The rheological properties of paper coating suspensions and their application

Conclusions  The experimental results lead to the following observations:

Influence of structure and surface chemistry on the cohesion of paper coatings

The effects of particle size, particle shape and surface chemistry on the cohesion of pigmented coatings based on clay, calcium carbonate and polystyrene (PS) latex, using carboxymethylcellulose (CMC) as a binder, has been determined. The critical (minimum) binder content (CBC) required to form a coherent film was assessed by an abrasion test. Z-direction strength was characterized by a delamination (90° peel) test. The results indicate that coating cohesion, assessed by CBC or delamination, increases with increasing pigment particle size, for the three pigments examined. Differences between clay and CaCO₃ are ascribed mainly to a shape effect. Coatings based on plate-like clay are more resistant to in-plane stresses, and coatings based on isometric CaCO₃, to out-of-plane stresses. The significant difference in both CBC and peel strength between isometric CaCO₃ and PS (at similar equivalent spherical diameter) is ascribed to much weaker acid-base interactions between pigment and the CMC binder in the case of the PS latex. Size distribution (CaCO₃ is polydisperse, PS is monodisperse) might play a role in stress distribution.     

Synthesis of CaCO3–P(MMA–BA) nanocomposite and its application in water based alkyd emulsion coating

As part of broader effort to synthesize a new class of water-based composite, hybrid emulsion polymerization was carried out with acrylic monomers [methyl methacrylate (MMA), n-butyl acrylate (BA)]. Nanocomposite of P(MMA–BA)/nano CaCO₃ was synthesized by in situ emulsion polymerization. Water-based alkyd coating with various proportions nano CaCO₃, P(MMA–BA) and its nanocomposite was formulated. Extent of polymerization with and without nano CaCO₃ was measured using gravimetric method. Thermal properties of neat polymer, nanocomposite and coating films were evaluated by TGA and DSC, DTA analysis. Uniform dispersion of nano CaCO₃ in polymer matrix was ensured from SEM/TEM images. Incorporation of nanoparticles to hybrid polymer and nanocomposite to alkyd emulsion showed significant enhancement in mechanical and thermal properties. Dual role of nanocomposite in coating; as a partial binder and a filler to improve property profile of neat coating has been reported.     

Synthesis of CaCO3–P(MMA–BA) nanocomposite and its application in water based alkyd emulsion coating

As part of broader effort to synthesize a new class of water-based composite, hybrid emulsion polymerization was carried out with acrylic monomers [methyl methacrylate (MMA), n-butyl acrylate (BA)]. Nanocomposite of P(MMA–BA)/nano CaCO₃ was synthesized by in situ emulsion polymerization. Water-based alkyd coating with various proportions nano CaCO₃, P(MMA–BA) and its nanocomposite was formulated. Extent of polymerization with and without nano CaCO₃ was measured using gravimetric method. Thermal properties of neat polymer, nanocomposite and coating films were evaluated by TGA and DSC, DTA analysis. Uniform dispersion of nano CaCO₃ in polymer matrix was ensured from SEM/TEM images. Incorporation of nanoparticles to hybrid polymer and nanocomposite to alkyd emulsion showed significant enhancement in mechanical and thermal properties. Dual role of nanocomposite in coating; as a partial binder and a filler to improve property profile of neat coating has been reported.     

Conductive coating films based on low density In2O3 powders and polymer latexes

Several kinds of conductive coating films were prepared from a low-density indium(III) oxide powder (which was employed because it provides a much higher volume for the same weight) and polymer latexes. The low-density In₂O₃, which is an electrically conductive pigment, was prepared by pyrolysis followed by the combustion of water-swellable polymer microspheres imbibed with In(NO₃)₃, the precursor of In₂O₃. Either acrylamide/N,N'-methylenebisacrylamide or poly(vinylalcohol)/glutaricdialdehyde was used to generate spherical hydrogel particles. The polymer latexes with which the In₂O₃ was mixed had a soft core and a hard shell structure to ensure that the coating film has suitable mechanical properties in addition to conductivity. Acrylonitrile/butadiene/styrene copolymer ABS or acrylonitrile/butylacrylate/styrene copolymer ABAS latexes were used as binders for the conductive pigment. The powder coating followed by hot pressing, the water-borne coating consisting of low-density In₂O₃ and polymer latexes followed by curing, or the colloidal dispersion coating was used to deposit flexible conductive coating films on polyester sheets. The conductive pigment density and the polymer latexes' size and flowability are the factors that affect the characteristics of the film. We found that the colloidal suspension coating procedure based on ABAS latexes achieves better electrical and mechanical properties for the coating films. © 1996 John Wiley & Sons, Inc.     

