Heat Distortion Vicat Softening Temperature Tester

Micrometers and gauges are used to measure the width and thickness of the test specimen, accurate to 0.01 mm.
Deflection measuring instruments can be calibrated direct-reading micrometers or other suitable instruments, with the deflection measured at the midpoint of the specimen support span accurate to within 0.01 mm.
Heating rate: A: 12±2°C/6min
Principle: The standard specimen is subjected to a three-point bending constant load in a flat position, generating one of the bending stresses specified in the relevant parts of GB/T 1634. Under uniform heating conditions, the temperature at which the standard deflection corresponding to the specified bending strain increment is reached is measured.
GB/T 17037.1-1997 Preparation of injection-molded test specimens of thermoplastic materials - Part 1: General principles and multipurpose specimens and long
Instrument zeroing: Raise the temperature of the heating device at a uniform rate of 50°C/±5°C/h or 120°C/h±10°C/h; when using a heater, fully stir the liquid during the test; for extended tests, use a heating rate of 50°C/h.
Specimens: Use at least two specimens per test sample. The specimens should be squares with a side length of 10 mm or circles with a diameter of 10 mm, with a thickness of 3 to 6.5 mm, flat and parallel surfaces, and no flash. Specimens should be prepared according to the specifications of the material being tested. If not specified, any appropriate method may be used to prepare the specimens.
Procedure: Place the specimen horizontally under the unloaded indenter. The indenter should be no less than 3 mm from the edge of the specimen, and the surface of the specimen in contact with the instrument base should be flat.
Test report should include the following information: reference to the relevant part of GB/T 1634, i.e., GB/T 1634.2 or GB/T 1634.3;
Standard test method for water absorption of plastics - ASTM D 570
Cooling method: Natural cooling above 150°C
Place the assembly into the heating device, start the stirrer. At the beginning of each test, the temperature of the heating device should be 20~23°C. When using a heating bath, the bulb of the thermometer or the sensing part of the temperature measuring instrument should be at the same level as the specimen and as close as possible to the specimen. If preliminary tests show that starting the test at other temperatures does not cause errors for the material being tested, other starting temperatures may be used.
GB/T 2918 Plastics - Standard atmospheres for conditioning and testing (GB/T 2918-2018, ISO 21, 2008, MOD)
The load rod and metal frame components should have the same expansion coefficient; differences in the length changes of components can cause errors in the apparent deformation readings of the specimen.
Specimen inspection: The specimen should be free of distortion, and its adjacent surfaces should be perpendicular to each other. All surfaces and edges should be free of scratches, pits, dents, and flash. Ensure that all machined surfaces of the specimen are as smooth as possible, and any unavoidable machining marks are along the long axis. To meet these requirements, place the specimen against a straightedge, triangle, or flat plate, and visually inspect or measure with a micrometer caliper.
Loading rod mass for applying test force, in kilograms (kg); m. - additional mass of weights, in kilograms (kg); F - total force applied to the specimen, in newtons (N); F. - force generated by the instrument's load spring, in newtons (N).
Power supply: AC220V±10% 20A 50Hz
Note 1: Maintaining a constant time of 5 min is used to partially compensate for the creep displayed by some materials under specified bending stress at room temperature. The creep that occurs within the first 5 min usually accounts for the vast majority of the creep that occurs within 3 min. If the material being tested does not show significant creep within the first 3 min at the starting temperature, a constant time of 5 min can be considered.
For some types of instruments, the force F generated by the micrometer spring acts upward, thus reducing the downward load applied by the loading rod. In another case, F acts downward, increasing the load applied by the loading rod. For such instruments, the magnitude and direction of force F should be determined so that it can be compensated (see 8.1). Since F. of some micrometers varies considerably over the measuring range, it should be measured within the part of the range to be used.
GB 8802 Method for determination of Vicat softening temperature of unplasticized polyvinyl chloride (PVC-U) pipes and fittings
Specimen holder automatically rises and lowers,
GB/T 1634.2 specifies specific requirements for plastics (including filled plastics and fiber-reinforced plastics with fiber length not exceeding 7.5 mm) and hard rubber, and GB/T 1634.3 specifies specific requirements for high-strength thermoset laminated materials. This part is applicable to evaluating the relative performance of different types of materials under load at high temperatures at a specified heating rate. The results obtained do not necessarily represent the highest applicable temperature because the main factors in actual use, such as time, load conditions, and nominal surface stress, may differ from the test conditions. Only data obtained from materials with the same room temperature flexural modulus are truly comparable. This part specifies the preferred dimensions of the specimens used. This part is commonly referred to as HDT (heat deflection test), although no official document uses this symbol.
