聚醚胺類衍生高分子之製備、性質與應用

Abstract

本論文旨在製備不同聚醚胺類衍生物並探討其在相容劑、靜電分散及環氧樹脂硬化方面的效果。研究發現， in situ反應合成的PP-g-MA-co-POPs共聚物，對於PA6/PP摻合物的增容效果，比使用傳統的PP-g-MA相容劑更好。因為PP-g-MA-co-POPs共聚物在摻混過程中，可與PA6反應形成混合的PP-g-MA-co-POP-PA6、PP-g-MA-co-POP-co-PA6及/或PP-g-MA-co-PA6共聚物。這些共聚物為更有效的相容劑。研究顯示POP聚醚胺的分子量是控制PP-g-MA-co-POPs共聚物是否能成為有效相容劑的關鍵。本研究中，當POP聚醚胺的分子量為2000時，PP-g-MA-co-POPs共聚物為最有效的相容劑。而以SMA-co-M-2070-co-DAP共聚物作為PA6/PS摻合系統相容劑時，可能M-2070鏈段的長度不夠長，與PA6間雖然有氫鍵的作用但不夠多，因此無法成為有效的相容劑。研究顯示PS主幹及聚醚胺的分子量都是控制SMA-co-M-2070-co-DAP共聚物是否能成為有效相容劑的關鍵。 由POE聚醚胺衍生的環氧樹脂及聚醚胺-聚酯共聚物的研究知道，高分子表面經由POE鏈段吸收水分，此水分部份解離後，可促進電子的傳導，進而降低材料表面電阻。因此材料的靜電分散能力與POE鏈段的長度、含量、移動性及結晶性有關。結果顯示，結構中POE鏈段含量越高、鏈段越長及移動性越佳，表面電阻降的越多。而結晶不利於表面電阻的降低。這是因為結晶的形成使得POE鏈段親水性及移動性都降低所造成的結果。與PEG-2000共聚所得到的聚酯高分子比較，更加證明醯胺官能基吸水的重要性。除了表面電阻值外，在機械性質上亦發現了一個有趣的現象。在網狀與梳子狀混合結構中，當ED-2001添加量為25wt%及MEA添加量為9wt%時所得到的環氧樹脂，擁有一個類似彈性體的性質。 利用聚醚胺與酚類合成一系列Mannich胺混合產物，並用GPC、1H-NMR和胺值滴定去分析產物的組成和結構，可知反應之主產物與反應物性質的關聯性大，整體來說，此系列之Mannich反應在甲醛的量提高時，容易形成兩尾端帶酚的結構。而且寡聚合物的量也會增加，使得整體混合物的分子量上升。將此系列之Mannich胺應用在環氧樹脂之硬化反應時， Mannich胺與環氧樹脂硬化之反應放熱最大溫度，比單獨使用聚醚胺與環氧樹脂硬化的溫度低，因為此化合物結構中的酚基(phenoxyl)能降低胺與環氧基之反應溫度，使反應更容易進行。與純聚醚胺比較，Mannich胺所硬化之高分子的Tg較高，因為Mannich胺結構中的苯環在環氧樹脂裡是屬於較硬性(rigid)的結構，使得整體高分子的強度提高，此點與機械性質的表現是一致的，由Mannich胺所硬化之高分子的抗拉強度和抗折強度大於由聚醚胺所硬化之高分子。而加入催化劑使酚基參與反應時，硬化後高分子的Tg和機械性質比較高，因為其交聯密度提高的緣故。此一硬性的結構也使得Mannich胺所硬化之高分子的耐熱性隨著整體結構中苯環含量增加而上升。 雙環戊二烯經由酚之反應，再第二步與胺及甲醛形成Mannich胺，已證明可行。雙環戊二烯與酚的產物，藉由共硬化劑與環氧樹脂硬化發現，材料結構隨著雙環戊二烯含量增加而更柔軟。而其Mannich胺混合D-400與環氧樹脂硬化之材料。其機械性質如強度、模數、延伸率皆比商業化Jeffamine® D-400佳。

