【作者】 邵瑜；

【导师】 李彦锋；

【作者基本信息】 兰州大学 ， 高分子化学与物理， 2008， 博士

【摘要】 芳香聚酰亚胺具有优异的热和化学稳定性、机械性能和电学性能。因此,被广泛应用于诸如电子、封装材料、复合材料和膜材料等领域。为了满足应用的需求,旨在改善聚酰亚胺材料加工性能所进行的可溶性聚酰亚胺的开发和研究已成为目前聚酰亚胺功能化研究中最引人注目的热点之一。本论文简述了聚酰亚胺的发展过程,并在分子水平上探讨了可溶性聚酰亚胺分子所具有的结构特点以及各种改性方法对聚酰亚胺溶解性的贡献,结合各种有利的因素,设计合成了一系列不对称芳香二胺,通过元素分析、红外光谱、核磁共振和质谱等现代分析表征手段对单体结构进行了分析和鉴定。基于新单体与四种芳香二酐—3,3′,4,4′-二苯醚四羧酸二酐(ODPA),3,3′,4,4′-二苯甲酮四羧酸二酐(BTDA),4,4′-(六氟异丙基)双邻苯二甲酸酐(6FDA)和均苯四酸二酐(PMDA)的聚合反应,制备了四个系列可溶性聚酰亚胺,利用元素分析、红外光谱、核磁共振等表征手段对所得聚酰亚胺的结构进行了全面的表征确认,并利用紫外及可见光谱、TGA、DSC、广角X射线衍射、溶解性能、机械性能和介电性能等测试对相应聚酰亚胺树脂或薄膜的各种性能进行了全面讨论。本论文的主要研究工作如下:1.以对苯二酚为起始原料,经三步反应成功制备了含氟不对称二胺单体—1,4-(2′-三氟甲基-4′,4″-二氨基苯氧基)苯(PAPB),并与一系列芳香二酐,通过“二步法”制备了一系列新型可溶性聚酰亚胺。这些聚酰亚胺在极性有机溶剂中都有比较好的溶解性能,同时具有优异的热性能和机械性能。玻璃化转变温度及氮气氛围中热降解温度分别为232-272和525-582℃,拉伸强度及断裂伸长率分别为74.5-121.7 MPa和6-13%;同时这些聚酰亚胺薄膜还具有比较低的介电常数,10 MHz频率下为1.82-2.53。从溶解性的测试结果可以得知,所合成的聚酰亚胺在普通溶剂中具有优异的溶解性能。2.以对苯二酚为原料,与邻氯硝基苯/间二硝基苯反应,成功合成了两种新的异构化芳香二胺单体:1,4-(2′,4″-二氨基苯氧基)苯(OAPB)和1,4-(3′,4″-二氨基苯氧基)苯(MAPB),并与一系列芳香二酐通过“二步法”聚合制备了两个系列新型可溶性聚酰亚胺。由二胺OAPB制备的系列聚酰亚胺薄膜具有优异的热性能,机械性能和较低的介电常数,其玻璃化转变温度及氮气氛围下热降解温度分别为230.2-299.0℃和519.9-562.0℃,拉伸强度及杨氏模量分别为41.4-108.5 MPa和1.15-1.68 GPa,断裂伸长率为5-13%。10 MHz频率下介电常数为2.24-2.80。二胺(MNPB)制备的系列聚酰亚胺也具有相类似的性能,其玻璃化转变温度及氮气氛围下热降解温度分别为234.8-280.9℃和526.5-595.1℃,700℃下的残留为23.4-41.3%。3.以间苯二酚、对氯硝基苯及2-氯-5-硝基三氟甲苯为起始原料,经三步反应成功合成了一种新型含三氟甲基不对称二胺单体—1,4-(2′,4″-二氨基苯氧基)苯(PMAPB),与一系列芳香二酐通过“二步法”聚合制备了一个系列新型含氟聚酰亚胺。这个系列的聚酰亚胺有较高的分子量、优异的溶解性能和热性能以及较低的介电性能。其玻璃化转变温度和氮气氛围下热分解温度分别为204-260℃和521-555℃,表明得到的该类聚酰亚胺具有很高的热稳定性。10MHz频率下介电常数为2.15-2.71。含三氟甲基的聚酰亚胺较不含三氟甲基的聚酰亚胺具有更好的溶解性和更低的介电常数。该类聚酰亚胺不但在非质子极性溶剂中,如DMF,DMAc及NMP中表现出优异的溶解性能,而且在低沸点的普通溶剂中也具有比较好的溶解性能。更多还原

