铸造用改性高强度酚醛树脂的研究

针对目前国内生产的酚醛树脂覆膜砂强度低，树脂用量大的现状，进行了在酚醛树脂中加入以已内酰胺为改性剂和以硅烷为偶联剂的改性实验。结果表明，改性后的酚醛树脂，可以使覆膜砂的强度提高３０％，覆膜砂的韧性也有所提高，并改善其溃散性     

聚酚氧树脂/酚醛树脂混合物用于制备覆膜砂的研究

聚酚氧树脂具备高韧性高软化点的特点,其与热塑性酚醛树脂共混可以显著提高酚醛树脂的韧性,提高常温强度和热强度,并改善覆膜砂溃散性.将聚酚氧树脂与酚醛树脂共混制备覆膜砂,实验结果表明,聚苯氧树脂添加10％时,覆膜砂拉伸强度提高15.2％,弯曲强度提高12.8％,熔点提高3℃,溃散率提高提高20％,在铝合金铸件上面具有较好的...     

生产经验二则

粉粒状酚醛树脂中粉状达40％以上；片状酚醛树脂经破碎形成大小不等的小块，其中仍有15％左右的粉状。粉粒状表面积大，在贮存中易吸潮和氧化失效；配制覆膜砂时熔化太快而结成团，被筛出浪费，从而降低了覆膜砂的树脂比例，必须增加用量；配制覆膜砂粉尘飞扬，污染环境。片状树脂虽比粉状好，但由于大小与厚薄不匀，在贮存与混制覆膜砂时仍有结块现象。     

氧化铁添加物对覆膜砂热裂倾向的影响

在酚醛树脂覆膜砂中，加入适量的氧化铁添加物可以起到提高混合料的热塑性和吸热反应的热屏蔽作用，可显著减轻酚醛树脂覆膜砂的热开裂倾向。在生产实际中，为有效地减少或防止壳型法铸件的脉纹或飞翅缺陷，氧化铁的添加量以占砂重的０．５％～１．Ｏ％为宜。     

酚醛树脂游离酚对覆膜砂强度的影响

分析了国内３种生产工艺和材料基本相同的酚醛树脂和国外一种覆膜砂专用酚醛树脂的性能和覆膜砂强度的关系。提出为了提高覆膜砂强度,降低酚醛树脂中游离酚含量,必须要使树脂的软化点保持在相对较低的水平,使分子量较低的观点,为改进覆膜砂专用酚醛树脂的生产工艺指明了方向     

基于传热分析下酚醛树脂覆膜砂的溃散性研究

通过数学方法建立砂芯传热模型再现了砂芯在整个浇注过程中内部发生的各种变化,研究了铝合金铸件生产过程中浇注温度和溃散剂对酚醛树脂覆膜砂溃散性的影响.结果表明,提高浇注温度和使用具有强氧化性的溃散剂均能增加覆膜砂中树脂烧蚀层的厚度,这对研究酚醛树脂覆膜砂的溃散性很有意义.     

轻合金覆膜砂专用酚醛树脂的开发研究

采用具有不饱和脂肪直链的EPA改性剂参与合成酚醛树脂，用不饱和脂肪直链段部分取代亚甲基键，使酚醛树脂具有高强度和较低温度分解的特性。研究了EPA的加入量对树脂性质和覆膜砂力学性能的影响，10％是最佳值。热失重试验和高温变形曲线试验结果证明，使用该树脂混制的覆膜砂，具有强度高、溃散性好等特点。实践证明：使用该种覆膜砂浇注铸件后，工人的清砂劳动量下降，工作效率显著提高。     

提高铸造用酚醛树脂流动性的研究

用润滑剂改性的方法试制了改性酚醛树脂，使流动性从40～60mm提高到80～140mm。介绍改性树脂的合成工艺，覆膜砂的生产工艺，树脂性能及覆膜砂性能测试方法。与普通树脂覆膜砂相比，改性树脂覆膜砂的强度提高1～2倍，发气量和灼减量也降低。     

专利摘要

<正>160801壳型铸造用热塑性酚醛树脂及其覆膜砂的制备[欧洲]US2014187667,2014.07.03,Takama Tomohiro,Mori Keiichi,Takama Tomohiro[日本]目前,壳型铸造用覆膜砂都是采用热塑性酚醛树脂粘结剂、乌洛托平固化剂和硬脂酸钙分离剂等热法覆膜制成的,用它生产内燃机复杂的缸盖时,壳芯在浇注时容易出现裂纹,这是由于覆膜砂的韧性差和热膨胀系数大等造成的。本专利提供一种壳型铸造用热塑性酚醛树脂及其覆膜砂的制备方法。该酚醛树脂及其覆膜砂的主要特点是,热膨胀性小和热韧性高。这种新型壳型铸造用热塑性酚醛树脂的合成方法     

铸造用高强度改性酚醛树脂的研究

叙述了改性酚醛树脂的性能、覆膜砂制备配方及其性能测定.改性后的酚醛树脂韧性增强,覆膜砂抗拉强度和抗弯强度明显提高,型砂的溃散性得到了改善.     

