1. Key Lab of Biobased Polymer Materials of Shandong Provincial Education Department College of Polymer Science and Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China
2. National Engineering Laboratory of Medical Implantable Devices & Key Laboratory for Medical Implantable Devices of Shandong Province WEGO Holding Company Limited Weihai 264210 P. R. China
3. College of Chemical Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China