Rheological Properties Of Composites Research Articles

Hybrid enhancement of silica and aramid pulp on improving performance and reducing dynamic heat generation of natural rubber composites

AbstractThe composites with excellent mechanical, low rolling resistance, and low heat build‐up are the potential materials for preparing green tires. In this study, we prepared silica‐natural rubber latex (silica‐NRL) masterbatch, which improved the processing and dispersion properties of silica in the natural rubber, proved by the rheological properties of composites. Furthermore, the idea of partial replacement of silica with low content modified aramid pulp (AP) for preparing hybrid enhanced natural rubber with high mechanical properties and low heat build‐up was put forward and evaluated the feasibility of this strategy. We find that replacing 5 phr silica with 1 phr AP, the performances of the rubber composites were all superior to the composites with only filled 50 phr silica, and replacing 10 phr silica with 2 phr AP, the mechanical and fatigue property was improved remarkably and dynamic heat generation was reduced the most at same time. The strategy of preparing silica‐NRL masterbatch and partial replacement of silica with AP provides a novel reference for the preparation of low heat build‐up green tire.

Beeswax as a natural alternative to synthetic waxes for fabrication of PLA/diatomaceous earth composites

In this study, injection moulding was applied to produce biocomposites consisting of polylactide (PLA) and amorphous diatomaceous earth used as a filler at different concentrations. Natural wax and synthetic wax were added to improve processing properties, comparing the resulting biocomposites. The use of natural beeswax makes the composite environmentally friendly. The prepared composites contained 2.5, 5, 10 and 15% w/w filler. The test samples have been injection moulded. Rheological, mechanical, surface and other properties were assessed for the fabricated composites. The testing has shown that the use of wax additives has a significant influence on the mechanical properties (tensile strength, flexural strength, impact strength) and the hydrophilicity/hydrophobicity of composite surfaces. The addition of natural wax, especially at lower concentration, has a positive effect on the rheological properties of composites (melt flow rate, MFR), flexural modulus and impact strength. Different composite parameters are modified by different wax types so both natural and synthetic waxes, can be used interchangeably, depending on the required final material characteristics.

The effect of silicon dioxide nanoparticle‐covered graphene oxide on mechanical properties, thermal stability and rheological performance of thermoplastic polyurethanes

AbstractA two‐step grafting procedure has been used to graft tetraethylenepentamine (TEPA) and nano silicon dioxide (SiO2), onto graphene oxide (GO) surface. The resulting modified GO, that was TGOS, which was used as a reinforcement in thermoplastic polyurethanes (TPUs). Mechanical properties, thermal stability and rheological properties of composites were investigated. Results showed that the addition of TGOS significantly improved the mechanical properties of TPU compared with the pure TPU sample. Tensile strength and elongation at break of TPU were increased by 50.8 and 18.6%, respectively, when the addition amount was only 0.5 wt%. TG results showed that the addition of TGOS improved the heat resistance of TPU. Complex viscosity, storage modulus (G') and loss modulus (G") of TPU composites with different additions were analyzed by rheological tests, the results showed that the addition of TGOS improved the deformation resistance of TPU. Meanwhile, TPU composites present high G', G", and complex viscosity with the increase of TGOS filling amount in the low frequency region.

Physico-mechanical and technological characteristics of composite materials based on mixtures of secondary thermoplastics

The physico-mechanical and technological characteristics of mixed waste of thermoplastic polymers, including that from the recyclable electronic and electrical equipment based on ABS plastic, were investigated. Target modifying additives were introduced into the composite system to improve the compatibility of polymer components of mixtures and the stable rheological properties of composition during processing. It is established that the secondary polymers behavior in their mixtures is caused by combination of their rheological characteristics and other parameters of mutual compatibility, that has significant impact on phase composition and microphases mutual order. Dispersed additives make a significant contribution to these processes, affecting the structuring of the associated polymer microvolumes. Target regulation of the rheological properties of components will ensure the achievement of acceptable and reproducible physico-mechanical characteristics and technological parameters of process, which will create prerequisites for the production of competitive products with a high guaranteed service life without use of scarce raw materials. Composite materials have been developed that are adapted to stable processing by extrusion, injection molding, and formation molding into technical products with acceptable performance characteristics.

