聚砜类原位复合材料微纤结构的形成

合成了二种液晶性共聚酯Bp-LCP和BPM-LCP,将低分子量和高分子量的共聚酯以不同的配比分别与聚砜类共混制备原位复合材料.探讨了液晶共聚酯的分子结构、分子量和组分含量对原位复合材料微纤形成的影响,以及剪切力和拉伸力对微纤结构的作用,讨论了各种因素在形成微纤中的相互牵制的关系,并提出相容性与微纤关系的初步观点.研究获得,分子量高的Bp-LCP当含量较多时,在聚砜类中能形成显着的微纤结构.     

液晶聚合物/聚苯胺复合材料的导电性能研究

以4,4'-二羟基-a,a'-二甲基苄连(DDBA)羟基硅油合成了系列带有磺酸基团的液晶离聚物(LCI).合成的LCI与聚苯胺原位聚合制备出系列复合材料.采用红外光谱表征了LCI和复合材料的结构;用差示扫描量热法表征了复合材料的液晶性能;交流阻抗法测量了复合材料的电导率;结果表明:掺杂后的最大电导率能达到9.0×10-5/cm.     

液晶高分子及其原位复合材料研究进展

综述了近年来液晶聚合物及其原位复合材料的研究进展，重点阐述了目前商品化的液晶共聚酯的性能及结构，热致液晶聚合物(TLCP)与热塑性工程塑料(TP)进行原位复合时TLCP微纤化形成的机理及流变学性能，从而探讨复合材料微观结构与力学性能的关系，聚合共混物的加工性能。另外，还介绍了液晶聚合物原位复合材料的界面相容性，不同的相容剂对共混物界面附着力的改善作用。     

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。     

含二苯并-14-冠-4冠醚环主链型液晶共聚酯的设计与合成

以4,4-′(α,ω-亚烷基二酰氧)二联苯甲酰氯(M1)、顺(反)式-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4(M2、M3)和1,10-癸二醇(M4)为单体,通过溶液共缩聚反应,合成了两个系列新的含冠醚环的主链型液晶共聚酯。共聚酯的分子量不高。单体的化学结构通过IR、UV-Vis1、H-NMR和元素分析等方法确证。共聚酯的性质采用[η]、DSC、TG、WAXD和POM等方法进行了研究。发现所有的共聚酯加热到各自的熔融温度以上都能形成液晶态,在液晶态可以观察到向列相的丝状织构或纹影织构。共聚酯的熔融温度(Tm)和各向同性温度(Ti)随共聚酯分子中柔性间隔基的改变呈规律性变化。     

超支化聚酯/聚对苯二甲酸乙二醇酯复合材料的结构与性能

以分别具有端羟基、端十六烷基和端苯基的超支化聚酯(HBP)对聚对苯二甲酸乙二醇酯(PET)进行共混改性,研究了HBP的端基类型和用量对HBP/PET复合材料拉伸强度、冲击强度、结晶性能及动态黏弹性的影响。结果表明: 当端苯基超支化聚酯(HBP-Bz)、端十六烷基超支化聚酯(HBP-C16)和端羟基超支化聚酯(HBP-OH)的质量分数分别为0.1%、0.4%和0.2%时,HBP/PET复合材料的拉伸强度和冲击强度均达到最大值;3种超支化聚酯在其质量分数为0.1%~0.4%的范围内,复合材料的结晶度都得到了提高,与HBP-C16和HBP-OH相比,HBP-Bz的加入明显加快了PET的结晶速率;低用量(0.1wt%~0.4wt%)的HBP在PET共混改性中起到了增黏的效果,HBP/PET复合材料熔体表现出假塑性流体的流变行为,HBP的加入在一定程度上增加了PET大分子的链缠结和物理交联点,从而使HBP/PET复合材料的拉伸强度、冲击强度以及熔体黏度均得到提高。     

