{"id":15309,"date":"2018-04-11T17:01:53","date_gmt":"2018-04-11T15:01:53","guid":{"rendered":"https:\/\/www.rct-online.de\/magazin\/?p=15309"},"modified":"2025-11-28T13:56:19","modified_gmt":"2025-11-28T12:56:19","slug":"viscosity-and-viscoelasticity","status":"publish","type":"post","link":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/","title":{"rendered":"What Are Viscosity and Viscoelasticity?"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_73 ez-toc-wrap-center counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Short_Definition_of_Both_Behaviours\" title=\"Short Definition of Both Behaviours\">Short Definition of Both Behaviours<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Viscosity\" title=\"Viscosity\">Viscosity<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Viscoelasticity\" title=\"Viscoelasticity\">Viscoelasticity<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Derivation_of_Viscosity\" title=\"Derivation of Viscosity\">Derivation of Viscosity<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Newtonian_and_Non_Newtonian_Fluids\" title=\"Newtonian and Non Newtonian Fluids\">Newtonian and Non Newtonian Fluids<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Types_of_Non_Newtonian_Fluids\" title=\"Types of Non Newtonian Fluids\">Types of Non Newtonian Fluids<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#Influence_of_Temperature\" title=\"Influence of Temperature\">Influence of Temperature<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#How_Exactly_Does_Viscoelasticity_Behave\" title=\"How Exactly Does Viscoelasticity Behave?\">How Exactly Does Viscoelasticity Behave?<\/a><\/li><\/ul><\/nav><\/div>\n<p style=\"text-align: justify;\"><strong>Honey, water, ketchup and a starch solution represent four liquids with four very different flow behaviours. Honey flows slowly and thickly, but it can be made thinner by gentle heating. Water, on the other hand, seems to flow at a constant speed, while ketchup initially resists and does not flow until it suddenly becomes thin from one moment to the next. Finally, a starch solution is thin at rest but thickens when it is stirred continuously. The differing behaviour of these four liquids is described by their varying viscosities. This must not be confused with viscoelasticity, which describes the behaviour of solids and occurs frequently in plastics.<\/strong><\/p>\n<p><center><a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30372\/high-tech-cyanoacrylate-adhesive-plastic\/metal\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1593 size-full\" title=\"High-Tech Cyanoacrylate Adhesive | Plastic\/Metal\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/cyanacrylester-kleber-kunststoff-metall.jpg\" alt=\"High-Tech Cyanoacrylate Adhesive | Plastic\/Metal\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/cyanacrylester-kleber-kunststoff-metall.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/cyanacrylester-kleber-kunststoff-metall-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/two-component-adhesives\/30377\/ptfe-adhesive-based-on-synthetic-rubber-contact-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1594 size-full\" title=\"PTFE Adhesive based on Synthetic Rubber (Contact Adhesive)\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/ptfe-kleber-auf-synthetischer-kautschukbasis-kontaktkleber.jpg\" alt=\"PTFE Adhesive based on Synthetic Rubber (Contact Adhesive)\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/ptfe-kleber-auf-synthetischer-kautschukbasis-kontaktkleber.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/ptfe-kleber-auf-synthetischer-kautschukbasis-kontaktkleber-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/center><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Short_Definition_of_Both_Behaviours\"><\/span>Short Definition of Both Behaviours<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Viscosity\"><\/span>Viscosity<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">Viscosity describes the thickness or internal friction of fluids, more precisely the resistance of a liquid to a shear force. More accurately, this is referred to as shear viscosity to distinguish it from dynamic viscosity and kinematic viscosity.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Viscoelasticity\"><\/span>Viscoelasticity<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">Viscoelasticity occurs in fluids and solids. A polymer melt, for example, can be viscoelastic. Viscoelastic material shows a mixed behaviour, partly viscous and partly elastic, combining characteristics of liquids and solids. Viscoelasticity depends on time, temperature and the frequency acting on a solid.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Derivation_of_Viscosity\"><\/span>Derivation of Viscosity<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">The description and mathematical derivation of viscosity in liquids is often illustrated using the following model: a liquid is located between two plates separated by a defined gap, and the liquid is mentally divided into layers. One of the plates is moved parallel to the other stationary plate at a defined speed.<\/p>\n<blockquote>\n<p style=\"text-align: justify;\">The top liquid layer close to the moving plate travels at nearly the same speed, decreasing continuously toward the stationary plate.