The Effects of γ-Ray Irradiation and Microcrack on Ethanol-Induced Crack Healing in Poly(Methyl Methacrylate)

加馬射線及微裂縫對聚甲基丙烯酸酯之乙醇引發的裂縫癒合產生的影響

林宴同(Yang-Tong Lin)

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(2009年)

https://doi.org/10.6843/NTHU.2009.00426

摘要

The crack healing induced by ethanol in poly(methyl methacrylate) was studied at temperatures 40℃~60℃. We can made microcracks on the crack surface to improve the phenomenon of high degree of swelling, which is responsible for the incomplete recovery of mechanical strength. We also presented the effect of γ-Ray irradiation on crack healing induced by ethanol in poly(methyl methacrylate). The transport phenomenon can be described by anomalous diffusion of CaseΙ diffusion mixing with CaseⅡ mass transport. It is also found that the higher degree of γ-Ray irradiation causes the lower mechanical strength and the shorter time for reaching the maximum fracture strength.

關鍵字

裂縫癒合

並列摘要

裂縫癒合已是個被從多方面因素探討的主題。諸如溶劑引發、熱癒合、焊接癒合等等，在這個實驗中，我們主要是利用照射過γ-ray的聚甲基丙烯酸酯來探討乙醇的質傳行為及其所引發之裂縫癒合。我們發現乙醇在聚甲基丙烯酸酯的質傳在40℃~55℃是混合CaseⅠ及CaseⅡ的不正常擴散。其質傳行為可利用Harmon model 作曲線配合。
並且發現當照射γ-ray劑量在15~35kGy之間時，癒合強度會隨著
劑量越高而降低，並且隨著劑量提升，癒合強度達到最高值的時間也隨著縮短。此外，從以前的參考文獻我們也發現，當聚甲基丙烯酸酯浸泡乙醇時會有過度膨脹導致裂縫癒合的接面會有產生破壞的情形。我們在這篇論文當中，也引入探討在裂縫面做更小的橫向裂縫，利用這些橫向裂縫來探討它對癒合強度的影響。我們發現當橫向裂縫的數目越多，能有效提升聚甲基丙烯酸酯的癒合強度，並且在癒合強度達到最高值時，不會因過度膨脹而使癒合強度發生迅速下滑的情形。

參考文獻

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