Mechanical properties of styrene–butadiene–styrene block copolymer composites filled with calcium carbonate treated by liquid polybutadienes

The factors influencing the mechanical properties of styrene–butadiene–styrene block copolymer (SBS) composites filled with liquid polybutadiene (LB)‐surface‐treated calcium carbonate (CaCO₃) were investigated with respect to the molecular structure of the LB, the amount of the LB adsorbed on the CaCO₃ surface, the heat treatment conditions, and the surface treatment method. The mechanical properties, such as the modulus, tensile strength at break, tear strength, storage modulus, and tension set, of the SBS composites were improved remarkably through the filling of CaCO₃ surface‐treated with a carboxylated LB with a high content of 1,2‐double bonds. The heat treatment of LB–CaCO₃ in air was also effective in enhancing such properties. When SBS, CaCO₃, and LB were directly blended (with the integral blend method), secondary aggregation of CaCO₃ took place, and the mechanical properties of the composite were significantly lower. In the integral blend method, LB functioned as a plasticizer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Plasticization of nano‐CaCO3 in polystyrene/nano‐CaCO3 composites

The shear rheological properties of polystyrene (PS)/nano‐CaCO₃ composites were studied to determine the plasticization of nano‐CaCO₃ to PS. The composites were prepared by melt extrusion. A poly(styrene–butadiene–styrene) triblock copolymer (SBS), a poly(styrene–isoprene–styrene) triblock copolymer (SIS), SBS‐grafted maleic anhydride (SBS–MAH), and SIS‐grafted maleic anhydride were used as modifiers or compatibilizers. Because of the weak interaction between CaCO₃ and the PS matrix, the composites with 1 and 3 phr CaCO₃ loadings exhibited apparently higher melt shear rates under the same shear stress with respect to the matrix polymer. The storage moduli for the composites increased with low CaCO₃ concentrations. The results showed that CaCO₃ had some effects on the compatibility of PS/SBS (or SBS–MAH)/CaCO₃ composites, in which SBS could effectively retard the movement of PS chain segments. The improvement of compatibility, due to the chemical interaction between CaCO₃ and the grafted maleic anhydride, had obvious effects on the rheological behavior of the composites, the melt shear rate of the composites decreased greatly, and the results showed that nano‐CaCO₃ could plasticize the PS matrix to some extent. Rheological methods provided an indirect but useful characterization of the composite structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Influence of aspect ratio of fillers on the properties of acrylonitrile butadiene styrene composites

Aspect ratio (shape) of the filler is one of the key factors which play a vital role in determining the properties of the composites. Fillers like talc and calcium carbonate (CaCO₃) have different aspect ratios and affect the properties differently. This study was carried out to investigate the effect of aspect ratio of the filler on the properties of the acrylonitrile butadiene styrene (ABS) polymer. The rheological, mechanical, thermal properties, and fracture morphology were studied for the ABS composites filled with talc and CaCO₃ at various filler loading. Coupling agent was added to improve the interfacial adhesion between the filler and the ABS matrix. The aspect ratio of fillers affected the flow behavior at lower shear rate, and was insignificant at higher shear rates. The flow‐induced morphology was more effective in case of talc giving a significant increase in the bending modulus. Tensile and flexural strength showed a slight decrease in the values with talc showing better performance as compared to CaCO₃. The reverse was observed in case of impact strength, with CaCO₃ showing lower drop in the values. Aspect ratio of filler had no significant effect on the thermal properties of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46023.     