<\/p>\n<\/blockquote>\n<p style=\"text-align: justify;\">A force F is required for the movement of the liquid layers, which is ideally proportional to the area of the plate and the velocity and inversely proportional to the distance between the plates. The proportionality constant that relates these variables is called the dynamic viscosity. It is measured in the unit poise (P).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-15319\" title=\"Dynamic viscosity of various media at 20 \u00b0C\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/viskositaet-diagramm-e1524575810328-engl.jpg\" alt=\"Dynamic viscosity of various media at 20 \u00b0C\" width=\"600\" height=\"549\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/viskositaet-diagramm-e1524575810328-engl.jpg 596w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/04\/viskositaet-diagramm-e1524575810328-engl-300x274.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p style=\"text-align: justify;\">For practical applications, the unit centipoise (cP) is commonly used. For example, at +20 \u00b0C the viscosity of water is 1 cP, ethanol is 1.2 cP and honey is around 10<sup>4<\/sup> cP. Closely related to dynamic viscosity is kinematic viscosity, which is defined as the ratio of dynamic viscosity to the density of the substance and measured in stokes (St).<\/p>\n<figure id=\"attachment_1562\" aria-describedby=\"caption-attachment-1562\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1562 size-full\" title=\"Crude oil\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Rohoel.jpg\" alt=\"Rohoel\" width=\"600\" height=\"400\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Rohoel.jpg 600w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Rohoel-300x200.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><figcaption id=\"caption-attachment-1562\" class=\"wp-caption-text\">\u00a9 anankkml \/ Fotolia.com<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">In practice, dynamic viscosity plays a major role in the transport of liquids through piping systems, for example in the long-distance transport of crude oil through oil pipelines.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Newtonian_and_Non_Newtonian_Fluids\"><\/span>Newtonian and Non Newtonian Fluids<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">As early as 1687, Newton studied the internal friction of liquids and described it as follows:<\/p>\n<blockquote>\n<p style=\"text-align: justify;\">\u201cThe resistance arising from the lack of slip within a liquid is, assuming all other conditions remain equal, proportional to the velocity at which the liquid particles are separated from one another.\u201d<\/p>\n<\/blockquote>\n<p style=\"text-align: justify;\">All fluids that obey these laws are referred to as Newtonian fluids. Non Newtonian fluids, by contrast, do not show a linear relation between viscosity and applied speed but may change their behaviour due to shear force or time.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Types_of_Non_Newtonian_Fluids\"><\/span>Types of Non Newtonian Fluids<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">Non Newtonian fluids can be divided into three groups: shear thinning fluids, shear thickening fluids and so called Bingham media.<\/p>\n<p style=\"text-align: justify;\">Polymer solutions often exhibit the effect known as shear thinning, meaning that their viscosity decreases under higher shear forces. The individual polymer chains can more easily move past each other as shear increases, causing the solution to become thinner. These are known as shear thinning fluids.<\/p>\n<p><center><a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30375\/high-tech-electrical-conductivity-adhesive-one-component\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1664 size-full\" title=\"High-Tech Electrical Conductivity Adhesive | Heat-curing, one-component\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/elektro-leitfaehigkeitskleber-einkomponenten.jpg\" alt=\"elektro-leitfaehigkeitskleber-einkomponenten\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/elektro-leitfaehigkeitskleber-einkomponenten.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/elektro-leitfaehigkeitskleber-einkomponenten-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/two-component-adhesives\/30379\/fluoroelastomer-universal-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1665 size-full\" title=\"Fluoroelastomer Universal Adhesive | For bonding of fluoroelastomers \" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/fluorelastomer-universalkleber.jpg\" alt=\"fluorelastomer-universalkleber\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/fluorelastomer-universalkleber.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/fluorelastomer-universalkleber-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/center><\/p>\n<p style=\"text-align: justify;\">In shear thickening fluids, viscosity increases with shear force. This is the case for starch solutions that become thicker when stirred with <a href=\"https:\/\/www.rct-online.de\/en\/laboratory-equipment\/stirring-and-mixing\/stirrers-and-stirring-devices\">stirring devices<\/a>.<\/p>\n<p style=\"text-align: justify;\">A Bingham medium behaves like an elastic body below its yield point but becomes thinner over time once the yield point is exceeded. After the external force stops, it slowly returns to its original viscosity. A common example is ketchup, which must be shaken vigorously to start flowing and then gradually thickens again.