医用镁合金表面肝素/蒙脱石涂层耐蚀性研究

目的 为解决镁合金血管支架使血管内皮化、造成再狭窄等问题,在AZ31镁合金表面制备具有抗凝特性的肝素(HS)/蒙脱石(MMT)复合涂层,并研究其耐蚀性能.方法 采用水热法在AZ31镁合金表面制备钠蒙脱石(Na-MMT)涂层,在此基础上通过浸泡法以蒙脱石为载体,制备肝素/蒙脱石复合涂层.利用扫描电子显微镜(SEM)、傅里...     

The effect of microstructure evolution on mechanical properties in novel alumina-montmorillonite composites

Fabrication of alumina matrix composites reinforced with montmorillonite (MMT) is introduced in this work. Specimens were prepared with the use of powder metallurgy and consolidated using the Spark Plasma Sintering (SPS) method. Investigations were then carried out on the influence of MMT addition on microstructure, mechanical properties and tribological performance of the alumina matrix composites. Scanning Electron Microscopy (SEM) revealed significant changes in microstructure where elongated, abnormally overgrown grains of alumina can be observed in areas contacted with montmorillonite. This unusual bimodal microstructure greatly influenced the measured mechanical properties and friction study. Tribological examinations exhibited outstanding results, where samples with montmorillonite addition demonstrate significant improvement in the wear in comparison to pure unmodified alumina sinters.     

Conducting polyaniline–montmorillonite composites

Polyaniline (PANI)–montmorillonite (MMT) composites were prepared in two ways: (a) by the polymerization of aniline hydrochloride with ammonium peroxydisulfate (APS) in aqueous suspensions of MMT, (b) by the intercalation of aniline hydrochloride into MMT in aqueous suspension followed by the oxidation with APS, i.e. by the surface and intercalative polymerizations of aniline. The products were analyzed by SEM, XRD, TGA, FTIR and Raman spectroscopies. The formation of red coloration after interaction of MMT with aniline is discussed. The conductivity of PANI–MMT composites increased to units S cm^?1 as the content of PANI reached 50–60 wt.%. The intercalation of aniline into MMT before the polymerization had no marked effect on the conductivity of resulting composites, which was determined mainly by the PANI present at the MMT particles surfaces.     

Poly(3-hexadecylthiophene)/montmorillonite clay nanocomposites: Influence of preparation and type of clay on their structures

A nanocomposite of poly(3-hexadecylthiophene) (PHDT) with montmorillonite (MMT) was prepared by in situ polymerization (PHDT/MMT) and nanocomposites of PHDT with organomontmorillonite clay (OrgMMT) were prepared by both in situ polymerization (PHDT/OrgMMT) and by the solvent casting method (PHDT/OrgMMT-sc). The nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). PHDT/OrgMMT was also characterized by transmission electron microscopy (TEM). FTIR spectra indicate the presence of the clay in the polymer matrices and show variations on the frequency of the Si–O–Si stretching vibration. The XRD diffractograms indicate that PHDT/MMT and PHDT/OrgMMT-sc are intercalated nanocomposites, while PHDT/OrgMMT is mostly exfoliated, but present also some intercalation, as confirmed by TEM.     

装载缓蚀剂的蒙脱土对环氧涂层耐蚀性能的研究

将不同比例的装载缓蚀剂蒙脱土和环氧树脂混合制备出纳米复合环氧涂层。根据电化学阻抗谱 (EIS) 和盐雾实验对涂层的耐蚀性进行表征。结果表明,3%装载蒙脱土环氧涂层的水扩散系数为9.89×10^-11 cm²/s,孔隙率为2.22×10^-8,整个浸泡过程中阻抗值在10⁹ Ωcm²以上,表现出最佳的耐蚀性。     

Effect of polyaniline–montmorillonite nanocomposite powders addition on corrosion performance of epoxy coatings on Al 5000

