Dong-Ju Park

Catalytic conversion of carbon dioxide to polymer blends via cyclic carbonates

In the present study, synthesis of (2-oxo-l,3-dioxolan-4-yl)methyl vinyl ether(OVE) from carbon dioxide and glycidyl vinyl ether(GVE) was investigated using quaternary ammonium salts as catalyst. Among the salts tested, the one having larger alkyl group and more nucleophilic counter anion exhibited a better catalytic activity. Polymers bearing pendant 5-membered cyclic carbonate groups were prepared by radical copolymerization of OVE with acrylonitrile. The monomer reactivity ratio could be estimated as r1(OVE)=0.36 and r2(AN)=1.21 by Finemann-Ross method. The miscibility of blends containing poly(OVE-co-AN) and poly(styrene-co-acrylonitrile)(SAN) has been studied by the optical clarity and DSC. All of the OVE-AN/SAN blends studied were miscible.

A kinetic study on the reaction between glycidyl vinyl ether and carbon dioxide with quaternary ammonium salts as catalyst

The kinetics of the reaction between glycidyl vinyl ether (GVE) and carbon dioxide has been studied by using quaternary ammonium salts as catalyst. The catalysts having larger cations and more nucleophilic counter-anions showed higher activity. In a semi-batch reactor where CO2 is continuously supplied, the reaction is first order with respect to the concentration of GVE. In a high pressure batch reactor, the reaction is first order with respect to both GVE and CO2 and second order overall. In the latter case, a simple method to evaluate the rate constant and Henrys constant is also proposed.

Catalytic conversion of carbon dioxide using phase transfer catalysts

Abstract In the present study, synthesis of 5-membered cyclic carbonates from CO 2 and epoxides, such as glycidyl methacrylate(GMA) and diglycidyl 1,2-cyclohexane dicarboxylate(DCD), were investigated in view of the characteristics of phase transfer catalysts, reaction mechanisms and kinetics. Quaternary salts showed a good conversion of epoxide at 1 atm of CO 2 pressure. Among the salts tested, the one having a larger alkyl group and a more nucleophilic counter anion exhibited a better catalytic activity. Kinetic studies in a semi-batch reactor, through which a slow stream of CO 2 is continuously passed, showed that the reaction rate was pseudo-first order with respect to the concentration of epoxide. In a batch autoclave reactor with high CO 2 pressure, however, the reaction rate showed second order kinetics. The reaction was also carried out with an insoluble phase transfer catalyst, quaternary ammonium chloride(QCl) anchored to metal oxide, to facilitate the recovery of catalyst.

ABSORPTION AND REACTION OF CO2 WITH 2,3-EPOXYPROPYL PHENYL ETHER USING ALIQUAT 336 AS CATALYST

A kinetic study on the absorption and reaction of carbon dioxide with 2,3-epoxypropyl phenyl ether (phenyl glycidyl ether, PGE) in benzene solution has been carried out at room temperature in the presence of tricaprylylmethyl ammonium chloride (Aliquat 336) as catalyst. A simple method of measuring the absorbed volume of CO2 was proposed to obtain the reaction rate constant, and it was based on the film theory accompanied by a chemical reaction. The enhancement factor (β-NCO2/NCO2o) increased with increasing bulk concentration of PGE and Aliquat 336. The flux of CO2 was proportional to the agitation speed.

Catalytic utilization of carbon dioxide to polymer blends via cyclic carbonate

In the present study, the synthesis of bis(cyclic carbonate) from carbon dioxide and bisphenol A (or bisphenol S)-diglycidyl ether was investigated using quaternary ammonium salts as catalyst. Among the salts tested, the one having a larger alkyl group and more nucleophilic counter anion exhibited a better catalytic activity. Poly(hydroxyurethane)s were prepared by the polyaddition reaction of bis(cyclic carbonate) and diamine. The poly(hydroxyurethane) has shown higher thermal stability than conventional polyurethane, and is expected as novel reactive polyurethane. The miscibility of blends containing poly(hydroxyurethena) and poly(styrene-co-acrylonitrile)(SAN) has been also studied by the optical clarity method and DSC.

Catalytic oxidation of H2S to elemental sulfur over mesoporous Nb/Fe mixed oxides

Abstract The mesoporous Nb/Fe mixed oxides with different Nb/Fe ratios were prepared by short- chain amine (hexylamine) templating method via co-precipitation process, and found to be an efficient catalyst for the selective oxidation of H 2 S to elemental sulfur. Compared with the conventional co-precipitated Nb/Fe mixed oxide, the mesoporous oxide shows higher yields (ca. 91 % at 493 K) of elemental sulfur. The high catalytic activity and good stability is believed to be due to the high surface area and the relatively thick pore wall of mesoporous Nb/Fe mixed oxide.

Collision and Singularity Avoidance Path Planning of 6-DOF Dual-Arm Manipulator

In this paper, we propose a collision and singularity avoidance path planning of 6-DOF dual-arm manipulator. A manipulator with free DOF has an infinite solution depending on the position of the end effector, and it requires avoidance of singularities. The value of the joint can’t be determined, which means that falling into a singularity trap. So we propose a path planning for end-effectors by applying singularity avoidance using artificial ellipses obtained from Jacobian matrices and applying them with Artificial Potential Fields. The dual - arm manipulator solves this problem by using the manipulability measure and generates a path that avoids the singularity. Because Inverse Kinematics has much value as the D.O.F increases. Next, it merges with APF (Artificial Potential Field) planning is verified through experiments.

Leader-follower formation control for multiple mobile robots by a designed sliding mode controller based on kinematic control method

In this paper, a combination of kinematic controller and dynamic controller is proposed to solve the problem of leader-follower formation control for multiple wheeled mobile robots(WMR). Lidar sensor which is equipped on the leader robot is utilized to search and measure the relative distance and angle between the leader robot and each follower robot. With the relative information, a kinematic controller is designed to generate the command velocity and then the generated command velocity is taken as the reference input to the designed dynamic controller which is based on sliding mode control(SMC) strategy. Lyapunov stability theory verifies that with the designed controller all the error signals can converge to 0. Finally, a real experiment with one leader and three followers is carried out to demonstrate the effectiveness of the proposed control system.

Development of robot manipulation technology in ROS environment

A new manipulation strategy has been proposed to grasp various objects stably using a dual-arm robotic system in the ROS environment. The grasping pose of the dual-arm has been determined depending upon the shape of the objects which is identified by the pan/tilt camera. For the stable grasping of the object, an operability index of the dual-arm robot (OPIND) has been defined by using the current values applied to the motors for the given grasping pose. When analyzing the motion of a manipulator, the manipulability index of both arms has been derived from the Jacobian to represent the relationship between the joint velocity vector and the workspace velocity vector, which has an elliptical range representing easiness to work with. Through the experiments, the OPIND applied state and the non — applied state of the dual-arm robotic system have been compared to each to other.

Driving Control by Based upon the Slip Pattern of the Ball Robot

This paper proposes a driving course plans using the slip patterns of an Mecanum wheel Ball Robot. Slip of Mecanum wheel Ball Robot causes uncertainty on the driving. This solution is necessary in order to reduce the uncertainty of the robot. Analyzing the slip pattern according on the driving angle change of the robot, which was shown in the graph for slip pattern. On the basis of a formal slip pattern can establish the moving performance of the Mecanum wheel Ball Robot and the optimal path planning. Using a self-produced robots, the experiment on the optimal path planning using a slip pattern and the performance was evaluated.