<\/p>\n<p><center><a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30366\/silicone-rubber-adhesive-small-scale-adhesion\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1668 size-full\" title=\"Silicone Rubber Adhesive | small-scale adhesion | Particularly suited for electrical assemblies and repairs\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk-kleinflaechen.jpg\" alt=\"Silicone Rubber Adhesive | small-scale adhesion | Particularly suited for electrical assemblies and repairs\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk-kleinflaechen.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk-kleinflaechen-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30370\/tangit-pvc-u-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1669 size-full\" title=\"Tangit\u00ae-PVC-U Adhesive | Solvent-containing special adhesive for tensile-resistant connection between pressure pipes\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/tangit-pvc-u-kleber.jpg\" alt=\"Tangit\u00ae-PVC-U Adhesive | Solvent-containing special adhesive for tensile-resistant connection between pressure pipes\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/tangit-pvc-u-kleber.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/tangit-pvc-u-kleber-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/center><\/p>\n<p style=\"text-align: justify;\">These behaviours must be considered when processing plastics at high temperatures, since they often behave like non Newtonian solutions.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Influence_of_Temperature\"><\/span>Influence of Temperature<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p style=\"text-align: justify;\">In addition to time and shear force, temperature has a major influence on the viscosity of fluids and gases. Viscosity is temperature dependent. It decreases in liquids as temperature rises, which must be considered when using lubricating oils.<\/p>\n<blockquote>\n<p style=\"text-align: justify;\">The viscosity index is used in this context, describing the kinematic viscosity as a function of temperature.<\/p>\n<\/blockquote>\n<p style=\"text-align: justify;\">Oils should have a high viscosity index to minimise temperature dependent variations. Even in gases, internal friction plays a role although it is weak due to the low particle density compared to liquids. It is the reason why the viscosity of gases increases measurably with temperature and pressure, both of which raise particle density.<\/p>\n<p><center><a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30365\/high-tech-adhesive-for-metal-and-ceramic-bonding\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1672 size-full\" title=\"High-Tech Adhesive | for Metal and Ceramic Bonding \" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-keramik-und-metall.jpg\" alt=\"High-Tech Adhesive | for Metal and Ceramic Bonding \" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-keramik-und-metall.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-keramik-und-metall-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30367\/silicone-rubber-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1673 size-full\" title=\"Silicone Rubber Adhesive | Excellently suited for extremely high temperatures up to +315 \u00b0C\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk.jpg\" alt=\"kleber-fuer-silikon-kautschuk\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/kleber-fuer-silikon-kautschuk-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/center><\/p>\n<h2><span class=\"ez-toc-section\" id=\"How_Exactly_Does_Viscoelasticity_Behave\"><\/span>How Exactly Does Viscoelasticity Behave?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Viscoelastic material changes its behaviour over time when subjected to external stress. Under constant load, the plastic deforms gradually, a phenomenon known as creep. The less common term is retardation.<\/p>\n<figure id=\"attachment_1565\" aria-describedby=\"caption-attachment-1565\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1565 size-full\" title=\"Honey on a laboratory spoon\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Honig-auf-Laborloeffel.jpg\" alt=\"Honig auf Laborloeffel\" width=\"600\" height=\"400\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Honig-auf-Laborloeffel.jpg 600w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Honig-auf-Laborloeffel-300x200.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><figcaption id=\"caption-attachment-1565\" class=\"wp-caption-text\">\u00a9 zayacsk \/ Fotolia.com<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">In such cases, the plastic behaves like a liquid. At the same time, plastics are also elastic to a certain degree, meaning they return to their original form but not fully. The elastic component is responsible for spontaneous and reversible deformation, while the viscous component causes a time dependent, unlimited and irreversible deformation. The extent of viscoelastic behaviour differs between materials, as does the way in which the two components interact.<\/p>\n<blockquote>\n<p style=\"text-align: justify;\">Viscoelasticity is also temperature dependent, as the processes occur more rapidly at higher temperatures.<\/p>\n<\/blockquote>\n<p style=\"text-align: justify;\">This is especially important when assessing ageing processes. Viscoelasticity plays a major role when selecting <a href=\"https:\/\/www.rct-online.de\/en\/seals-and-gaskets\">gaskets<\/a> or <a href=\"https:\/\/www.rct-online.de\/en\/seals-and-gaskets\/o-rings\">O rings<\/a>. Since the material gradually loses its shape, plastics must be chosen whose viscoelasticity meets the specific requirements.