Surface coating properties of different shape and size pigment blends

The effect of different shape and size of pigments in blends on latex coating surface properties was investigated. Two pigment blends were compared. Both blends were made of plate-like kaolin pigment but with different size prismatic precipitated calcium carbonate at different volume ratios. All coatings were applied on absorbent as well as non-absorbent substrates. Surface coating properties investigated include surface morphology, surface chemistry and surface energy. Surface morphology was characterized by measuring gloss and roughness, surface chemistry was characterized by X-ray Photoelectron Spectroscopy and surface energy was estimated by Kaelable approach.     

Calcium sulphate as pigment for improved functional properties of coated paper

In the last few years, interest and demand of high bright paper have forced paper manufacturers to think new ways to improve brightness and whiteness of coated paper. Pigment coating is widely used to enhance the optical properties such as brightness, whiteness, and gloss of paper and paperboard. These optical properties are the most important for end user and also determine the final cost of coated paper. Calcium sulphate has inherent better optical properties compared to other conventional pigments for example ground calcium carbonate, precipitated calcium carbonate and kaolin clay. The present study was carried out with an aim to synthesize calcium sulphate using waste procured from phosphoric acid industry and to study its impact on the rheology of coating color as well as optical properties of coated paper. Addition of calcium sulphate improved the water retention property of coating color which can be helpful for improving the machine runnability. The results also revealed that calcium sulphate can be used as a pigment to produce coated paper of high brightness and whiteness. The brightness and whiteness of the coated paper were improved 4 and 15 points, respectively by using 50 parts of calcium sulphate as a pigment replacing clay from the coating formulation. The surface strength in terms of IGT pick value of coated sheets was found significantly comparable using calcium sulphate as pigment. The print gloss results were observed analogous with matt grade coated paper.     

Influence of particle size distribution of calcium carbonate pigments on coated paper whiteness

The optical properties of pigments used for paper coating are linked to their morphology. The light scattering through coated layers depends upon the size and the size distribution of the pigments and their packing behavior. In this report the effect of particle packing of various calcium carbonate pigments on the whiteness of the final coated paper is studied. Different grades of calcium carbonate pigments of different particle size distribution and optics were used for coating applications on base papers. Base papers of different optics were also selected. The entire study was carried out at different coat weights. It was observed that the overall scattering from the coated sheet depends upon the light scattering from the base paper as well as through the coated layer. Higher light scattering through the coated layer will lower the effect of the base paper, whether it is dark or bright. So high bright and white pigments are not only the criteria for an enhancement in the optical properties of coated paper; the particle size and size distribution should also be considered before introducing any pigment into a coating formulation. The base optics should also be chosen on the bases of the pigments’ optics and their morphology.     

Studies on surface properties of polymeric coated paper material

Surface properties of a polymeric coating system have a strong influence on its performance and service life. However, the surface of a polymer coating may have different chemical, physical, and mechanical properties from the bulk. Significant progress has been made during the last three decades in the improvement of coating on materials. It has been established that polymeric blends have great potential in replacing economically many conventional materials because of their high specific strength. It is needed today, constantly, to improve the surface finish of any material for efficiency and shiny appearance in the severity of working environment. In packaging, materials having longer service lives and those are less corrosive are highly used. The effect of polymer based coating on the paper material improves its mechanical properties and flame resistance. Effect of flame retardant polymer coating illuminates the surface of the sheet. Important application of the material sheets will be for corrosion receptivity and humidity resistance of this material will certainly improve. Blends of PMM/PVDF are mainly used to improve piezoelectric properties of PVDF. In the present study we report the measurement of surface properties of thin layer of polymer blend coated on the cardboard sheet substrate material. Polymer blend solutions of PMMA/PVDF was prepared at 90/10 (w/w) proportions in miscible solvent of toluene and DMF. Thin film was prepared on the surface of cardboard by dipping the cardboard material in the solution. Thickness of the dried polymer coated paper sheet was measured to see uniformity of coating and for different concentrations. Surface properties such as flexibility index, yellowness, and gloss reflectance were also measured. The study on these polymer coated paper will help in improving the surface property of paper as well as its use in packaging. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4167–4171, 2006     