Temperature measuring instruments matched with air or nitrogen ovens, accurate within 0.5°C. Place the sensor (thermocouple or P100) in an appropriate position near the indenter load rod or specimen holder.
Flexural stress: The nominal stress on the outer surface at the center of the specimen span. Note: Expressed in megapascals (MPa).
When the current sample's thermal curve exhibits one or more additional/missing melting/annealing endotherms, exotherms, or other thermal events not observed on the reference thermal curve, it should not be considered qualified, with the following three exceptions: A. Endotherms known to be related to moisture loss in amorphous nylons; B. Annealing endotherms related to glass transition (stress relaxation); C. Differences in thermal events caused by molding history should not lead to disqualification; D. Endothermic responses of < |20| μW should not be a reason for disqualification. Endothermic response is measured by total height (heat flow measured as deflection relative to the baseline). This is the distance (in microwatts) from the lowest point of the peak to the extension of the baseline between the maximum values on both sides of the lowest point, drawn perpendicular to the heat flow axis.
If the spring presses down on the specimen, the force is positive; if the spring thrust is opposite to the direction of the loading rod's descent, the force is negative; if such an instrument is not used, the force is zero.
Standard test method for shear strength of plastics by punch tool - ASTM D 903
The instrument mainly includes:
Raise the temperature of the heating bath at a uniform rate of (120±10)°C/h, record the temperature when the net increase in the initial deflection of the spline reaches the standard deflection, which is the load deflection temperature under the bending stress specified in GB/T 1634.2 or GB/T 1634.3. The standard deflection is a function of the thickness, span used, and the bending strain increment specified in GB/T 1634.2 or GB/T 1634.3. Calculated according to formula (4): L.aA.-2-Ar(…………………………(4)
In this type of instrument, the dial indicator spring force is upward and should be subtracted from the load; if this force is downward, it should be added to the load.
The thickness and width anywhere in the middle 1/3 length of each specimen should not deviate by more than 2% from the average value. Specimens should be prepared according to the relevant provisions of GB/T 1634.2 or GB/T 1634.3.
Weights should be equipped with a set of weights to load the specimen to the required bending stress. These weights should be adjustable in increments of 1g.
4.2 Indenter, preferably made of hard steel, a cylinder with a length of 3 mm and a cross-sectional area of 1000 mm²±0.015 mm². Fixed at the bottom of the load rod, the lower surface of the indenter should be flat, perpendicular to the axis of the load rod, and free of burrs.
Terms and definitions: The following terms and definitions apply to this document, flexural strain
Note 1: If several specimens are tested simultaneously, it may be useful to equip each specimen position in the heating bath with an established temperature measuring instrument. Note 2: At the time of publication of this part, there is no standard for calibrating temperature measuring instruments.
Place the specimen on the supports so that the long axis of the specimen is perpendicular to the supports. Place the loading device (5.1) into the heating bath and apply the calculated load to the specimen to produce the bending stress on the specimen surface as specified in GB/T 1634.2 or GB/T 1634.3. After the force has acted for 5 min, record the reading of the deflection measuring device (5.5) or adjust the reading to zero (see Note 1).
GB/T 1634 Plastics - Determination of temperature of deflection under load - Test method
Vicat softening point is defined as the temperature at which a flat-ended needle with a circular cross-section of 1 mm² penetrates the thermoplastic specimen to a depth of 1 mm (0.039 inches) under a specified load at a uniform heating rate.
The test method for Vicat softening point of polymeric materials should be as described in ASTM D 1525 (ISO 306) Standard Test Method for Vicat Softening Temperature of Plastics.
At speed B: 50N±1N
Complies with standards:
Specimens made of rigid materials with low expansion coefficients (such as Invar alloy or borosilicate glass) should be used for blank tests to calibrate each instrument, including its temperature range, and determine a correction term for each temperature. If the correction term is 0.02 mm or greater, note its algebraic sign and add it algebraically to the apparent penetration. Apply this correction term to each test. Instruments made of low-expansion alloys are recommended.
