PP/Talc复合材料的非等温结晶动力学

用差示扫描量热法(DSC)研究聚丙烯(PP)及PP/Talc复合材料的非等温结晶过程,加入滑石粉后,PP/Talc的结晶速率、结晶度得到明显提高。结合Avrami和Ozawa方程得出一个适合于非等温的结晶动力学方程,并由此获得PP/Talc复合材料的非等温结晶动力学参数,计算表明Talc能促进PP材料的结晶。

基于Logistic模型对TALC模型各阶段的定量划分——兼论美国十大国家公园的旅游生命周期模式

TALC模型是旅游学界讨论最多的模型之一,在诸多讨论的议题中,关于该模型各阶段的划分和确认一直是一个未能解决的难题。文章基于用Logistic模型解决TALC模型各阶段定量划分的目的,在运用微分知识分析Logistic模型数学性质的基础上,发现了该模型有3个时间节点。然后分析了Logistic模型对TALC模型各阶段的定量划分的适用性,并对美国十大国家公园上百年的时间序列数据进行回归分析,实证了美国十大国家公园的旅游生命周期模式。分析得出:(1)Logistic模型可以很好地拟合TALC模型的前5个阶段,即探查-参与阶段、发展阶段、巩固阶段、停滞阶段;(2)利用Logistic模型求得划分TALC模型的3个时间节点((a-1.317)/r,K/(4.732))、(a/r,K/2)、((a+1.317)/r,K/(1.268));(3)美国国家公园的旅游生命周期模式可以分为3类:Ⅰ型—标准型、Ⅱ型—断崖型、Ⅲ型—跳跃型。研究发现TALC模型各阶段可以进行定量划分和确认,文章得出的3个时间节点就是一次探索性尝试。

磷酸酯偶联剂(FX-1)对PP/POE/Talc复合材料性能的影响

通过熔融共混法制备了PP/POE/Talc复合材料,研究了偶联剂磷酸酯(FX-1)不同含量对滑石粉表面性能的影响,得出了偶联剂磷酸酯(FX-1)的最佳质量分数为1%;同时,考察了超细滑石粉经偶联剂磷酸酯(FX-1)改性前后与基体PP界面的粘接情况对PP/POE/Talc复合材料力学性能的影响。

超分散剂改性Talc/PP复合材料结晶行为及微观结构分析

合成了YB超分散剂并制备talc/PP复合材料。采用红外光谱(FT-IR)、差示扫描(DSC)、X衍射(XRD)和扫描电镜(SEM)等方法研究了复合材料的结晶行为和微观结构。结果表明:改性后的talc表面连接了新的有机基团;talc的加入具有异相成核作用,提高了PP结晶温度,但无晶型转变,当talc用量超过30%,异相成核作用减弱;超分散剂与talc存在异相成核协同作用,进一步提高结晶温度,并且对β晶型具有诱导效应,YB超分散剂加入,使部分α晶型向β晶型转变;同时使复合材料的冲击断面从脆性断裂转变为强韧性断裂。

Talc/GF复合增强PA66材料的协同效应

采用滑石粉(Talc)/玻纤(GF)作为复合增强体系,通过双螺杆挤出机制备了一系列增强尼龙66(PA66)材料。研究了Talc与GF的配比对增强PA66复合材料力学性能的影响,并用扫描电镜(SEM)和差示扫描量热(DSC)方法对复合材料的微观结构、非等温结晶过程进行了研究。研究结果表明,当PA66/Talc/GF质量配比为70/5/25时Talc与GF复合增强PA66有明显的协同效应,复合材料的拉伸强度、弯曲强度以及缺口冲击强度都明显提高。Talc和GF对PA66具有有效的异相成核作用,其加入使得结晶度增大,结晶温度升高;Talc以及GF在PA66基体中分散均匀,GF沿Talc面取向明显,相互协同形成了特殊的三维网络结构。

Mineralogical Characteristics of Unusual Black Talc Ores in Guangfeng County, Jiangxi Province, China

