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Article: Synthesis and properties of polybenzoxazine modified polyurethanes as a new type of electrical insulators with improved thermal stability.(Report)
- Article from:
- Polymer Engineering and Science
- Article date:
- July 1, 2008
- Author:
CopyrightCOPYRIGHT 2008 Society of Plastics Engineers, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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INTRODUCTION
Polyurethanes constitute one of the most versatile classes of polymeric materials with a vast spectrum of physical, chemical, and mechanical properties [1, 2]. Despite the possibility of tailoring their properties according to requirements, polyurethanes suffer from some disadvantages such as low resistance to moisture, low resistance to polar solvents, and mainly poor thermal stability. The acceptable mechanical properties (strength, modulus, etc. ) of polyurethanes disappear above 80-90[degrees]C and thermal degradation takes place above 200[degrees]C (3).
Because of special properties, like low dissipation factor and dielectric constant ...