本研究合成以開發新穎的熱固性高分子樹脂為目標，選擇米氏酸(Meldrum’s acid, MA)為反應官能基。米氏酸在高溫下，會進行裂解反應而放出一個分子的丙酮與二氧化碳，並生成具有高反應性的烯酮(ketene)官能基，此官能基可以進行[2+2]加成反應成四元環的二酮結構，也對其他雙鍵或是親核基(nucleophile)具有高反應性，因此米氏酸適合用於建構熱致交聯反應系統和設計與合成新穎的熱固性高分子。本研究首先合成帶有米氏官能基之單體，並引入可與烯酮基進行加成反應的官能基於單體結構之中，如呋喃基和苯乙烯，以此為單體進行熱固性交聯反應，建立第一個米氏酸熱固性高分子。
第一個部分，帶有呋喃與苯乙烯結構的單體(MA-FS)與帶有一對苯乙烯結構的單體(MA-SS)，分別利用Knoevenagel condensation與condensation reaction反應進行合成，並逕由傅立葉轉換紅外線光譜儀(FT-IR)、核磁共振儀(NMR)、元素分析儀(EA)與氣相層析質譜儀(GC/MS)等方法確認其化學結構。
將MA-FS與MA-SS進行加熱加工，製備成塊材，並檢測其物理性質。於實驗結果發現MA-FS所形成的熱固性樹脂具有較佳的在熱穩定性以及較高的炭焦生成率，此導因於MA-FS的結構具有呋喃基，與烯酮基反應形成一六環結構，其結構比起四環結構來得穩定，所以熱穩定性較好。在空氣下之TGA圖譜分析下， MA-SS的熱固性樹脂則具有較高的焦炭生成率，顯示其具有較佳的抗氧化熱穩定性。
在機械性質分析方面，兩者在室溫的儲存模數差異不大，約為2.7Gpa且在210 oC下沒有出現明顯的玻璃轉移溫度，可歸因於此樹脂的高交聯密度限制了分子運動，因此，在高溫區的儲存模數也相當高。在SEM與TEM的觀察下，其表面與截面的型態都相當平坦且均勻，此外，在TEM圖譜中發現有層狀結構的自組裝行為。因為聚合過程中釋放氣體小分子，而使得此熱固性樹脂的自由體積高於熱情傳統樹脂，使其具有非常低的介電常數，約為2。
本研究第二個部分仍以製備新穎米氏酸單體為出發點，設計雙端帶有米氏酸官能基的化合物，並逕由FT-IR、NMR、EA與GC/MS等方法確認成功製備出新穎米氏酸單體(MAPMA)。
利用醇基可催化米氏酸開環反應的特性，與不同結構的雙醇基單體進行等當量摻混，製備主鏈上帶有脂肪族基的熱固性材料。此材料具有良好的熱穩定性。
生物降解測試實驗中，兩個月的重量損失至70%，證明此材料確實擁有生物降解的能力。在SEM上也可以觀察到不論是截面或是表面，皆有被酵素液腐蝕的情況出現。因此，本研究成功開發出一種直接合成具有生物降解特性的熱固性高分材料。
本研究第三部分，直接以米氏酸為單體，透過使用Knoevenagel condensation反應與雙官能基的鹵化物聚合出帶有米氏酸結構的聚合物，並逕由FT-IR、NMR與GPC等方法確認其結構以及分子量。
此高分子可直接進行熱交聯而獲得熱固性高分子薄膜，具有良好的熱穩定性與機械強度。此外，也擁有介電常數低達2左右良好電器特性。此部分研究除發明直接以米氏酸單體進行聚合反應的新穎高分子合成途徑外，所合成之高分子結構可視為具有米氏酸官能基的類聚乙烯高分子，提供一種合成官能基化聚乙烯高分子的新穎而簡便的方法。

Meldrum’s acid (MA) could perform thermolysis reaction, with releasing acetone and CO2 molecules, to generate a highly reactive ketene group, which could perform self-dimerization to generate 4-membered cyclic 1,3-dione group and addition reactions toward other unsaturated groups and nucleophile groups. Consequently, MA is highly potential for involving in thermally induced crosslinking reactions and preparation of corresponding thermosetting resins. The features of MA and its derivatives have been utilized in this work for developments of new types of thermosetting resins and crosslinked polymers.
The first part of this work involves design and synthesis of multi-functional MA derivatives to be used as reactive monomers, like other conventional thermosetting resins, for demonstration a new type of MA-based thermosetting resins. Two monomers, MA-SS which is a MA compound possesses two styrenic groups and MA-FS possessing one styrenic and one furan group, have been synthesized and spectrally characterized. Both monomers result in thermosetting resins showing high glass transition temperatures above 210 oC, high thermal stability (>350 oC), and satisfied mechanical strength. It is noteworthy that the MA-based resins exhibit relatively low dielectric constants of about 2.0, which has been attributed to their high free volume fractions generated with the evolved acetone and CO2 molecules in the curing processes. Hence, a new type of MA-based thermosetting resins possessing inherent low dielectric constants has been explored.
