阅读说明：本技术 一种测定含填料聚合物玻璃化转变温度的方法 (Method for measuring glass transition temperature of polymer containing filler ) 是由 秦元斌 解德刚 单智伟 付琴琴 于 2020-11-19 设计创作，主要内容包括：本发明公开了一种测定含填料聚合物玻璃化转变温度的方法,利用纳米力学测试仪的动态力学分析功能,结合加热台,对含填料聚合物的玻璃化转变温度进行测量,可以获得平滑的存储模量-温度曲线,损失模量-温度曲线以及损失模量与存储模量的比值-温度曲线,进而根据玻璃化转变温度的定义,获得准确的玻璃化转变温度。该方法在聚合物材料应用、玻璃化转变温度测量等领域具有良好的应用前景。(The invention discloses a method for measuring the glass transition temperature of a polymer containing a filler, which utilizes the dynamic mechanical analysis function of a nanometer mechanical tester and combines a heating table to measure the glass transition temperature of the polymer containing the filler, so that a smooth storage modulus-temperature curve, a loss modulus-temperature curve and a ratio of the loss modulus to the storage modulus-temperature curve can be obtained, and the accurate glass transition temperature can be obtained according to the definition of the glass transition temperature. The method has good application prospect in the fields of polymer material application, glass transition temperature measurement and the like.)

1. A method for determining the glass transition temperature of a polymer containing a filler, comprising the steps of;

the method comprises the following steps:

processing a column with a micro-nano scale on the surface of a polymer sample containing fillers by adopting a focused ion beam, wherein the diameter of the column is determined according to requirements, and the whole column contains as much fillers as possible;

step two:

fixing a sample on a heating table of a nano mechanical tester, setting a quasi-static loading function, and pre-compressing the top of the cylinder by adopting a flat pressure head to obtain the top of the cylinder which is as flat as possible;

step three:

setting a dynamic loading function, and carrying out dynamic mechanical test on the cylinder under the condition that the cylinder only generates elastic deformation to obtain the storage modulus, loss modulus and Tan-Delta of the polymer cylinder containing the filler;

step four:

changing the temperature, and continuously carrying out dynamic mechanical test on the same cylinder after the temperature is stable to finally obtain the storage modulus, loss modulus and Tan-Delta of the high polymer cylinder containing the filler at different temperatures and different frequencies;

step five:

and (3) drawing the storage modulus, loss modulus and Tan-Delta variation curve with temperature of the high polymer cylinder containing the filler, and determining the glass transition temperature according to the definition of the glass transition temperature.

2. The method of claim 1, wherein the length to diameter ratio of the cylinder in step one is between 3:1 and 2: 1.

3. A method for determining the glass transition temperature of a polymer containing fillers according to claim 1, characterized in that in step three the maximum load is set so that the cylinder is only elastically deformed, the amplitude of the dynamic load is set so that the amplitude of the displacement is between 1 and 4nm, and the frequency is set according to the requirements, typically 1 Hz.

4. The method for determining the glass transition temperature of a polymer containing a filler according to claim 1, wherein the quasi-static loading function in the second step is specifically 5s loading, 2s holding, 5s unloading, and the maximum load is 10 mN.

Technical Field

The invention relates to the technical field of glass transition temperature evaluation, in particular to a method for measuring the glass transition temperature of a polymer containing a filler.

Background

Glass transition is a property inherent in an amorphous high molecular polymer material, and the glass transition temperature (T)_g) The temperature is one of the characteristic temperatures of high polymer materials, directly influences the service performance and the process performance of the materials, and determines the service temperature of the materials, so that the temperature is an important content of high polymer physical research for a long time. In-situ glassDuring glass transition, many physical properties, especially mechanical properties, change sharply, and the polymer changes from a rigid glassy state to a soft rubbery state. In principle, all physical properties which change abruptly or discontinuously during the glass transition, such as modulus, specific heat, coefficient of thermal expansion, refractive index, thermal conductivity, dielectric constant, dielectric loss, mechanical loss, nuclear magnetic resonance absorption, etc., can be used for measuring the glass transition temperature. Therefore, there are many methods for measuring the glass transition temperature, such as dilatometry, refractive index, thermomechanical method (temperature-deformation), differential thermal analysis, nuclear magnetic resonance, and Dynamic Mechanical Analysis (DMA). Among them, the dynamic mechanical analysis method has excellent reliability and repeatability, and thus is widely used in the measurement of glass transition temperature.