热致液晶高分子聚酯醚砜及其共混物流变行为的研究

利用于板流变仪及熔融指数仪研究了一种新型热致液晶高分子材料聚酯醚砜（ＰＥＥＳ）的流变行为，测定了该聚合物的熔体粘度－温度、粘度－剪切速率关系，以及聚合物的熔融指数－温度关系。实验结果表明，该聚合物具有热致液晶的流变特性。同时研究了该液晶聚合物与含酚酞侧基的聚芳醚砜（ＰＥＳ－Ｃ）组成的不同组分含量的原位复合材料在３６０℃下的熔融指数变化，表明该液晶聚合物能降低ＰＥＳ－Ｃ的熔体粘度，进一步说明此液晶聚合物具有改善ＰＥＳ－Ｃ的熔融加工性能的作用。     

热致液晶共聚酯/蒙脱土纳米复合材料的制备与微结构

采用一定量的有机蒙脱土和40 mo1%的聚对苯二甲酸丁二酯(PBT)与60 mol%的对羟基苯甲酸(p-HBA)的原位乙酰化法反应,制备了PBT40-PHB60热致液晶共聚酯/蒙脱土纳米复合材料.实验结果表明液晶共聚酯和蒙脱土之间存在强烈的相互作用,蒙脱土以完全剥离的形态分散于液晶高分子形成了全剥离型的热致液晶共聚酯/蒙脱土纳米复合材料,其中LCP仍然表现出原有的向列型液晶行为,但液晶微区随蒙脱土含量的增加而明显细化,纹影结构的向错点也变得模糊.     

新型含磷氮阻燃性液晶高分子阻燃剂的合成

热致型液晶共聚酯（TLCP）本身具有良好的力学性能和加工性能,与热塑性聚合物形成原位复合材料,还可赋予复合材料优秀的力学性能。而通过在侧基上引入含有阻燃元素磷,获得了一种新型阻燃性液晶共聚酯。将该材料与热塑性聚合物共混以期达到同时增强和阻燃的作用。但全芳型液晶的加工温度一般太高,不利于其与常用工程塑料的共混。     

LLDPE/煤粉/乙炔黑复合材料流变性能研究

采用熔融共混制备了LLDPE/乙炔黑/煤粉复合材料,并通过毛细管流变仪对复合材料的流变性能进行了研究。详细讨论了复合材料的组成、剪切应力和剪切速率及温度对熔体流变行为、熔体黏度的影响。结果表明,LLDPE/乙炔黑/煤粉体系呈假塑性流体,表观黏度随着剪切速率增加而降低。当填料乙炔黑/煤粉含量在0%~40%范围内时,随着含量的增加,复合材料的表观黏度先增大后减小。填料乙炔黑/煤粉可以有效地增加粘流活化能,当含量为30%时,体系的表观黏度最大。     

复合材料复合型二次强度准则

本文用张量不变量,给出单向正轴复合材料二次函数强度准则的一般方程,考虑纤维增强复合材料的两种基本破坏形式,得到适用于纤维增强复合材料的复合型二次强度准则。同现行准则进行验证、比较表明,这种合理准则同试验结果符合较好,也较简单,适合工程应用。     

碳纤维表面的X—射线光电子能谱(XPS)的研究—Ⅱ

本文用XPS研究了碳纤维及经不同表面处理的碳纤维表面组成。C_1s光电子谱表明,碳纤维表面经处理后,使表面碳氢碳逐步转化为 和-CO₂H等基团的碳,这种活性基团的形成是表面氧化作用的结果,它的含量随处理时间的增加而上升达一平衡值。     

带半无限长界面裂纹的内界面模型

本文分析了现有内界面模型[1,3,4]在裂纹尖端邻域失效的原因,建议了一个内界面两侧位移差[u]与界面应力σ的非局部关系式(见公式(6)).特别地,对裂尖处应力具有(1/2)阶奇性的情形,以法向分量为例,导出了简单的关系式(参见§3中的公式(10)):其中d₁为某非局部特征长度,K₁为内界面常数,x为从裂尖标起的内界面线坐标.对切向分量也有类似结果,新模型保留了原有模型简洁的形式,且在远离裂尖处退化为原有模型.     