Influence of rubber particle size on mechanical properties of polypropylene–SEBS blends

Isotactic polypropylene blends with 0–20 vol % thermoplastic elastomers were prepared to study the influence of elastomer particle size on mechanical properties. Polystyrene-block-poly(ethene-co-but-1-ene)-block-polystyrene (SEBS) was used as thermoplastic elastomer. SEBS particle size, determined by means of transmission electron and atomic force microscopy, was varied by using polypropylene and SEBS of different molecular weight. With increasing polypropylene molecular weight and, consequently, melt viscosity and decreasing SEBS molecular weight, SEBS particle size decreases. Impact strength of pure polypropylene is almost independent of molecular weight, whereas impact strength of polypropylene blends increases strongly with increasing polypropylene molecular weight. The observed sharp brittle–tough transition is caused by micromechanical processes, mostly shear yielding, especially occurring below a critical interparticle distance. The interparticle distance is decreasing with decreasing SEBS particle size and increasing volume fraction. If the polypropylene matrix ligament between the SEBS particles is thinner than 0.27 μm, the blends become ductile. Stiffness and yield stress of polypropylene and polypropylene blends increase with increasing polypropylene molecular weight in the same extent, and are consequently only dependent on matrix properties and not on SEBS particle size. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1891–1901, 1998     

粒度分布对磷石膏-石灰-粉煤灰胶结材物理性能的影响

针对磷石膏-石灰-粉煤灰体系胶结材大量利用磷石膏时,强度发展以及耐水性能的缺陷,采用机械粉磨以改善其粒度分布。探究了不同粒度分布对磷石膏-石灰-粉煤灰体系胶结材的物理性能和耐水性的影响。将磷石膏样品与生石灰以及粉煤灰按一定比例混合,陈化24h再通过粉磨不同时间,达到不同的粒度分布。将不同粒度的样品外掺5%水泥,3%AC增强剂以及0.5%聚羧酸减水剂,按照标准稠度用水量加水在160 mm×40 mm×40 mm试模中成型,在养护室中养护到规定龄期再测定试件的物理性能以及微观分析。结果表明,磷石膏掺量达到40%,通过粉磨的物理活化,该体系按照水泥砂浆砌块成型,28 d抗压强度≥27.76 MPa,软化系数达到86%的胶凝材料,并且无废水排除,杜绝二次污染。     

不同表面活性剂包覆的LMH对LLDPE性能影响

采用气泡液膜法制备了不同表面活性剂包覆的疏松型氢氧化镁(LMH),通过对常规力学性能和极限氧指数(LOI)的测试、燃烧实验和热重分析,研究了不同表面活性剂包覆的LMH对线型低密度聚乙烯(LLDPE)性能的影响.结果表明:不同表面活性剂包覆的LMH对LLDPE拉伸强度、弯曲强度和LOI的影响不大,但会显著影响材料的冲击强度、热释放速率、燃烧质量损失率及热稳定性;以聚乙二醇6000包覆的LMH可使LLDPE的力学性能、阻燃性能及热稳定性能较优.     

改性纳米TiO_2对纸张涂料及涂布纸性能的影响

研究了改性纳米TiO2对纸张涂料流变行为和涂布纸性能的影响。研究发现,在同一剪切速率下,随着改性纳米TiO2用量的增加,纸张涂料的表观黏度逐渐增大,且含改性纳米TiO2的纸张涂料具有较高的弹性模量和黏性模量,相位角则较低;随着改性纳米TiO2的用量在0~10%范围内增加,涂布纸的光学性能和印刷适性持续改善,且涂层表面结构的SEM和AFM观察显示,含改性纳米TiO2的纸张涂层表面具有较优的微观孔隙结构。     

不同晶粒尺寸对CVD金刚石膜机械性能的影响

采用热丝辅助化学气相沉积（CVD）工艺制备出纳米、微米及细晶粒金刚石膜材料。观察了这三种金刚石膜的表面形貌并对上述金刚石膜的物理机械性能包括抗弯强度和耐磨性进行了实验性研究。结果表明,细晶粒结构的金刚石膜具有最高的抗弯强度．纳米结构的金刚石膜耐磨性最好。综合两个技术指标认为：细晶粒金刚石膜是三种晶粒结构中最佳的刀具制造材料。     

