크릴 점착제는 우수한 내열성을 보였으며 절단면의 관찰에서 가교제의 함량이 증가할수록 절단면이 매끄럽고 깨끗하였다. 종합적으로 점착제의 초기점착력, 응집력, 표면에너지, 절단면의 상태 등을 고려하여 적정 가교제의 투입량을 1.0 wt%로 확정하였다.