共缩聚醚酯聚酰胺亚胺的合成和性能研究

用对－氨基苯甲酸酯封端的聚（四次亚甲基）醚（ＡＰＴＭＯ），４，４－二氨基二苯酰胺（ＤＡＢＡ）及均苯四甲酸二酐（ＰＭＤＡ），利用溶液聚两步法合成了一系列不同硬段含量的共缩聚醚酯聚酰胺亚胺。用动态力学分析（ＤＭＡ）、示差扫描量热（ＤＳＣ）研究了样品的热性能和相态结构，用热重分析（ＴＧＡ）和应力－应变试验测定了材料的热稳定性能和力学性能。结果表明，共缩聚醚酯聚酰胺亚胺具有两相结构，有良好的力学性能和热稳     

共聚酰胺6改性研究进展

共聚酰胺由两种或多种酰胺单体或缩聚体聚合而成，通过调节共聚组份结构及组成比例，可以调控材料柔韧性、溶解性、熔融温度等性能，有利于扩宽材料加工、应用窗口，实现产品差异化应用开发。为了进一步提升共聚酰胺综合性能，相关改性研究已成为材料领域热点之一。本文综述了共聚酰胺6/66、共聚酰胺6/12、共聚酰胺6/11及三元共聚酰胺改性的研究进展，从改性方法、改性材料、提升性能、应用领域等方面进行了概述，并对共聚酰胺应用前景进行了展望。     

半芳族共聚酰胺合成及表征

采用低温溶液法制备不同链长的均聚酰胺、交替共聚酰胺和嵌段共聚酰胺,探究反应条件对聚酰胺序列结构的影响.结果表明,红外可定性区分半芳族及脂肪族聚酰胺,二胺链节中间碳原子的13 C-NMR化学位移和峰裂分情况可用于鉴别不同碳链长度的均聚酰胺、交替共聚酰胺及嵌段共聚酰胺.交替共聚酰胺PA6T/66、PA4T/46和PA3T/...     

UV-770在聚酰胺6合成中的应用

在己内酰胺开环聚合过程中加入一定量的双(2,2,6,6-四甲基-4-哌啶基)癸二酸酯(UV-770),合成改性聚酰胺6树脂。研究了UV-770对聚酰胺6光稳定性、热氧稳定性和末端氨基含量的影响。结果表明:UV-770的加入能明显提高聚酰胺6的耐紫外光及热氧稳定性,空气氛围下的起始分解温度提升20℃左右,相对黏度明显下降,在185℃空气氛围下老化30min,改性聚酰胺6相对黏度下降百分比极低(UV-770含量0.2%,下降比为纯聚酰胺6的18%),热氧稳定性明显得到改善。同时,聚酰胺6的末端氨基含量增加,加入量为0.05%时,末端氨基含量提高了3.9mmol/kg,对染色性能有所改善。而UV-770对聚酰胺6的热稳定性、结晶温度与熔融温度影响不大。     

酚酞型聚芳醚腈砜的合成与性能研究

以酚酞、２，６二卤苯甲腈、４，４’，二氯二苯砜和４，４’，二羟基二苯砜为主要原料进行共缩聚反应，合成了酚酞型聚芳醚腈砜（ＰＰ－ＰＥＮＳ）。采用红外光谱、热分析等方法对共聚物的结构、热氧稳定性和玻璃化转变温度进行了表征，并对酚酞结构单元含量和腈基含量对聚芳醚腈砜性能的影响进行了讨论     

共聚酰胺增强热塑性淀粉材料的性能

将热塑性淀粉(淀粉与甘油的质量比3：1)与低熔点共聚酰胺以不同的比例共混挤出，得到增强的热塑性淀粉材料。性能测试结果表明，共混物各组分间有较好的相容性，共聚酰胺对热塑性淀粉材料具明显的增强作用。经热水浸泡后，共混物的保留强度与单纯热塑性淀粉相比均有不同程度的提高，尤其共聚酰胺含量大于30％时，耐水性显著提高。通过流变性能分析，共聚酰胺的加入使流动活化能下降，增加了共混物的流动性。     

4,4‘—二苯醚二甲酸改性PET的热性能研究

采用示差扫描量热和热重分析的方法和对合成的不同４，４‘－二苯醚二甲酸（ＯＢＢＡ）的含量的共聚酯的热性能进行了研究。结果发现共聚酯的熔点和热结晶温度与ＰＥＴ相比有所降低；而冷结晶温度则升高。随着ＯＢＢＡ添加量的增加，在恒温热分析中热失重速率常数减小；在升温热重分析中，热失重活化能则增加。所有的实验结果皆表明，芳族醚键的引入对提高共聚酯的热性能有重要作用。     

