The Tg of a resin system defines when a polymer goes from an amorphous rigid state to a more flexible state. Tg is an abbreviation for Glass Transition Temperature. The most important information that the Tg provides is: What is the nature of the polymer at its service temperature? Is it rigid and glassy or is it flexible and rubbery?
The normal state of most thermoset polymers is to be an amorphous solid at room temperature. The arrangement of the polymer molecules is a random arrangement, meaning the polymer structure does not have a repeating arrangement of polymer chains. An amorphous solid is different than a crystalline solid where the polymer molecules would be in a structured, repeating arrangement . At temperatures below the Tg, the molecular chains do not have enough energy present to allow them to move around. The polymer molecules are essentially locked into a rigid amorphous structure due to short chain length, molecular groups branching off the chain and interlocking with each other, or due to a rigid backbone structure. When heat is applied, the polymer molecules gain some energy and they can start to move around. At some point the heat energy is enough to change the amorphous rigid structure to a flexible structure. The polymer molecules move freely around each other. This transition point is called the glass transition temperature.
Instruments used: We use DSC and DMA instruments for testing Tg of materials. For low temperature TG we use DMA in Liquid nitrogen atmosphere.
The ‘enthalpy’ of fusion is a latent heat, because during melting the heat energy needed to change the substance from solid to liquid at atmospheric pressure is latent heat of fusion, as the temperature remains constant during the process. The liquid phase has a higher internal energy than the solid phase.
Latent heat of vaporization of liquid is defined as the amount of heat required to change the unit mass of liquid at boiling point into vapour at the same temperature. So, latent heat of steam is defined as the amount of heat required to change a unit mass of water from100to steam at the same temperature.
Heat of vaporization is different from heat of fusion because heat of vaporization is the energy needed for a substance from liquid to gas. While heat of fusion is the heat of adsorbed by a substance to turn it from a solid to liquid.M
It is necessary to know heats o fusion for a material to estimate its purity and engergy requirements during processing.
Instrument used: We use DSC for testing heats fusion and evaporation of materials.
Polymers are a great and very important category of organic compounds that have changed our lifestyle. In the last eighty years, we have used them for the most varied applications, and from the first structural ones we began to investigate their durability, which can be fatal in the successful completion of the application for which the material was designed. Over the last thirty years, the environmental problems related to the disposal of polymers that have completed their lifecycle have begun to arise, and the need to foresee their end of life has become increasingly urgent. In this manuscript, the reliability of the lifetime predictions of polymeric materials is faced with comparing measurements obtained at low temperature with those carried out at high temperatures, in the molten state. The obtained data were treated by a well-established kinetics model and discrepancies were observed in the two different conditions (high and low temperatures), which led to a mismatching between expected and real data. A correction of the data extrapolated from measurements obtained at high temperatures, by using a novel equation which takes into account the induction period (IP) of the degradation process, is proposed. Considerations about the useful parameters, namely initial decomposition temperature (Ti ), activation energy of degradation (Ea), and glass-transition temperature (Tg), to be used for making predictions, are also carried out.
Instrument used: We use TGA instrument for life estimation.
Identification of polymer and plastic materials, assisting your product development, materials selection, identification and reverse engineering
Expert polymer and plastic identification testing is required during polymer product development, competitive analysis, reverse engineering, deformulation, layer identification, for material fingerprinting and polymer problem solving.
Identification of plastics and polymers is important to confirm that the correct material has been used in an application or to identify an unknown material. Identification testing can also help a developer to compare several materials assisting the selection of the most suitable material in terms of composition or quality.
Plastics and polymer formulations are usually comprised of a polymer material and a range of other additives such as UV absorbers, colourants, or plasticisers. Experienced testing expertise is required to identify the polymer and to carry out the analysis using a range of laboratory techniques.
Our experts provide plastic and polymer identification testing for materials and finished products, such as packaging, and can support you during critical innovation steps, helping you to ensure that your materials and products meet regulatory or industry specifications and requirements.
