硅灰石在高压电瓷中的应用研究

首次利用龙江县硅灰石研制出了高压电瓷 ,并测试了其晶相组成和性能。实验结果表明 :硅灰石可以用于生产高压电瓷 ,且硅灰石的加入量为 5 0 %左右时 ,高压电瓷的性能较佳     

锂云母—高岭石—石英—硅灰石低温日用瓷研制

介绍以锂云母质石为主要原料，配以高岭土、石英并引入少量硅灰石制作日用瓷，这种组成的日用瓷烧成温度为１１５０℃－１１８０℃，Ｘ－射线衍射分析表明瓷相由玻璃相、英来石、钙长石晶相、残留石英和α－方石英组成。按目前日用瓷的划分规律，将研制的的这种低温瓷称为锂云母质瓷。     

景德镇高压电瓷的岩相结构特征

一、绪言由于电力工业的飞跃发展,高压电瓷绝缘子所使用的条件越来越严酷。为了改进和提高电瓷坯釉的性能、制造优质制品以及发展新型高压电瓷材料,研究单位和生产部门多年来不断地致力于生产工艺的研究,并取得了一定的成绩。高压电瓷制品是由其中的相组成、相分布及其结构所表征的。这就是说制品的岩相组成和显微结构反映了制品的物理——化学本性。但是制品的岩相结构却密切地受生产工艺过程     

钙长石涂层中晶体形成机制的研究

为提高日用陶瓷的强度，适应机械化洗涤和自动化生产线中罐装、捋瓶的需要，以传统陶瓷工业中常用的方解石、石英和α-Al₂O₃为原料配制涂层浆料，在长石质瓷表面制备了以钙长石为主晶相的涂层材料，研究了煅烧温度和保温时间对涂层物相和微观形貌的影响，并通过DTA-TG分析进一步分析了钙长石生成的反应过程。研究结果表明：硅灰石和钙铝黄长石是钙长石生成的中间产物，1200℃以上中间产物消失，钙长石为主晶相。保温时间延长晶粒尺寸增大，进一步延长至3 h，晶体在长度方向略有增长，宽度不变。     

锂云母—高岭石—石英—硅灰石低温日用瓷研制

介绍以锂云母质瓷石为主要原料,配以高岭土、石英并引入少量硅灰石制作日用瓷,这种组成的日用瓷烧成温度为1150℃－1180℃,X－射线衍射分析表明瓷相由玻璃相、莫来石、钙长石晶相、残留石英和α－方石英组成。按目前日用瓷的划分规律,将研制的这种低温资称为程云母质瓷。     

一次低温快烧高强瓷质外墙砖的研制

使用江西的硅灰石、滑石粘土、长石、粘士为原料研制生产一次低温快烧瓷质外墙砖,配方属SiO_(2)－Al_(2)－CaO - MgO四元系统,SiO_(2)/Al_(2)O_(3)=11,其烧成温度仅1120±6℃.研究表明瓷相主要由石英、顽火辉石、钙长石及玻璃相 组成,晶相含量70％－80％。这种组成的配方烧成后不形成莫来石晶相。     

晶化时间对硅渣微晶玻璃析晶和性能的影响

以硅渣为主要原料制备了Ca O-Mg O-Al2O3-Si O2-Ti O2(CMAST)体系微晶玻璃,并借助差热分析(DTA)、X射线衍射(XRD)和扫描电镜(SEM)研究了不同晶化时间对硅渣微晶玻璃的晶相含量、显微结构、析晶机理和性能的影响规律。结果表明:主晶相是透辉石(Ca Mg Si2O6)和铁板钛矿(Fe2Ti O5)的复合晶相,次晶相是钙长石[Ca(Al2Si2O8)]相和尖晶石(Mg Al2O4)相;晶粒均为球状结构。在最佳晶化时间为1.5 h,试样抗折强度为270 MPa,维氏显微硬度为834.8 MPa,化学性能优良。     

含钛高炉渣还原提取钛硅合金后尾渣制备钙长石-尖晶石轻质多孔材料研究

以含钛高炉渣提取硅钛合金后的尾渣为主要原料,采用发泡法制备了钙长石-尖晶石质轻质多孔材料.研究了尾渣的物相组成,尾渣和朔州土及石英加入量、发泡剂、促凝剂、稳定剂、煅烧温度等工艺参数对材料物相组成、气孔率、体积密度以及孔径分布等性能的影响.结果表明:提取硅钛合金后尾渣的主要物相为铝酸一钙(CA)、二铝酸一钙(CA2)、镁铝尖晶石(MA)以及少量钙铝黄长石(C2AS);多孔轻质材料的主晶相为钙长石,含有少量镁铝尖晶石;多孔轻质材料的显气孔率可以稳定控制在75％左右,体积密度控制在0.35～0.85 g/cm3之间;适宜的烧成制度为1300℃×3h.     