Standard test method for deflection temperature of plastics under flexural load - ASTM D 648
When performing all DSC consistency assessments, the repeatability of test results and sample behavior should be considered on a case-by-case basis to allow for prudent standard exceptions.
L - Distance between the contact lines of the specimen and supports (span), in millimeters (mm).
Defined by the relevant parts of GB/T 1634.2 or GB/T 1634.3, the deflection increment corresponding to the bending strain increment a on the specimen surface. Recommended to be in millimeters (mm) [see formula (4) in figure 3].
Tolerance: The change in corresponding endothermic melting events and glass transition temperature (see definitions of melting temperature and glass transition temperature) between the current thermal curve and the corresponding reference thermal curve should be within 5°C.
Check the span between the specimen supports (see 5.1) and adjust to the appropriate value if necessary. Measure and record this value accurately to 0.5 mm for use in calculations.
Overall dimensions: 720mm×700mm×1380mm
Load plate, mounted on the load rod, with suitable weights added centrally so that the total thrust applied to the specimen is 10 N ±0.2 N for A and Am, and 50N±1N for B. and B. The downward thrust of the load rod, indenter, load plate, and dial indicator spring combination should not exceed 1 N.
Device for generating bending stress: This device consists of a rigid metal frame, with the basic structure shown in Figure 1. Inside the frame, there is a loading rod that can move freely in the vertical direction, equipped with a weight carrier and a loading indenter. The base plate of the frame is connected to the specimen supports. These components and the vertical part of the frame are made of alloys with the same linear expansion coefficient as the loading rod.
The test results obtained may be related to the molding conditions used to prepare the specimens, although this dependency is not common. When test results depend on molding conditions, special annealing or pretreatment steps may be used before testing by agreement of the parties involved.
Calibrate the temperature measuring instrument at the immersion depth specific to the instrument used. The temperature-sensitive element of the temperature measuring instrument should be within (2±0.5) mm of the center of the specimen but not in contact with it.
Features and uses:
Precision: For plastics and hard rubber, precision data are available (see GB/T 163.2). For high-strength thermoset laminated materials and long fiber-reinforced plastics (see GB/T 1634.3), no precision statement was available at the time of publication of this part.
Heating equipment: Heating bath containing liquid or forced air circulation nitrogen oven. The heating equipment should be equipped with a controller to raise the temperature uniformly at 50°C/±5°C/h or 120°C/±10°C/h as required. During the test, the temperature change every 6 min should be 5°C±. Adjust the instrument to automatically cut off the heater and sound an alarm when the specified pressure is reached.
If the test requires a temperature change of (12±1)°C every 6 min, this requirement should also be considered. The temperature difference of the liquid between the two ends and the center of the specimen in the heating bath should not exceed ±1°C.
Standard method for climbing - Roller peel test of adhesives - ASTM D 1781
B: 5±1°C/6min
Dimensions and shape of the specimen, number of specimens
The Vicat softening temperature of the material being tested is expressed as the arithmetic mean of the Vicat softening temperatures of the specimens. If the range of individual test results exceeds 2°C, record the individual test results and repeat the test with another set of at least two specimens.
If the test sample is a molded material (powder or pellets), it should be molded into specimens with a thickness of 3 to 6.5 mm according to the relevant provisions of the material being tested. If not specified, mold the specimens according to GB/T 9352, GB/T 17037.1, or GB/T 1997. If these are not applicable, follow other methods that minimize changes in material properties.
Test at least two specimens. To reduce the effect of warpage, test with different faces of the specimen facing the loading indenter. If repeat tests are required (see GB/T 1634.2 and GB/T 1634.3), two additional specimens are required for each repeat test. For quality control purposes or by agreement of the parties involved, testing may be performed on one side of the specimen. In this case, specify the loaded surface in the test report. 7 Conditioning
Exceptions should be considered for curve differences that meet the requirements determined in the "Test Considerations Based on Compound Changes" table in the "Polymer Changes" section of this standard. For example, if the curve difference is determined to be due to a change in catalyst additive (e.g., N,N-ethylenethiourea), the change is considered acceptable without testing according to procedure code "O" of the polymer change table. Similarly, if the curve difference is determined to be due to a change in the content of inorganic pigments (e.g., titanium dioxide) at ≤5% or lubricant additives (e.g., ethylene bis(stearamide)), the change is considered qualified if it meets the requirements of test procedure code "A" (flame, minimum thickness for all flame ratings assigned to the original material formulation).
b) If the sheet thickness is less than 3 mm, stack up to three specimens directly so that the total thickness is between 3 and 6.5 mm, with the top sheet at least 1.5 mm thick. Stacking thinner sheets may not yield the same test results.
