PREPARATION AND CHARACTERIZATION OF POLY ( METHYL METHACRYLATE ) ( PMMA ) AND POLY ( VINYL CHLORIDE ) ( PVC ) ALLOYS
Alloys of Poly (Methyl methacrylate) (PMMA) and Poly (vinyl Chloride) (PVC) were prepared by solvent casting techniques. Physiochemical characteristics of the products were studied. It was found that at certain relative concentration, some of these properties were enhanced, while in some, degraded relative to the constituent homopolymers. These results were interpreted in terms of the interactions between the components of these blends. By means of FT infra red studies, it was established that functional groups were the major players in interactions. Other modes include dipole-dipole, van der waals and mere physical entanglements.
Polymer alloys and blends : thermodynamics and rheology
Polymer alloys and blends: thermodynamics and rheology , Polymer alloys and blends: thermodynamics and rheology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
Thermal-mechanical fully coupled analysis of high-speed angular contact ball bearings
The thermal and mechanical properties of angular contact ball bearings are critical to their operating accuracy and service life. On the basis of the theory of dynamics and frictional heat generation, this work establishes a thermal-mechanical fully coupled model. The high-speed motion characteristics, temperature, and dynamic stiffness are analyzed, and the simulation results are compared with the theoretical calculation and experimental results. Then, the temperature and axial deformation of the bearings under different rotation speeds are analyzed, and the laws of mechanical and thermal characteristics of the bearings are obtained. Results show that an increase in the rotation speed of the inner ring causes the temperature of each component to increase, with the contact area of the balls showing the greatest increase in temperature. An increase in rotation speed also increases the axial deformation of the inner ring.