The second part is preparation of biodegradable polyesters with MA derivatives. A bifunctional aliphatic MA compound is prepared as used as a monomer to reactive various aliphatic diol and triol compounds to result in the corresponding linear and crosslinked aliphatic polyesters. The polyesters have been subjected to biodegradability tests, and the biodegradation behavior has been observed with weight loss and SEM. The polyesters show a high fraction of biodegradation-induced weight loss of 70 wt%. It is concluded here that a novel and convenient approach for preparation of biodegradable polyesters has been demonstrated.
The final part of this work is about the developments of polymerization routes directly using MA as a monomer. MA has been reacted with dihalide compounds through dehydrohalide reaction to result in the corresponding polymers possessing MA pendent groups. The prepared polymers hence are reactive polymers which could carry out further polymer modification and crosslinking reaction through the pendent MA groups. The chemical structures and molecular weights of the obtained polymers have been characterized with spectral methods and gel permeation chromatography method, respectively. It is noteworthy that the crosslinked products of the MA-containing polymers still shows low dielectric constants of about 2.0, providing addition supports to that MA based polymers could exhibit inherent low-dielectric constants.

1. Holly, F. W.; Cope, A. C., Condensation Products of Aldehydes and Ketones with o-Aminobenzyl Alcohol and o-Hydroxybenzylamine. Journal of the American Chemical Society 1944, 11, (66), 1875-1879.
2. Burke, W. J., 3,4-dihydro-l,3,2H-benzoxazines. Reaction of p-substituted phenols with N,N-dimethylo lamines. Journal of the American Chemical Society 1949, 71, (2), 609-612.
3. Fillion, E.; Fishlock, D.; Wilsily, A.; Goll, J. M. Meldrum’s Acids as Acylating Agents in the Catalytic Intramolecular Friedel-Crafts Reaction J. Org. Chem 2005, 70, 1316-1327.
4. Burke, D. J.; Kawauchi, T.; Kade, M. J.; Leibfarth, F. A.; McDearmon, B.; Wolffs, M.; Kierstead, P. H.; Moon, B.; Hawker, C. J. Ketene-Based Route to rigid Cyclobutanediol Monomers for the Replacement of BPA in High Performance Polyesters ACS Macro Lett 2012, 1, 1228−1232.
5. Wolffs, M.; Kade, M. J.; Hawker, C. J., An Energy Efficient and Facile Synthesis of High Molecular Weight Polyesters using Ketenes Chem. Commun 2011, 47, 10572–10574.
6. Gonzalez, L.; Ramis, X.; Salla, J. M.; Mantecon, A.; Serra, A. Reduction of the Shrinkage of Thermosets by the Cationic Curing of Mixtures of Diglycidyl Ether of Bisphenol A and 6,6-dimethyl-(4,8-dioxaspiro[2.5]octane-5,7-dione) J Polym Sci Part A: Polym Chem 2006, 44, 6869–6879.
7. Leibfarth, F. A.; Wolffs, M.; Campos, L. M.; Delany, K.; Treat, N.; Kade, M. J.; Moon, B.; Hawker, C. J. Low-Temperature Ketene Formation in Materials Chemistry Through Molecular Engineering Chem. Sci 2012, 3, 766–771.
8. Meldrum, A. N. A β-lactonic acid from acetone and malonic acid J. Chem. Soc. Trans 1908, 93, 598-601.
9. Davidson, D.; Bernhard, S. A. The Structure of Meldrum's Supposed β-Lactonic Acid Journal of the American Chemical Society 1948, 70, 3426–3428.
10. Oikawa, Y.; Sugano, K.; Yonemitsu, O. Meldrum's acid in Organic Synthesis. 2. A General and Versatile Synthesis of .Beta.-Keto Esters J. Org. Chem 1978, 43, 2087.
11. Pemberton, N.; Jakobsson, L.; Almqvist, F. Synthesis of Multi Ring-Fused 2-Pyridones via an Acyl-Ketene Imine Cyclocondensation Org. Lett 2006, 8, 935.
12. Perreault, S.; Spino, C. Meldrum's Acid-Derived Thione Dienophile in a Convergent and Stereoselective Synthesis of a Tetracyclic Quassinoid Intermediate Org. Lett 2006, 8, 4385.
13. Danheiser, R. L.; Renslo, A. R.; Amos, D. T.; Wright G. T. Preparation of Substituted Pyridines via Regiocontrolled [4+2] Cycloaddition of Oximinosulfonates: Methyl 5-Methylpyridine -2-Carboxylate Org. Synth. 2003, 80, 133.