Note 2. Liquid paraffin, transformer oil, glycerol, and silicone oil are suitable liquid heat transfer media. Other fluids can also be used. For fluidized beds, alumina can be used.
Unless otherwise specified by the material being tested, conditioning and test environment should comply with GB/T 2918. Procedure: Calculation of applied force In the three-point loading method adopted in GB/T 1634, the force F applied to the specimen, in newtons (N), is a function of the bending stress: F_20,·b·h'………………………(1)
Standard test method for tensile properties - Impact energy to break plastics and electrical insulating materials - ASTM D 1822
Regularly check the heating rate by inspecting automatic temperature readings or manually verifying the temperature at least every 6 min.
The radius of the support contact head and loading indenter should be (3.0±0.2) mm, and the edge line length should be greater than the width of the specimen. Unless all vertical components of the instrument have the same linear expansion coefficient, differences in the length changes of these components will cause errors in the apparent deflection readings of the specimen. Use standard specimens made of rigid materials with low linear expansion coefficients and thickness comparable to the test specimen for blank tests on each instrument. Blank tests should cover the temperature ranges used in actual determinations, and a correction value should be determined for each temperature. If the correction value is 0.01 mm or greater, record its value and algebraic sign. Apply it algebraically to each specimen's apparent deflection reading during each test.
Calibrated micrometer (or other suitable measuring instrument) capable of measuring the indentation of the indenter into the specimen by 1 mm±0.01 mm and recording the thrust of the micrometer as part of the thrust on the specimen.
Bending strain increment: The specified increase in bending strain produced during heating.
Exception considerations: The above criteria are intended as general guidelines to aid in understanding the considerations used in DSC data comparative analysis. Although these guidelines are based on empirical evidence, experience shows that deviations are sometimes a function of certain material types and their associated instrument responses; therefore, understanding the operational results requires theoretical knowledge of operations, appropriate training, and direct experience with the instrument.
Maximum test load: 10N±0.2N at speed A
Preliminary thermal cycling may be used to confirm or eliminate thermal effects due to molding history. Once preliminary thermal cycling is completed, reheat the sample using the standard method typically used for the material and record the curve.
Standard test method for dielectric breakdown voltage and dielectric strength of solid electrical insulating materials at commercial power frequencies - ASTM D 149
Three specimens can be tested at once.
Principle: When heating at a uniform rate, determine the temperature at which a standard indenter penetrates the surface of a thermoplastic specimen to a depth of 1 mm under one of the load conditions given in Chapter 1. 4 Instrument
Test results depend on the heat transfer rate between the circulating air or nitrogen and the specimen. Due to the relatively small size of the specimen and the contact between the lower surface of the specimen and the specimen holder, the temperature of the air or nitrogen should not be taken as VST; instead, the temperature indicated by the sensor near the indenter load rod or specimen holder should be taken as VST.
After 5 min, with the indenter in a stationary position, add sufficient weights to the load plate so that the total thrust applied to the specimen is 10N±0.2N for An and A, and 50N±1N for Bm and Bm. Then, record the reading of the dial indicator (or other indentation measuring instrument) or set it to zero.
Temperature measuring instrument: Any suitable, calibrated temperature measuring instrument with an appropriate measuring range, readable to 0.5°C or more accurately.
The minute change per unit length on the outer surface at the midpoint of the specimen span, expressed as a fraction. Recommended to be expressed as a dimensionless ratio or percentage (%).
Standard test method for comparative tracking index of electrical insulating materials - ASTM D 3638
A - Specimen thickness, in millimeters (mm).
Load rod, equipped with a load plate, fixed on a rigid metal frame, capable of free movement in the vertical direction. The base of the metal frame is used to support the specimen under the indenter at the end of the load rod (see Figure 1).
