Concentration Of Polyethylene Glycol Solution Research Articles

Effect of the molecular weight and concentration of PEG solution on microstructure and mechanical properties of Si3N4 ceramics fabricated by gel-casting

Gel-casting is a promising preparation technology of Si3N4 structural ceramics. The process involves drying of the “green” gel-cast parts before densification. And the drying of green gel-cast bodies is an important step in the gel-casting manufacturing process. In this work, the Si3N4 gel-cast green bodies were dried in polyethylene glycol (PEG) solution with the purpose of obtaining Si3N4 ceramics with good mechanical properties. The effect of the molecular weight and concentration of PEG solution on drying rate, microstructure and mechanical properties of Si3N4 ceramics was studied. The results indicated that with the increase of molecular weight of PEG, the drying rate increased obviously and the structure became more uniform and dense when the concentration of solution was 20 wt%. The Si3N4 ceramics after sintering have the excellent flexural strength (662.6 MPa) under PEG600 drying condition. Furthermore, the concentration of PEG600 solution had a positive effect on drying and sintering of the green body. Therefore, the bending strength reached 871.1 MPa under 65 wt% PEG 600 solution drying condition. Overall, the drying process (drying in 65 wt% PEG600 solution) promotes the efficiency and quality of drying of Si3N4 gel-cast green bodies, which is beneficial for the subsequent drying and sintering process.

聚乙二醇/二氧化钛一维光子晶体的制备及其性质研究

Multilayer polyethylene glycol / titanium dioxide( PEG / TiO2) one-dimensional photonic crystal films were fabricated by using spin coating technique. PEG / TiO2one-dimensional photonic crystal membranes with different photonic stopbands were fabricated by changing the time of spin coating,spin speed and the mass concentration of polyethylene glycol solution. The experiment results show that PEG / TiO2 film has a dual response to dimethyl sulfoxide( DMSO) and strong alkali solution.

Drying Behaviour of Gelcast Green Alumina Parts Utilizing PEG Solution

In this work, gelcast alumina green parts were dried by utilizing polyethylene glycol (PEG) solution as the liquid desiccant medium. The parts lost about 30–40 wt% of internal water in a reasonable period of time, i.e. 2–3 h and accomplished most of the shrinkage uniformly, then the part could continue drying in air at the room conditions. Finally, a defect-free porous part could be obtained after the process of the binder burnout at 900oC. The results show that the green part loses more weight at a higher rate while drying in the PEG6000 solution than in the other PEG solutions with different PEG molecular weight. The solid loading of the alumina slurry and the concentration of PEG solution also affect the drying process significantly.