Impact Strength and Crystallization Behavior of Nano‐SiOx/Poly(phenylene sulfide) (PPS) Composites with Heat‐Treated PPS

The effects of heat treatment on the crystal structure and impact strength of poly(phenylene sulfide) (PPS) and nano‐SiO_x/ PPS nanocomposites were studied. The molecular weight of heat‐treated neat PPS was increased by 28% due to the crosslinking reaction that changed its crystal morphology. Also, the crystallinity was reduced by 18%, leading to an improvement of the Izod impact strength by 66%. Nano‐SiO_x/PPS composites were manufactured by intensive compounding with 3 wt.‐% nano‐SiO_x particles treated by an epoxy functional group. Test results showed that the Izod impact strength of nano‐SiO_x/heat‐treated PPS composites was 91% better and the crystallinity 27% less compared to the same properties of “as received” neat PPS. Nano‐SiO_x has a high specific surface area and a high surface energy; its grafted epoxy group promotes interfacial adhesion with the PPS matrix, hence increasing the Izod impact strength of the nanocomposites.

TEM micrograph of NHTM‐PPS with 3 wt.‐% nano‐SiO_x.     

Study of surface‐functionalized nano‐SiO2/polybenzoxazine composites

A series of the surface‐functionalized nano‐SiO₂/polybenzoxazine (PBOZ) composites was produced, and an attempt was made to improve the toughness of PBOZ material, without sacrificing other mechanical and thermal properties. A benzoxazine functional silane coupling agent was synthesized to modify the surface of nano‐SiO₂ particles, which were then mixed with benzoxazine monomers to produce the nano‐SiO₂‐PBOZ nanocomposites. The notched impact strength and the bending strength of the nano‐SiO₂‐PBOZ nanocomposites increase 40% and 50%, respectively, only with the addition of 3 wt % nano‐SiO₂. At the same load of nano‐SiO₂, the nano‐SiO₂‐PBOZ nanocomposites exhibit the highest storage modulus and glass‐transition temperature by dynamic viscoelastic analysis. Moreover, the thermal stability of the SiO₂/PBOZ nanocomposites was enhanced, as explored by the thermogravimetric analysis. The 5% weight loss temperatures increased with the nano‐SiO₂ content and were from 368°C (of the neat PBOZ) to 379°C or 405°C (of the neat PBOZ) to 426°C in air or nitrogen with additional 3 wt % nano‐SiO₂. The weight residue of the same nanocomposite was as high as 50% in nitrogen at 800°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Comprehensive high‐performance epoxy nanocomposites co‐reinforced by organo‐montmorillonite and nano‐SiO2

Comprehensive high‐performance epoxy nanocomposites were successfully prepared by co‐incorporating organo‐montmorillonite (o‐MMT) and nano‐SiO₂ into epoxy matrix. Because of the strong interaction between nanoscale particles, the MMT layers were highly exfoliated, and the exfoliated nanoscale MMT monoplatelets took an interlacing arrangement with the nano‐SiO₂ particles in the epoxy matrix, as evidenced by X‐ray diffraction measurement and transmission electron microscopy inspection. Mechanical tests and thermal analyses showed that the resulting epoxy/o‐MMT/nano‐SiO₂ nanocomposites improved substantially over pure epoxy and epoxy/o‐MMT nanocomposites in tensile modulus, tensile strength, flexural modulus, flexural strength, notch impact strength, glass transition temperature, and thermal decomposition temperature. This study suggests that co‐incorporating two properly selected nanoscale particles into polymer is one pathway to success in preparing comprehensive high‐performance polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Nano‐sio2‐reinforced ultraviolet‐curing materials for three‐dimensional printing

As an additive manufacturing technology, ultraviolet (UV)‐curing three‐dimensional printing, which requires the use of a photocurable resin, is increasingly being used to produce customized end‐user parts of many complex shapes. In this study, to improve the strength and ductility of printing materials, nano‐SiO₂‐reinforced photocurable resins were prepared by a planetary ball mill; then, the morphology, photochemistry, thermal property, and mechanical properties of the nanocomposites were investigated and characterized. Transmission electron microscopy analysis indicated that the modified nano‐SiO₂ was well dispersed in the photocurable resin. The glass‐transition temperature increased from 67.2°C for the unfilled resin to 71.7 and 80.1°C for nanocomposites with nano‐SiO₂ contents of 0.3 and 0.7 wt %, respectively. The tensile strength and impact strength were increased by 46.7 and 165.3% for nanocomposites with 0.3 wt % nano‐SiO₂. The flexural modulus of the nanocomposites increased from 1.7 to 8.0 GPa when 0.7 wt % nano‐SiO₂ was added to the photocurable resin; this appeared to originate from the relatively high level of dispersion and the intimate combination of the nano‐SiO₂ with the matrix. The investigation of the physical and chemical properties of such UV‐curing materials showed that the low filler concentration (<1 wt %) of nano‐SiO₂ did not affect the processability of the nanocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42307.     