炭黑并用对NR／ENR共混胶力学性能及减震性能的影响

对比N660研究了N330／N660、N660／N990炭黑填充体系对天然橡胶（NR）／环氧化天然橡胶（ENR）共混胶力学性能、压缩疲劳生热性能及减震性能的影响,并采用橡胶加工分析仪（RPA）对其加工性能进行了分析。结果表明：N660／N330和N660／N990两种填充体系硫化胶的力学性能,基本上是单用一种炭黑所得硫化胶力学性能的加权平均;不同粒径炭黑并用均能使共混胶的贮能模量E′下降,并且有利于拓宽NR／ENR减震材料的减震范围;不同粒径炭黑并用有利于改善NR／ENR共混胶料的加工性能。     

Influence of natural inhibitor,pigment and extender on corrosion of polymer coated steel

Lupine (Lupinous albus L.) seeds extract was incorporated into a vinyl chloride–vinyl acetate copolymer based paint formulation to control steel corrosion in 0.5 M NaCl. Evaluation of this system included the use of electrochemical impedance spectroscopy (EIS) and a salt spray cabinet for accelerated aging tests. The EIS data demonstrated that highest protection was attained at a lupine threshold concentration of 0.025 g/L. Two white color pigments (ZnO and TiO₂) and three extenders (CaCO₃, mica and talc) were tested as paint additives. The accelerated aging tests showed that the coated steel panels containing TiO₂ had a high degree of blistering while those containing ZnO exhibited reasonable hiding power and better protection efficiency. Field tests indicated that the presence of TiO₂ enhanced the growth of fouling organisms over the coated steel surface.     

Influence of natural inhibitor,pigment and extender on corrosion of polymer coated steel

Lupine (Lupinous albus L.) seeds extract was incorporated into a vinyl chloride–vinyl acetate copolymer based paint formulation to control steel corrosion in 0.5 M NaCl. Evaluation of this system included the use of electrochemical impedance spectroscopy (EIS) and a salt spray cabinet for accelerated aging tests. The EIS data demonstrated that highest protection was attained at a lupine threshold concentration of 0.025 g/L. Two white color pigments (ZnO and TiO₂) and three extenders (CaCO₃, mica and talc) were tested as paint additives. The accelerated aging tests showed that the coated steel panels containing TiO₂ had a high degree of blistering while those containing ZnO exhibited reasonable hiding power and better protection efficiency. Field tests indicated that the presence of TiO₂ enhanced the growth of fouling organisms over the coated steel surface.     

Dynamic mechanical properties of polyurethane–urea microcapsules on coated paper

Polyurethane–urea microcapsules were prepared by an interfacial polymerization method. Dynamic mechanical measurements were carried out on the polyurethane–urea microcapsules coated on a paper substrate. The glass transition temperatures (T_g) of capsule wall were observed in the temperature scan data. T_g as the temperatures of tan δ peaks were decreased with increasing amounts of core materials. The apparent activation energies of the glass transition were estimated at about 100 kcal/mol. Master curves were obtained by shifting the tan δ spectra along the frequency axis, and the glass transition regions were unaffected by core materials studied. The shift factors were found to depend on the core/wall ratio and discussed in terms of a morphological change of microcapsules. © 1994 John Wiley & Sons, Inc.     

The effects of filler size on the properties of thermoplastic polyolefin blends

The effects of filler size on the properties of a thermoplastic polyolefin (TPO) blend were examined by using wollastonite and talc with particle sizes ranging from 1.2 to 40 μm. While addition of filler produced significant changes in the mechanical properties of the blend, filler size affected only impact strength. However, filler size, filler coating, and injection speed had a major effect on the surface properties of the blend. Faster injection produced denser “shear zone layers” which exhibited better scratch resistance and poorer paint adhesion than those obtained with slower injection. Scartch resistance and paint adhesion also decreased with increasing filler particle size. Filler coatings altered the scratch and adhesion properties of the polypropylene (PP) blends.     