With the rapid development of science and technology, functional instruments are increasingly miniaturized, and the application of micro-nano scale polymer materials is more and more extensive. Researches show that the properties of the micro-nano scale material are probably different from those of a block material, and the glass transition temperature of the micro-nano scale polymer material needs to be directly measured. For even micro-nano scale polymer materials, reliable and repeatable glass transition temperature can be obtained by utilizing a dynamic mechanical analysis method of a nano mechanical tester. Usually, the frequency sweep indentation test is carried out at different positions of a sample under different temperatures and within a certain frequency range, and the storage modulus, loss modulus and Tan-Delta of the high polymer material under different temperatures and different frequencies are obtained. The glass transition temperature can be obtained by storing the change relation of the modulus, the loss modulus and the Tan-Delta with the temperature. However, for the micro-nano scale polymer material containing the filler, especially for the micro-nano scale polymer material containing the filler, the size of the filler is not uniform, and when the size of the filler is not uniform, the storage modulus and the loss modulus measured at different positions of a sample, even the Tan-Delta, are greatly different, the storage modulus, the loss modulus and the change curve of the Tan-Delta along with the temperature obtained by the method greatly fluctuate, and the accurate glass transition temperature is difficult to obtain or even cannot be obtained.

Disclosure of Invention

In order to overcome the above-mentioned disadvantages of the prior art, it is an object of the present invention to provide a method for determining the glass transition temperature of a polymer containing a filler, which allows an accurate and stable glass transition temperature to be obtained according to the definition of the glass transition temperature.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for determining the glass transition temperature of a polymer containing a filler, comprising the steps of;

the method comprises the following steps:

processing a column with a micro-nano scale on the surface of a polymer sample containing fillers by adopting a focused ion beam, wherein the diameter of the column is determined according to requirements, and the whole column contains as much fillers as possible;

step two:

fixing a sample on a heating table of a nano mechanical tester, setting a quasi-static loading function (the loading is as large as possible on the premise of not damaging the whole cylinder), and pre-compressing the top of the cylinder by adopting a flat pressure head to obtain the top of the cylinder which is as flat as possible;

step three:

setting a dynamic loading function, and carrying out dynamic mechanical test on the cylinder under the condition that the cylinder only generates elastic deformation to obtain the storage modulus, loss modulus and Tan-Delta of the polymer cylinder containing the filler;

step four:

changing the temperature (the temperature change amplitude is determined according to the precision requirement, the smaller the change amplitude is, the higher the measurement precision is, and the heating rate is not limited), after the temperature is stable, continuously carrying out dynamic mechanical test on the same cylinder, and finally obtaining the storage modulus, the loss modulus and Tan-Delta of the high polymer cylinder containing the filler at different temperatures and different frequencies;

step five:

and (3) drawing the storage modulus, loss modulus and Tan-Delta variation curve with temperature of the high polymer cylinder containing the filler, and determining the glass transition temperature according to the definition of the glass transition temperature.

The length-diameter ratio of the cylinder in the first step is between 3:1 and 2: 1.

And thirdly, setting the maximum load to enable the cylinder to only generate elastic deformation, setting the dynamic load amplitude to enable the displacement amplitude to be 1-4nm, and setting the frequency according to the requirement, wherein the frequency is generally 1 Hz.

And in the second step, the quasi-static loading function is specifically 5s loading, 2s load retention and 5s unloading, and the maximum load is 10 mN.

The invention has the beneficial effects that:

the invention can obtain smoother storage modulus, loss modulus and Tan-Delta variation curve with temperature of the polymer containing the filler, and further can obtain more accurate and stable glass transition temperature. The larger the size difference of the filler is, the more uneven the distribution is, and the more obvious the effect of the invention is.

