超细CaCO_3的表面改性及应用

本文系统介绍了超细碳酸钙填料生产及表面改性的方法，并对其在造纸。塑料、橡胶工业中的应用进展进行了综述。

微波法合成红色荧光粉CaCO_3:Eu^(3+)

采用微波法合成了红色荧光粉CaCO_3:Eu^(3+)。通过SEM,XRD和PL-PLE光谱等对样品的性能进行了表征和分析。同时,研究了微波功率对样品发光性能的影响。结果表明:样品在不同功率下会生成球霰石型的花片状、方解石型的立方体和文石型的针状等不同晶型的碳酸钙,颗粒的分散性好。波谱分析说明,掺杂Eu^(3+)作为发光中心进入到CaCO_3晶格中,其激发光谱主要由200～300 nm的Eu^(3+)—O^(2-)电荷迁移跃迁形成,属于宽带激发,在319,395,465,535 nm等处有窄的激发峰出现。在发射光谱中,由于磁偶极跃迁~5D_0→~7F_1受到不同晶体场的作用而分裂为593和589 nm两个峰,最强的发射峰为614 nm,对应于Eu^(3+)的电偶极跃迁~5D_0→~7F_2,属于纯正的红色发光。此外,随着微波功率的提高,基质的晶型逐渐由花片状的球霰石向针状的文石型过渡,样品的红色发射强度也逐渐增强。

中国北方四剖面CaCO_3含量变化及其反映的古降水量

中国北方自西向东的4个剖面,各地层CaCO3的含量呈现逐渐减少的规律。科尔沁剖面和延长剖面、西宁盘子山剖面CaCO3含量曲线表现出的特征为:在每一个古土壤单元的下部一定深度内CaCO3曲线都表现为一个明显的峰;新疆塔勒德剖面的各古土壤的CaCO3含量表现为表层比中、下部要高。利用CaCO3淀积深度恢复出来的部分区域的古降水量显示,末次间冰期期间盘子山剖面的古降水量大为352mm,延长剖面和科尔沁剖面的古降水量大约为500～550mm;末次冰期的间冰阶阶段科尔沁剖面的古降水量大致为320～360mm;延长剖面古降水量大约为443mm;全新世以来盘子山剖面的古降水量大约为306mm,延长剖面和科尔沁剖面的古降水量大约为320～380mm。这些数据可为半定量恢复地质历史时期古环境状况提供依据。

我国CaCO_3填料表面改性及在塑料中的应用

介绍了我国CaCO_3填料改性聚烯烃,聚氨酯和聚氯乙烯等塑料的方法和机理。结果表明:CaCO_3颗粒的形状和粒径、CaCO_3在塑料中的分布状态,CaCO_3与树脂之间的界面状态、制品制备工艺条件,以及相容剂和表面改性剂的种类、分子量大小和分子结构等因素塑料的拉伸强度、断裂伸长率、硬度、亲水性、熔体流动指数、密度和白度等性能的改善起着十分重要的作用。

纳米CaCO_3对PE–HD/CF复合材料力学性能的影响

针对高密度聚乙烯(PE–HD)/碳纤维(CF)二元复合材料随CF含量的增加,拉伸强度和弯曲强度增大、冲击强度却逐渐下降的情况,在二元体系中添加纳米CaCO3制得PE–HD/CF/CaCO3三元复合材料,对比分析了两种复合材料的力学性能,并采用扫描电子显微镜对三元复合材料的冲击断面进行观察。结果表明,纳米CaCO3的加入使得三元复合材料的拉伸强度略有降低,但弯曲强度和冲击强度在一定范围内增大;当纳米CaCO3含量为10份时,复合材料的综合力学性能最佳。

CaCO_3改性对UV固化木器涂料性能的影响

在木器漆应用领域,UV涂料与传统涂料相比以明显优势,逐渐成为当下主流,同时也引领着未来的发展。但UV也有其缺陷,笔者着重于利用CaCO_3对木地板UV涂料进行改性,并对其力学性能和光学性能进行测试研究,旨在寻找一种具有较高性能的木质地板改性UV涂料。