Reinforcement of Polylactic Acid for Fused Deposition Modeling Process with Nano Particles Treated Bamboo Powder.

The focus of this report was to understand the tensile properties and dynamic mechanical properties of bamboo powder (BP) reinforced polylactic acid (PLA) composite filaments which were treated with nano calcium carbonate (CaCO3), cellulose nanofibers (CNF), and micro-crystalline cellulose (MCC) using impregnation modification technology. The storage modulus (E’) of nano CaCO3-BP/PLA, MCC-BP/PLA, and CNF-BP/PLA composite filaments increased compared with BP/PLA composite filaments before the glass transition temperature Tg. When the temperature was above Tg, the reinforcement effect of nano CaCO3, MCC, and CNF gradually became less apparent. The loss modulus (E’’) and loss factor (tan δmax) of the nano CaCO3-BP/PLA, MCC-BP/PLA, and CNF-BP/PLA composite filaments was higher than that of BP/PLA composite filaments produced by the “one-step” method. The tensile strength (TS) results showed a similar trend. Compared with the control samples, the TS of nano CaCO3-BP/PLA, MCC-BP/PLA, and CNF-BP/PLA composite filaments produced by the “one-step” method (and the “two-step” method) increased by 40.33% (and 10.10%), 32.35% (and −8.61%), and 12.32% (and −12.85%), respectively. The TS of nano CaCO3-BP/PLA, MCC-BP/PLA, and CNF-BP/PLA composite filaments produced by the “one-step” method was slightly higher than those produced by the “two-step” method. The elongation at break (EAB) of BP/PLA composite filaments was higher than that of BP/PLA samples treated with nano CaCO3, MCC, or CNF. The PLA and modified BP were readily accessible through a simple mixing process. The rheological investigation of such mixtures showed that nano CaCO3, CNF, and MCC have different effects on the processability and rheological properties of composites.

Poly(lactic acid) green composites filled with linseed cake as an agricultural waste filler. Influence of oil content within the filler on the rheological behavior

ABSTRACTThe rheological behavior of poly(lactic acid) (PLA) composites filled with linseed cake (LC) has been investigated in relation to the amount of the filler and the fat content in the natural waste agricultural filler. Natural waste fillers characterized with 17.4 and 28.7 wt % content of linseed oil were incorporated in different amounts (5–40 wt %) into a polymeric matrix. The main task was to investigate the plasticization effect of PLA by oil residue present in LC which was used as a low‐cost filler in highly filled biocomposites. The application of oscillatory rheological measurements and capillary rheometry allowed to get a detailed description of the changes in the composites' rheological behavior in reference to the plasticizing effect caused by the oil that migrated from the filler. The rheological properties of composites with natural filler with high oil content were evaluated also with rheological tests related to processing properties: the torque rheometry and melt flow index. It has been proven that the application of natural fillers from the food industry with high oil content allows to produce highly filled thermoplastic composites with improved processing properties due to the lubricating and plasticizing effect of the oil on the PLA matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47651.

