經紫外光照射之聚乳酸/聚甲基丙烯酸甲酯共混物的穿透率演變

Evolution of Transmittance in UV-Irradiated PLA/PMMA Blends

黃柏穎(Huang, Po Ying)

指導教授 ： 李三保

國立清華大學/工學院/材料科學工程學系/碩士(2016年)

摘要

關於紫外光和伽瑪射線對高分子材料的影響已被廣泛地研究。本文針對經紫外光照射的聚乳酸、聚甲基丙烯酸甲酯以及其共混物的穿透率演變進行探討。
照射紫外光之聚乳酸、聚甲基丙烯酸甲酯以及其共混物皆有色心生成，導致穿透度下降。然而聚乳酸以及聚甲基丙烯酸甲酯兩種高分子本身光學性質不同，因此在等溫退火的過程中，吸收度的變化也被分為三類進行分析：第一類是聚甲基丙烯酸甲酯之吸收度隨退火時間增加而下降；第二類是聚乳酸之吸收度隨退火時間增加而呈現兩階段上升；第三類是共混物在短時間退火過程中吸收度隨時間減少，長時間退火過程中吸收度卻隨時間增加而上升。我們將波長330奈米的吸收度視為與色心濃度成正比關係，並利用一階動力學模型進行分析，發現與實驗結果相當吻合。以此所得到的反應速率符合阿瑞尼士方程式，反應活化能皆隨著照射劑量增加而上升。

關鍵字

聚乳酸 ； 聚甲基丙烯酸甲酯 ； 紫外光 ； 色心

並列摘要

The evolution of transmittance in UV and gamma irradiated polymers at elevated temperature was extensively investigated. We focus on the evolution of transmittance in UV-irradiated PLA/PMMA blends.
The transmission loss caused by UV light was attributed to the generation of color centers. The optical properties of PLA and PMMA are contrary. Therefore, after isothermal annealing, the optical absorbance change is classified into three cases: PLA, PMMA and PLA/PMMA blends. The absorbance at the wavelength of 330 nm was assumed to be proportional to the concentration of color centers. A first-order kinetic model was proposed to analyze the experimental data. The rate constant satisfies the Arrhenius equation, with the activation energy slightly increasing with the increase of UV dose.

並列關鍵字

PLA ； PMMA ； UV irradiation ； color center

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