表面处理CaCO_3对单组分聚氨酯密封剂性能的影响

对轻质CaCO3、重质CaCO3和滑石粉3种填料进行了表面处理,考察了它们对聚氨酯密封剂性能的影响。结果表明:使用表面处理轻质CaCO3作填料的聚氨酯密封剂与使用未处理轻质CaCO3作填料制备的聚氨酯密封剂相比,其邵氏硬度降低,伸长率提高。此外,使用表面处理轻质CaCO3作填料时在增加填料用量的同时,能确保密封剂的物理机械性能。

PP/CaCO_3复合过滤板失效分析

介绍PP/CaCO3 复合过滤板在使用过程中存在的质量问题 ,如表面黄斑、熔接痕、小凸台成型不好、表层剥离、板内有气孔及易脆断等 ,着重从成型工艺和刚性填料对过滤板相结构、性能的影响上来分析这些问题 。

CaCO_3在CaCO_3-CuO和CaCO_3-Bi_2O_3体系中的分解动力学

用恒温热重法研究了CaCO_3在CaCO_3-CuO和CaCO_3-Bi_2O_3体系中的分解动力学,求出CaCO_3的分解方程式。实验结果表明:在上述两体系中,CaCO_3的表观分解活化能均为120 kJ·mol^(-I),并初步分析了CaCO_3的分解机理。

Effects of Soil Texture and CaCO_3 on Turnover of Organic Material in Chao Soils

Decomposition experiments of 14C-labelled sickle alfalfa in chao soils of different texture and these soils after removal of CaCO3 were carried out under field and laboratory conditions respectively. The amount of residual 14C in, or 14CO2 evolved from, the soils at intervals after the beginning of decomposition were measured and the distribution of native and labelled C between particle size fractions isolated from these soils was edtermined. Results showed that contents of both labelled (14C) and non-labelled (12C) carbon decreased with increasing particle size. The enrichment factor for 14C was higher than that for 12C in the clay fraction, the reverse being true for the silt enrichment factors. The effect of soil texture on the decomposition of plant material could not be observed in chao soils when the clay content was lower than 270g kg-1, while it became obvious once CaCO3 was removed from these soils. The decomposition rate of plant material in the soil from which the native CaCO3 was removed was correlated significantly to both the clay content of the soil and the application rate of CaCO3. A preliminary correction equation describing the effect of clay and CaCO3 on the decomposition of organic material in chao soil was derived from the results obtained.

Al2_3/Al2O3 Joint Brazed with Al2O3-particulate-contained Composite Ag-Cu-Ti Filler Material

Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy （SEM）, electron probe microscopy analysis （EPMA）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied. The experimental results indicated although there were Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.

Interfacial reaction and growth behavior of reaction layer of Si_3N_4/Si_3N_4 joint brazed by Cu-Zn-Ti filler alloy

Si3N4 ceramic was jointed to itself using a filler alloy of Cu-Zn-Ti by the reaction between Ti and Si3N4. The microstructure of the interface in the joint is found to be Si3N4 ceramic/TiN reaction layer/Ti5Si3 reaction layer. The grain size of the TiN and Ti5Si3 reaction layer is 0.1μm and 1-2μm, respectively. There is no crystal orientation relationship between TiN reaction layer and Si3N4 ceramic or Ti5Si3 reaction layer. The kinetic equation for calculating the thickness of the reaction layer was obtained. When a （CuZn）85Ti15 alloy is used as the filler alloy, the apparent activation energy of the growth of the reaction layer is 201.69kJ/mol.

P123/Mg^(2+)水溶液中CaCO_3结晶及形貌的调控研究

在三嵌段共聚物P123与Mg2+的混合水溶液中,通过控制反应条件对CaCO3的微粒形貌进行调控。探讨了Mg2+浓度、反应时间、反应温度及P123浓度对CaCO3粒子形貌和晶型的影响。采用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)对合成样品进行了表征。结果表明,Mg2+与Ca2+的质量比对CaCO3粒子形貌和晶型具有重要的影响。

Evaluation of the Properties of Si3N4/Si3N4 Joint Brazed Using a Filler Alloy Containing Pd

Si3N4 ceramic was jointed to itself using a filler alloy of Cu76.5Pd8.5Ti15, and the mechanical properties of the jointwere measured and analyzed. By using a filler alloy of Cu76.5Pd8.5Ti15, the SisN4/SisN4 joints were obtained bybrazing at 1373～1473 K for 0.9～5.4 ks under a pressure of 2×10-3 MPa. The effect of brazing parameters on theshear strength of the joint was investigated. When the brazing temperature and holding time is 1423 K and 5.4 ksrespectively, the maximum shear strength of the Si3N4/Si3N4 joint is obtained to be 198 MPa.