Dispersion state of carbon black in polystyrene produced with different dispersion media and its effects on composite rheological properties

The dispersion state and aggregate structure of carbon black in polystyrene composites prepared by solvent casting suspensions in different dispersion media, i.e., chloroform, tetrahydrofuran, and toluene, with different particle contents and their effects on the bulk rheological properties of the composites were investigated by transmission electron microscopy, ultrasmall-angle and small-angle X-ray scattering, and dynamic viscoelasticity measurements. The macroscopic dispersion state of carbon black in the solvent-cast films was largely affected by the dispersion medium, reflecting the stability of the suspension in the polystyrene solution. The mass fractal dimension of carbon black in the polymeric matrix, which was evaluated by X-ray scattering techniques with a resolution of nanometers, tended to exhibit a higher value for the dispersion media with less carbon black dispersibility. The surface fractal dimension of carbon black in the polymer was independent of the dispersion medium and exhibited a lower value than carbon black powder due to physical adsorption of the polymer on the particle surface. The viscoelastic moduli for the melt polymer composites below and above the percolation limit varied according to the dispersion media, reflecting the difference in the macroscopic dispersion state and aggregate structure of carbon black in polystyrene. The dispersion state and aggregate structure of carbon black in polystyrene composites prepared by solvent casting suspensions in different dispersion media with different particle contents and their effects on the bulk rheological properties of the composites were investigated by transmission electron microscopy, ultrasmall-angle and small-angle X-ray scattering, and dynamic viscoelasticity measurements. The viscoelastic moduli of the melt polymer composites below and above the percolation limit varied with the dispersion medium, reflecting the difference in the macroscopic dispersion state and aggregate structure of carbon black in polystyrene.

RESEARCH OF INFLUENCE OF DISPERSION OF AN EXCIPIENT OF A PHYTOGENESIS ON PHYSICAL AND CHEMICAL AND RHEOLOGICAL BEHAVIOR OF COMPOSITIONS ON THE BASIS OF SECONDARY POLYPROPYLENE

Now development and creation of polymeric composites is a serious scientific problem. Introduction of natural excipients to a polymeric matrix allows to create material with new properties. The nature of the entered excipient can affect set of physicomechanical and physical and chemical properties of composites. In work physicomechanical and rheological properties of compositions on the basis of secondary polymeric raw materials and filler of natural origin — a rice peel are studied. The sample of secondary polypropylene corresponding to primary polypropelene of the FF/3350 brand and a rice peel of various dispersion have been considered as objects of a research. Modeling of process of processing of polymeric materials carried out at the laboratory station (plastograf) of PlastographEC (Germany). Deformation and strength properties of material defined on the pressed samples of material 1 mm thick. Pressing was carried out on an automatic hydraulic press of AutoMH-NE (USA). Physicomechanical properties of polymeric composites at a gap defined by explosive ShimadzuAGS-X car (Japan) at a temperature of 20°C and speeds of the movement of mobile hijacking of the explosive car of 1 mm/min. Rheological measurements of polypropelene fusion and compositionally the filled materials on its basis carried out on a modular dynamic reometr of HaakeMarsIII at 220°C. It is established that introduction of filler leads to increase in size of torque, reduction of value of an indicator of fluidity of fusion, growth of dynamic viscosity of fusion, but is not followed by increase in elasticity. To increase in viscosity it is obviously connected with adsorption of polymer on the surface of filler. It is shown that during filling of secondary polypropylene minor change and deformation and strength properties of composition happens a rice peel. At introduction to composition up to 10 mass part a rice peel will allow to form the materials which aren’t conceding on the physicomechanical indicators to initial secondary polypropylene and capable at the same time to biodegradation. Besides the higher dispersion of filler, the all mentioned indicators change stronger.

Approximation of the Rheological Properties of Composite Materials

The rheological properties of polymer composite materials for special purposes in molecular, structural and complex plasticization are investigated. The possibility of approximating the rheological properties of epoxy composites to protect against radiation by a multiplicative polynomial-exponential function is shown (approximation of the functions of two arguments in the form of a product of two one-dimensional functions). Analytical dependences of the viscosity of epoxy binder on temperature and percentage of additive are given. The results of optimization (optimal concentration of plasticizer) are indicated.