Talc is a hydroxyled, magnesium-rich, layered silicate that has the ideal chemical formula Mg3Si4O10(OH)2. Due to its unique properties, such as softness, chemical inertness, high thermal stability, low electrical conductivity, lamellar habit, adsorption properties, and occurrence of a wide range of particle sizes that can be easily reduced by milling and high specific surface area, talc is widely used in many industries. A stratified deposit of unusual black talc, an occurrence of talc estimated to be more than half a billion tons, was found exposed in the late Neoproterozoic Dengying Formation, located in Guangfeng County, Jiangxi Province, southeastern China. The ores occur primarily as oolitic structures (Fig. 1). The mineralogical and geochemical characteristics of the ores were investigated by using multiple techniques. The ores were found to mainly consist of talc (30%–70%), dolomite, quartz, and magnesite. Most of talc crystals are ultrafine (with an average crystallite size of smaller than 5 μm) and appear as irregular broken or distorted lamellar flakes. The total organic carbon (TOC) content of the black talc ore samples is generally lower than 1.0%. Electron-microprobe analysis (EPMA) revealed low contents of Na, K, Ca and Mn, Fe, Ni, Al in the talc oolitic particles. The talc ores have low contents of toxic elements and relatively high contents of Li and Zn. The infrared spectrum of the black talc is similar to that of white talc from Trimouns (Pyrenees, France), and their Brunauer–Emmett-Teller (BET) specific surface areas, ranging from 15.7 to 23.2 m2/g, is much higher than those of white talc (normally lower than 5.0 m2/g), which may be due to the small size of the talc crystals.

Selective depression behavior of guar gum on talc-type scheelite flotation

The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic analyses. The flotation results for monominerals, mixed minerals, and actual mineral samples indicated that guar gum exhibited much higher selective depression for talc than for scheelite. Bench-scale closed-circuit tests showed that a tungsten concentrate with a WO_3 grade of 51.43% and a WO_3 recovery of 76.18% was obtained. Adsorption tests, zeta-potential measurements, and infrared spectral analyses confirmed that guar gum absorbed more strongly onto the talc surface than onto the scheelite surface because of chemisorption between guar gum and talc. This chemisorption is responsible for the guar gum's highly selective depression for talc and small depression for scheelite. The flotation results provide technical support for talc-type scheelite flotation.

Flotation separation of molybdenite and talc using tragacanth gum as depressant and potassium butyl xanthate as collector

Tragacanth gum(TG)was explored as a depressant to realize the flotation separation of molybdenite and talc.The flotation experiments indicated that when using potassium butyl xanthate(PBX)as a collector,molybdenite showed excellent floatability while talc was completely depressed by TG,thus realizing the flotation separation of the two minerals.X-ray photoelectron spectroscopy(XPS)analysis results showed that TG was adsorbed on molybdenite surface via chemisorption.The results of contact angle measurement,Fourier transform infrared(FTIR)spectroscopy,and time-of-flight secondary ion mass spectrometry(ToF-SIMS)indicated that the pre-adsorption of TG on molybdenite could not hinder the further chemisorption of PBX on molybdenite.Because PBX has no collecting ability on talc,the flotation separation of molybdenite and talc came true using PBX to collect molybdenite and TG to depress talc.

Preparation of Ultra-nano Talcum in Sand Mill and Its Application in the Polypropylene

The grinding of ultra-fine talcum powder and its application in a polypropylene （PP） matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling process. The talcum powder exhibited polymodal distribution. The layered morphology of talcum particles in a horizontal sand mill was rarely damaged or destroyed. PP-talcum nanocomposites were prepared by melt blending using a twin-screw extruder. Nano talcum can be seen as a single particle, although it is not very apparent. The bending strength of talcum-filled PP was gradually increased by approximately 28%. The impact strength linearly decreased as the filler weight ratio increased. The overall maximum improvement in mechanical properties was recorded when the filler ratios increased from 15 wt% to 20 wt%.