Nano CaCO_3 : An Unique Condensation Agent for the Preparation of Monosubstituted Calix[4]arene by Ring-opening Reaction

Nano CaCO3 was used as a condensation agent in the ring-opening reaction of p-tert-butylcalix[4]arene with epichlorohydrin to afford 5,11,17,23-tetra-tert-butyl-26,27,28-trihyd- roxy-25-(1-chloro-2-hydroxy-3-propyl)calix[4]arene regioselectively in 52% yield. The yield was less than 2% by using normal CaCO3 instead of nano one under the same conditions.

THE EFFECT OF MATRIX TOUGHNESS ON THE BRITTLE-DUCTILE TRANSITION OF HDPE/CaCO_3 BLENDS

The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO_3blends are investigated. Not all HDPE can be toughened by CaCO_3 particles. The ability of thematrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (I_(sc)≈45J/m) below which HDPE can not be toughenedobservably by CaCO_3 particle at given average size, and above which the critical matrix ligamentthickness (τ_?) is proportional to matrix impact strength.

Strength and interfacial microstructure of Si3N4 joint brazed with amorphous Ti-Zr-Ni-Cu filler metal

In this paper, the vacuum brazing of Si3N4 ceramic was carried out with Ti40Zr25Ni15Cu20 amorphous filler metal. The interfacial microstructure was investigated by scanning electron microscopy （ SEM ）, energy dispersive spectroscopy （EDS） etc. According to the analysis, the interface reaction layer was mode up of TiN abut on the ceramic and the Ti-Si, Zr-Si compounds. The influence of brazing temperature and holding time on the joint strength was also studied. The results shows that the joint strength first increased and then decreased with the increasing of holding time and brazing temperature. The joint strength was significantly affected by the thickness of the reaction layer. Under the same experimental conditions, the joint brazed with amorphous filler metal exhibits much higher strength compared with the one brazed with crystalline filler metal with the same composition. To achieve higher joint strength at relatively low temperature, it is favorable to use the amorphous filler metal than the crystalline filler metal.

超细CaCO_3制备聚烯烃填充母料

介绍了以超细ＣａＣＯ３制备聚烯烃填充母料的生产原材料、工艺、配方及设备。

利用稻草灰分制备SiO_2纳米颗粒和SiO_2/CaCO_3纳米复合物

利用稻草灰分制备Si O2纳米颗粒和Si O2/Ca CO3纳米复合物,并将其用作造纸填料。通过XRD、XRF、TEM、FT-IR及Zeta电位等分析来表征Si O2纳米颗粒和Si O2/Ca CO3纳米复合物的性能。与加填商品PCC相比,加填Si O2纳米颗粒和Si O2/Ca CO3纳米复合物,可提高纸张的亮度、白度及不透明度等光学性能,但会略微降低纸张强度性能。Si O2纳米颗粒为半晶体相,其在纸张中的留着率高;Si O2/Ca CO3纳米复合物的留着率随Si O2与Ca CO3摩尔比的增大而增大。

碱溶性聚酯/碳酸钙/聚酯(COPET/CaCO_(3)/PET)多孔纤维制备及性能研究

采用自制的碱溶性聚酯/碳酸钙(COPET/CaCO_(3))母粒与聚酯(PET)母粒,经熔融纺丝实现对传统PET纤维的改性,结合单因子控制变量法优选碱酸处理制备COPET/CaCO_(3)/PET多孔纤维的最佳工艺参数,并对纤维性能进行测试与表征。结果表明,当NaOH质量分数为4%、HCL质量分数为3%时,纤维具有较好的表观形态和孔隙结构。在最优处理条件下,纤维内部含有较多分布均匀的孔隙,孔径主要集中分布在15~54nm。此时,纤维的断裂强度、线密度、比表面积和熔融温度分别为1.29cN/dtex、4.84dtex、5.5273m^(2)/g和253.85℃。