Functional silane-modified calcium carbonate

In the course of graft polymerization of styrene on a calcium carbonate powder surface treated with a silance coupling agent such as γ-methacryloxypropyltrimethoxysilane, gelation of the reaction mixture was observed just as on silane-modified clay. Infrared spectroscopic and gel-permeation chromatographic studies have revealed that the extracts of styrene monomer from the powder surfaces contained polymeric silane coupling agent, having crosslinking ability, besides monomeric silane coupling agent. The catalytic effect on the condensation of the silane coupling agent on the powder surface was found to be increased in following order: CaCO₃ < P-CaCO₃ < clay, where P-CaCO₃ is a calcium carbonate modified with phosphoric acid. The order was parallel to the gelation tendency and to the acidity order (H₀ ? 6.8) on the surfaces. Direct evidence for bonding between the silane coupling agent and the phosphate moiety on calcium carbonate was not available; however, the silane-modified P-CaCO₃ filler exhibited more reinforcing effects in peroxide-cured ethylene–propylene–diene rubber (EPDM) and in sulfur-cured styrene–butadiene rubber (SBR) than the silane-modified calcium carbonate. These reinforcing effects are also discussed in relation to the molecular weight distribution of the silane coupling agent extracted.     

Barrier and Mechanical Properties of Clay-Reinforced Polymeric Nanocomposites

In this work, clay-based nanocomposites films were prepared by addition of clay-Na⁺ natural montmorillonite in pectin and hydroxypropyl methylcellulose (HPMC) matrices. Mechanical (tensile strength, elastic modulus, and elongation) and barrier (Water Vapor Permeability (WVP), and Oxygen permeability (O₂P)) properties were investigated. From results, it was observed that the WVP and O₂P decreased when nanoclay was included into the HPMC and pectin matrix films. Additionally, the incorporation of nanoclay in the films significantly improved the mechanical properties because the reinforcing effect of clay from its high aspect ratio and its enormous surface area. These results are very important in packaging area.     

Mechanical,thermal, and microstructural properties of polypropylene/polyamide‐6/styrene‐ethylene‐butadiene‐styrene polymer alloys

Interfacial agents as compatibilizers have recently been introduced into polymer blends to improve the microstructure and mechanical properties of thermoplastics. In this way, it is possible to prepare a mixture of polymeric materials that can have superior mechanical properties over a wide temperature range. In this study, an incompatible blend of polypropylene (PP) and polyamide‐6 (PA₆) were made compatible by the addition of 10% styrene–ethylene–butadiene–styrene copolymer (SEBS). The mixing operation was conducted by using a twin‐screw extruder. The morphology and the compatibility of the mixtures were examined by SEM and DSC techniques. Furthermore, the elastic modulus, tensile and yield strengths, percentage elongation, hardness, melt flow index, Izod impact resistance, heat deflection temperature (HDT), and Vicat softening point values of polymer alloys of various ratios were determined. It was found that the addition of SEBS to the structures decreased the tensile strength, yield strength, elastic modulus, and hardness, whereas it increased the Izod impact strength and percentage elongation values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3485–3491, 2003     

The Relationship between Microstructure and Properties in PP/Rubber Powder/nano‐CaCO3 Ternary Blends

Summary: A new kind of rubber powder with “salami” structure (RPS) was prepared by spray drying the mixture of styrene‐butadiene rubber latex and nano‐CaCO₃ slurry. It was found that RPS is an effective toughener with synergistic toughening effect on poly(propylene) (PP). The Izod impact strength of PP/RPS blend is not only higher than that of PP/rubber powder or PP/nano‐CaCO₃ blends, but also higher than that of a PP/rubber powder/CaCO₃ blend. TEM images show that the microstructure of the PP/RPS blend is an “island‐sea” structure with “salami” structure in RPS, in which nano‐CaCO₃ particles are embedded in styrene‐butadiene rubber particles. The relationship between properties and microstructure has been studied by using TEM, SEM, DSC, etc.

     

Effect of Silane Coupling Agent on the Mechanical Properties of Clay Filled Styrene Butadiene Rubber

Abstract

The effect of treatment of coupling agent [Bis (3-triethoxy-silyl-propyl) tetrasulphide] on mechanical properties of composites made from styrene butadiene rubber and clay is reported in this paper. The coupling agent in the form of solution (1.0%) was used for treatment of the filler. The treatment resulted in enhancement of mechanical properties of composites when compared with composites containing untreated clay. The properties under consideration were tensile strength, modulus at 100% and 400%, Young's modulus, hardness, etc. Good reinforcement was observed due to treatment of 1% coupling agent. Tensile strength was improved by 11%, modulus at 400% was found to improve by 237%, elongation at break was improved by 250%, while Young's modulus also was improved by 298% for treated clay composites, respectively, at 0.41 volume fraction when compared with untreated clay composites.     