Coincorporation of nano‐silica and nano‐calcium carbonate in polypropylene

In this study, various polypropylene (PP) nanocomposites were prepared by melt blending method. The effects of different spherical nanofillers, such as 50 nm CaCO₃ and 20 nm SiO₂, on the linear viscoelastic property, crystallization behavior, morphology and mechanical property of the resulting PP nanocomposites were examined. Rheological study indicated that coincorporation of nano‐SiO₂ and nano‐CaCO₃ favored the uniform dispersion of nanoparticles in the PP matrix. Differential scanning calorimeter (DSC) and polarizing optical microscopy (POM) studies revealed that the coincorporation of SiO₂ and CaCO₃ nanoparticles could effectively improve PP crystallizability, which gave rise to a lower supercooling temperature (ΔT), a shorter crystallization half‐life (t_1/2) and a smaller spherulite size in comparison with those nanocomposites incorporating only one type of CaCO₃ or SiO₂ nanoparticles. The mechanical analysis results also showed that addition of two types of nanoparticles into PP matrix gave rise to enhanced performance than the nanocomposites containing CaCO₃ or SiO₂ individually. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Investigation on the mechanical performances of ternary nylon 6/SEBS elastomer/nano‐SiO2 hybrid composites with controlled morphology

The distribution of maleated styrene‐hydrogenated butadiene‐styrene (mSEBS) elastomer and nano‐SiO₂ in nylon 6 matrix was controlled by varying the blending procedure. Nano‐SiO₂ particles with different surface properties (hydrophilic versus hydrophobic) were adopted to adjust their interactions with other components. Two different structures, separate dispersion of nano‐SiO₂ and elastomer particles as well as encapsulation of nano‐SiO₂ fillers by the elastomer, were obtained. The structures were confirmed through scanning electron microscope (SEM) investigation. The mechanical measurement results showed that the microstructure and the interactions among the components had dramatic influences on the final mechanical properties, especially Izod fracture toughness, for the ternary nanocomposites. The nanocomposites containing hydrophilic nano‐SiO₂ had better mechanical performances compared with the composites filled with hydrophobic SiO₂ when they were in the same microstructure. The nanocomposites with separate dispersion structure showed higher stiffness compared with those of encapsulation type. However, the separately dispersed nano‐SiO₂ particles restricted the cavitation of elastomer phases that led to low toughening effectiveness. The difference of cavitation intensity for elastomer phase was revealed by SEM investigation on the facture surfaces for the nanocomposites with the two different microstructures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of the mixing sequence on the morphology and properties of a polypropylene/polydimethylsiloxane/nano‐SiO2 ternary composite

Ternary composites of polypropylene (PP), polydimethylsiloxane (PDMS) elastomer, and nano‐SiO₂, prepared with three different mixing sequences, were studied for dispersion morphology and its effect on the crystallization of PP and the mechanical properties. The mixing sequence produced a significant effect on the dispersion morphology and, thereby, on the mechanical properties of the composites. A two‐step mixing sequence, in which nano‐SiO₂ was added in the second step to the PP/PDMS binary system, produced a significant encapsulation of nano‐SiO₂ by PDMS, and this, in turn, resulted in the poor modulus and impact strength of the composite. A one‐step mixing sequence of all three components produced a separated dispersion of PDMS and nano‐SiO₂ phases in the PP matrix with the occurrence of a fine band of nano‐SiO₂ particles at the boundaries of the PDMS domains and the presence of some nano‐SiO₂ filler particles inside the PDMS domains. This one‐step mixing sequence produced an improvement in the tensile modulus but a decrease in the impact strength with increasing nano‐SiO₂ content. In the third sequence of mixing, which involved a two‐step mixing sequence through the addition of PDMS in the second step to the previously prepared PP/nano‐SiO₂ binary system, the morphology of the dispersion showed separately dispersed PDMS and nano‐SiO₂ phases with a loose network of nano‐SiO₂ particles surrounding the PDMS domains. This latter series of ternary composites had the highest impact strength and exhibited high shear deformation under tensile and impact conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A novel method of hyperbranched poly(amide‐ester) modifying nano‐SiO2 and study of mechanical properties of PVC/nano‐SiO2 composites

