摘要
为评估正电子湮没技术对研究聚合物玻璃化转变的适用性,测量了聚甲基丙烯酸甲酯(PMMA)和两种改性PMMA的正电子寿命谱和热-机械曲线。对于PMMA和未交联的改性PMMA,正电子素湮没寿命τ_3随温度的变化给出一个玻璃化转变温度T_8,该T_8真比由热-机械曲线测得的T_8低几度。由此看来正电子湮没技术不能用来测定部份交联的聚合物的T_8。
In order that assess the applicability of positron annihilation technique (PAT) to study the glass transition of polymers, positron lifetime spectra and thermomechanical curves for poly (methyl methacrylate)(PMMA) and two types of modified-PMMA s were measured. For the PMMA and the modified PMMA which is non crossed, the variation of τ3 (the lifetime of ortho-positronium annihilating) with temperature indicated a glass transition temperature(Tg) about a few degree below that measured on a theromechanical curve. It would seem that the PAT can hardly be used to measure the Tg of partly cross-linking polymers.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
1993年第3期129-131,共3页
Polymer Materials Science & Engineering
关键词
正电子湮没
聚甲基
丙烯酸甲酯
positron annihilation, poly (methyl methacry late), glass transition.