TMC-210与Talc联合对PLLA结晶调控及性能研究

为了克服聚乳酸(PLLA)结晶速率慢、专用单一成核剂(TMC-210)价格昂贵的不足,采用TMC-210与Talc(滑石粉)协同调控PLLA的结晶与性能,利用差示扫描量热仪(DSC)、X射线粉末衍射仪(XRD)、小角X射线散射仪(SAXS)、扫描电子显微镜(SEM)、偏光显微镜(POM)和力学性能测试评估了TMC-210联合Talc对PLLA结晶和力学性能的协同影响。结果表明,TMC-210和Talc协同改善了PLLA的结晶能力,使成核密度增加、结晶速率加快,晶体尺寸和长周期均减小,但对PLLA的结构和晶型没有影响。力学测试表明,在PLLA中同时添加质量分数为0.2%的TMC-210和质量分数为4%的Talc,PLLA/TMC-210/Talc三元共混物的断裂伸长率达到23.6%,比PLLA/TMC-210二元共混物提高了262%;当添加质量分数为0.2%的TMC-210和质量分数为1%的Talc时,PLLA/TMC-210/Talc三元共混物的韧性达到5.65kJ/m2的最大值,比PLLA/TMC-210二元共混物、PLLA分别提高了29.3%和210%。

滑石粉(Talc)填充聚丙烯复合材料收缩率的研究

介绍了滑石粉在塑料改性中的应用以及滑石粉的加入对塑料性能的影响;通过分析塑件成型收缩机理、原因,从材料特性、模具结构、注塑工艺条件三个方面来阐述对塑料成型收缩率的影响因素。最后,将不同用量滑石粉(Talc)添加到聚丙烯(PP)中,结合CAE模拟技术,研究了滑石粉(Talc)对聚丙烯复合材料收缩率的变化规律。研究表明:随着滑石粉的质量分数越来越大,制品收缩率降低,最佳配比为25%,收缩率为2.1036%,低于未添加滑石粉的3.3871%。滑石粉填充改性PP有利于提高产品品质。

Using pectin to separate talc and molybdenite through the surface modification with Cu^(2+):Applications and mechanism

Organic depressants have low selectivity in separating molybdenite and talc because their metal sites lack activity for organics chemisorption.In this study,surface modification by copper sulfate was used to induce the differential adsorption of pectin onto molybdenite and talc surfaces for enhanced flotation separation.Contact-angle experiments,scanning electron microscopy,adsorption measurements,timeof-flight secondary-ion mass spectrometry,and X-ray photoelectron spectroscopy analyses were conducted to reveal the interaction mechanism.Results illustrated that molybdenite and talc could not be separated using pectin alone,while molybdenite was selectively depressed after surface modification by copper sulfate and this effect was strengthened under alkaline conditions.Metal sites(Mg,Si and Mo)of talc and molybdenite themselves were unable to react with pectin,whereas Cu+would deposit and further function as active site for pectin chemisorption after surface modification.However,the quantity of deposited Cu sites dropped on talc surface and increased on molybdenite surface with increased pH,and the Mo atoms of molybdenite crystal were activated to take part in pectin chemisorption.Therefore,more pectin was adhered on molybdenite surface,which imparted molybdenite stronger wettability.Herein,surface-modification through metal ions can enable the differential adsorption of organic depressants and enhance the flotation separation of minerals.

Insights into the adsorption performance and mechanism of hydrated Ca ion on talc(001) basal surface from DFT calculation

The utilization of Ca ion as assistant depressant of CMC on talc has been widely reported.Thus,the study on the adsorption mechanism of Ca ion on talc surface is very crucial for understanding the performance of CMC on talc depression.In this paper,mechanism insights into hydrated Ca ion adsorption on talc(001) basal surface were creatively provided using DFT calculation.[Ca(H_(2)O)_6]^(2+) and [Ca(OH)(H_(2)O)_(3)]^(+) were determined as the effective hydrate components for Ca ion adsorption,and the top O site was the most favorable position for their adsorptions on talc surface.Furthermore,the adsorption mechanisms of [Ca(H_(2)O)_6]^(2+) and [Ca(OH)(H_(2)O)_(3)]^(+) on talc surface were found to be not the Ca-O chemical bond,but the hydrogen bonding formed by the H atom of the H_(2)O ligand and the surface O atom.H_(2)O acted like a bridge to connect them to the talc surface.Moreover,the hydrogen bonding was formed due to the hybridization of H 1s orbital with the O 2s,O 2p orbitals.Simultaneously,electrons transferred between the H atom and the surface O atom.This work provides theoretical insights into the Ca ion adsorption on talc surface,which can help deeply understand the talc flotation using CMC as depression.