With our expertise we can help you to gain to gain insight into the identity, character and performance of the material in order to accelerated innovation, materials or vendor assessment, reverse engineering/deformulation, failure analysis, litigation support or research into new additives. Laboratory identification testing is also available for polymer additives, fillers, colorants, UV inhibitors, and other materials.
Wherever your interest in the polymer supply chain, from resin production to final application, our polymer and plastics identification experts are available to discuss your specific requirements.
Instruments used: We use FTIR and DSC for identification of polymers and rubbers in the sample.
Polymers are large molecules, a type of macromolecule. Their chemical properties are similar to those of simple molecules. As it does not have a sharp melting point, the temperature at which this occurs is termed the melt transition temperature, T m . Above this temperature, the polymer is amorphous.
He melting point is an important physical property of a compound. The melting point can be used to identify a substance and as an indication of its purity. The melting point of solid is defined as the temperature at which the solid exists in equilibrium with its liquid under an external pressure of one atmosphere.
They too are held together by very strong covalent bonds. There are greater intermolecular forces between the long chains compared with smaller simple molecules. This means that polymers have a higher melting point than many other organic molecules.
Their elastic modulus changes significantly only at high (melting) temperature. It also depends on the degree of crystallinity: higher crystallinity results in a harder and more thermally stable, but also more brittle material, whereas the amorphous regions provide certain elasticity and impact resistance.
Instruments used: DSC & DMA
External influences such as UV radiation (light), temperature, atmospheric oxygen, atmospheric loads (e.g. impurities) or chemical/biological media lead to premature aging in organic materials, which might considerably influence their usage properties or might even lead to the failure of parts in which they are used as a component. The most common cause of chemical aging (e.g. chain degradation) is oxidation, which makes oxidation stability an important criterion for applications with oils, fats, lubricants, fuels or plastics. The oxidation stability can be determined via the Oxidation Induction Temperature / Oxidation Induction Time (OIT) by means of differential scanning calorimetry (DSC) in standardized procedures.
In practice, two different methods are used: dynamic and isothermal OIT tests. In the dynamic technique, the sample is heated at a defined constant heating rate under oxidizing conditions until the reaction begins. The Oxidation Induction Temperature OIT (also called Oxidation Onset Temperature OOT) is the same as the extrapolated onset temperature of the exothermal DSC effect which occurs. In isothermal IOT tests, the materials to be investigated are first heated under a protective gas, then held at a constant temperature for several minutes to establish equilibrium and subsequently exposed to an atmosphere of oxygen or air. The time span from the first contact with oxygen until the beginning of oxidation is called the Oxidation Inductive Time, OIT.
Instrument used: We use DSC for testing OIT of polymer.
Because of the material temperature increase, the internal particle velocity increases and so does thermal conductivity. This increased velocity transfers heat with less resistance. The Wiedemann-Franz law describes this behavior by correlating thermaland electrical conductivity to temperature Thermal conductivity is one of the thermophysical properties. It is going describe the ease with which we can transfer the heat from one point to another point. Higher the thermal conductivity faster the heat is going to transfer between given two points. Generally all the electrical conductors are having high thermal conductivity eg- copper,aluminium etc .. But their is an exception for the above statement, diamond is having high thermal conductivity but it is not a electrical conductor. Diamond is having high thermal conductivity because of good crystalline structure.
Thermal conductivity shows us how much rate of heat transfer a material can perform. For example, Young’s Modulus is used during tensile and compressive designing, similary Thermal Conductivity is used for thermal designing.
Thermal conductivity (often denoted by k, λ, or κ) refers to the intrinsic ability of a material to transfer or conduct heat. … Heat moves along a temperature gradient, from an area of high temperature and high molecular energy to an area with a lower temperature and lower molecular energy.
Factors Affecting Thermal Conductivity. Thermal conductivity, also called heat conduction, is the flow of energy from something of a higher temperature to something of a lower temperature. … Several factors affect thermal conductivity and the rate that energy is transferred.
Thermal Conductivity. Thermal conductivity is the measurement of the heat transfer ability of the material itself. It is influenced by the material constitution, porosity,temperature of the surroundings, and the direction of the heat current.
Instrument used: Thermal Conductivity Instrument.
