Effect of Temperature and Frequency on Dynamic Mechanical Properties of Poly(Methyl Methacrylate)

Autor: Hong Chao Li, Xi Yan Luo, Xiu Juan Li, Jun Fei Li, Dun Hou Tan, Rong Guo Zhao, Chao Zhong Chen
Rok vydání: 2011
Předmět:
Zdroj: Advanced Materials Research. :1081-1086
ISSN: 1662-8985
DOI: 10.4028/www.scientific.net/amr.311-313.1081
Popis: The temperature sweep tests at defferent frequencies and heating rates, and frequency sweep tests at various temperatures for the samples of poly(methyl methacrylate) are carried out on a dynamic mechanical thermal spectrometer EPLEXOR® 500N-Gabo. The effects of temperature, frequency and heating rate on dynamic mechanical properties of poly(methyl methacrylate) are investigated. The results indicate that the glass transition temperature of poly(methyl methacrylate) increases with increasing frequency from 1 to 100Hz, and increases with increasing heating rate from 3 to 8°C/min as well. The temperature sweep curves at various heating rates suggest that the storage modulus of poly(methyl methacrylate) is non-sensitive at heating rate 3°C/min or 8°C/min, while heating rate is 5°C/min, there exists a critical temperature, within which the storage modulus versus temperature curves depart from each other, and beyond which the curves overlap one another. The glass transition temperature determined by the peak of loss modulus curve is smaller than that defined by the peak of loss tangent. The frequency sweep curves at a constant temperature show that a drop in storage modulus and a peak in loss tangent appear at a certain critical frequency, and the critical frequency increases with increasing temperature. For amorphous polymer, a competitive mechanism between frequency and temperature is observed. Higher temperature accelerates molecular motion, while higher frequency restrains molecular motion, so that the critical frequency corresponding to the peak of loss tangent shifts toward the direction of high temperature.
Databáze: OpenAIRE