硅氧烷表面改性聚醚酯聚酰亚胺的研究

通过两种方法。即将γ-氨丙基封端的聚二甲基硅氧烷和对氨基苯甲酸酯封端的聚(四亚甲基)醚与均苯四甲酸二酐共缩聚,和将两种预制的聚酰胺酸溶液共混,合成了一组硅氧烷改性的聚醚酯聚酰亚胺材料。ESCA能谱和表面水接触角测量研究材料的表面性质发现,硅氧烷在材料表面富集,对聚醚酯聚酰亚胺材料具有显著的表面改性作用,硅氧烷改性的聚醚酯聚酰亚胺,其热稳定性能和气体透过性能有一定程度的提高,但抗张强度和介电性能有所降低。     

聚醚聚氨酯-聚醚聚酰亚胺合金相结构的研究

通过不同分子量的对－氨基苯甲酸酯封端的聚（四次亚甲基）醚和均苯甲甲酸二酐反应,合成了聚醚聚酰胺酸;然后以不同重量比将聚醚聚氨酯和聚醚聚酰胺酸溶液混合反应亚胺化,制备了一系列不同硬段含量的聚醚聚氨酯－聚醚聚酰亚胺合金。用傅立叶变换红外光谱、动态力学分析、示差扫描量热、广角Ｘ－衍射、应力应变试验等分析测试方法对合金进行了研究,结果表明聚醚聚氨酯－聚醚聚酰亚胺合金具有很好的相分离结构,是一类新型耐高温、有韧性的热塑性弹性体。聚醚分子量相同的聚氨酯和聚酰亚胺形成的合金软段相容,合金具有两相结构;聚醚分子量不同的聚氨酯和聚酰亚胺形成的合金软段存在相分离,合金具有三相结构,表现在材料外观上分别为透明不透明的韧性膜,少量聚酰亚胺的掺入,能大大增加材料的耐热性能,而合金的材料力学性能没有明显变化。     

含有聚醚链段的可溶性聚酰亚胺气体分离膜材料及其性能

将4,4'-六氟亚异丙基-邻苯二甲酸酐(6FDA)和1,3-苯二胺(mPDA)与二端氨基聚醚缩聚, 得到含有聚醚柔性链段的聚酰亚胺气体分离膜材料. 所合成的共聚聚酰亚胺在N-甲基吡咯烷酮(NMP)和四氢呋喃(THF)等有机溶剂中具有良好的溶解性能. 研究了O2, N2, H2, CH4和CO2在聚酰亚胺均质膜中的渗透性能, 考察了二端氨基聚醚的含量、链长和化学结构对气体渗透性能的影响. 结果表明, 聚醚链段的引入增大了气体的扩散系数, 气体的渗透系数显著增大; 聚醚链段与CO2相对较强的相互作用, 增大了对CO2/N2的溶解选择性, CO2/N2的分离性能优于CO2/CH4, 同时CO2比H2优先透过膜.     

气体膜分离用过渡金属有机络合物聚酰亚胺杂化材料的研究

用三苯二醚四酸二酐 (HQDPA)或二苯酮四酸二酐 (BTDA)与二氨基二苯甲烷 (MDA)缩聚合成出聚酰胺酸溶液 ,将此溶液与过渡金属有机络合物共混 ,再经热亚胺化即可制备出一类新型的气体膜分离用过渡金属有机络合物 聚酰亚胺杂化材料 .对所得杂化材料的各项性能进行了研究 ,结果表明 ,制得的杂化材料保持了聚酰亚胺良好的力学性能、耐热性能和耐溶剂性能 .用广角X 射线衍射和液体天平对所得材料的结构进行了表征 ,结果表明 ,过渡金属有机络合物的加入能够增加聚酰亚胺材料的分子链间距 .因此 ,与相应的聚酰亚胺相比 ,杂化材料的透气系数增大而透气选择性变化不大 .     

可溶性聚酰亚胺的制备及其在液晶显示器上的潜在应用

以3,5-二硝基苯甲酰氯和4-羟基联苯为原料,合成了功能性二胺单体3,5-二氨基苯甲酸联苯酯(DABBE).用此单体与3,3′-二甲基-4,4′-二氨基二苯甲烷(DMMDA)、3,3′,4,4′-二苯醚四甲酸二酐(ODPA)共缩聚,采用低温缩聚-化学亚胺化的方法,通过调节共聚物组成制备了5种聚酰亚胺(PI).利用FT-IR、NMR、UV-Vis与DSC等手段对合成二胺单体及聚酰亚胺进行了结构表征和性能测试;研究了其溶解性能、透光性能、取向性能和耐热性能.结果表明,5种聚酰亚胺均可溶于NMP、DMF等极性溶剂;对液晶分子取向时的预倾角随DABBE的比例增加而增大,可达1.8°.但当DABBE的比例增加时,PI的分子量降低,将影响其成膜性能.此外,实验所得的PI透过率大于80%,玻璃化转变温度在220℃以上.     