All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 352-1988 Preparation of compression-molded test specimens of thermoplastics (neq ISO 293:1986) GB/T 11997-1989 Preparation and use of multipurpose test specimens of plastics (eqv ISO 3167:1983)
When measuring b and h, be accurate to 0.1 mm; when measuring L, be accurate to 0.5 mm. The span and bending stress should comply with the provisions of GB/T 1634.2 or GB/T 1634.3. When applying the test force F, consider the influence of the loading rod mass m, and include it as part of the test force. If a spring-loaded instrument is used, such as a dial indicator, also consider the magnitude of the spring force F. and its direction relative to the total force F, whether positive or negative (see 3.5). Place additional weights of mass m. on the loading rod to produce the required total force F as specified in formula (2): F=981(m. + m,) + F,……………………W. = F - m,………………………… where m.
Standard test method for high-voltage, low-current, dry arc resistance of solid electrical insulation - ASTM D 495
This document provides a description of the standards applied in the comparative analysis of DSC data for all product categories. The existence of product category-specific consistency standards will supersede this document. A compliant result indicates that the current sample shows the same thermal characteristics within the instrument detection and the standards described herein. A non-compliant result indicates that compositional and/or morphological changes have been observed in the current sample.
Water cooling or natural cooling below 150°C
Thermal events are characterized by onset temperature, magnitude of heat flow, and recovery or reestablishment of the baseline.
Standard test method for Vicat softening temperature of plastics - ASTM D 1525 Standard for apparent density of rigid cellular plastics - ASTM D 1622
Preparation of test specimens (idt ISO 294-1:1996)
Standard test method for impact resistance of plastics and electrical insulating materials - ASTM D 256
Temperature controller sets heating rate,
Weight: 180Kg
Deformation measurement range: 0--1mm
If the specimen thickness exceeds 6.5 mm, reduce the thickness to 3~6.5 mm by single-sided machining according to ISO 2818, leaving the other surface as is. The test surface should be the original surface.
Deformation measurement error: 0.01mm
The actual applied force should be the calculated force F (1±2.5)%.
Standard test method for tensile strength of adhesives using bar and rod specimens - ASTM D 2095
Temperature measuring instrument: Heating bath, partially immersed glass thermometer or other temperature measuring instrument with an appropriate range, accurate within 0.5°C. Calibrate the glass thermometer at the immersion depth required by 7.2.
Technical parameters:
Melting extrapolated end temperature - The intersection of the tangent drawn at the point of maximum slope on the transition curve with the extrapolated baseline after the melting peak.
Note 2: The purpose of this note is to emphasize the fact that the initial deflection caused by the detailed test load is not constant. Therefore, the final criterion of the test is not the absolute strain value; only the increase in deflection is monitored (see 3.4).
Note 2: If the specimen deflection is known to be a function of specimen humidity, this may be useful in interpreting the test results. If reliable, it is recommended to perform at least two tests, and each specimen should be used only once. Unless agreed by the parties involved to test only on one side of the specimen, to reduce the effect of specimen asymmetry (such as roughness) on the test results, test pairs of specimens with opposite faces facing the loading indenter.
Standard test method for resistance of plastics to chemical reagents - ASTM D 543
Specimen supports consist of two metal bars with cylindrical contact surfaces with the specimen, with the two contact lines on the same horizontal plane. The span dimension, i.e., the distance between the two contact lines, is specified by GB/T 1634.2 or GB/T 1634.3. Mount the supports on the base plate of the frame so that the vertical force applied to the specimen by the loading indenter is at the midpoint (±1 mm) of the two supports. The edge lines of the supports should be parallel to the edge line of the loading indenter and at a right angle to the long axis of the specimen symmetrically placed on the supports.
The instrument can be designed to automatically stop heating when the standard deflection is reached.
This part of GB/T 1634 specifies methods for determining the deflection temperature of plastics under load (bending stress under three-point loading). To accommodate different types of materials, different types of specimens and different constant test loads are specified.
At the start of each test, the temperature of the heating device (3.2) should be below 27°C, unless previous tests have shown that starting the test at a higher temperature does not cause errors for the specific material being tested. 8.3 Measurement
Where; F---- load, in newtons (N); σ, - bending stress on the specimen surface, in megapascals (MPa); b-- specimen width, in millimeters (mm); h--- specimen thickness, in millimeters (mm);
Standard test method for ignition of materials by hot wire sources - ASTM D 3874
Deformation measured by dial indicator,
Standard test method for liquid contaminants, inclined plane tracking, and erosion of insulating materials - ASTM D 2303
GB/T 1633 Determination of softening temperature (VST) of thermoplastics
The four methods specified in this standard are only applicable to thermoplastics and measure the temperature at which thermoplastics begin to soften rapidly.
