Characterization and modification of fillers for paints and coatings

This paper highlights the possibility of inverse gas chromatography for the surface characterization of common fillers (CaCO₃, talc, SiO₂,) for paints and coatings. Divided solids are described, on the one hand, by the dispersive component of their surface energy and, on the other, by a specific parameter indicating their acid-base interaction potential. The role of the surface morphology at a molecular level is also examined. It is demonstrated that steric effects play an important role in the adsorption of probes on lamellar solids like talc. The consequences of surface treatments as well as examples of practical applications are also reported.     

Water uptake and tensile properties of carboxylated styrene butadiene rubber based water born paints: Models for water uptake prediction

Despite significant advances in water based surface coating technology, the presence of surfactants in emulsion polymer binders leads to loss of performance after prolonged immersion in water, relative to solvent based coatings that are free of surfactant impurities. This study begins with water uptake evaluation of a range of emulsion polymer binders. A carboxylated styrene butadiene rubber latex (c-SBR) performed best in the latter evaluations and was selected for the formulation of an exterior grade paint and construction of a mathematical model to predict water uptake of the dry film. The c-SBR was then compounded with a range of inorganic fillers and water uptake and tensile properties were evaluated. Talc was found to be the best performing filler, and was used in a three factorial central composite design study where the simultaneous effects of talc, titanium dioxide and phenolic stabiliser on water up take were evaluated and fitted to response equations. A quadratic model was found to provide the most accurate prediction of effects associated with interactions between talc and TiO₂. Certain combinations of talc and titanium dioxide were found to be synergistic in reducing the water uptake. This was considered to be associated with a packing effect stemming from the vast difference in particle size between talc and titanium dioxide particles. An optimised formulation was finally prepared to meet one of the final formulation objectives; i.e., minimised water uptake. Preparation of such a formulation showed that the predicted and measured water uptake responses were in excellent agreement. This study illustrates the effectiveness of statistical experimental design methods in predicting the water uptake characteristics of water-based coatings.     

高流动性高韧性PP/POE共混材料研制

用聚烯烃弹性体(POE)代替传统的弹性体,对聚丙烯(PP)增韧改性,探讨了基体树脂、POE、HDPE、滑石粉、纳米CaCO3以及加工助剂EBS的用量对共混体系力学性能和流动性的影响.并通过扫描电镜观察冲击断面,研究共混物的形态结构.结果表明,POE能大幅度的改善材料的冲击韧性,HDPE和POE具有协同增韧效应,加工助剂EBS能改善PP共混材料的流动性,制得的PP改性材料具有高韧性和离流动性,可用于制造汽车装饰件.     

Transesterification of Canola Oil to Biodiesel Using CaO/Talc Nanopowder as a Mixed Oxide Catalyst

A series of heterogeneous catalysts including different molar ratios of CaO/talc was synthesized to study the transesterification reaction of canola oil and methanol under different reaction conditions. Characterization and kinetic results revealed that the activity of this catalyst was enhanced due to the increase of CaO/talc molar ratio value leading to an improvement in the biodiesel production. Moreover, the effect of various parameters on the activity of the undertaken catalysts was studied in order to determine the optimum process conditions. Leaching measurements and the durability of the CaO/talc catalyst under several reaction cycles were evaluated and proved it to be a stable catalyst.     

Comparison in composite performance after thermooxidative aging of injection molded polyamide 6 with glass fiber,talc, and a sustainable biocarbon filler

Degradation is an unavoidable part of a material's life making it important to both monitor and control the aging behavior of plastics. This study compares thermooxidative degraded composites of a novel bio-based and sustainable filler, Biocarbon (MBc), against that of traditional and commercially available fillers (glass fiber and talc) used in the automotive industry. The influence of thermooxidative degradation on the composites was studied under accelerated heat aging for 1000 h at 140°C. The mechanical properties of the composites were evaluated using notched Izod impact as well as both tensile and flexural tests. Morphological structure of the composites was investigated using a scanning electron microscopy. Dynamic mechanical analysis and differential scanning calorimetry were used to evaluate the physical transitions both before and after aging. The glass-filled composites displayed the best performance; while, both the talc and biocarbon composites possessed similar strength and ductility performances. Advantageously, the biocarbon composites experienced an 11% reduction in density as compared to talc-filled composites with similar weight content. After aging, all composites exhibited reduced tensile and flexural strengths ranging from 5 to 67% partly due to chain scission. Whereas, the modulus of all composites increased with a range of 1–24% due to an annealing effect. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48618.     

Preparation and properties of enstatite ceramic foam from talc

The effective method of preparation, stabilization and high temperature treatment of enstatite ceramic foam is described in this work. The technique is based on foaming of suspension of talc, on the stabilization of foam structure and on final high temperature treatment after drying. The spontaneous delamination of aggregates and the redistribution of talc particles in foam are driven by decreasing surface energy. The changes of phase composition as well as the mechanism and the kinetics of processes which take place during the thermal treatment were described. The treatment within the temperature range from 1150 to 1250 °C provides the ceramic foam via sintering without melted phase, whereas a liquid phase sintering occurs at higher temperatures. The final temperature of sintering is 1300 °C. Increasing amount of melted phase supports the formation of enclosed porosity and formed glass stabilizes the high temperature protoenstatite polymorph in the foam.     

挤出共混中的高剪切应力对PP-HDPE-滑石粉共混材料力学性能的影响

采用提高双螺杆挤出机螺杆转速的方法,研究了双螺杆挤出机的高剪切应力作用对聚丙烯(PP)、PP-滑石粉和PP-高密度聚乙烯(HDPE)-滑石粉共混材料力学性能的影响.结果表明:双螺杆挤出机的高螺杆转速、高剪切应力作用,可促进材料中滑石粉颗粒的均匀分散、促进HDPE均匀分散于PP基体的乙丙共聚物的相态之中,可引起PP或HDPE的断链反应、引起HDPE大分子自由基与PP基体中的EPR相以及与滑石粉表面偶联助剂之间的结合反应,引起共混材料缺口冲击强度的显著增大;少量极性烯类单体的加入和较低的挤出反应温度条件(180℃)有利于形成的大分子自由基与极性烯类单体的接枝、嵌段反应、界面间的偶联结合反应及其原位增粘作用,并引起PP-HDPE-滑石粉共混材料缺口冲击强度的进一步增大.     

滑石处理含镍废水的试验研究

采用吸附实验方法,利用滑石处理含镍废水,探讨了滑石用量、反应时间和溶液pH值单因素对处理效果的影响,利用正交试验研究了综合因素对处理效果的影响,并确定最优工艺条件。结果表明:滑石对含镍废水处理效果良好,滑石处理含镍废水的各因素的影响关系大小为:溶液pH值滑石用量反应时间,最优工艺条件为A3B3C3,即滑石用量为7.0 g/L,反应时间为5 h,pH值为8.0。     

Preparation of dehydroxylated and delaminated talc: Meta-talc

The roentgen-amorphous delaminated and dehydroxylated phase was prepared applying intensive milling procedure and subsequent thermal treatment of talc. Due to the similarity in properties and in thermal behavior of this material with roentgen-amorphous delaminated and dehydroxylated kaolinite phase, i.e. meta-kaolinite, the name meta-talc was suggested for this material. The properties and the behavior during thermal treatment were investigated using thermal analysis, x-ray diffraction analysis, infrared spectroscopy and scanning electron microscopy. The suggested procedure changes the activation energy of dehydroxylation, the behavior during thermal treatment and the phase composition of the product. The kinetics and thermodynamics of the thermal transition were evaluated using Kissinger equation and Eyering law.