THE ABSENCE OF PHYSICAL AGING EFFECTS ON THE SURFACE RELAXATIONS OF RUBBED POLYSTYRENE
Upon cooling a polymer melt, its volume and enthalpy begin to deviate from the equilibrium liquid value at glass transition temperature (Tg). When the cooling is stopped the glass spontaneously evolves towards its equilibrium thermodynamic state. Associated with the changes in thermodynamic structure are the changes in the mechanical, dielectric, etc., responses of the material that have come to be referred to as physical aging 1. The linear viscoelastic properties of polymers follow the broad outlines put forward by Struik 1 and often referred to as following a time-aging time superposition principle. Physical aging also exists in thin films. Study on thin supported films of PS aged below Tg suggests the existence of a surface layer of the order of 10 nm in which aging is complete within 103s, while the rest of the film essentially has thermal properties identical to bulk samples.
K.C.Wong Zongyi Qin Z.Yang
Department of Physics,The Hong Kong University of Science and Technology,Clearwater Bay,Kowloon,Hong Kong,China
国际会议
International Symposium on Polymer Physics(2008年国际高分子物理学术会议PP2008)
厦门
英文
149-151
2008-06-08（万方平台首次上网日期，不代表论文的发表时间）