降低烧成温度 发展低温陶瓷制品

(三) 为了研制低温烧成的配方,在坯料组成方面,摆脱传统观念束缚,积极寻找新原料,节约燃料和传统的陶瓷原料。西班牙采用硅灰石制成低温瓷,在910～1080℃下烧成,烧成周期为5～6小时,其性能和传统的硬质瓷相近。采用硼酸铅熔块10～20％,硅灰石30～40％,高岭土30～60％,粘土0～5％。坯料具有良好的注浆性能,可以快速干燥和烧成。瓷胎中主要晶相是钙长石和硅灰石,外加0.054％Li_2O(以碳酸盐形式),在冷却时使硅灰石由α转变为β形式,制得很白的制品。该低温瓷是自己出釉制品,在表面直接可进行装饰,在制造中节省能源50％。     

CaO—Al2O3—SiO2系统玻璃晶化时首析晶相及TiO2的作用机理预测和…

通过ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系统玻璃的结构分析预测玻璃晶化时首析晶相是钙长石。选取ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２三元相图成玻璃区内的某点作为基础玻璃的组成，在基础玻璃吕加入ＴｉＯ２。用ＤＴＡ，ＸＲＤ和ＳＥＭ方法的研究结果表明，不玻璃中加ＴｉＯ２与否，晶化时首先析出的晶相都是钙长石，且均为从表面向内部生长，驰预测相符。     

腐植酸在农业方面的应用

论述腐植酸的组成、分类,腐植酸在改良土壤、增加肥效、增加药效、提高植物品质、保持生态环境等方面的作用,以及对植物生长的刺激作用。     

聚丙烯反应器合金化研究

研究了丙烯本体聚合后在聚丙烯基体中进行乙丙共聚合的各种反应条件,发现共聚合金中的共聚物含量和乙烯含量都随反应温度的升高、时间的延长、气相中乙烯含量增加和气相压力的增加而增加。其中气相乙烯含量和气相压力的改变对共聚物的组成影响最显著,随着气相乙烯含量和气相压力的增加,合金中EP和乙烯含量随之增加,同时也发现,聚丙烯合金中的乙烯含量高达27％时,聚合物粒子仍有较好的流动性。这对工业生产具有非常重要的指导意义。     

功能液晶聚酯

综述了新型功能液日聚酯材料的大分子链结构、液晶相变温度与应用前景。这类功能液晶聚酯或者其主链含有大量碳碳双键，或者其侧链上含有大量氟碳链节或偶氮链节。功能液日聚酯的玻璃化转变温度和液日相变温度通常比传统高强度、高模量液日聚酯要低，尤其具有高强度、高模量液晶聚酯所不具备的特殊性能，如交联化、凝胶和感光作用，使其可以作为全息储存膜和其他功能材料。     

Intriguing liquid crystalline behavior of liquid crystalline polyrotaxane containing azobenzene mesogens

A series of liquid crystalline polyrotaxanes containing azobenzene mesogenic moieties (AzoPR) with different length of spacer were synthesized, and the relationship between the spacer length and the liquid crystalline behavior was investigated. The molecular characterization of the AzoPR was performed with ¹H NMR, FT-IR, and gel permeation chromatography. The thermal stability was investigated via thermogravimetric analysis. Their phase structures and liquid crystalline properties were studied by differential scanning calorimetry, polarized optical microscopy and wide-angle X-ray diffraction. The experimental results suggested that AzoPR with spacer length of 2 and 4 failed to show the liquid crystalline behavior, and AzoPR with spacer length of 6 showed the columnar nematic phase. However, when the spacer length increases to 11, the columnar nematic phase formed, meanwhile, the liquid crystalline domains with high ordered structure were developed by azobenzene mesogens.     

