scholarly journals The effect of the structure of network junction point on the properties of model polyurethane networks.

1992 ◽  
Vol 65 (11) ◽  
pp. 701-709 ◽  
Author(s):  
Tetsuo YOKOYAMA ◽  
Kyoko HIRAOKA ◽  
Xiao-dan LI
Keyword(s):  
Junction Point ◽  
Polyurethane Networks ◽  
Network Junction

scholarly journals Selection criteria and a mathematical model for the additional source of reactive power in a backbone network

2020 ◽  
pp. 105-112
Author(s):  
Guram Makharadze ◽  
◽  
David Japaridze ◽  
Keyword(s):  
Mathematical Model ◽  
Reactive Power ◽  
Quality Criterion ◽  
Junction Point ◽  
Additional Source ◽  
Economic Criterion ◽  
Backbone Network ◽  
Junction Points ◽  
Compensating Devices ◽  
Network Junction

In a backbone network (𝑈􀯡 ≥ 220 𝑘𝑣), when the high-voltage lines are loaded with power less than natural power, we have excess reactive power. Supplying this power into the lower-voltage networks (𝑈􀯡 ≤ 110 𝑘𝑣) would be technically and economically unfeasible and requires compensation on site. In the article, in accordance with the electricity quality criterion, and taking into account the principle of a systemic approach, and using the self- and mutually reactive impedances of the network junction points, a mathematical model for selecting a compensating device in a backbone network is adopted. The quality criterion of electricity involves enforcement of requirements for the operating voltages in the junction points of a backbone network. According to the obtained mathematical model, in the junction points nodes where the operating voltages exceed their permitted values, there will be installed the compensating devices for receiving excess reactive power. However if any junction point has a high reactive load and the voltage, in this context, is below its permitted value, then, according to a model, there is a need for installing the source of reactive power in this junction point. Herewith, according to economic criterion, the model envisages the optimal redistribution of mentioned source of reactive power between the junction points of a distribution network connected to backbone network junction point.

scholarly journals Recyclable Self-Healing Polyurethane Cross-Linked by Alkyl Diselenide with Enhanced Mechanical Properties

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 773 ◽  
Author(s):  
Yuqing Qian ◽  
Xiaowei An ◽  
Xiaofei Huang ◽  
Xiangqiang Pan ◽  
Jian Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Amide Bond ◽  
Self Healing ◽  
Healing Efficiency ◽  
Polyurethane Networks ◽  
Combined Action ◽  
Cross Linker ◽  
Dynamic Structures ◽  
External Interventions

Dynamic structures containing polymers can behave as thermosets at room temperature while maintaining good mechanical properties, showing good reprocessability, repairability, and recyclability. In this work, alkyl diselenide is effectively used as a dynamic cross-linker for the design of self-healing poly(urea–urethane) elastomers, which show quantitative healing efficiency at room temperature, without the need for any catalysts or external interventions. Due to the combined action of the urea bond and amide bond, the material has better mechanical properties. We also compared the self-healing effect of alkyl diselenide-based polyurethanes and alkyl disulfide-based polyurethanes. The alkyl diselenide has been incorporated into polyurethane networks using a para-substituted amine diphenyl alkyl diselenide. The resulting materials not only exhibit faster self-healing properties than the corresponding disulfide-based materials, but also show the ability to be processed at temperatures as low as 60 °C.

Stimuli-Responsive Y-Shaped Polymer Brushes Based on Junction-Point-Reactive Block Copolymers

2012 ◽  
Vol 24 (41) ◽  
pp. 5559-5563 ◽  
Author(s):  
Christoph Tonhauser ◽  
Ali A. Golriz ◽  
Christian Moers ◽  
Rebecca Klein ◽  
Hans-Jürgen Butt ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Polymer Brushes ◽  
Junction Point ◽  
Stimuli Responsive

scholarly journals Studies of the molecular dynamics in polyurethane networks with hyperbranched crosslinkers of different coordination numbers

2007 ◽  
Vol 105 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Przemyslaw Czech ◽  
Lidia Okrasa ◽  
Jacek Ulanski ◽  
Gisele Boiteux ◽  
Francoise Mechin ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Coordination Numbers ◽  
Polyurethane Networks

Synthesis and properties of polyurethane networks derived from new soybean oil-based polyol and a bulky blocked polyisocyanate

2008 ◽  
Vol 57 (12) ◽  
pp. 1385-1394 ◽  
Author(s):  
Mehrdad Jalilian ◽  
Hamid Yeganeh ◽  
Mehdi Nekoomanesh Haghighi
Keyword(s):  
Soybean Oil ◽  
Polyurethane Networks
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