新型含酯基结构的具有低线膨胀系数和吸水性的聚酰亚胺的合成

将2种主链中含有酯基结构的二胺单体:二(4-氨基苯基)对苯二甲酸酯(BPTP)和4-氨基苯基-4-氨基对苯甲酸酯(APAB),与几种常见的酸酐聚合,合成了一系列主链中含有酯基结构的新型聚酰亚胺膜材料.结果表明,所制备的聚酰亚胺薄膜表现出优良的热稳定性、机械性能和低吸水性,其中聚合物的表观玻璃化转变温度高达526℃,在空气和N2气气氛下5%的热失重温度分别在498和507℃以上,表明薄膜具有非常优异的热性能.由于聚合物主链中引入酯基结构而表现出低的线膨胀系数和吸水率.     

几种聚醚酰亚胺的气体透过性能

本文研究了一系列芳环聚醚酰亚胺(PEI)对H_2、CO_2、O_2和N_2的透过性能与分子结构之间的关系。单醚酐型聚醚酰亚胺具有较高的透氢系数和H_2/N_2分离系数。由半刚性的4,4′-二氨基二苯酮(DABP)与柔性的三苯二醚四酸二酐(HQDPA)、二苯醚四酸二酐(ODPA)缩聚得到的聚醚酰亚胺具有很高的H_2/N_2、CO_2/N_2和O_2/N_2分离系数。     

侧链含邻苯二甲酰亚胺的聚酰亚胺液晶垂直取向剂的制备与表征

以邻苯二甲酰亚胺和溴代正辛烷为原料,合成了功能性二胺单体N-辛基-4(3,5-二氨基苯甲酰基)-氨基邻苯二甲酰亚胺(D8).用此单体与3,3’-二甲基-4,4’-二氨基二苯甲烷(DMMDA)、3,3’,4,4’-二苯醚四甲酸二酐(ODPA)共缩聚,采用低温缩聚-化学亚胺化方法,通过调节共聚物组成制备了5种聚酰亚胺(PI).利用FTIR、NMR、UV-Vis与DSC等手段对合成的二胺单体及聚酰亚胺进行了结构表征和性能测试;研究了其摩擦取向性能、透光性能、溶解性能和耐热性能.结果表明,5种聚酰亚胺均可溶于常见极性溶剂,如NMP、THF等;随着D8含量的增加,PI膜对液晶分子取向时的预倾角逐渐增大至垂直,当D8含量大于20%,且经过5次摩擦后,预倾角仍能保持在89°以上.此外实验所得PI透过率大于80%,玻璃化转变温度在260℃以上.     

对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯共缩聚反应及醚键形成的研究

监测了对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯(PET)共缩聚反应过程中1HNMR图谱及特性粘度的变化,对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究。并研究了以低分子量PET或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。     

含砜基和二氮杂萘酮结构的聚酰亚胺无规共聚物的合成与性能

芳香聚酰亚胺是重要的高性能工程塑料品种之一 ,但是大多数刚性棒状分子链的全芳聚酰亚胺不溶于普通的有机溶剂 ,而且直至其分解温度也不熔 ,这给聚酰亚胺的加工带来困难 ,因此 ,限制了它的使用[1 ] .提高聚酰亚胺的可加工性并能保持其优异的耐热性能是目前研究的热点 .为了提高聚酰亚胺的溶解性能 ,基于分子设计的基本原则[2 ] ,合成了一种鲜见报道的非对称的含二氮杂萘酮结构的新型二酐单体 ,其结构为 :ＯＯＯＯＮＮＯＯＯＯ　　本文以 4,4′ 二氨基二苯醚和 4,4′ 二氨基二苯砜为共缩聚型聚酰亚胺的二胺单体 ,与等当量的该二酐单体利用“…     

Properties and hydrolysis of PLGA and PLLA cross-linked with electron beam radiation

Radiation has been used as a processing tool to modify the properties of polymers. The aim of this study is to understand how electron beam radiation, together with pentaerythritol tetraacrylate (PTTA) as a tetra-functional monomer, can alter the properties (i.e. thermal and mechanical) and hydrolysis rates of PLGA and PLLA. The effects of radiation dose and PFM concentration on the physical properties of the polymers were investigated. The results showed that upon irradiation PLGA and PLLA cross-linked, and an increased in gel content was observed. Glass transition temperature (T_g) and mechanical properties of the polymers also increased. Cross-linked PLGA and PLLA samples were found to retard hydrolytic degradation. The mechanical properties of these polymers were also unaffected by hydrolysis. In summary, PLGA and PLLA cross-linked with PTTA were found to have enhanced mechanical properties and were able to retard hydrolytic degradation.     

