Effects of Stretching and Calendering on Structure of PEEK and iPP
|Course||Materials Processing Engineering|
|Keywords||Rapid compression Amohous PEEK Drawing Critical crystal strain Crystall Calendering Compression ratio|
As is known to all, in the process of polymer processing, the external force field is an indispensable important factors,in the terms of the crystalline polymer multi-scale microstructure, the external force field can change spherulites into the fibrous structure; induce crystal orientation and transformation; cause the orientation of molecular chain to crystallization of amorphous materials, etc. These results would eventually lead to the changing of macro properties, thus the products people need to have different properties is prepared. This topic researchs the effects of stretching and calendering on the polymer microstructure evolution and mechanics proties respectively:the one is the study of strain-induced crystallization behavior of amorphous poly (ether ether ketone) under different tensile process;the other is the research of the effects of calendering crystal structure and mechanical properties of isotactic polypropylene including beta nuclear agent.Our research content mainly includes two aspects:1. The crystallization behavior of PEEK prepared by Rapid Compression and Quenched Cold drawn at different drawing temperatures and drawing speeds were studied by WAXD in this paper. The results showed that:(1)the critical crystallization strains of RC samples were lower than that of QC samples under the same drawing conditions and reduced with drawing temperature and speed increasing;(2)Crystallinity of samples drawn under the same temperature changed unconspicuously with the drawing speed increasing;(3)As drawing temperature increased, crystallinity was improved obviously, The results showed that crystallinity depended on drawing temperature mainly.2. Calendering was used to study the effects of different forming temperature and different compression ratio on the crystallization behavior, crystal transformation and the mechanical properties of iPP including nuclear agent. Results show that:(1) After the calendering, the tensile strength of sample was greatly improved, while impact strength decreased;(2) After calendering, due to the crystal crushing, crystal tilted slippage, the crystallinity and β crystal content and β crystal size become smaller, a crystal rise slightly, morever, a crystal size become bigger;(3) Compared to the original sample and the sample (CR=2) the structure of the sample of that the compression ratio is4become more uniform, crystallinity and orientation degree is almost is the same from the cortex to the core layer;(4) Crystallinity and mechanical properties of the material mainly depends on the compression ratio.