Enhanced inhibition of talc flotation using acidified sodium silicate and sodium carboxymethyl cellulose as the combined inhibitor

The flotation separation of chalcopyrite and talc is challenging due to their similar natural floatability characteristics.Besides,it is usually difficult to effectively inhibit talc by adding sodium carboxymethyl cellulose(CMC)alone during chalcopyrite flotation.Here,a combined inhibitor comprising acidified sodium silicate(ASS)and CMC was employed to realize effective flotation separation of chalcopyrite and talc,and the combined inhibition mechanism was further investigated.Microflotation results showed that adding ASS strengthened the inhibitory effect of CMC on talc and improved the separation of chalcopyrite and talc.The zeta potential,Fourier transform infrared,and X-ray photoelectron spectroscopy analysis indicated that CMC was mainly adsorbed on the talc surface via hydroxyl and carboxyl groups.Moreover,the addition of ASS improved the adsorption of carboxyl groups.Furthermore,the adsorption experiments and apparent viscosity measurements revealed that adding ASS dispersed the pulp well,which reduced the apparent viscosity,improved the adsorption amount of CMC on the talc surface,and enhanced the inhibition of talc in chalcopyrite flotation.

Magnesite and talc origin in the sequence of geodynamic events in Veporicum, Inner Western Carpathians, Slovakia

This paper summarizes recent data about magnesite and talc genesis in Carboniferous host rocks of Western Carpathians (Slovakia) , which occur in two distinct belts in tectonic superunit Veporicum and its contact zone with Gemericum. The northern Sinec magnesite and talc belt (with main deposits Kokava, Sinec, Samo, Hnust'a-Mutnik) contains economic accummulation of magnesite and talc, while in the southern Ochtina belt ( main deposits in Dubrava massif-Dubrava, Mikova, Jedl'ovec; Lubenik, Ochtina, Kosice-Bankov, Banisko, Medvedia) the magnesite is dominating.The magnesite genesis by successive replacement of Carboniferous calcite to dolomite and magnesite during metamorphic process Ml (northern belt 280-400℃; , southern belt 370-420℃: ; Radvanec & Prochaska, 2001; Kodera & Radvanec, 2002) , being supplied by Mg from Permoscythian evaporitic bittern brines, relates to Variscan post-collisional (post-VD) evolution. The extensional tectonics and the high heat flow facilitated the generation of a hydrothermal system.The time-separated later metamorphic and sourcely different fluid flow event (M2; 1. c. ) produced talc. Tectonic, microtectonic, metamorphic and geochronological data relate the talc origin with the Alpine Upper Cretaceous (88-84 Ma; Maluski in Kovacik et al. , 1996) tectonothermal event AD2. This event, being the consequence of Alpine collisional ( AD1 ) crustal thickening and metamorphic core complex origin, meant regional extension and pervasive fluid flow of open system in crustal discontinuities. This process was prominent in the northern belt ( Sinec shear zone) located more closely to Veporic thermal dome, while towards its peripheral parts (southern Ochtina belt) the M2 metamorphic process and steatitization gradually weakened.Studies from Sinec shear zone (being the prominent AD2 -AD3 structure of northern Sinec belt) , where the dolomite/magnesite lenses (replacement in M1) and their accompanying lithology were in AD1 sandwitched between more competent basement blocks, proved in AD2 the pervasite steatitization, the talc and dolomite 2 origin in extensional microstructures ( metamorphic process M2; 490 -540℃, 240-330 MPa, 1. c. ).The economic accummulations of talc in Sinec belt are the products of antithetic shearing during the AD3 phase, being the gradual continuation of AD2 ( change of kinematics from unroofing to regional transpressional shearing). Contrary to the northern Sinec belt having located the AD3 deformation into narrow shear zone with soft lithology surrounded by hard lithology, in southern Ochtina belt the deformation AD3 was accommodated by wide soft rock column with rigid carbonate blocks floating inside. The lower P-T ( M2)conditions and deformational gradient in Ochtina belt during AD2 and AD3 phases caused why no economic talc accummulations developed there.The results of presented study can be used as general criteria for magnesite and talc prospection in Alpine type terranes.