A new method of surface chemical modification of nano‐SiO₂ was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO₂ reacted with AB₂‐type monomer (N,N‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO₂ surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO₂ composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO₂ grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO₂ composites reached the best when weight percent of nano‐SiO₂ in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO₂/PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Effect of nano‐SiO2 on granule characteristic and fusion process of Poly(vinyl chloride‐co‐vinyl acetate)/nano‐SiO2 composite resin

Poly(vinyl chloride‐co‐vinyl acetate) (PVVA)/nano‐SiO₂ composite resin was prepared by radical suspension polymerization of the monomers in the presence of fumed nano‐SiO₂ particles premodified with γ‐methylacryloxypropyl trimethoxysilane. The cool dioctyl phthalate absorption percentage, granule porosity, and specific surface area of the composite resin were enhanced through incorporation of nano‐SiO₂ into the PVVA. Scanning electron microscope pictures showed the resin had higher porosity. PVVA/nano‐SiO₂ composite resin was mixed with pure PVC resin to form a mixture sample (polymer‐composite blend [PCB]) and the mixture was fused in the torque rheometer. The rheological test results indicated that, at a certain nano‐SiO₂ content, the fusion speed of PCB was accelerated and the fusion temperature of PCB was decreased, owing to nano‐SiO₂ dispersed evenly in the polymer matrix. When excessive nano‐SiO₂ was loaded, the fusion torque, the fusion time, and the fusion temperature of PCB were all increased. These properties are correlative to the dispersive density of nano‐SiO₂ in the polymer matrix. This study also demonstrated that the introduction of small amounts of nano‐SiO₂ into the resin increased the impact strength and tensile strength of PCB simultaneously. J. VINYL ADDIT. TECHNOL., 20:230–236, 2014. © 2014 Society of Plastics Engineers     

Nanocomposites of a bismaleimide resin with octaphenylsilsesquioxane or nano‐SiO2

Nanocomposites were prepared from the resin of 4,4′‐bismaleimido‐diphenylmethane (BDM) with dipropargyl ethers of hexafluorobisphenol A (DPBPF) and octaphenylsilsesquioxane (OPS) or nano‐SiO₂. The nanocomposites were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, dynamic mechanical analysis and thermogravimetric analysis. The results exhibited that OPS or nano‐SiO₂ particles could be easily dispersed in the nanocomposites and the glass transition and decomposition temperatures of c‐BDM‐DPBPF‐OPS and c‐BDM‐DPBPF‐SiO₂ nanocomposites were higher than those of c‐BDM‐DPBPF resin. The reinforcement of OPS was more effective than that of nano‐SiO₂ in the nanocomposites. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Fabrication and characterization of in situ synthesized nano‐CaCo3‐reinforced polypropylene composite materials

To improve the impact toughness of polypropylene (PP), nano‐CaCO₃ was prepared by an in situ synthesis. The surface of the nano‐CaCO₃ was modified by KH‐550 silane coupling agent and NDZ‐401 titanium acid ester coupling agent. Nano‐CaCO₃/PP composite materials were fabricated through a melt‐blending method and characterized, and their mechanical properties were analyzed. The impact toughness and the tensile strength of the PP were improved significantly by the incorporation of nano‐CaCO₃. When the weight fraction of nano‐CaCO₃ was 2%, the maximum impact toughness and tensile strength of the PP nanocomposites were 293% and 259%, respectively, of the values for neat PP. Observation of the impact fracture surface of the nanocomposites indicated that the dispersion of nano‐CaCO₃ modified by NDZ‐401 coupling agent was more homogeneous than that of nano‐CaCO₃ modified by the KH‐550 silane coupling agent. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Effect of amphoteric dispersant on the dispersion properties of nano‐SiO2 particles

An amphoteric polycarboxylate dispersant (APC) was synthesized by copolymerization of acrylic acid (AA), methacryloxyethyltrimethyl ammonium chloride (DMC), and isopentenol polyoxyethylene ether (IPEG). The molecular structure of APC was characterized by FT‐IR, ¹H‐NMR, and GPC. Effect of the dosage of APC on the rheological performance of nano‐SiO₂ suspension was investigated by measurements of the plastic viscosity. The results indicated that the best dispersion effect of APC was obtained when the dosage of APC was about 10 wt % (by the weight percent of nano‐SiO₂), which can maintain the dispersion of nano‐SiO₂ suspension uniformly for 4 h without settlement. Meanwhile, the zeta potential value on the surface of nano‐SiO₂ particles shows that the better dispersion performance of APC was attributed to the solvation water film formed by the polyoxyethylene side chains and the electrostatic repulsion formed by positively groups (C?N⁺) on the APC structure combined with ‐SiO^– groups on the surface of nano‐SiO₂ particles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45075.     