<\/p>\n<p><center><a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/30373\/high-tech-cyanoacrylate-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1676 size-full\" title=\"High-Tech Cyanoacrylate Adhesive | very low viscosity, fast curing\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/cyanacrylester-kleber-fuer-schwer-klebbare-kunststoffe.jpg\" alt=\"High-Tech Cyanoacrylate Adhesive | very low viscosity, fast curing\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/cyanacrylester-kleber-fuer-schwer-klebbare-kunststoffe.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/cyanacrylester-kleber-fuer-schwer-klebbare-kunststoffe-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/adhesives-and-lubricants\/adhesives\/one-component-adhesives\/31275\/pevicol-pvc-adhesive\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1677 size-full\" title=\"PeViCol-PVC Adhesive | adhesion of plastic valves, fittings, pipes and hoses made of PVC\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/pevicol-kleber-fuer-pvc.jpg\" alt=\"PeViCol-PVC Adhesive | adhesion of plastic valves, fittings, pipes and hoses made of PVC\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/pevicol-kleber-fuer-pvc.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/pevicol-kleber-fuer-pvc-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/center><\/p>\n<p style=\"text-align: justify;\">In summary, viscosity and viscoelasticity are two key properties that significantly influence the behaviour and application range of solutions, fluids and materials.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Honey, water, ketchup and a starch solution represent four liquids with four very different flow behaviours. Honey flows slowly and thickly, but it can be made thinner by gentle heating. Water, on the other hand, seems to flow at a constant speed, while ketchup initially resists and does not flow until it suddenly becomes thin &hellip;<\/p>\n","protected":false},"author":7,"featured_media":11406,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,3028,2748,3029],"tags":[3306,3598,3599,3308,3593,3594,3595,3596,3600,3604,2775,2776,3605,3597,2769,3049,3606,3601,3602,3603],"class_list":["post-15309","post","type-post","status-publish","format-standard","has-post-thumbnail","","category-all-articles","category-alle-beitraege-en","category-materials-in-chemistry","category-werkstoffe-in-der-chemie-en","tag-adhesive","tag-ceramic","tag-conductive-adhesive","tag-contact-adhesive","tag-cyanacrylate","tag-electro","tag-fluids","tag-fluoroelastomer","tag-metal","tag-pevicol-en","tag-ptfe-en","tag-pvc-en","tag-pvc-u-en","tag-rubber","tag-silicone","tag-silikon-en","tag-tangit-en","tag-universal-adhesive","tag-viscoelasticity","tag-viscosity"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v23.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine<\/title>\n<meta name=\"description\" content=\"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine\" \/>\n<meta property=\"og:description\" content=\"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/\" \/>\n<meta property=\"og:site_name\" content=\"Reichelt Chemietechnik Magazine\" \/>\n<meta property=\"article:published_time\" content=\"2018-04-11T15:01:53+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-11-28T12:56:19+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"800\" \/>\n\t<meta property=\"og:image:height\" content=\"600\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Dr. Karl-Heinz Heise\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Dr. Karl-Heinz Heise\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"8 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/\",\"url\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/\",\"name\":\"What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine\",\"isPartOf\":{\"@id\":\"https:\/\/www.rct-online.de\/magazin\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg\",\"datePublished\":\"2018-04-11T15:01:53+00:00\",\"dateModified\":\"2025-11-28T12:56:19+00:00\",\"author\":{\"@id\":\"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/de5369aedc25d1f064871d823629e056\"},\"description\":\"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.\",\"breadcrumb\":{\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage\",\"url\":\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg\",\"contentUrl\":\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg\",\"width\":800,\"height\":600,\"caption\":\"\u00a9 runique \/ Fotolia.com\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.rct-online.de\/magazin\/en\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"What Are Viscosity and Viscoelasticity?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/#website\",\"url\":\"https:\/\/www.rct-online.de\/magazin\/\",\"name\":\"Reichelt Chemietechnik Magazine\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.rct-online.de\/magazin\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/de5369aedc25d1f064871d823629e056\",\"name\":\"Dr. Karl-Heinz Heise\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2024\/07\/KH_Heise.jpg\",\"contentUrl\":\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2024\/07\/KH_Heise.jpg\",\"caption\":\"Dr. Karl-Heinz Heise\"},\"description\":\"Dr. Karl-Heinz Heise studierte an der Martin-Luther Universit\u00e4t Halle-Wittenberg Chemie und der vormaligen Technischen Hochschule Dresden Radiochemie und Chemische Kerntechnik. Danach war er bis zur politischen Wende 1989 als wissenschaftlicher Mitarbeiter am Zentralinstitut f\u00fcr Kernforschung Rossendorf (ZfK) der Akademie der Wissenschaften in verschiedenen Bereichen der Isotopenproduktion und Markierungschemie t\u00e4tig. 1990 wurde er im neu gegr\u00fcndeten Leibnitz-Forschungszentrum Dresden - Rossendorf, dem heutigen Helmholtz-Zentrum, mit der Leitung der Abteilung f\u00fcr Organische Tracerchemie des Instituts f\u00fcr Radiochemie betraut, die sich mit umweltchemischen Prozessen in den Hinterlassenschaften des Uranbergbaus der DDR befasste. Dr. Heise ist begeisterter Hobby-Numismatiker und besch\u00e4ftigt sich dabei vornehmlich mit der h\u00f6fischen Medaillenkunst des 19. Jahrhunderts in Sachsen.