Investigation of nano-talc as a filling material and a reinforcing agent in high density polyethylene (HDPE)

An experiment of producing high density polyethylene (HDPE) nano-composite filled with 4wt.% talc was presented. Acting as filler and a reinforcing agent in the HDPE, talc powder, sized at around 5 μm, was surface-treated with aluminum diethylene glycol dinitrate coupling agent before adding to the HDPE. Analyses of the reinforced HDPE nano-composite show significant improvement in its mechanical properties including, tensile strength (>26 MPa), break elongation (<1.1%), flexural strength (>22 MPa), and friction coefficients<0.11. The results demonstrate that, after surface-treated, talc can be used as a promising filling material and a reinforcing agent in making HDPE nano-composite.

Studies on the Structure and Properties of Cordierite Synthesized by Talc-Magnesite

Homogeneous cordierite has been synthesized at low cost by talc-magnesite and coal gangue as the main raw materials. The mechanism of synthesizing cordierite under such a composing system of raw materials, and the effect of temperature on the crystal cell parameters and microstructure and thermal expansion coefficient of cordierite crystal have been studied via testing methods of XRD, SEM, etc. The result shows that the homogeneous cordierite can be synthesized by the systematic composing materials of ＂talc-magnesite-coal gangue-talc＂ with heat pre-servation at 1350 ℃ for 1 h; as the keeping time is prolonged, Al^3＋ and Mg^2＋ in cordierite crystal are replaced by a few impurity ions such as Fe^3＋, Fe^2＋, etc., and the crystal cell parameters of cordierite present an increase trend; as the high-temperature heat preservation is prolonged, the content of glassy phase in the sample is increased, its density is improved, and its thermal expansion coefficient presents an increase trend.

A Talc-Based Cement-Poor Concrete for Sealing Boreholes in Rock

Deep investigation boreholes in crystalline rock for site selection of repositories for high-level radioactive waste are proposed to be sealed by installing a series of dense concrete and clay plugs. These should prevent radionuclides from leaking canisters at depth to migrate to the biosphere through the holes. The concrete seals will be installed where the holes intersect water-bearing fracture zones to serve as stable and low-permeable supports for adjacent clay plugs. Low porosity and microstructural stability must be guaranteed for many thousands of years and ordinary Portland cement with organic superplastizer will not fulfill the requirements since the high pH will cause degradation of contacting clay and the organic additive can produce colloids with a capacity to carry radionuclides up to the biosphere. Very cement-poor concrete (

汽车电子产品中的TALC应用指南

通过对TALC技术进行定义,阐述触觉、外观、灯光、颜色在汽车中的重要性。介绍汽车音响所包括的TALC技术内容,重点对汽车音响的按键手感、灯光进行分析,为正确使用TALC技术,提升汽车品质提供了应用指南。

Talc-Based Concrete for Sealing Borehole Optimized by Using Particle Packing Theory

The paper describes assessment of the performance of cement-poor concretes on the basis of packing theory. The concretes are intended for sealing segments of deep boreholes and have a small amount of cement for minimizing the mutual chemical impact on the contacting clay seals. The composition is examined by application of packing theory with respect to the cement/aggregate ratio and the gradation of the aggregate material which is crushed quartzite for providing high internal friction after maturation, as well as to talc added for fluidity and to the small amount of cement. Low porosity and micro-structural stability must be guaranteed for very long periods of time. The study exemplifies how packing theory assist designers in selecting optimal proportions of the various components. Optimum particle packing implies minimizing the porosity and thereby reducing the amount of cement paste needed to fill the voids between the aggregate particles. The use of talc as inorganic super-plasticizer since ordinary organic additives for reaching high fluidity at casting are undesirable, and since talc reacts with cement and provides high strength in along-term perspective.