4，4＇－二苯醚二甲酸改性PET的热性能研究

采用示差扫描量热和热重分析的方法对合成的不同４，４＇－二苯醚二甲酸（ＯＢＢＡ）含量的共聚酯的热性能进行了研究。结果发现共聚酯的熔点和热结晶温度与ＰＥＴ相比有所降低；而冷结晶温度则升高。随着ＯＢＢＡ添加量的增加，在恒温热重分析中热失重速率常数减小；在升温热重分析中，热失重活化能则增加。所有的实验结果皆表明，芳族醚键的引入对提高共聚酯的热性能有重要作用。     

热致液晶共聚酯/PA6/RSMA原位复合材料1.RSMA对热致液晶共聚酯/PA6共混体系的增容作用

选用Vectra A950热致液晶共聚酯（LCP）,制备热致液晶共聚酯（LCP）／聚酰胺6（PA6）／苯乙烯－马来酸酐无规共聚物（RSMA）三元共混物,采用注射成型的方法实现原位复合,测定复合材料的熔体流变性能,FTIR光谱,动态力学性质和共混物形态结构,研究了RSMA对聚酰胺6／热致液晶共聚酯共混体系的增容作用,结果表明,RSMA的加入提高了LCP／PA6共混体的熔体粘度：RSMA与LCP和PA6发生酯化,酰胺化反应,改善了LCP与PA6之间的相容性,使两者的玻璃化温度相互靠近,了LCP在PA6基体中的分散,增强了两者之间的界面粘接。     

P（ET—EPC）共聚酯的结构及气体透过性机理研究

通过对不同组成的共聚酯的热分析（ＤＳＣ）及密度测定，并推导出它们的ＷＬＦ自由体积分数，分析了共聚酯的基本结构以及极性对它们的影响；研究了结构、极性对共聚酯的气体透过性能的影响。     

Modification of polyurethane with wholly-rigid poly (m-phenylene isophthalamide)

Flexible polyurethane (PU) was reinforced by wholly-rigid aromatic polyamide poly (m-phenylene isophthalamide) (PmlA) (Nomex) by physical polyblending and chemical copolymerization. Three polyurethane elastomers were blended physically with various amounts of high molecular weight Nomex to form twelve PU/Nomex polyblends in order to modify their physical properties. Also three multiblock copolyamides (PU-Nomex)were synthesised with a low molecular weight diamine-terminated Nomex prepolymer as a hydrogen donor for chain extending. From differential scanning calorimetry and Rheovibron measurements it was shown that both the polyblends and multiblock copolyamides exhibited a glass transition temperature under 0 °C and had a higher storage modulus, E, than those of the polyurethane. Scanning electron microscopy revealed that the polyblends and multiblock copolyamides had a dispersed phase structure. From the wide-angle X-ray diffraction pattern of the polyurethane and multiblock copolyamides it was found that the degree of stress-induced crystallization was dependent on the composition of the soft and hard segments and also the degree of its stretching. With regard to mechanical properties, it was found that both the tensile strength and elongation of the multiblock copolyamides had a more significant reinforcing effect than those of the polyblends and polyurethanes.     

The block copolymer of nylon-6 with semi-rigid poly(p-diphenylmethyl terephthalamide)

In this study, the flexible nylon-6 was reinforced by the semi-rigid aromatic polyamide poly(p-diphenylmethyl terephthalamide) through chemical copolymerization using p-aminophenylacetic acid as a coupling agent. From differential scanning calorimetry it was discovered that theT _g andT _m of multiblock copolyamides were higher than those of triblock copolyamides. From observation by scanning electron microscopy the multiblock copolyamides exhibited a homogeneous texture rather than an aggregated one. We found that in wide-angle X-ray diffraction patterns the triblock copolyamides had two diffraction peaks, i.e. 2=20 and 24. However, the multiblock had only one peak at 2=20 which evidently indicates that a new crystal structure of multiblock copolyamides was formed. As for the mechanical properties, the multiblock copolyamides were found to have more significant reinforcing effects than those of triblock copolyamides.     

Modification of nylon-6 with semi-rigid and wholly-rigid aromatic polyamides

Nylon-6 was reinforced by two semi-rigid aromatic polyamides, poly(p-diphenylmethyl terephthalamide) (PMA), and poly(p-diphenyloxide terephthalamide) (POA), and also one wholly-rigid aromatic polyamide, poly(m-phenylene isophthalamide) (PmlA) by physical blending and chemical copolymerization usingp-amino phenyl acetic acid (P-APA) as a coupling agent. From the results of differential scanning-calorimetry, it was shown that both the polyblends with semi-rigid and wholly-rigid polyamides exhibited a glass transition temperature,Tg, higher than that of nylon-6 homopolymer. It also showed that theT _gs of wholly-rigid polyblends were higher than those of semi-rigid polyblends. Nevertheless, the multiblock copolyamides appeared to have even higherT _g andT _m, and better thermal stability. Morphological observations revealed that all the polymer alloys (polyblends and copolymers) were a dispersed phase structure, although the multiblock copolyamides were more homogeneous and compatible. Based on wide-angle X-ray diffraction, it was found that the polyblends had two diffraction peaks, i.e. 2 = 20.5 ° and 24 °. However, the multiblock copolyamides had only one peak at 2 = 20 °, evidently indicating a new crystal structure of the multiblock copolyamides formed. For the mechanical properties, it was found that the multiblock copolyamides had a more significant reinforcing effect than those of polyblends, especially those copolymerizing with wholly aromatic polyamides.     