Enhancing coated paper mechanical properties via doping kaolin with ammonium molybdate

Mechanical properties of paper coating layers are very important in converting and printing operations. Kaolin is commonly used in paper coating as cheap pigment in addition to its superior properties. In this study, a new approach for improving coated paper mechanical properties using doped kaolin with ammonium molybdate was presented. Kaolin and modified kaolin were characterized using several analyses tools (e.g., XRD, SEM, and EDX), and then they were applied in paper coating mixture. The results revealed that the dopant was found in the kaolin as MoO_x; this oxide form with its needle shapes led to change in the kaolin crystals, and its presence in high concentrations led to exfoliation of kaolin. Also, at high concentration it was found that MoO_x reacted with γ-alumina that is found in kaolin after its heating at 300°C to form aluminum molybdate. It can be observed that modified kaolin increased the coated paper porosity and consequently the opacity; also bulk and thickness were increased. Significant improvement in coated paper tensile strength, bursting strength, tensile energy absorption, and bending stiffness was also noticed. Thermal study also showed that increasing the concentration of ammonium molybdate increased the heat stability of the coated paper.     

Influence of pigment properties on UV‐curing efficiency

The curable formulations containing monomer‐diacrylate, photoinitiator‐p‐methoxybenzoyldiphenylphosphine oxide/benzyldimethylketal, additive reactive‐triethylamine, and inorganic thermoresistant pigments‐white, red, green, and blue were cured by UV exposure films. A series of experiments was carried out to investigate the relationship between the particle size distribution of the inorganic pigment and the colorimetric and mechanical properties of the UV acrylic curable coatings. Pendulum hardness and appearance of the films depend on the content and particle size distribution of the pigment. Optimal particle size distribution and pigment content were established to obtain the best films concerning their pendulum hardness and chromatic parameters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 247–252, 2007     

Influence of carbon nanotubes with different functional groups on the morphology and properties of PPO/PA6 blends

Carbon nanotubes with different functional groups were prepared and then incorporated into the poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 (PPO/PA6) blend via melt blending. The influence of different carbon nanotubes on the morphology and properties of the blend was studied. The results show that addition of pristine CNTs, CNTs‐OH, CNTs‐NH₂ leads to the evolution of the phase structure of PPO/PA6 (mass ratio: 60/40) blend from sea‐island to cocontinuous, whereas incorporation of CNTs‐COOH does not change the blend morphology due to serious aggregation of the carbon nanotubes. Incorporating different CNTs into PPO/PA6 blend increases the tensile modulus and storage modulus of the blends, whereas decreases slightly the tensile strength. At the same time, the glass transition temperatures (T_g) of PA6 and PPO are enhanced. ΔT_g, the gap between the T_g of PA6 and PPO, decreases with the addition of carbon nanotubes due to the stronger interaction of carbon nanotubes with PA6 than PPO. A similar tendency was found in the storage modulus (G′) and complex viscosity (η*) of the composites. The dispersion state of different carbon nanotubes and their interaction with polymer components are different, which causes the different confinement effect to the macromolecular chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Chitosan‐coated paper: Effects of nisin and different acids on the antimicrobial activity

Chitosan coatings prominently improved both the gloss and oxygen barrier properties of paper. The gloss value in the machine direction was increased as a function of added chitosan. An oxygen‐permeability value of 1.1 cm³/m² d was obtained when 6.9 g/m² chitosan was applied to 80 g/m² copy paper. In addition, the effects on the mechanical properties were positive, but not significant. The water‐vapor permeability of the paper increased as a result of the chitosan coating. Chitosan dissolved in 1.6, 3.2, and 6.4% lactic acid showed antimicrobial activity against Bacillus subtilis, whereas acetic and propionic acids (1.6, 3.2, and 6.4%) did not produce any notable activity. Nisin (0.08 g/L) did not enhance the antimicrobial activity of coatings prepared from chitosan dissolved in different acids. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 986–993, 2004