Acrylonitrile butadiene nanocomposites containing different clays by latex compounding method

Considering elastomers nanocomposites, most of the works are focused on natural rubber, styrene butadiene rubber and rubber blends, while few of them deal with nitrile butadiene rubber (NBR). This article presents the reinforcing effect of two raw sodic montmorillonites (Mts) and one organoclay on NBR matrix prepared by the latex compounding method. Raw Mts increase the mechanical properties of neat matrices. A pseudoplastic behavior is observed with the incorporation of clays into the NBR latex, indicating interactions between polymer chains and clay sheets, in agreement with the results of zeta potential analysis. X‐ray diffraction evaluates changes in the interlayer distance of the clay, indicating the NBR intercalation phenomenon in all cases. Matrices with different clay proportions present variations in the mechanical properties, depending if the aggregation phenomenon is promoted. Morphological analysis of clays and nanocomposites as well as thermal analysis were performed. The variation in mechanical properties after an aging process was studied, evaluating the effects on the tensile strength, ultimate strain and 300% modulus. POLYM. ENG. SCI., 59:736–744, 2019. © 2018 Society of Plastics Engineers     

Influence of polymer polarity on photochromic behavior of naphthodipyran doped in different polymeric matrixes

Photochromic polymer films were prepared by doping the naphthodipyran into different polymers such as Polyvinylpyrrolidone (PVP), styrene‐butadiene‐styrene (SBS) triblock copolymer, and polymethyl methacrylate (PMMA) at different concentrations. The kinetics of the photochromism/decoloration in the thin films was quantified by fitting biexponential equations to their photochromic decay curves after UV irradiation. The results show that the fastest decoloration process was in SBS, and the slowest one was in PVP. The DSC results indicate that T_g of polymeric matrix has no obvious effect on the decoloration rate of naphthodipyran. The decreasing order of the decoloration constant of naphthodipyran was consistent with increasing polarity of polymer matrixes as PVP > PMMA > SBS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

高性能钠离子电池黏合剂的研究进展

为了实现钠离子电池优异的电化学性能,除了从电极材料的搭配方面入手,作为维持电极结构稳定性的关键材料,黏合剂的选择也至关重要。本文对黏合剂的主要作用与性能要求进行了讨论,系统综述了近年来高性能钠离子电池黏合剂的研究进展,分别阐述了聚偏氟乙烯、羧甲基纤维素、海藻酸钠、聚丙烯酸以及交联聚合物等5类黏合剂的特性：聚偏氟乙烯的化学稳定性良好,黏合效果较好,但存在溶胀率较大的问题;羧甲基纤维素具有良好的分散性,机械强度较大,由于脆性较大而需与丁苯橡胶搭配使用;海藻酸钠环保且廉价,保形性好,但稳定性较差;聚丙烯酸拥有较高的弹性模量和抗拉强度,但是力学性能较差;交联聚合物的机械强度大,弹性较好,可能存在网络缺陷。结合已有的研究报道,探讨了这些黏合剂在钠离子电池系统中的应用,展望了今后黏合剂在拓宽来源领域、匹配适合的电极材料以及消除水性黏合剂对电池性能的负面影响等方面的发展方向。     

Mechanical properties and morphology of coal gasification fine slag glass bead-filled acrylonitrile–butadiene–styrene (ABS) composites

Coal gasification fine slag glass beads (CGFSGBs) were processed via an efficient pneumatic separation technique. CGFSGB products (CGFSGB-S1, CGFSGB-S2, and CGFSGB-S3) with different sizes were acquired. The heavy calcium carbonate (CaCO₃) was used as comparative filler. Effects of particle size and geometric shape on mechanical strengths, flow properties, and solid density of filled acrylonitrile–butadiene–styrene (ABS) were investigated. The mechanical strengths of composites decreased with increasing CGFSGB weight fraction, while MFR and solid density increased. The mechanical strengths were found to increase with decreasing CGFSGB size, and spherical surface of the CGFSGB is more beneficial to improve interface adhesion strength than square surface of the CaCO₃. The flow property analysis showed that the ABS/CaCO₃ composites have better fluidity and the advantages in the processing energy consumption. However, the incorporation of CaCO₃ resulted in the higher solid-state density. In summary, CGFSGBs have the potential to replace CaCO₃ in the ABS market. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48601.     