Polymers and Composites Produced from Epoxy Resins Cured with 3,5-Diethyltoluenediamine: Synthesis and Properties

The kinetics of curing of epoxy resins characterized by different functionality with 3,5-diethyltoluenediamine was studied. The kinetic constants and temperature ranges of reactions were determined. Polymers and composites were synthesized according to the established regimes. The rheological properties of composites and physicomechanical, thermomechanical, and impact properties of polymers and high-strength organoplastics were determined. Polymers based on trifunctional epoxy-novolak resin UP-643 are characterized by the highest thermal stability.

Properties of nylon-6-based composite reinforced with coconut shell particles and empty fruit bunch fibres

ABSTRACTNovel natural fibre composites of nylon-6 reinforced with coconut shell (CS) particles and empty fruit bunch (EFB) fibres have been investigated. Fillers were alkali treated before melt compounding with nylon-6. Mechanical, thermal and rheological properties of composites were measured. Tensile modulus was found to improve with both fillers up to 16% for nylon-6/CS composite and 10% for nylon-6/EFB composite, whereas a moderate increase in tensile strength was observed only with CS composites. Differences in the strengthening mechanisms were explained by the morphology of the two fillers, empty fruit bunch fibres having a weaker cellular internal structure. Observation of composite morphology using SEM showed that both fillers were highly compatible with nylon-6 due to its hydrophilic nature. Both fillers were found to cause a slight drop in crystallinity of the nylon matrix and to lower melt viscosity at typical injection moulding strain rates. Moisture absorption increased with addition of both fillers.

Rheological and rutting evaluation of composite nanosilica/polyethylene modified bitumen

In this research, composite nanosilica/polyethylene modified binder samples were prepared at varying concentration of nanosilica. The modified binder samples are prepared by adding 1%, 2% and 3% nanosilica by weight of bitumen in to 6% linear low density polyethylene (LLDPE) polymer modified binder. Effects of nanosilica on physical and rheological properties of composites were investigated through penetration, softening point, temperature susceptibility, dynamic mechanical analysis and rutting resistance evaluations. Results shows that, nanosilica affects the rheological properties of LLDPE modified binder due to decrease in penetration and increase in softening point observed with increase in nanosilica content, this enhances composite binders hardness and resistance to temperature. Temperature susceptibility shows that, composite modified binders are less susceptible to temperature compared to LLDPE modified binder. DSR rheological analysis shows that, nanosilica enhances the composite modified binders properties at intermediate to high temperatures. Also rutting parameter evaluation indicates that composite modified binders have high resistance to rutting deformations due to increase in elastic behavior and stiffness of the composites.

Effect of Micro Glass Flake on Morphological and Rheological Behaviour of Epoxy Vinyl Ester Composite Coatings

In the present work, attempts were made to investigate the reinforcement and treatment effect of GF on morphological and rheological behaviour of GF/epoxy vinyl ester composites. GF was incorporated into epoxy vinyl ester resin by sonication, and mechanical agitation. Rheological and morphological properties were studied as a function of particle treatment and size distributions. The dispersion morphology, agglomeration degree and homogeneity of additives were analyzed by scanning electron microscopy SEM, and optical microscopy. Effect of mixing method, surface treatment, and particle size distribution on rheological properties of composites were investigated with a modular compact rheometer. The results showed that the mechanical agitation decreases GF aspect ratio more than sonication. SEM fractography shows finer particles improve toughness properties of the composites in comparison with larger ones. GF with larger circular diameter and length is more sensitive to shear than the smaller one. Rheological investigations showed that surface treatment improves the interaction between the polymer matrix and GF. These results indicated that the finer the GF, the better the rheological properties will be displayed.

THE ANTIWEAR AND EXTREME-PRESSURE PROPERTIES, AND VISCOSITY-TEMPERATURE CHARACTERISTICS OF THE LUBRICANTS CONTAINING VEGETABLE OIL AND AW/EP ADDITIVES

The lubricating and rheological properties of compositions based on vegetable oil mixtures and selected additives were examined. The additives were dedicated both to vegetable oils as well as to petroleum products. The additives varied in chemical structure and the content of active elements. It was concluded that the nature of particular additives as well as their concentration in the composition significantly altered the initial lubricating and rheological properties of the base oil. The differences were diverse and highly dependent on the composition. The most beneficial effects were obtained when the additives containing phosphorus and nitrogen were added to the base oil.