The invention enables the test result to reflect the average performance of the sample, and has more guiding significance for the practical application of the polymer containing the filler.

The invention relies on the existing nanometer mechanics tester and the heating device attached to the tester, and in principle, no additional equipment is required to be built.

The invention can finish all tests on the same micro-nano cylinder without frequently replacing the test position in the test process.

Drawings

Fig. 1 uses a focused ion beam machined micro-cylinder.

FIGS. 2(a) - (c) are graphs of storage modulus, loss modulus and Tan-Delta versus temperature, respectively, for underfill (epoxy with silica filler) tested according to the present invention at a test frequency of 1 Hz; (d) - (f) are respectively the storage modulus, loss modulus and Tan-Delta variation curve with temperature measured by the existing method, and the test frequency is 1 Hz.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The first embodiment is as follows: glass transition temperature test pieces of micrometer-scale underfill (epoxy resin with silica filler) samples:

underfill adhesive (epoxy resin with silica filler)

The test procedure was as follows:

a focused ion beam (model FEI Helios NanoLab 600) was used to machine a cylinder about 10 μm in diameter and about 30 μm in length on the surface of the underfill sample, as shown in FIG. 1. FIG. 1 is a scanning electron micrograph of a micron cylinder processed with focused ion beams showing that the underfill contains silica particles of varying sizes and non-uniform distribution.

Fixing the processed underfill sample on a heating table of a nano mechanical tester, setting a quasi-static loading function (5s loading, 2s load retention, 5s unloading, maximum load of 10mN), and pre-compressing the top of the micro-column by adopting a flat pressure head at room temperature to obtain the top of the round column which is as flat as possible.

Setting a dynamic loading function (the maximum quasi-static load is 8mN, the dynamic load amplitude is 120 muN, and the frequency is 1Hz), setting the temperature of the heating table to be 50 ℃, and after the temperature of the heating table is stable, carrying out dynamic mechanical test on the micron column by using a flat pressure head to obtain the storage modulus, the loss modulus and the Tan-Delta of the filler-containing polymer column.

And raising the temperature by using a heating table, and continuously performing dynamic mechanical test on the same micron column after the temperature is stable to finally obtain the storage modulus, loss modulus and Tan-Delta of the high polymer column containing the filler at different temperatures.

The storage modulus, loss modulus and Tan-Delta of the underfill microposts were plotted against temperature, as shown in FIGS. 2(a), (b) and (c). The glass transition temperature is determined according to the definition of the glass transition temperature. There are different ways of defining the glass transition temperature, and if the temperature defining the starting point of the sharp decrease in storage modulus is the glass transition temperature, T_gAbout 119 ℃; t if the temperature corresponding to the peak defining the loss modulus is the glass transition temperature_gAbout 136 ℃; if the temperature corresponding to the peak value of Tan-Delta is defined as the glass transition temperature, T_gAbout 142 c.

FIGS. 2(d) - (f) are the storage modulus, loss modulus and Tan-Delta variation curves with temperature measured by the prior art method, respectively, and the test frequency is 1Hz, compared with (a) - (c), it is obvious that the results measured by the prior art method fluctuate greatly.

In summary, the present invention addresses such a situation: when the glass transition temperature of the micro-nano scale polymer material containing the filler (especially when the size of the filler is different and the distribution is not uniform) is measured, the storage modulus and the loss modulus measured at different positions of a sample even the Tan-Delta have large difference, the obtained storage modulus, the loss modulus and the change curve of the Tan-Delta along with the temperature have large fluctuation, and the accurate glass transition temperature is difficult to obtain or even cannot be obtained. The invention can obtain the storage modulus, loss modulus and Tan-Delta variation curve with temperature of the smooth polymer containing the filler, and further can obtain more accurate and stable glass transition temperature. The larger the size difference of the filler is, the more uneven the distribution is, and the more obvious the effect of the invention is. The invention has important significance for the application and development of high polymer materials and the measurement of glass transition temperature.