\",\"url\":\"https:\/\/www.rct-online.de\/magazin\/en\/author\/k-heise\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine","description":"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/","og_locale":"en_US","og_type":"article","og_title":"What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine","og_description":"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.","og_url":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/","og_site_name":"Reichelt Chemietechnik Magazine","article_published_time":"2018-04-11T15:01:53+00:00","article_modified_time":"2025-11-28T12:56:19+00:00","og_image":[{"width":800,"height":600,"url":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg","type":"image\/jpeg"}],"author":"Dr. Karl-Heinz Heise","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Dr. Karl-Heinz Heise","Est. reading time":"8 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/","url":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/","name":"What Are Viscosity and Viscoelasticity? - Reichelt Chemietechnik Magazine","isPartOf":{"@id":"https:\/\/www.rct-online.de\/magazin\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage"},"image":{"@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage"},"thumbnailUrl":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg","datePublished":"2018-04-11T15:01:53+00:00","dateModified":"2025-11-28T12:56:19+00:00","author":{"@id":"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/de5369aedc25d1f064871d823629e056"},"description":"What is meant by viscosity and viscoelasticity? The RCT-Online Magazine takes a closer look at these two types of material behaviour and explains their relevance in industry.","breadcrumb":{"@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#primaryimage","url":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg","contentUrl":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2018\/05\/Was-bedeuten-Viskositaet-und-Viskoelastizitaet.jpg","width":800,"height":600,"caption":"\u00a9 runique \/ Fotolia.com"},{"@type":"BreadcrumbList","@id":"https:\/\/www.rct-online.de\/magazin\/en\/viscosity-and-viscoelasticity\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.rct-online.de\/magazin\/en\/"},{"@type":"ListItem","position":2,"name":"What Are Viscosity and Viscoelasticity?"}]},{"@type":"WebSite","@id":"https:\/\/www.rct-online.de\/magazin\/#website","url":"https:\/\/www.rct-online.de\/magazin\/","name":"Reichelt Chemietechnik Magazine","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.rct-online.de\/magazin\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/de5369aedc25d1f064871d823629e056","name":"Dr. Karl-Heinz Heise","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.rct-online.de\/magazin\/#\/schema\/person\/image\/","url":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2024\/07\/KH_Heise.jpg","contentUrl":"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2024\/07\/KH_Heise.jpg","caption":"Dr. Karl-Heinz Heise"},"description":"Dr. Karl-Heinz Heise studierte an der Martin-Luther Universit\u00e4t Halle-Wittenberg Chemie und der vormaligen Technischen Hochschule Dresden Radiochemie und Chemische Kerntechnik. Danach war er bis zur politischen Wende 1989 als wissenschaftlicher Mitarbeiter am Zentralinstitut f\u00fcr Kernforschung Rossendorf (ZfK) der Akademie der Wissenschaften in verschiedenen Bereichen der Isotopenproduktion und Markierungschemie t\u00e4tig. 1990 wurde er im neu gegr\u00fcndeten Leibnitz-Forschungszentrum Dresden - Rossendorf, dem heutigen Helmholtz-Zentrum, mit der Leitung der Abteilung f\u00fcr Organische Tracerchemie des Instituts f\u00fcr Radiochemie betraut, die sich mit umweltchemischen Prozessen in den Hinterlassenschaften des Uranbergbaus der DDR befasste. Dr. Heise ist begeisterter Hobby-Numismatiker und besch\u00e4ftigt sich dabei vornehmlich mit der h\u00f6fischen Medaillenkunst des 19. Jahrhunderts in Sachsen.","url":"https:\/\/www.rct-online.de\/magazin\/en\/author\/k-heise\/"}]}},"_links":{"self":[{"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/posts\/15309"}],"collection":[{"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/comments?post=15309"}],"version-history":[{"count":18,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/posts\/15309\/revisions"}],"predecessor-version":[{"id":15329,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/posts\/15309\/revisions\/15329"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/media\/11406"}],"wp:attachment":[{"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/media?parent=15309"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/categories?post=15309"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rct-online.de\/magazin\/en\/wp-json\/wp\/v2\/tags?post=15309"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}