Effect of starch/polylactic acid ratio on the interdependence of two-phase and the properties of composites

Starch/polylactic acid (PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature (T g), melting temperature (T m) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature (T c) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.

The Influence of the Degree of Filling of Epoxy Composites with Microcalcite of Different Degree of Dispersion on Their Rheological Properties

The results of investigating the influence of the degree of dispersion, the degree of filling, and the nature of calcium carbonate on the rheological properties of composites with the use of modified epoxy resin ED-20 as the binder are set out.

Effects of Washing of Raw Material on Properties of Carbon Nanotube Containing Poly(Ethylene-Terephthalate) Composites

Our interest has been focused on mechanical recycling of poly(ethylene-terephthalate) (PET) bottle waste, because recycling of plastic waste has crucial importance nowadays. The present article deals with the effects of washing of the secondary raw materials on properties of carbon nanotube (CNT) reinforced composites. In the first step advantageous washing compounds and their concentration were determined. After selecting the proper washing method extrusion moulding characteristics of PET granulates were investigated, and effects of carbon nanotubes as reinforcing additives and also application of coupling agents on the mechanical and rheological properties of composites were studied.

Recycling leather waste: Preparing and studying on the microstructure, mechanical, and rheological properties of leather waste/rubber composite

Leather tanning processes cause environmental impact as a result of the generation of solid waste, wastewater, and release of gases. The improper disposal of such waste may promote the oxidation of chromium, for example, changing it from chromium (III) to chromium (VI), in which becomes extremely toxic. In this study, composites were prepared from natural rubber (NR) with industrial leather waste (Lw), varying the waste amount from 20 to 80 phr, with the aim of recycling leather waste. The microstructure, mechanical properties and rheological properties of composites were investigated. The results showed that Lw increased tensile strength and hardness, with good reproducibility, and uniformity of residuals distributed as fillers (miscible materials). These properties indicate that this composite material can be used as raw material for the manufacture of shoes, bags, upholstery, etc. POLYM. COMPOS., 36:2275–2281, 2015. © 2014 Society of Plastics Engineers

Alumina Whisker Selection to Design Fiber-Reinforced Polyethylene Composites

New polyethylene composites with α-Al2O3 whiskers are produced using four fibers (unpurified, cleaned, ribbon-shaped and silica-coated) differing in their purification level or surface. The influence of different fibers on the morphological, thermal and rheological properties of composites is analyzed. The composites with the ribbon-shaped and the silica-coated whiskers show the most suitable morphology and the best rheological properties together with a lower cost. The nucleating action of these fibers increases the crystallization temperature and the crystallinity of polyethylene. The enhancement in degradation temperature and flexural parameters prove that both types of alumina whiskers produce a clear reinforcement in polyethylene matrix.

Rheological properties of polymer composites with flexible fine fibers

Effect of the addition of polymeric fine fibers on the rheological properties is studied employing poly(lactic acid) PLA as a matrix. Fine fibers of poly(butylene terephthalate) PBT, whose melting point is higher than that of PLA, is prepared in a PLA matrix by melt-stretching with rapid cooling. Then, the rheological properties of the composites are evaluated at the temperature between melting points of PLA and PBT. It is found that only 1 wt. % of PBT fibers greatly enhances the elongational viscosity, although shear viscosity is hardly changed. In particular, the composite shows strain-hardening behavior, which has not been detected for polymer composites with rigid fibers. Elastic deformation of network composed of flexible PBT fibers, leading to bending of fibers and/or friction between fibers, will be responsible for the strain-hardening. The marked elasticity is also detected for a composite of silicone oil containing the PBT fine fibers.