Preparation and characterization of nano‐Sb2O3/poly(butylene terephthalate) composite powders based on high‐energy ball milling

In this work, a kind of composite powders with good dispersion and distribution of nano‐Sb₂O₃ particles in poly(butylene terephthalate) (PBT) was prepared by the high‐energy ball milling (HEBM). The effects of the milling time on the structure, morphology, particle size distribution, and thermal behavior of the nano‐Sb₂O₃/PBT composite powders were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, laser diffraction particle size analyzer, and thermal analysis (TGA, DTG and DSC) techniques. The results showed that the regular shape of PBT powders was converted into flakes and the nano‐Sb₂O₃ particles were well deagglomerated and better dispersed in the PBT matrix during the HEBM process. The mechanochemical activation that was provided by the HEBM process caused a reduction in the molecular weight of PBT, which result in favoring the first step of thermal degradation. Furthermore, two T_g’s were obtained in the case of the nanocomposite powders when the milling time was over 3 h, one of them being slightly higher than that of the pure PBT, which indicated that there was a special interaction between PBT and nano‐Sb₂O₃ particles. However, the HEBM process leaded to a decreasing of the PBT crystallinity. J. VINYL ADDIT. TECHNOL., 25:91–97, 2019. © 2018 Society of Plastics Engineers     

The crystallization,thermal and mechanical properties of nano‐Sb2O3 filled poly(butylene terephthalate)

Nano‐Sb₂O₃ particles were modified by a combination modifier of cetyltrimethyl ammonium bromide (CTAB) and KH‐560 via the mechanochemical method based on high‐energy ball milling. Then, the testing specimens of the nano‐Sb₂O₃/PBT composites of differing compositions were prepared by melting blending technology. The crystallization, thermal, and mechanical properties of composites were characterized by X‐ray diffraction, differential scanning calorimetry, thermogravimetric analyzer, and mechanical performance test. The tensile and impact fracture surfaces of composites were determined by scanning electron microscopy. Besides, the influence of the Sb₂O₃ nanoparticles surface modification on crystallinity, mechanical properties of the composites, and the interfacial adhesion between nano‐Sb₂O₃ and PBT was systematically investigated. The results indicate that the main crystalline characteristics of PBT matrix remain unchanged in the nanocomposites. However, the addition of nano‐Sb₂O₃ particles plays a heterogeneous nucleation and can effectively improve the crystallization of PBT matrix. In addition, the compound modification of the nano‐Sb₂O₃ can effectively enhance mechanical properties of the composites and interfacial interaction between nano‐Sb₂O₃ and PBT. The enhanced fracture properties in the nanocomposites were caused by the assisted void formation at the edge of the nano‐Sb₂O₃ particle. When the nano‐Sb₂O₃ mass fraction is 3%, the composites show excellent comprehensive performance. The interfacial adhesion parameter B and the half‐debonding angle θ of composites were assessed to quantitatively characterize the interfacial adhesion strength between nano‐Sb₂O₃ and PBT. Finally, the reinforcement and toughening mechanisms were described. J. VINYL ADDIT. TECHNOL., 26:268–281, 2020. © 2019 Society of Plastics Engineers     

Effect of nano‐silica on the mechanical,thermal, and crystalline properties of poly(vinyl alcohol)/nano‐silica films