Standard test method for thermal endurance of flexible sheet materials for electrical insulation by the curved electrode method - ASTM D 1830
Applicable ASTM test procedure reference list Standard test methods for softening point by ring-and-ball apparatus - ASTM E 28
When the indenter penetrates the specimen to a depth exceeding the initial position specified in 7.3 by 1 mm±0.01 mm, record the oil temperature measured by the sensor, which is the Vicat softening temperature of the specimen.
And meets the requirements of standards such as ISO 75, ISO 306, ISO 2507, etc.
Heating medium: Methyl silicone oil
Oven, capable of circulating air or nitrogen at a rate of 6 times/min. The volume of each oven should be not less than 10L, with air or nitrogen flowing perpendicular to the specimen surface at a speed of 1.5~2 m/s.
Standard test method for tensile properties of plastics - ANSI/ASTM D 638
DSC compliance standard C1 Background and purpose: Differential scanning calorimetry (DSC) is one of the identification tools used to analyze a variety of materials. When samples suitable for DSC analysis are received for original research, they should be tested to establish a reference thermal curve. This thermal curve is considered representative of the test sample. The reference curve is retained for future comparison.
Normative references: The provisions of the following standards, through reference in this standard, constitute the provisions of this standard. At the time of publication of this standard, the editions indicated were valid.
When using a heater, take the measured temperature of the liquid near the specimen as the Vicat softening temperature (VST) (see 7.5). Liquid paraffin, transformer oil, glycerol, and silicone oil are suitable heat transfer media; other liquids can also be used.
Calibrate the temperature measuring instrument according to the manufacturer's instructions.
Deflection: During bending, the distance that the top or bottom surface at the center of the specimen span deviates from its original position. Note; in millimeters (m).
Melting extrapolated onset temperature - The intersection of the tangent drawn at the point of maximum slope on the melting curve with the extrapolated baseline before the melting peak.
Standard test method for linear dimensional changes of plastics - ASTM D 1042
Note: All formulas involving bending performance are correct only when applied to situations where the stress/strain relationship is linear. Therefore, for most plastics, 8.2 Starting temperature of the heating device
Throughout the stroke, the force applied to the dial indicator spring changes significantly, so this force should be determined throughout the stroke.
The test report should include the following: ) Complete identification of the material tested, method used (An or AnB, or for composite specimens made of more than one layer, indicate the thickness and number of layers; specimen preparation method; heat transfer medium used; 1) Conditioning and annealing methods;
Applicable for testing Vicat softening point temperature and heat deflection temperature of polymer materials.
During initial calibration, it should be proven by test that the temperature displayed by the sensor is consistent with that displayed by an additional calibration sensor placed near a blank specimen. Commercial ovens often come with suitable air or nitrogen circulation devices; if not, directed circulation airflow plates perpendicular to the specimen surface must be installed to ensure heat transfer speed.
Extrapolated onset temperature - The intersection of the tangent drawn at the point of maximum slope on the transition curve with the extrapolated baseline before the transition.
GB/T 1634.1-2019 Plastics - Determination of temperature of deflection under load - Part 1: General test method
Standard test methods for DC resistance or conductance of insulating materials - ASTM D 257
Number and type of thermal events: When using the same test method (e.g., temperature program). The current sample should exhibit the same number and type of significant thermal events as the cited reference thermal curve. Typically, thermal event types include melting point, glass transition, crystallization, and curing.
The second heating does not require a preheating cycle as part of the DSC test method; therefore, various molding conditions may affect the material's response to DSC testing.
For sheets, the specimen thickness should be equal to the original sheet thickness, except as follows:
Standard test method for strength properties of adhesives in shear by tensile loading (metal-to-metal) - ASTM D 1002
If defects that do not meet the above requirements are measured or observed on the specimen, discard it or machine it to suitability before testing.
