- 學位論文
以有機膠奈米模板合成高分子之結構與性質研究
Structures and properties of polymers prepared using organogels as nano-templates
摘要
本研究是利用有機膠奈米模板合成高分子之結構與性質的研究，利用1,3:2,4-Dibenzylidene sorbitol(DBS)作為模板溶於styrene單體中，經由流變性質分析，證實其為一有機膠。隨後加入起始劑 Benzoyl peroxide (BPO)及交聯劑Divinyl benzene (DVB)以熱起始聚合反應合成高分子，經由AFM的結構分析鑑定可知，DBS在Polystyrene中是一3D網狀結構之奈米纖維，其平均直徑隨著DBS含量增加而增加；當加入DVB後，DBS自組裝奈米纖維其糾纏現象較未加入DVB時有增加的趨勢；DVB含量的增加對於奈米纖維直徑並無明顯的影響，。 利用GPC分析可知添加DBS合成後的高分子可些微提升其分子量。由TGA、DSC可得知DVB及DBS濃度的增加亦有助於熱裂解溫度及玻璃轉移溫度的提升。由DMA可知其機械性質亦隨著DVB及DBS濃度的增加而提升。經BET分析可知，當去除有機膠模板後，其比表面積會隨著DBS奈米纖維直徑增加而增加，但上升幅度隨濃度上升而下降；當未加入DVB時DBS分散性會較加入DVB時好，因此比表面積較大；加入DVB後，其比表面積亦會隨DVB含量增加而上升，因低濃度時模板分子較容易自聚，因此在去除模板後所得到之孔洞平均尺寸會較大，而隨著DVB濃度上升，其孔洞平均尺寸隨之下降，因此，其比表面積變化隨DVB濃度上升而上升。
並列摘要
We describe the preparation of nanostructured polymeric materials by polymerizing a monomer within a scaffold composed of self-assembled 1,3:2,4-Dibenzylidene sorbitol (DBS) nanofibrils. Here, we induce DBS nanofibrils in styrene and then thermally initiate the free-radical polymerization of the monomer. AFM results show that the DBS network consisted of nanofibrils measuring from 10 nm to 100 nm in diameter. The diameter sizes of DBS nanofibrils are slightly thicker at the higher DBS concentration. However, the sizes of DBS nanofibrils not affected by the addition of DVB. The DBS nanofibrils of PS samples with DVB are much more closely-packed and entangled than those without DVB. By GPC analysis, we found that adding DBS in polystyrene (PS) samples can slightly increase the molecular weights. The thermal and mechanical properties of PS/DVB/DBS are higher than those of the neat PS. The DBS nanofibrils can also be subsequently extracted from the polymer leaving behind a network of nanoscale pores. The porosity of the resulting polymer has been characterized by the BET technique. Without the amounts of DVB, entangled DBS nanofibrils would cause the decrease of the surface areas of samples after washing. The surface areas of PS samples with DBS by adding DVB are found to increase with the increase of DVB contents. It is possible that a higher degree of chemical cross-linking may lead to less interconnected pores and thus gives smaller spaces for the presences of DBS nanofibrils On the other hand, the higher DBS contents or larger sizes of DBS nanofibrils both could cause the higher surface areas after washing DBS nanofibrils .