邻位取代基对芳—脂族共聚酰胺热致液晶性能的影响

通过芳香二酰氯邻位取代基和芳香二元胺邻位取代基对所生成的大分子链的酰胺基的空间阻碍作用和脂肪族二胺与芳香族二胺的适宜配合，使大分子链的刚性和在分子链之间由酰胺基团所形成的氢键减弱，从而降低了熔融温度，达到了主链型热致液晶聚酰胺链组成设计的目的。‘     

Evaluation of thermal and dielectric behaviour of some anionic nylon 612 copolymers

The anionic nylon 612 copolymers consisting of ?-caprolactam and 0.0–50.0 wt.% of laurolactam comonomer were synthesized and some of their characteristics were compared. The melting temperature, degree of crystallinity (first and second heating scan) and crystallization temperature of the nylon 612 copolymers are influenced by the presence of comonomer (laurolactam) decreasing proportionally to the amount of the laurolactam in the initial monomer mixture. The thermal stability of the copolyamides is good and equal to that of PA 6. Dielectric measurements performed on the polymers under study, over a frequency range of 10⁰–10⁶ Hz, at temperatures from 173 to 373 K have evidenced that modification of the dielectric permittivity and dielectric loss values occur in concordance with increase/decrease of the homogeneity in the polymer chains structure induced by incorporation of laurolactam segments.     

两步掺杂合成法制备LiFePO4-C复合材料及其性能

通过两步掺杂碳采用高温固相反应法合成了锂离子电池正极LiFePO4-C复合材料.利用SEM、XRD、TG/DTA等方法对该正极材料的晶体结构、表面形貌、粒径大小和热反应进行了分析研究.实验结果表明,LiFePO4-C具有单一的橄榄石结构,前驱体掺杂14%(质量分数)、预分解后掺杂6%(质量分数)葡萄糖合成的材料具有良好的充放电性能和循环稳定性能.在0.1C倍率下进行充放电测试,首次放电比容量可达158.5mA·h/g,具有良好的电化学性能.     

Manganese Local Environment Modulation via SiO4 Substitution to Boost Sodium Storage Performance of Na4MnCr(PO4)3

Manganese-based Na superionic conductors (NASICONs) Na₄MnCr(PO₄)₃ with three-electron reaction are attractive cathode materials for sodium-ion batteries. However, the irreversible distortion of Mn local structure leads to sluggish electrode kinetics, voltage hysteresis, and poor cycling stability. Here, SiO₄ is introduced to substitute PO₄ to modulate the local environment of Mn to activate the redox activity and stabilize the reversibility of Na₄MnCr(PO₄)_2.9(SiO₄)_0.1 (NMCP-Si). A combined experimental and theoretical investigation have been undertaken to reveal the evolution of electronic structures and Na storage properties associated with SiO₄ substitution. The NMCP-Si exhibits much-enhanced rate capability and cycling stability, being attributed to the unique Jahn-Teller distortion (Mn³⁺) that facilitates sodium de/insertion kinetics by optimizing the Na ion diffusion channels. This work addresses the challenge of stabilizing the structure of Mn-based NASICONs and represents a breakthrough in understanding how to improve the Na⁺ conductivity by regulating local structure.     

Cl对LiAlH4解氢性能影响的第一性原理研究

采用基于密度泛函理论的第一性原理方法,计算了LiAlH4-Cl体系的晶体与电子结构及稳定性能。计算生成焓发现,Cl-均可替代LiAlH4晶体结构中不同位置的H原子、[AlH4]单元体及占间隙位,其占位难易程度从易到难依次为:间隙位H2位H4位H3位H1位[AlH4]单元体。H原子解离能的计算发现:在Cl-替代[AlH4]单元和占据间隙位时,LiAlH4体系的结构稳定性变差,对应体系的放氢能力提高。其中,Cl-占据间隙位时,其对应体系放氢能力最强。费米能级附近能隙ΔEH-L值变小,对应体系的结构稳定性降低,是提高LiAlH4体系放氢能力的根本原因。     

LiFePO4正极材料的研究进展

橄榄石型LiFePO4正极材料具有原料来源丰富、无毒、环境友好、理论容量较高、热稳定性和循环性能好等特点,有望成为新一代锂离子电池正极材料.介绍了LiFePO4正极材料的结构、充放电机理、性能特点及存在的问题,综述了LiFePO4的合成工艺,添加导电材料和掺杂改性等方面的研究进展.