A series of polyaniline (PANI)/montmorillonite (MMT) nanocomposite materials has been successfully prepared by in-situ emulsion polymerization in the presence of inorganic nanolayers of clay with camphorsulfonic acid (CSA) and ammonium peroxydisulfate (APS) as surfactant and initiator, respectively. The nanocomposite materials were characterized by Fourier Transformation Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Epoxy resin was used as a binder for the nanocomposites in order to obtain a thick and uniform coating. In order to understand the effect of MMT and PANI on the corrosion inhibition performance of the epoxy coatings in 3.5% saline solution at 65 °C, the epoxy (E), epoxy blend with polyaniline (EP), epoxy blend with polyaniline and MMT (EPM) coatings were investigated by electrochemical impedance spectroscopy (EIS). The results showed that EPM coatings with 5% clay on pretreated aluminum by anodizing were much superior in corrosion protection, with respect to the other samples. Incorporation of PACN nanocomposites inside the epoxy significantly increases the resistance of the coating in comparison to the other coatings in 3.5% saline solution at 65 °C. These phenomena can be attributed to specific morphology of the nanocomposite.     

The preparation and properties of sodium and organomodified-montmorillonite/polypyrrole composites: A comparative study

Two montmorillonites, an inorganic sodium montmorillonite (NaMMT) and an organo-modified montmorillonite (OMMT), were used for the preparation of montmorillonite/polypyrrole (MMT/PPy) composites. MMT particles were modified by the in situ polymerization of pyrrole in water, in aqueous solution of dodecylbenzenesulfonic acid (DBSA) used as anionic surfactant, and in water/methanol. Ferric chloride was used as oxidant in each case. Wide angle X-ray scattering (WAXS) measurements proved the intercalation of PPy into the galleries of NaMMT regardless the reaction media. In contrast, for OMMT/PPy composites, the increase of interlayer spacing depends on the preparation conditions, the highest increase in interlayer spacing was achieved in water/DBSA solution. The WAXS patterns of OMMT/PPy composites synthesized in methanol/water showed no change in interlayer spacing and the electrical conductivity of these composites was low, similar to that of NaMMT/PPy composites prepared under the same conditions. Conductivity about 1.1 S cm⁻¹ was reached for OMMT/PPy composites containing 13.3 wt% PPy prepared in the presence of DBSA. The NaMMT/PPy composite containing 15.6 wt% PPy and prepared under the same conditions showed a conductivity of 0.26 S cm⁻¹. X-ray photoelectron spectroscopy (XPS) proved that the surface of NaMMT/PPy composites is rich in MMT, whereas more PPy was found on the surface of OMMT/PPy composites. The conductivity of composites correlated with the N/Si atomic ratio determined from XPS results, which was taken as a semi-quantitative measure of the PPy surface fraction.     

Effect of Nanoclay on the Corrosion Protection Efficiency of UP/CuEDA2-MMT Nanocomposite Coatings Assessed by EIS Measurements

Protection of Metals and Physical Chemistry of Surfaces - Unsaturated polyester/montmorillonite nanocomposite were obtained and characterized. Montmorillonite (MMT) used as inorganic filler was...     

一步法制备四氧化三铁/蒙脱土磁性复合材料(英文)

报道了一步法制备四氧化三铁/蒙脱土磁性纳米复合材料。使用XRD,TEM,VSM对材料进行了相关测试,从测试结果发现,用水热法制备的磁性纳米复合材料具有典型的层型结构。实验结果证明四氧化三铁纳米颗粒分别存在于蒙脱土的层间和片的表面,而且该层型复合材料保持了较高的比表面积(143m2/g)。这种新型磁性层型复合材料对于重金属离子具有很好的吸附能力。     

蒙脱土改性聚甲基丙烯酸甲酯复合材料的硫酸腐蚀行为

对乳液聚合法制备出的聚甲基丙烯酸甲酯/蒙脱土(PMMA/MMT)复合材料在硫酸介质中的腐蚀情况进行了研究,探讨了蒙脱土含量、硫酸浓度以及腐蚀时间对腐蚀速率的影响。结果表明,硫酸浓度较低且腐蚀时间较短时,含有2%~3%蒙脱土的复合材料的腐蚀速率比PMMA明显降低;PMMA及其复合材料的腐蚀速率随腐蚀时间的延长而下降,随硫酸浓度的增加而上升;硫酸浓度越高或腐蚀时间越长,复合材料中蒙脱土的片层阻隔作用越不明显。