Effect of surface modifiers and surface modification methods on properties of acrylonitrile–butadiene–styrene/poly(methyl methacrylate)/nano‐calcium carbonate composites

Nano‐calcium carbonate (nano‐CaCO₃) was used in this article to fill acrylonitrile–butadiene–styrene (ABS)/poly(methyl methacrylate) (PMMA), which is often used in rapid heat cycle molding process (RHCM). To achieve better adhesion between nano‐CaCO₃ and ABS/PMMA, nano‐CaCO₃ particles were modified by using titanate coupling agent, aluminum–titanium compound coupling agent, and stearic acid. Dry and solution methods were both utilized in the surface modification process. ABS/PMMA/nano‐CaCO₃ composites were prepared in a corotating twin screw extruder. Influence of surface modifiers and surface modification methods on mechanical and flow properties of composites was analyzed. The results showed that collaborative use of aluminum–titanium compound coupling agent and stearic acid for nano‐CaCO₃ surface modification is optimal in ABS/PMMA/nano‐CaCO₃ composites. Coupling agent can increase the melt flow index (MFI) and tensile yield strength of ABS/PMMA/nano‐CaCO₃ composites. The Izod impact strength of composites increases with the addition of titanate coupling agent up to 1 wt %, thereafter the Izod impact strength shows a decrease. The interfacial adhesion between nano‐CaCO₃ and ABS/PMMA is stronger by using solution method. But the dispersion uniformity of nano‐CaCO₃ modified by solution method is worse. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Cell evolution and compressive properties of styrene–butadiene–styrene toughened and calcium carbonate reinforced polystyrene extrusion foams with supercritical carbon dioxide

Polystyrene (PS) foams have been used in various fields, whereas its broader application is limited by its low mechanical strength and brittle features. In this study, styrene–butadiene–styrene (SBS) and calcium carbonate (CaCO₃) nanoparticles were melt‐blended with PS and extrusion‐foamed with supercritical carbon dioxide as a blowing agent to simultaneously toughen and reinforce PS foams. Under the same foaming conditions, the addition of SBS and CaCO₃ was shown to have a significant influence on the cell structure and the compressive properties of the composite foams. We found that the cell structure evolution was highly correlated with the system viscosity. When the rubbery‐phase SBS content was 20%, the cell diameter decreased by 20.7%, and the compressive modulus was enhanced by 289.5%. With the further addition of 5% rigid CaCO₃ nanoparticles, the cell diameter was further reduced by 72.2% and the compressive modulus was improved by 379.2%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43508.     

Preparation and properties of nano‐CaCO3/acrylonitrile‐butadiene‐styrene composites

CaCO₃/acrylonitrile‐butadiene‐styrene (ABS) and CaCO₃/ethylene‐vinyl acetate copolymer (EVA)/ABS nanocomposites were prepared by melting‐blend with a single‐screw extruder. Mechanical properties of the nanocomposites and the dispersion state of CaCO₃ particles in ABS matrix were investigated. The results showed that in CaCO₃/EVA/ABS nanocomposites, CaCO₃ nanoparticles could increase flexural modulus of the composites and maintain or increase their impact strength for a certain nano‐CaCO₃ loading range. The tensile strength of the nanocomposites, however, was appreciably decreased by adding CaCO₃ nanoparticles. The microstructure of neat ABS, CaCO₃/ABS nanocomposites, and CaCO₃/EVA/ABS nanocomposites was observed by scanning electron microscopy. It can be found that CaCO₃ nanoparticles were well‐dispersed in ABS matrix at nanoscale. The morphology of the fracture surfaces of the nanocomposites revealed that when CaCO₃/EVA/ABS nanocomposites were exposed to external force, nano‐CaCO₃ particles initiated and terminated crazing (silver streak), which can absorb more impact energy than neat ABS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008