14. Danishefsky, S. Electrophilic Cyclopropanes in Organic Synthesis Acc. Chem. Res 1979, 12, 66.
15. Danishefsky, S.; Singh, R. K. A Spiroactivated Vinylcyclopropane J. Org. Chem 1975, 40, 3807.
16. Huang, X.; Liu, Z. Solid-Phase Synthesis of 4(1H)-Quinolone and Pyrimidine Derivatives Based on a New ScaffoldPolymer-Bound Cyclic Malonic Acid Ester J. Org. Chem 2002, 67, 6731.
17. Dumas, A. M.; Fillion, E. Meldrum's Acids and 5-Alkylidene Meldrum's Acids in Catalytic Carbon-Carbon Bond-Forming Processes Accounts of Chemical Research 2009, 43, 440-454.
18. Lipson, V. V.; Gorobets, N. Y. One Hundred Years of Meldrum's acid: Advances in the Synthesis of Pyridine and Pyrimidine Derivatives Mol Divers 2009, 13, 399-419.
19. Hawker, C. J.; Moon, B.; Leibfarth, F. A.; Campos, L. M.; Kang, M.; Ham, M.; Gupta, N., A facile route to ketene-functionalized polymers for general materials applications. Nature Chemisdtry 2010, 2, 207-212.
20. Shirokava, E. A.; Segal, G. M.; Torgov, I. V. Bioorg., Use of Meldrum's acid in the syntheses of low molecular weight bioregulators. 3. Synthesis of coumarin-3-carboxylic acids and their derivatives. Khim. 1988, 14, 236–242.
21. Fildes, D.; Caignaert, V.; Villemin, D.; Jaffres, P. A., Potassium exchanged zirconium hydrogen phosphateZr(O3POK)2: a heterogeneous basic catalyst for Knoevenagel reaction without solvent. Green Chem. 2001, 3, 52–56.
22. Bandgar, B. P.; Uppalla, L. S.; Sadavarte, V. S., Lithium perchlorate and lithium bromide catalyzed solvent free one pot rapid synthesis of 3-carboxycoumarins under microwave irradiation. J. Chem. Res. Synop. 2002, 40–41.
23. Hu, Y.; Wei, P.; Huang, H.; Le, Z.-G.; Chen, Z.-C., Organic reactions in ionic liquids. Ionic liquid ethylammonium nitrate-promoted Knoevenagel condensation of Meldrum's acid with aromatic aldehydes. Synth. Commun. 2005, 35, 2955–2960.
24. Mudhar, H.; Witty, A., One-pot conversion of alkyl aldehydes into substituted propanoic acids via Knoevenagel condensation with Meldrum's acid. Tetrahedron Lett. 2010, 51, 4972–4974.
25. Song, A.; Wang, X.; Lam, K. S., A convenient synthesis of coumarin-3-carboxylic acids via Knoevenagel condensation of Meldrum’s acid with ortho-hydroxyaryl aldehydes or ketones. Tetrahedron Lett. 2003, 44, 1755–1758.
26. Rao, P. S.; Venkatratnam, R. V., Indian Anhydrous zinc chloride catalysis in carbonyl-methylene condensations: synthesis of arylideneacetonitriles and arylidene heterocycles. J. Chem. 1993, 32B, 484.
27. Villemin, D., Dry-catalyzed condensation of Meldrum's acid. Chem. Ind. 1983, 478–479.
28. Thorat, M. T.; Jagdale, M. H.; Mane, R. B.; Salunkhe, M. M.; Wadagaonkar, P. P., Clay-catalyzed Knoevenagel condensation. Curr. Sci. 1987, 56, 771–772.
29. Bandgar, B. P.; Uppalla, L. S.; Kurule, D. S., Solvent-free one-pot rapid synthesis of 3-carboxycoumarins. Green Chem. 1999, 1, 243–245.
30. Davidson, D.; Bernhard, S. A., The structure of Meldrum's supposed β-lactonic acid. J. Am. Chem. Soc. 1948, 70, 3426–3428.
31. Corey, E. J., The mechanism of the decarboxylation of α,β- and β,γ-unsaturated malonic acid derivatives and the course of decarboxylative condensation reactions in pyridineJ. Am. Chem. Soc. 1952, 74, 5897–5905.
32. Kraus, G. A.; Krolski, M. E., Synthesis of a Precursor to Quassimarin. J. Org. Chem. 1986, 51, 3347–3350.
33. Bigi, F.; Carloni, S.; Ferrari, L.; Maggi, R.; Mazzacani, A.; Sartori, G., Clean Synthesis in Water. Part 2: Uncatalysed Condensation Reaction of Meldrum's acid and Aldehydes. Tetrahedron Letters 2001, 42, 5203–5205.
