ACS树脂的结构与热性能

通过相差显微图片和红外光谱分析ACS树脂[丙烯腈(AH)-氯化聚乙烯(CPE)-苯乙烯(S_t)]的结构,利用差热分析(DTA)和热失重(TG)曲线剖析ACS树脂的热性能。结果表明,ACS树脂系CPE、CPE-g-AS和AS以分散的橡胶相(CPE相)与连续的塑料相(AS相)共存的多相抗冲体系。CPE和ACS的热解聚机理均为脱氯化氢,氧化降解。ACS热稳定性明显优于CPE。     

HDPE 2100 J结构-性能-加工关系的研究

利用红外光谱、差示扫描量热法、流变表征、Ｘ射线衍射等方法对北京燕山石油化工有限公司生产的高密度聚乙烯２１００Ｊ、２２００Ｊ以及进口２１００Ｊ的结晶行为、流变行为、力学性能等进行了对比分析,并对北京燕山石油化工有限公司生产的２１００Ｊ的加工－结构－性能关系进行了研究,以期对２１００Ｊ的推广应用有所帮助。     

Aromatic Polyamide/Sepiolite Nanocomposite Materials: Synthesis,Structure, and Properties

Polycondensation reaction of an aromatic sulfone ether diamine (containing four flexible ether and one sulfone groups) with terephthaloyl dichloride led to the preparation of a flexible aromatic polyamide thin film. By the introduction of different amounts of sepiolite nanoparticles into the backbone of polyamide matrix, related novel nanocomposites were prepared and their structures were characterized. Morphology of the polymer and nanocomposites were studied and compared through scanning electron microscopy, transmission electron microscopy, and X-ray methods. In comparison to pristine polymer, improvement in thermal and mechanical properties was observed in the nanocomposites containing sepiolite.     

含硅聚氨酯改性水性环氧固化剂的制备与性能

以聚醚二元醇(N210)、异佛尔酮二异氰酸酯(IPDI)、羟基硅油为原料,合成了异氰酸酯基封端的含硅聚氨酯预聚体(PU-Si),再以PU-Si、环氧树脂E-51、丁基缩水甘油醚单封端的四乙烯五胺(TEPA-660a)为主要原料,制备了含硅聚氨酯改性水性环氧树脂固化剂,将制得的环氧树脂固化剂与环氧树脂E-51混和制得固化膜。用FTIR、TEM、SEM、TG和水接触角测试仪对聚合物的结构与性能进行了表征与测试,并考察了PU-Si含量对固化剂乳化性能、固化膜力学性能、热性能、断面形貌及吸水率的影响。结果表明:当固化膜中PU-Si的质量分数达到18%时,固化膜的综合性能最佳,此时冲击强度为22.45 k J/m~2,拉伸强度为44.7 MPa,热失重5%和50%时的温度分别为205.0和373.8℃,水接触角为96.8°,吸水率仅1.35%,与纯环氧树脂固化膜相比,其柔韧性、耐热性、耐水性等性能均有显著提高。     

茂金属聚乙烯材料结构与加工性能研究

研究了茂金属聚乙烯结构,发现茂金属聚乙烯(mPE)具有比传统聚乙烯更规整的结构、更窄的分子量分布;指出:通过改进mPE的合成技术,使用复配催化剂生产双峰或宽峰聚乙烯,改进树脂加工设备等手段可以制得性能优良的茂金属乙烯制品。     

Processing and thermal properties of mayenite electride

A mayenite-based electride is being considered for field emitter applications where it will be critical to have a good understanding of processing repeatability and thermal properties. This paper focuses on the details of processing of mayenite compounds in a strongly reducing graphite environment to form an electride solid-solution phase as Ca₁₂Al₁₄O₃₂(C₂,O₂)_1-x(e₂)_x. The work reports, in addition to processing details, several thermal properties. The electride phase was found to have coefficient of thermal expansion (CTE) of 7e-6 K⁻¹, thermal diffusivity between 0.0063 and 0.0102 cm²/s, and thermal conductivity between 1.9 and 3.1 W m⁻¹ K⁻¹. Rattling motion of O²⁻ or C₂²⁻ ions in cage structure has been suggested to explain low thermal conductivity of the electride phase.     

