Preparation And Dielectric Properties Of Polyurethane Urea Composite Materials

Polyurethane as a polymer containing carbamate chain segments has a unique excellent properties, Such as:high elasticity、resistance to ozone、 wear-resisting and good oil resistance and so on,so it has been widely applied in mang fields of military affairs, national defense, civil industry, physical edueation, space flight. But Polyurethane containing some weaknesses limits its application.In order to improve its properties,mang researchers use mang methods to modify of PU. Scholars has been paied more attention to both attapulgite (ATT) and carbon nanotube (CNT) on polyurethane modified, They have good thermal performance, Electrical conductivity and mechanical property,which used in modification of polymers to improve its performance.This paper preparate optical polyurethane urea with optical activity(R-PUU and S-PUU) and racemic polyurethane urea(PUU) through hydrogen transfer addition polymerization method by using naphthalene group structure rigidity and axial asymmetry.R-PUU and PUU are characterized by FT-IR,XRD,TGand so on,and test the dielectric properties.In this paper, by analyzing the structure-activity relationship between the polymer structure and dielectric properties,TTry to explore novel ways of adjusting polymer dielectric properties and new ways.Specific results are as follows:The spectral of FTIR showed that polyurethane urea was preparated successfully through hydrogen transfer addition polymerization method.The test analysis of XRD showed that polymer belong to the semi-crystalline polymer in crystalline state.It is known that optical rotation dielectric properties of polymer is higher than racemic polymer dielectric properties, through the test of dielectric constant.This paper preparate polyurethane urea/carbon nanotube composite materials and polyurethane urea/attapulgite composite materials respectively by using In situ composite method.Composite materials are characterized by FT-IR,XRD,TGand so on.At the same time dielectric constant is measured.The SEM photographs revealed that Rod presents of attapulgite crisscrossed random phenomenon after treatment by silane coupling agent (KH-550), moreover modified attapulgite can be uniformly dispersed in the polymer matrix. There will be a reunion phenomenon with increased amount of modified attapulgite. In polyurethane urea/carbon nanotube composite material, Part of the modified carbon nanotubes is more evenly dispersed in the polymer matrix, Another part appear a significant phenomenon of reunion.The spectral of FTIR showed that inorganic particles were modified,At the same time, Modified inorganic particles and polymer matrix generates the nanocomposites.The test analysis of XRD thermogravimetric (TG) showed that polymer belong to the semi-crystalline polymer in crystalline state. The stability of composites is higher with increased amount of modified inorganic particles.It is known that dielectric properties of composite materials is higher with increased amount of modified inorganic particles, through the test of dielectric constant.