首页 | 本学科首页   官方微博 | 高级检索  
     检索      


The linear rheological responses of wedge‐type polymers
Authors:Miao Hu  Yan Xia  Christopher S Daeffler  Jinhua Wang  Gregory B McKenna  Julia A Kornfield  Robert H Grubbs
Institution:1. Department of Chemical Engineering, Texas Tech University, Lubbock, Texas;2. Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California
Abstract:The linear rheological responses of a series of specially designed wedge‐type polymers synthesized by the polymerization of large molecular weight monomers have been measured. These wedge polymers contained large side groups which contained three flexible branch chains per polymer chain unit. The master curves for these polymers were obtained by time temperature superposition of dynamic data at different temperatures from the terminal flow regime to well below the glass transition temperature, Tg. While these polymers maintained a behavior similar to that of linear polymers, the influence of the large side group structure lead to low entanglement densities and extremely low rubbery plateau modulus values, being near to 13 kPa. The viscosity molecular weight dependence was also somewhat higher than that normally observed for linear polymers, tending toward a power law near to 4.2 rather than the typical 3.4 found in entangled linear chains. The glassy modulus of these branched polymers is also found to be extremely low, being less than 100 MPa at Tg ?60 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 899–906
Keywords:branched  glassy polymers  macromonomers  rheology  viscoelastic properties  viscosity
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号