无规共聚聚丙烯(PP-R)结晶与流变性能的研究

研究了无规共聚聚丙烯的结构与加工性能,利用DSC研究了PP R的结晶速率与结晶动力学,通过改造的聚合物流变在线测量装置和毛细管流变仪研究了无规共聚聚丙烯(PP R)的熔体表观粘度与剪切应力的关系,熔体粘度与加工温度的关系以及挤出胀大现象。     

改性共聚酯切片的化学结构及热性能

在30 L聚合装置上,成功制备了一系列用聚乙二醇(PEG)和间苯二甲酸乙二醇酯-5-磺酸钠(SIPE)改性的共聚酯切片(MECDP)。核磁氢谱(1H-NMR)的测试结果表明:聚合物大分子链中的精对苯二甲酸(PTA)与SIPE单元的摩尔比以及PTA与PEG单元的质量比,与其相应的投料比基本一致;共聚酯的分子链化学结构与设想的分子链化学结构大致吻合。差示扫描量热法(DSC)试验结果表明:玻璃化转变温度(T)g、冷结晶温度(Tc)c和熔点(Tm)均随着PEG质量分数的增加而逐渐下降。色度(b值)变化的测试结果表明:PEG的质量分数越高,干燥温度越高,干燥时间越长,其b值会变得越大。     

一种高温环氧树脂的工艺及力学性能

对比研究了国产MERICAN 3768和国外CYCOM 890 RTM两种高温环氧树脂的工艺性和力学性能。同时选取典型航空结构,采用双轴向碳纤维织物和真空灌注工艺制备了对比零件。结果表明,国产MERICAN 3768树脂的浸润性、流变固化特性和力学性能均与国外CYCOM 890 RTM树脂相当,均具有优异的工艺性和力学性能,与纤维匹配性好,满足航空应用对树脂的要求。     

纳米凹凸棒土改性聚氨酯纤维的结构与性能

以物理共混的方法制备了纳米凹凸棒土(AT)/聚氨酯(PU)共混纤维。通过红外测试表明:AT与PU的硬段发生相互作用,增强了PU链段之间的氢键作用。动态力学性能分析的结果表明:AT可视作为物理交联点,限制了PU分子链的运动。相对于纯PU纤维,纳米AT/PU共混纤维的拉伸力学性能有了明显的提高,热稳定性能也有一定改善。     

化学改性对聚丙烯腈纤维及预氧纤维结构性能的影响

对聚丙烯腈纤维进行了化学改性,借助差示扫描量热分析（DSC）、定量傅立叶红外光谱（FT-IR）、平衡含水率、密度、力学性能等分析方法,对比研究了改性纤维、预氧化纤维、碳纤维与未改性纤维的结构性能的变化。研究表明：化学改性可促使聚丙烯腈纤维较未改性纤维初始环化反应温度前移,终止温度后移,从而有效缓解纤维在预氧化过程中的集中放热,有利于纤维结构和质量的控制;经硫酸羟胺改性后的纤维较未改性纤维制得的碳纤维抗拉伸强度提高16.3％。     

Preparation, Structure, and Properties of Thermally and Mechanically Improved Aluminum Titanate Ceramics Doped with Alkali Feldspar

Aluminum titanate (AT) ceramic materials doped with alkali feldspar ((Na_0.6K_0.4)AlSi₃O₈) have been prepared. These ceramics exhibited high sinterability, large resistance to thermal decomposition, and large flexure strength. The existence of liquid-phase feldspar at sintering temperatures promoted the formation of AT ceramics as the sintering agent. It was considered that silicon ions substituting for aluminum ions at the surface of AT crystal grains lowered the surface energy and hindered the diffusion of Ti⁴⁺ and Al³⁺, giving rise to the large resistance to thermal decomposition. As a result, doping with alkali feldspar was found to effectively improve the mechanical and thermal properties of AT ceramics.     