The object of this study was investigated the applications of different poly(oxyalkylene)amine derivatives in the field of compatibilizer, electrostatic dissipation and epoxy curing. The in situ formed poly(oxypropylene)-amide grafted polypropylene(PP-g-MA-co-POPs) were used as compatibilizers for the PA6/PP blends. The compatibilization effect was examined in terms of morphology, thermal and mechanical properties. Using these PP-g-MA-co-POP copolymers, the compatibilized blends show improvements in mechanical properties, including Izod impact strength and tensile toughness, over a conventional compatibilizer. The suitable molecular weight of the poly(oxypropylene) diamines in the range of 230 to 2000 is the key factor to act as an effective compatibilizer. During the compounding process, these compatibilizers further react with PA6 in situ to afford the mixture of PP-g-MA-co-POP-PA6, PP-g-MA-co-POP-co-PA6 and/or PP-g-MA-co-PA6 copolymers, which further improves the compatibilizing effect. However, the synthesized SMA-co-M-2070-co-DAP copolymers are less effective compatibilizers for the PA6/PS blends due to less interactions of M-2070 with PA6. The suitable molecular weight of the poly(oxyalkylene)amines and the PS backbone is the key factor to act as an effective compatibilizer. The electrostatic dissipating ability, probed by surface resistivity, of the poly(oxyalkylene)amine derived epoxies and polyesteramides is found to be affected by the nature, mobility and the weight content of poly(oxyethylene) segment in the polymer backbone, as well as the degree of crystallinity. The surface resistivity decrease is proportion to the nature, mobility and the weight content of poly(oxyethylene) segment and adversely affects by the degree of crystallinity. Comparing with PEG-2000 and ED-2001 derived polyesteramides, the presence of amide group can enhance the hydrophilic property. The polymer surfaces absorb moisture through hydrogen bonding by POE segment. The partial ionization of water into H＋ and OH－ promotes electronic conductivity. With a proper selection of mixed poly(oxyethylene-oxypropylene)diamine (25wt%) and 2-aminoethanol (9wt%), the DGEBA cured polymer was extremely ductile in appearance and shown over 500 % elongation at break under the mechanical tests. The high flexibility is rationalized by the balanced chemical structure of poly(oxyalkylene) segments and bisphenol-A distributed in a slightly crosslinking system. A family of novel Mannich bases were prepared from the Mannich reaction of phenols, formaldehyde, and poly(oxyalkylene)diamines with different molar ratios. The use of these novel Mannich bases for epoxy curing allowed us to study the structure/property relationship. By varying the ratio of phenols/amine and chemical structure of the starting poly(oxyalkylene)diamine, a series of products consisting of multiple functionalities of primary/secondary amines, phenols, and polyethers were prepared. The curing properties of these products toward diglycidyl ether of bisphenol-A (DGEBA) were examined by a differential scanning calorimeter (DSC). Mechanical properties of the cured polymers were also tested. The important features for these structures and curing properties were noticed: (1) Compared with poly(oxyalkylene)amines, the built-in phenols in the structures of Mannich bases can function as a accelerator for amine curing toward diglycidyl ethers which made Mannich bases exhibit a high curing rate (2) the tailored Mannich structures had a diversity of consecutive amine and phenol curings under catalytic (triphenyl phosphine) or different temperature conditions in a stepwise manner, which affected cured properties accordingly. (3) the polymers cured by the Mannich bases had demonstrated an improved mechanical properties, including tensile and flexural strength, over materials cured by the corresponding poly(oxyalkylene)diamines. The curing profiles and the mechanical properties of the cured polymers can be correlated with the Mannich structural variations. These NP/DCPD adducts mixed with novolak (PF1120) or JeffamineR D-400 amine as co-curing agents, the tricyclodecane structure was introduced into the epoxy network and resulted an improvement of flexibility. The improvement in tensile strength and elongation has been shown by using NP/DCPD derived Mannich amine as curing agents in comparison with poly(oxypropylene) diamine at 400 molecular weight and diethylenetriamine.