高性能聚芳酯纤维的研制和表征

介绍了热致性液晶聚芳酯纤维的制备。选用双酚A、对苯二甲酸、间苯二甲酸为单体进行熔融聚合,制得具有不同相对分子质量的双酚A-对/间苯二甲酸共聚酯,探索了后续固相聚合工艺,研究了后续固相聚合对原熔融聚合物相对分子质量、热性能以及力学性能的影响。原聚合物再经固相聚合及不经固相聚合的两种聚芳酯在不同的纺丝和热处理工艺条件下,可以获得力学性能相近的聚芳酯纤维,为进一步研制热致液晶型聚芳酯纤维生产路线提供可靠的工艺数据。     

Polymorphic crystallization of fractionated microbial medium-chain-length polyhydroxyalkanoates

By focusing on a range of fractions of medium-chain-length polyhydroxyalkanoates (mcl-PHA), a more in-depth understanding of the thermal properties and the crystalline structure has been gained. Dual-mode melting was observed for all the fractionated samples. Further DSC analysis revealed that such phenomenon was due to the presence of two crystalline phases (phase I and phase II), forming at different temperatures. As noted, for the samples with higher 3-hydroxytetradecanoate (HTD) comonomer composition, the crystallization rate of phase II was much depressed, which made phase I dominant. The WAXD and FTIR results indicate that the two phases differ in the crystalline structure. The in situ IR and WAXD registrations indicate that phase I would transform into phase II through a melting-recrystallization process during heating. The high similarity of IR spectra in the range of 1500–900 cm⁻¹ between phases I and II excludes the possibility of adopting different conformation. It is suggested that major differences between the two crystalline phases lie in the molecular packing.     

Time dependent crystallinity of polybutene-1

Isotactic Polybutene-1 can exist in 4 different crystalline phases of varying stability of which two are of greatest importance because they are involved in solidification from the melt initially, the melt cools into an unstable crystalline phase which gradually and spontaneously transforms into a stable, stronger, stiffer, more crystalline phase over a period of days. Rate of development of mechanical properties depends on crystallinity which depends on rate of phase change. However, optical properties develop in an unusual and irregualr way that is significantly affected by external factors, suxh as pressure, temperature, fillers nucleation and geometry.     

Synthesis and cure of liquid crystalline diallyl modifiers for bismaleimide resin

Three kinds of liquid crystalline aromatic azomethine modifiers were synthesized with high yield, and the modification of bismaleimide resin (BMI) with them was studied by scanning electron microscope, polarizing optical microscope, thermogravimetric analyzer, differential scanning calorimetry, and rheolometry. Blends cured at the temperature of liquid crystalline phase were found to have oriented liquid crystal‐rich phase and improved mechanical properties. The addition of o,o′‐diallyl bisphenol A in the blends of BMI decreases thermal properties but shows little effect on phase structures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4366–4371, 2006     

Diffusion of low‐molecular‐weight permeants through semi‐crystalline polymers: combining molecular dynamics with semi‐empirical models

A molecular dynamics‐based computational approach was used to study the diffusion of oxygen through a model semi‐crystalline polymer, namely linear low‐density polyethylene. The simulated molecules were validated by comparing the predicted properties with experimental values of available free volumes, on atomic scale, using positron annihilation lifetime spectroscopy and measured values of density. The semi‐crystalline polymer was considered as a composite network of a continuous amorphous phase and a dispersed crystalline phase. Based on this observation, the overall diffusion was simulated, including the diffusion through the crystalline phase, which has not been previously reported. A tight correlation was then achieved between experimental and simulated data by utilising several semi‐empirical and analytical models developed for composite materials. The proposed methodology in this work can be effectively used as a basis for designing polymer networks with controlled diffusion characteristics in a bottom‐up approach. © 2018 Society of Chemical Industry     

四苯基乙烯室温液晶发光材料的制备与表征

发光液晶兼具发光性能和液晶的有序性,作为一种具有重要应用前景的功能材料而受到研究人员的广泛关注。本工作采用离子自组装法制备了一种兼具聚集诱导发光和液晶性质的四苯基乙烯衍生物(TPE-Chol)。通过吸收光谱、荧光光谱和X射线衍射等实验对TPE-Chol的光物理性质和液晶结构进行了详细研究。实验结果表明,TPE-Chol在室温状态下具有液晶结构,并且表现出典型的聚集诱导发光行为,是一种新型室温液晶发光材料,在液晶显示等领域具有潜在的应用价值。