软段对IPDI基透明聚氨酯弹性体微相结构与性能的影响

采用不同结构的软段、扩链剂l,4-丁二醇和异佛尔酮二异氰酸酯(IPDI)为主要原料合成了透明聚氨酯弹性体。研究了软段结构变化对聚氨酯弹性体的微相结构、力学性能、热稳定性及光学透明性的影响。结果表明,相对分子质量高的软段比相对分子质量低的软段更易结晶,耐低温性能更好;与聚氧四亚甲基二醇(PTMG)相比,聚酯型聚己二酸丁二醇酯二醇(PBAG)更易结晶。结晶尺寸在纳米级,材料的透明性可达85％以上。软段含量增加对软段区的结晶影响较小,但力学性能下降明显。混合多元醇的加入进一步提高了聚氨酯弹性体的微相分离程度,有利于软段结晶,在宏观上表现为拉伸强度和弹性模量明显增加。     

含氟表面活性剂的结构、特性及应用研究

含氟表面活性剂是特种表面活性剂的一类。与传统的表面活性剂相比，由于其具有高表面活性，优良的耐热性和化学稳定性以及卓越的憎水、憎油性能和防污功能，因此含氟表面活性剂已经广泛应用于各个工业领域及家庭用品领域等。本文对含氟表面活性剂的分类结构、特性及应用领域进行简单综述。     

Synthesis and Properties of Polyimides Based on an Ether Ketone Diamine, 4,4'-Bis(4-aminophenoxy)benzophenone

A diamime monomer with ether-ketone group, 4,4'-Bis(4-aminophenoxy)benzophenone (II) was prepared through the nucleophilic substitution reaction of 1-chloro-4-nitrobenzene with 4,4'-Dihydroxybenzophenone in the presence of potassium carbonate in N,N-dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Polyimides (PI) V _a–f (H), V _a–f (C) and copolyimides (co-PI) V _{b–d/m(e–f)} were synthesized from II and six kinds of commercial aromatic dianhydrides (III _a–f )via thermal or chemical imidization method. Poly(amic acid) (IV _a–f )had inherent viscosities range from 0.81 to 0.98 dL/g. PI of thermal imidization method was showed poor solubility even sulfuric acid. But PI of chemical imidization method V _e,f (C) and (co-PI(C)) could be dissolved. The reason is that the ketone group of poly(amic acid) segments linked with the terminal amino group of polymer chains during thermal imidization. PI films V _a–f (H) had tensile strengths of 101–118 MPa, elongations to break of 11–32%, and initial moduli of 2.1–2.8 GPa. The glass transition temperatures of V series were in the range of 252–278°C, and the temperatures of 10% weight loss (T ₁₀) were above 529°C and their residues more than 50% at 800°C in nitrogen. V series also measured the color, dielectric constants and moisture absorptions. Their films had cutoff wavelengths between 378–421 nm, b ^* values ranging from 16.4 to 77.1, dielectric constants of 3.47–3.85 (1 MHz), and moisture absorptions in the range of 0.31–0.46 wt%.     

氟硅酸盐微晶玻璃的结构和性能

本文介绍了氟硅酸盐微晶玻璃的结构和性能,并指出了当前存在的几个问题。     

橡胶结构和性能的关系

从橡胶结构的角度,介绍和讨论了橡胶大分子的化学组成、分子量、分子量分布、集聚状况和外界条件对橡胶性能的影响。     

熔融挤出温度对PA6/CaCl2复合材料结构与性能的影响

采用熔融挤出的方法,制备了PA6/CaCl2复合材料,研究了熔融挤出温度对PA6/CaCl2复合材料的结晶行为和性能的影响。实验结果表明：随熔融挤出温度的提高,CaCl2与PA6的络合反应程度越大,PA6/CaCl2复合材料的结晶度越小,结晶不完善程度越大,复合材料的粘度越大,熔体流动速率越小。随熔融挤出温度的提高,复合材料的拉伸强度先增大后减小,最后近似趋于定值,冲击强度、弯曲强度随熔融挤出温度的提高总体呈增加趋势。     

Structure and Dielectric Properties of Lead Pyrochlores

This work investigates the structure and stability of the pyrochlore solid solution Pb _n Nb₂O_{5+ n} using a combination of high-resolution electron microscopy and electron diffraction. The microwave dielectric properties of the series 1.5 ≤ n ≤3.0 have been established, and the effect of the substitution of Ta⁵⁺ for Nb⁵⁺ on dielectric properties has also been investigated for n = 1.5 and 2.0. Single-phase cubic pyrochlore was obtained for n = 1.5. Compositions for which n > 1.5 showed discreet PbO-rich layers on {111}_cubic planes between alternating slabs of pyrochlore, similar in appearance to Ruddlesden–Popper phases. The occurrence of these layers results in a lowering of the overall symmetry to trigonal, and their presence was found to have a profound effect on the microwave dielectric properties.