Phase constitutions of MoSiN anti-oxidation multi-layer coatings on CC composites by fused slurry

To improve the oxidation resistance of MoSi fused slurry coating fabricated in vacuum, MoSiN multi-layer coatings were synthesized on C/C composites in nitrogen atmosphere by fused slurry using same Mo and Si element powders. The phase compositions and microstructures were characterized by X-ray diffractometry (XRD), optical microscopy (OM), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results indicate that the MoSiN coating contains SiC inner layer and MoSi₂/Si main layer, which was similar with MoSi coating. Additionally, a thin outer layer with nano-filiform morphology has been found on the coating surface, which consists of SiC, Si₃N₄, AlN, Al₂O₃ and sialon phase. Oxidation experiments show that the MoSiN multi-layer coating exhibits excellent oxidation resistance at 1400 °C and anti-oxidizing potential ability at 1450 °C.     

Metakaolin-based inorganic polymer composite: Effects of fine aggregate composition and structure on porosity evolution,microstructure and mechanical properties

This paper examines the phase transformation, pore evolution, microstructural and mechanical changes that occur in inorganic polymer cement (IPC) in the presence of three different grade of fine aggregates (ф < 100 μm) of ladle slag, nepheline syenite and quartz sand. Experimental results indicate that polycondensation was enhanced in nepheline syenite based specimens, compared to quartz sand, due to the increase in HMAS phases in relation to the dissolution and interaction of amorphous/disordered fraction of aggregates. HCS and HCAS with HMAS phases were identified in the ladle slag based specimens. The formation of these new phases reduced both the cumulative pore volume and pores size. The apparent increase in volume of capillary pores in ladle slag based specimens was explained by the residual bubbles from the carbonates included in raw slag. The flexural strength of the inorganic polymer cement increases from 4 MPa to 4.2, 4.8 and 6.8 MPa with the addition of 20 wt% of quartz sand, nepheline syenite and ladle slag respectively. These values increase significantly between 28 and 180 days of curing (9.1 MPa for ladle slag and 10.0 MPa for nepheline syenite). It was concluded that fines can be used to remove the HM and poorly bounded alumina oligomers in metakaolin based inorganic polymer matrices and improve the interfacial zone for the design of an optimum grade and high-performance composites.     

Surface modification on polyethylene terephthalate films with 2-methacryloyloxyethyl phosphorylcholine

In this study, the surface of polyethylene terephthalate (PET) was modified to improve the protein and cell adhesion behavior with low temperature ammonia plasma treatment followed by 2-methacryloyloxyethyl phosphorylcholine (MPC) grafting. The x-ray photoelectron spectroscopy (XPS) results showed that the COO^?, NCO and POH groups were successfully incorporated onto the sample surface after MPC grafting. Furthermore, formation of new bonds, N and NH on the sample surface grafted with MPC was recorded by Fourier transform infrared spectroscopy (FTIR). A large number of spherical particles at submicron to nanometer scale were also observed on the surface by atomic force microscopy (AFM). The cell adhesion experiments on PET film surfaces were evaluated and the highly hydrophilic surfaces could not promote cell adhesion and spreading. All results achieved in this study have clearly indicated that the method combining low temperature ammonia plasma treatment and MPC grafting is an effective way of producing a suitably hydrophilic PET surface with the capability of weakening the protein adsorption greatly.     

The effects of the SiOSi segment presence in BAPP/BPDA polyimide system on morphology and hardness properties for opto-electronic application

Recent technological advances demanded incorporation of SiOSi segment into polyimides (PI)s to improve versatility in terms of processing, morphology and optoelectronic properties. In order to study the role of SiOSi segment in the morphology and hardness properties of PI, the SiOSi segment have been introduced into the PI backbone through the conventional copolymerization and in PI matrix through sol gel method. The PI series were characterized by Fourier transform infra-red (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, solution viscosity and gel permeation chromatography (GPC). Scanning electron microscope (SEM) analysis suggested a microphase separation between the two components. FT-IR spectra confirmed the presence of silicone segment, as well as a complete imidization of PI series. Micrograph suggested a homogeneous phase between the PI and silicone segment for copolymerization series while sol gel technique revealed the inorganic particles were distributed homogenously in PI matrix. It was also found that the presence SiOSi segment in PI backbone and PI matrix influenced the opto-electronic properties.