Coefficient of Thermal Expansion (CTE) is a measure of the expansion or contraction of a material as a result of changes in temperature. … This is important because the volumetric Coefficient of Expansion will be much higher than the linear CTE for the same product under the same test conditions. he coefficient of thermal expansion describes how the size of an object changes with a change in temperature. Specifically, it measures the fractional change in size per degree change in temperature at a constant pressure. Several types of coefficients have been developed: volumetric, area, and linear.
Thermal expansion refers to a fractional change in size of a material in response to a change in temperature. For most materials, over small temperature ranges, these fractional changes… uses the SI unit inverse kelvin (K −1 or 1/K) or the equivalent acceptable non SI unit inverse degree Celsius (℃ −1 or 1/℃).
Composite’s thermal expansion coefficient depends mainly on its component materials, composite state and operation environment.
Thermal expansion coefficient of component materials is the most important factor. If it changes, composite’s thermal expansion coefficient will change. The content and modulus of components affect thermal expansion coefficient of composites, the component with high thermal expansion coefficient has more impacts on corresponding parameters of composites.
Thermal expansion coefficient of composites is also influenced greatly by reinforced (filled) materials’ arrangement and whether it is continuous in the matrix. If filler is not continuous and is distributed randomly, the thermal expansion coefficient is isotropic. If filler is continuous or arranged in certain direction, then it is anisotropic. For unidirectional continuous fiber composites, transverse thermal expansion coefficient is larger than the longitudinal. In addition, pre-stress of fiber also has some influence on it.
In operation environment, temperature has some impacts on thermal expansion coefficient too. In a certain temperature range, relative elongation is proportional linearly to temperature. In addition, thermal cycling will lead to micro-cracks in the interface of composites, and the matrix may further cure, so linear expansion coefficient and modulus will change, thus affecting thermal expansion coefficient.
Instrument used: We use TMA instrument for this purpose
Water covers around 70% of the Earth’s surface and its high specific heat plays a very important role as it is able to absorb a lot of heat without a significant rise in the temperature. When temperatures decrease, the heat which is stored is released, restraining a rapid drop in temperature.
Specific heat is defined by the amount of heat needed to raise the temperature of 1 gram of a substance 1 degree Celsius (°C). Water has a high specific heat capacity which we’ll refer to as simply “heat capacity”, meaning it takes more energy to increase the temperature of water compared to other substances.
Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass. The specific heat capacity of a material is a physical property. It is also an example of an extensive property since its value is proportional to the size of the system being examined. Specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. Now best example to Specific heat is Water, forwater specific heat is 1. real life example of specific heat: water takes more time to heat up and cool down. The specific heat of a substance is the amount of heat necessary to raise the temperature of one kilogram of the substance one Celsius degree. The greater thespecific heat of a substance, the greater the amount of heat necessary to raise the temperature per unit mass. The specific heat, also called specific heat capacity, is the measure of the heat energy that a substance in a unit quality absorbs or releases when the temperatureincreases or decreases 1 K. The bigger the specific heat is, the better the stability of the indoor temperature will be. So, a high value means that it takes MORE energy to raise (or lower) its temperature. A low value means that it does not take very much energy to heat or cool it. Adding heat to a “low specific heat” compound will increase its temperature much more quickly than adding heat to a high specific heat compound. The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat. … As a result, water plays a very important role in temperature regulation.
Instrument used: We use Thermal Conductivity instrument and DSC for this purpose.
Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow. Thermal resistance is the reciprocal of thermal conductance.
The heat resistant properties of Fine Ceramics are measured by the temperatures at which they begin to melt, and by their levels of thermal shock resistance. Thermal shock resistance refers to a material’s ability to withstand rapid changes in temperature. Silicon nitride, a particularly heat tolerant material, displays superior resistance to thermal shock, as tested by heating the material to 550℃ (1,022℉) and then rapidly cooling it by dropping it into water. Silicon nitride is thus suitable for applications involving extreme temperature variations, and in high-temperature industries such as metal manufacturing and energy generation.
Insstrment used: We use Thermal Conductivity instrument for this purpose