Synthesis and Properties of Novel Thermoplastic Poly(ester-ether-imide) Elastomers Derived from 4,4′-bis(N-trimellitimide)-diphenylether Unit with Excellent Thermal Stability

The novel poly(ester-ether-imide)s (PEEIs) were synthesized by 1, 6-hexanediol (HD), poly(tetramethylene glycol) (PTMG1000) and imide dicarboxylic acid was prepared from 1,2,4-trimellitic anhydride (TMA) and 4,4′-oxydianiline (ODA) by the traditional chemical two-step method. The structures of synthesized imide dicarboxylic acid and poly(ester-ether-imide)s were confirmed by FT-IR and ¹H-NMR spectroscopy, respectively. The intrinsic viscosities, thermal properties, dynamic mechanical properties, mechanical properties and solubility of these polymers were characterized. The results indicate that these polymers have good solubility, exhibit excellent thermal stability owing to the introduction of imide units, and the tensile strength of PEEIs increases with increasing the number of imide groups while maintaining the good elasticity of the polymers.     

全芳香族热致液晶聚合物与热塑性树脂聚砜的原位复合材料

用自制的四种全芳香族热致液晶聚合物ＢＰ ＬＣＰ、ＢＰＭ ＬＣＰ、ＢＰＡ ＬＣＰ、ＢＰＳ ＬＣＰ与热塑性树脂聚砜（ＰＳＦ）熔融共混，制备了一系列原位复合材料．研究了所得材料的微观形态、热性能、力学性能等，结果显示：四种液晶聚合物中，ＢＰ ＬＣＰ，ＢＰＳ ＬＣＰ在所用加工条件下可在ＰＳＦ中取向成纤，而且这两种共混物断面上存在皮 核效应；ＢＰＭ ＬＣＰ和ＢＰＡ ＬＣＰ未成纤，均以球状存在于ＰＳＦ中．这四种液晶聚合物与ＰＳＦ的相容性较差，各共混物的Ｔｇ均分别接近于二纯组分的Ｔｇ值，ＳＥＭ照片上明显的相界面也能说明以上问题．液晶聚合物对ＰＳＦ有增强作用，但增强效果不很显著，这可能是二者相容性较差所致     

Synthesis and dynamic mechanical properties of heterogeneous network polymers from poly(L-glutamic acid) and poly(oxyethylene glycol)

Heterogeneous network polymers composed of rigid polypeptide chains and flexible polyether chains were synthesized. That is, poly(L -glutamic acid) (PLGA) was crosslinked with poly(oxyethylene glycol) (PEG) at various carboxy/hydroxyl mole ratios K. The solubility tests and hydrolysis of heterogeneous network polymers suggest that the crosslinking reaction proceeds by esterification. The dynamic mechanical properties of these polymers(100 Hz, ?100–200°C) are greatly influenced by the presence of a trace of water and the weight per cent of PLGA. In addition, some of these polymers show only one maximum in the temperature dispersion of dynamic loss modulus E″ and tan δ, although their shape is rather broad. The x-ray photographs of these polymers show an amorphous halo or weak Debye-Sherrer rings. These findings suggest that these polymers are not simple adducts; neverthless PLGA and/or PEG domains exist.     

A small-angle neutron scattering and rheology study of the composite of chitosan and gelatin

The composite chitosan/gelatin solutions and films formed from these solutions were studied by rheological measurements, SANS and tensile tests. The relationship between the inter-molecule interactions with microstructure, rheological behaviour of a solution and eventually the mechanical performance of formed films was established. It was found that the complex formed between chitosan and gelatin was mainly through hydrogen bond but the size of the structure was also affected by electrostatic repulsions. The local structure (correlation length) and the global structure (large inhomogeneous structure size) in the composite solutions were found to be highly correlated to each other. It was also found that the interactions between these two polymers in solution were closely related to the mechanical properties of the formed films. This work will enable one to design films with desired mechanical properties through the combination of different polymers at optimum weight ratios.     

Preparation and properties of copolymer resin based on polybenzimidazole and bisoxazoline

Reaction between the NH groups in polybenzimidazole (PBI) and bisoxazoline compounds (1,3‐phenylene bisoxazoline, 1,3‐PBO) resulted in the successful preparation of novel network polymers. Adjusting the amount of the bisoxazoline compound, which is a cross‐linking agent for the preparation of network polymers, and obtaining dynamic mechanical measurements, electrical resistivity measurements, thermomechanical measurements, and tensile tests allowed the determination of the heat resistance and mechanical strength of these novel network polymers. Examination of the elementary reaction of PBI and the1,3‐PBO curing reaction by using model compounds revealed that the NH group in the PBI structure reacted with the oxazoline group of 1,3‐PBO. Comparison of noncross‐linked PBI with the PBI network polymers obtained through cross‐linking reaction with bisoxazoline compounds demonstrated improvements in heat resistance and mechanical strength of the PBI‐bisoxazoline network polymers.     