The heating device should be a heating bath containing a suitable liquid heat transfer medium, fluidized bed, or air heating furnace. The specimen should be immersed at least 5 mm deep in the medium and equipped with an efficient stirrer. The selected liquid heat transfer medium should be stable over the entire temperature range and should not affect the material being tested, e.g., cause swelling or cracking. In case of dispute or contradiction, the method using liquid heat transfer medium should be used as the reference method where temperature permits. The heating device should be equipped with a control element to raise the temperature at a uniform rate of (120±10)°C/h.
Extreme temperature - The intersection of the tangent drawn at the point of maximum slope on the transition curve with the extrapolated baseline after the transition.
Specimen overview: All specimens should be free of warpage caused by thickness asymmetry. Due to factors such as different cooling conditions during molding or structural asymmetry, the specimen may warp during heating, i.e., bend without load. Correct the shape and size by applying load on two opposite surfaces of the specimen.
Definitions: Thermal curve - In thermal analysis, a plot of the dependent variable (e.g., heat flow or weight loss) versus the independent variable, time or temperature, under defined time-temperature conditions. Peak temperature - The point where the tangents defining the melting extrapolated end temperature intersect. Melting temperature is defined as the peak temperature.
The specimen should be a rectangular bar (length > width b > thickness h), and the dimensions of the specimen should comply with the provisions of GB/T 1634.2 or GB/T 1634.3.
Maximum temperature error: ±1°C
Where Δs - standard deflection, in millimeters (mm); 1. - span, i.e., the distance between the contact axes of the specimen supports and the specimen, in millimeters (mm); Ar, - bending strain increment,
Conditioning: Unless specified or required by the material being tested, specimens should be conditioned according to GB/T 2918.
GB/T 1634.3 Plastics - Determination of temperature of deflection under load - Part 3: High-strength thermoset laminated materials (GB/T 1634.3-2004, ISO 75-3:2003, IDT)
Temperature range: Room temperature--300°C
Easy to operate, novel design, beautiful appearance, high reliability.
Load: Force applied to the midpoint of the specimen span to produce the specified bending stress. Recommended to be in newtons (N) [see formulas (1) in 8.1]. Temperature of deflection under load: The temperature at which the specimen deflection reaches the standard deflection value as the test temperature increases. Recommended to be in degrees Celsius (°C).

Expression of results: Unless otherwise specified in GB/T 1634.2 or GB/T 1634.3, the deflection temperature under load of the material being tested is expressed as the arithmetic mean of the deflection temperatures under load of the test specimens. Express the test result as the nearest whole number of degrees Celsius.
Glass transition temperature (Tg) - The point on the thermal curve (midpoint temperature 1) corresponding to half the heat flow difference between the extrapolated onset temperature and the extrapolated end temperature.
For some materials, when using a higher heating rate (120°C/h), the measured value may be up to 10°C higher than the Vicat softening temperature.
Note; Invar and borosilicate glass have been found suitable as blank test materials.
Heating bath: Contains liquid in which the specimen is immersed, equipped with a high-efficiency stirrer; the specimen immersion depth is at least 35 mm; ensure the selected liquid is stable at the use temperature and does not affect the material being tested, such as causing expansion or cracking.
Standard test method for rapid thermal degradation of solid electrical insulating materials by thermogravimetry - ASTM D 3850
Additionally, the qualitative presence or absence of crystallization and/or curing observed on the current thermal curve must be consistent with that observed on the reference thermal curve.
The Vicat softening temperature (VST) of the material, in °C, (if after two determinations, the difference between individual determination results exceeds the range specified, report the individual determination results). Record any abnormal characteristics of the specimen during the test or after removal from the instrument, h) Date of test and inspector.
Standard test method for peel strength of adhesives (T-peel test) - ASTM D 1876
As an indicator for quality control and identification of the thermal properties of new varieties,
Scope: Method A - Use a force of 10 N, heating rate of 50°C/h; Method B - Use a force of 50 N, heating rate of 50°C/h; Method An - Use a force of 10 N, heating rate of 120°C/h; Method B - Use a force of 50 N, heating rate of 120°C/h.
Standard test method for rubber property - Durometer hardness - ASTM D 2240
Maximum heating power: ≤4500 W
Heating power: 4Kw
GB/T 1634.2 Plastics - Determination of temperature of deflection under load - Part 2: Plastics and hard rubber (GB/T 1634.2-2019, ISO 75-2:2013, MOD)
Standard test methods for vulcanized rubber and thermoplastic elastomers—Tension - ASTM D 412