34. Chakrabarty, M.; Mukherjee, R.; Chakrabarty, M.; Arima, S.; Harigaya, Y., An Expeditious Approach to Knoevenagel Condensation of Meldrum's Acid on Neutral Alumina Using Microwave Irradiation. Lett. Org. Chem. 2006, 3, 868–871.
35. Kaupp, G.; Naimi-Jamal, M. R.; Schmeyers, J., Solvent-free Knoevenagel condensations and Michael additions in the solid state and in the melt with quantitative yield. Tetrahedron 2003, 59, 3753–3760.
36. Watson, B. T.; Christiansen, G. E., Solid phase synthesis of substituted coumarin-3-carboxylic acids via the Knoevenagel condensation. Tetrahedron Lett. 1998, 39, 6087–6090.
37. Darvatkara, N. B.; Deorukhkara, A. R.; Bhilarea, S. V.; Salunkhea M. M. Ionic Liquid–Mediated Knoevenagel Condensation of Meldrum's Acid and Aldehydes. Synthetic Communications 2006, 36, 3043-3051.
38. Wright, A. D.; Haslego, M. L.; Smith, F. X., Borohydride Reduction of Substituted Isopropylidene. Tetrahedron Lett 1979, 20, 2325-2326.
39. Hrubowchak, D. M.; Smith, F. X. The Reductive Alkylation of Meldrum's acid Tetrahedron Lett 1983, 24, 4951-4954.
40. Fillion, E.; Fishlock, D.; Wilsily, A.; Goll, J. M., Meldrum’s Acids as Acylating Agents in the Catalytic Intramolecular Friedel-Crafts Reaction. J. Org. Chem 2005, 70, 1316-1327.
41. Chioccara, F.; Novellino, E., A Convenient One Step Synthesis of 5-Cystein-S-yldopa Using Ceric Ammonium Nitrate. Synthetic communications 1986, 24, 185-188.
42. Chen, B. C.; Lue, P., A Convenient Preparation of 5,5-Dialkyl Meldrum's acids. Synthetic communications 1992, 16, 967-971.
43. Hawker, C. J.; Bazan, G. C.; Leibfarth, F. A.; Schneider, Y.; Lynd, N. A.; Schultz, A.; Moon, B.; Kramer, E. J., Ketene Functionalized Polyethylene: Control of Cross-Link Density and Material Properties. J. AM. CHEM. SOC. 2010, 132, 14706–14709.
44. Hawker, C. J.; Wollfs, M.; Kade, M. J., An energy efficient and facile synthesis of high molecular weightpolyesters using ketenes. Chem. Commun. 2011, 47, 10572–10574.
45. Choi, T. L.; Kim, J.; Kang, E. H., Cyclopolymerization To Synthesize Conjugated Polymers Containing Meldrum's Acid as a Precursor for Ketene Functionality. Macro Lett. 2012, 1, 1090−1093.
46. Bang, J.; Hawker, C. J.; Jung, H.; Leibfarth, F. A.; Woo, S.; Lee, S.; Kang, M., Moon, B., Efficient Surface Neutralization and Enhanced Substrate Adhesion through Ketene Mediated Crosslinking and Functionalization. Adv. Funct. Mater. 2012, 23, 1957-1602.
47. Pollet, E.; Averous, L., Environmental Silicate Nano-Biocomposites. Springer 2012, 450.
48. Catai B., Handbook of Biodegradable Polymers. Rapra Technology. Shrewsbury. 2005.
49. Nelson, D., Cox, M., Lehninger principles of biochemistry (5th ed.), W. H. Freeman 2008.
50. Yaszemski M., Biomaterials Science 2nd Edition. Academic Press 2004.
51. Andreas; Adam, S., Handbook of biodegradable polymers : synthesis, characterization and applications. Weinheim: Wiley-VCH. 2011.
52. Doi Y., Microbial polyesters. New York: VCH Publishers, Inc; 1990.
53. Bastioli C. Starch-polymer composites. In: Scott G, Gilead D, editors. Degradable polymers, principles and applications. London: Chapman & Hall 1995. 112–133.
54. Tokiwa Y., Suzuki T., Hydrolysis of polyesters by lipase. Nature 1977, 270, 76–78.
55. Hea, F., Lia, S., Verta, M., Zhuo, R., Enzyme-catalyzed polymerization and degradation of copolymers prepared from e-caprolactone and poly(ethylene glycol). Polymer 2003, 44, 5145–5151.
56. Shibata M., Ozawa K., Urata K., Teramoto N., Biodegradation of aliphatic polyester composites reinforced by abaca fiber. Polymer Degradation and Stability 2004, 86, 401-409.
57. Lin L. K., Liu Y. L., Hu C. C., Su W. C., Thermosetting resins with high fractions of freevolume and inherently low dielectric constants. Chem. Commun., 2015, 51, 12760-12763.