Poly(vinyl alcohol)/nano‐silica (PVA/nano‐SiO₂) films were prepared through extrusion blowing with the addition of water and glycerin as plasticizer. The characteristic properties of PVA/nano‐SiO₂ films were investigated by differential scanning calorimetry, dynamic mechanical analysis, Haake torque rheometry, and atomic force microscopy (AFM). The results showed that the mechanical properties of PVA/nano‐SiO₂ were improved dramatically. The tensile strength of the nanofilms increased from 62 MPa to 104 MPa with loading 0.3 wt % nano‐SiO₂ and the tear strength was improved from 222 KN/m to 580 KN/m. The crystallinity of the films loaded with 0.4 wt. % nano‐SiO₂ decreased from 32.2% to 21.0% and the AFM images indicated that the amorphous region of nanofilms increased with increasing nano‐SiO₂ content. The storage modulus and loss modulus increased to two and nearly three times with 0.3 wt % nano‐SiO₂ loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Phase characterization and mechanical and flame‐retarding properties of nano‐CaSO4/polypropylene and nano‐Ca3(PO4)2/polypropylene composites

An in situ deposition approach was used for the synthesis of nano‐CaSO₄ and nano‐Ca₃(PO₄)₂. The nanosize particles were confirmed with an X‐ray diffraction technique. Composites of polypropylene (PP) with 0.1–0.5 wt % nano‐ or commercial CaSO₄ or nano‐Ca₃(PO₄)₂ were prepared. The transition from the α phase to the β phase was observed for 0.1–0.3 wt % nano‐CaSO₄/PP and nano‐Ca₃(PO₄)₂/PP composites. This was confirmed by Fourier transform infrared. A differential scanning calorimetry analysis was carried out to determine the thermal behavior of the nanocomposites with increasing amounts of the nano‐CaSO₄ and nano‐Ca₃(PO₄)₂ fillers. Increases in the tensile strength and Young's modulus were observed up to certain loading and were followed by a decrease in the tensile strength. A continuous decrease in the elongation at break (%) was also observed for commercial CaSO₄ and larger nano‐Ca₃(PO₄)₂. A decrease in the mechanical properties after a certain loading might have been due to the agglomeration and phase transition of PP in the composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 670–680, 2007     

High‐temperature mechanical behavior of ZrB2‐based composites with micrometer‐ and nano‐sized SiC particles

Using micrometer‐ and nano‐sized SiC particles as reinforcement phase, two ZrB₂‐SiC composites with high strength up to 1600°C were prepared using high‐energy ball milling, followed by hot pressing. The composite microstructure comprised finer equiaxed ZrB₂ and SiC grains and intergranular amorphous phase. The temperature dependency of flexure strength related to the initial particle size of SiC. In the case of micrometer‐sized SiC, the high‐temperature strength was improved up to 1500°C compared to room‐temperature strength, but the strength degraded at 1600°C, with strength values of 600‐770 MPa. In the case of nano‐sized SiC, the enhanced high‐temperature strength was observed up to 1600°C, with strength values of 680‐840 MPa.     

Preparation and characterization of acrylic latex/nano‐SiO2 composites

Acrylic/nano‐silica composite latexes were prepared by blending via high shear stirring (SS) or ball milling (BM) and in situ polymerization (IS). For comparison, composites filled with micro‐silica were also prepared. The mechanical and optical properties of the polymers formed by the composite latex filled with nano‐ or micro‐silica were investigated using an Instron testing machine, by dynamic mechanical analysis, ultraviolet–visible spectrophotometry and transmission electron micrography. The results showed that SS and BM methods could obtain better nanocomposite latex and polymers than the IS method, characterized by better dispersion of nanoparticles, higher tensile strength and T_g for SS and BM than for IS. The increase in absorbance and reduction in transmittance of UV (290–400 nm wavelength) were observed as nano‐silica content increased, whereas the UV absorbance or transmittance basically were kept unchanged for the composites filled with micro‐silica. © 2002 Society of Chemical Industry     

Preparation and performance of high‐impact polystyrene (HIPS)/nano‐TiO2 nanocomposites

High‐impact polystyrene (HIPS)/nano‐TiO₂ nanocomposites were prepared by surface pretreatment of nano‐TiO₂ with special structure dispersing agent (TAS) and master batch manufacturing technology. The results show that when the nano‐TiO₂ content is 2%, the notched impact strength, tensile strength, and elastic modulus of HIPS/nano‐TiO₂ nanocomposites increased to a maximum. This result indicates that nano‐TiO₂ has both toughening and reinforcing effects on HIPS. The heat‐deflection temperature and flame‐retardance of HIPS/nano‐TiO₂ nanocomposites are also obviously improved as the nano‐TiO₂ content is increased. The nanocomposites manufactured by the two‐step method have better mechanical properties than that made by a one‐step method. HIPS/nano‐TiO₂ nanocomposites are also non‐Newtonian and pseudoplastic fluids. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 381–385, 2003