The influence of different fillers on mechanical and physical properties of high-molecular-weight biodegradable aliphatic polyesters

Poly(ethylene succinate) and poly(butylene succinate) are synthetic biodegradable polymers, and much attention is paid to study the properties of pure polymers and the polymers modified by different comonomers and filling materials. The literature data on the physical properties of these polymers vary widely depending on their method of preparation and subsequent modifications. Most of the studies deal with low- and moderate-molecular-weight polymers or commercial grade polymers, modified by different comonomers and chain-extension agents. The data on pure high-molecular-weight polymers are scarce. In this work, we have prepared high-molecular-weight (MW range of (1.4–1.8) × 10⁵) poly(ethylene succinate) and poly(butylene succinate) by direct polycondensation at 200°C in a nitrogen flow without chain-extension agents. We have further studied the properties of pure polymers and examined the effect of different fillers (carbon nanotubes, SiO₂, Aerosil®) on the mechanical and physical properties of these polymers. Because of high-molecular-weight, the polymers possess increased tensile and storage moduli and thermostability. Even very low filler contents (up to 1 wt %) have a pronounced influence on the polymer properties: the polymer tensile and the storage modulus increases, the elongation at break decreases, and the thermal stability of the polymers decreases slightly. The effects of fillers are less pronounced compared with those for low- and moderate-molecular-weight polymers. When mixed together, poly(ethylene succinate) and poly(butylene succinate) crystallize independently from each other as evident from the mechanical and thermal analysis data.     

Polydimethylsiloxane–vinyl block polymers. II. The synthesis and characterization of block polymers by the thermolysis of polydimethylsiloxane macroinitiators containing bis(silyl pinacolate) groups

The thermolysis of polydimethylsiloxanes containing thermally labile bis(silyl pinacolate) groups in the backbone in the presence of various vinyl monomers leads to the direct synthesis of block polymers. Depending on the monomer chosen, simple triblock or multisequence block polymers can be readily prepared. Analysis of the products of the block polymerizations using various styrenic-type monomers shows that only block polymers are obtained, i.e., no homo-polymers are formed. These block polymers display evidence of phase separation such as intense iridescence and solvent-dependent mechanical properties. The mechanical properties of these block polymers have been measured and found to be highly composition dependent. Depending on the block length and the relative portions of the hard (vinyl) and soft (polydimethylsiloxane) blocks, one can produce either thermoplastic elastomers or rubber-modified thermoplastics.     

PETN基PBX结合能和力学性能的理论研究

PETN(季戊四醇四硝酸酯)是著名的硝酸酯类猛炸药,用量子力学(QM)、分子力学(MM)和分子动力学(MD)方法,计算模拟其与高聚物组成的PBX(高聚物粘结炸药)的结合能和力学性能.以AM1-MO法和MM方法取PETN与系列高聚物的尺寸匹配原子簇模型,经几何全优化计算,发现两种方法求得的结合能彼此线性相关.对PETN超晶胞及其与系列氟聚物组成的双组分PBX,实施COMPASS力场下的分子动力学(MD)周期性模拟,求得其弹性系数、拉伸模量、体模量、剪切模量和泊松比,发现添加少量高聚物确能有效改善炸药的力学性能.     

Non-Covalent Interactions between Polyvinyl Chloride and Conjugated Polymers Enable Excellent Mechanical Properties and High Stability in Organic Solar Cells

The incorporation of insulating polymers into conjugated polymers has been widely explored as a strategy to improve mechanical properties of flexible organic electronics. However, phase separation due to the immiscibility of these polymers has limited their effectiveness. In this study, we report the discovery of multiple non-covalent interactions that enhances the miscibility between insulating and conjugated polymers, resulting in improved mechanical properties. Specifically, we have added polyvinyl chloride (PVC) into the conjugated polymer PM6 and observed a significant increase in solution viscosity, indicative of favorable miscibility between these two polymers. This phenomenon has been rarely observed in other insulating/conjugated polymer composites. Thin films of PM6/PVC exhibit a much-improved crack-onset strain of 19.35 %, compared to 10.12 % for pristine PM6 films. Analysis reveal that a “cyclohexyl-like” structure formed through dipole-dipole interactions and hydrogen bonding between PVC and PM6 acted as a cross-linking site in the thin films, leading to improved mechanical properties. Moreover, PM6/PVC blend films have demonstrated excellent thermal and bending stability when applied as an electron donor in organic solar cells. These findings provide new insights into non-covalent interactions that can be utilized to enhance the properties of conjugated polymers and may have potential applications in flexible organic electronics.