【Abstract】 Aromatic polyimides possess excellent thermal and mechanical,electrical,and chemical properties.Therefore,they are being used in many applications such as electrics,coatings,composite material,and membranes.However,the commercial use of these materials is often limited because of their poor solubility,and high softening or melting temperatures.To overcome these problems,more and more attempts have been focused on the preparation of novel polyimides with improved properties.This paper summarizes the structural characteristics of polyimides with excellent properties,and analyzed the contributions of several structural modification methods to each aspect of polyimide properties.Four novel unsymmetrical aromatic diamines, i.e.1,4-(2′-trifluoromethy1-4′,4″-diaminodiphenoxy)benzene(PAPB),1,4-(2′,4″-diaminodiphenoxy) benzene(OAPB),1,4-(3′,4″-diaminodiphenoxy)benzene(MAPB)and 1,3-(2′-trifluoromethyl-4′,4″-diaminodiphenoxy)benzene(PMAPB)were designed and prepared based on the viewpoint of molecular design,which structures were confirmed by elementary analysis,FT-IR,NMR and MS.Derived from the resulted diamines and dianhydrides such as 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA),4,4′-Oxydiphthalic anhydride(ODPA),3,3′,4,4′-benzophenonete-tracarboxylic dianhydride(BTDA)and Pyromellitic dianhydride(PMDA),four series of novel polyimides were successfully synthesized.The polymer constructions were confirmed by elementary analysis,FT-IR and ~1H-NMR.Their solubility,thermal property,mechanical property,aggregate structures,and dielectric property were investigated and discussed.A new aromatic unsymmetrical ether diamine with trifiuoromethyl pendent group, 1,4-(2′-trifluoromethyl-4′,4″-diaminodiphenoxy)benzene(PAPB),was successfully synthesized in three steps using hydroquinone as starting material and polymerized with various aromatic tetracarboxylic acid dianhydrides via the conventional two-step thermal or chemical imidization method to produce a series of the fluorinated polyimides.The polyimides were characterized by solubility tests,viscosity measurements,FT-IR,NMR spectroscopy,X-ray diffraction studies,and thermogravimetric analysis.The polyimides obtained had inherent viscosities ranged of 0.56-0.77 dL/g and were easily dissolved both in polar aprotic solvents and low boiling point common solvents.The resulting strong and flexible PI films exhibited excellent thermal stability with the decomposition temperature(at 5%weight loss)of above 522℃and the glass transition temperature in the range of 232-272℃. Moreover,the polymer films showed outstanding mechanical properties with the tensile strengths of 74.5-121.7 MPa,elongation at breaks of 6-13%and initial moduli of 1.46-1.95 GPa,and good dielectric properties with low dielectric constants of 1.82-2.53 at 10 MHz.The two novel unsymmetrial aromatic diamine monomers,i.e. 1,4-(2′,4″-diaminodiphenoxy)benzene(OAPB),1,4-(3′,4″-diaminodiphenoxy)benzene (MAPB),were successfully synthesized using hydroquinone as starting material and employed in the preparation of novel polyimides by polycondensation with several aromatic dianhydrides via the two-step method.The glass transition temperatures and the temperature at 5%weight loss in nitrogen of OAPB series and MAPB series were 230.2-299.0℃and 216.0-288.6℃,and 505-528℃and 515-530.6℃,respectively. The tensile strengths and modulus of OAPB series are 41.4-108.5 MPa and 1.15-1.68 GPa,respectively.The obtained OAPB films were also found fairly low dielectric constant of 2.24-2.80 at 10 MHz.And the tensile strengths and modulus of MAPB series are 39-116.0 MPa and 1.62-1.92 GPa,respectively.A new aromatic unsymmetrical ether diamine with trifluoromethyl pendent group, l,3-(2′-trifluoromethyl-4′,4″-diaminodiphenoxy)benzene(PMAPB),was successfully synthesized in three steps using resorcin as starting material and polymerized with various aromatic tetracarboxylic acid dianhydrides via the conventional two-step thermal or chemical imidization method to produce a series of the fluorinated polyimides.The resulting strong and flexible PI films exhibited excellent thermal stability with the decomposition temperature(at 5%weight loss)of above 540℃and the glass transition temperature in the range of 204.3-259.3℃.Moreover,the polymer films showed outstanding mechanical properties with the tensile strengths of 97.6-138.9 MPa,elongation at breaks of 7%-18%and initial moduli of 1.55-1.95 GPa,and good dielectric properties with low dielectric constants of 2.15-2.71 at 10 MHz.更多还原