CN102967620A - Method for evaluating service life of high-molecular material - Google Patents
Method for evaluating service life of high-molecular material Download PDFInfo
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- CN102967620A CN102967620A CN2012105323397A CN201210532339A CN102967620A CN 102967620 A CN102967620 A CN 102967620A CN 2012105323397 A CN2012105323397 A CN 2012105323397A CN 201210532339 A CN201210532339 A CN 201210532339A CN 102967620 A CN102967620 A CN 102967620A
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Abstract
The invention discloses a method for evaluating the service life of a high-molecular material, which comprises the following steps: carrying out a thermal decomposition experiment by selecting lignins of the high-molecular material as experimental materials; carrying out thermogravimetric analysis on the lignins respectively through a dynamics method and an isothermic experimental method; establishing a life equation with the life upper limit of 10% weightlessness of the lignins, and carrying out a comparative experiment on a nitrogen atmosphere and an air atmosphere; and determining the life of the lignins through a thermogravimetric point-slope method. According to the invention, the life, which is determined by the thermogravimetric point-slope method, of the 10% weightless lignins at different atmospheres and different temperatures is very approximate to the life determined by the dynamics method and the life determined by the isothermic experimental method, therefore the thermogravimetric point-slope method can well evaluate the service life of the high-molecular material.
Description
Technical field
The present invention relates to a kind of macromolecular material, particularly a kind of macromolecular material method in serviceable life of evaluating.
Background technology
Macromolecular material is widely used in commercial production, the resident living, such as device components, power lead etc.Because macromolecular material the phenomenons such as aging can occur in use or in the physical environment, will have a strong impact on enterprise safety operation, therefore easy, correctly evaluate macromolecular material serviceable life and seem extremely important in order in time process the material aging situation.
The test method of continuing to use for a long time both at home and abroad is conventional aging process (CA), and its principle is the inverse relation of being in line of logarithm and the absolute temperature of insulation life.
Artificial thermal aging test is the artificial accelerated aging test method of evaluation compound substance heat aging property.The research of thermal aging test method is comparative maturity, but desirable not enough.In recent years, the work of carrying out thermal ageing test research with oxygen adsorption method, differential thermal analysis (DTA), thermogravimetry is paid attention to widely and is developed.
Material at high temperature uses for a long time, performance descends gradually, is because the result of thermal degradation, the chemical reaction such as crosslinked has occured under the effect of light and heat homenergic, so the essence of thermal lifetime is the speed of aging speed, i.e. and the problem of reaction kinetics.The common material life-span at a lower temperature is often very long, but we can extrapolate the thermal lifetime of material in order to assess its term of life fast with the life-span under the uniform temperature.
Summary of the invention
The purpose of this invention is to provide a kind of method of evaluating macromolecular material serviceable life and extrapolate fast the thermal lifetime of material in order to assess its term of life.
Technical scheme of the present invention is: a kind of method of evaluating macromolecular material serviceable life is chosen the lignin macromolecular material as experiment material, carry out the thermal decomposition experiment, by dynamic method and isothermal experiment method lignin is carried out thermogravimetric analysis respectively, set up lignin weightless 10% and be the life-span equation of the life-span upper limit, and carry out the contrast experiment of nitrogen atmosphere and air atmosphere.
Described lignin claims again lignin (Lignin), is the synthetic a kind of natural organic high-molecular material of plant secondary metabolism.The multiple functional group of containing in the lignin structure such as aromatic proton, hydroxyl, carboxyl, methoxyl etc. have many-sided ability when synthetic macromolecular compound, so the structure of lignin makes it become the potential valuable source of a series of organic chemicalss.
Thermogravimetric analysis refers to supplement the mass change of measurement of species under the temperature and a kind of technology of temperature relation with money in program, usually be referred to as again thermogravimetry (TG), the recording curve that records is called thermogravimetric curve (TG curve), and its ordinate is the quality of sample, and horizontal ordinate is temperature or the time of sample.
The energy of activation of asking for the lignin thermal decomposition with Ozawa is E=91.54kJ/mol (in the nitrogen atmosphere) and E=108.67kJ/mol (in the air atmosphere), a=4781.11 (in the nitrogen atmosphere) and a=5675.57 (in the air atmosphere), the isothermal experiment method is asked for b=-7.61581 (in the nitrogen atmosphere) and b=-8.75879 (in the air atmosphere), finally obtains lignin life-span equation.
The life-span equation of described lignin is respectively lgt=4781/T-7.6185 (in the nitrogen atmosphere) and lgt=5675.57/T-8.7588 (in the air atmosphere).
Advantage of the present invention is: the life-span of utilizing lignin that the thermogravimetric point slope method the obtains life-span that weightless 10% life-span and dynamic method are obtained under the different temperatures in different atmosphere and isothermal experiment method to obtain also is to approach very much, so the thermogravimetric point slope method is the method in fine evaluation macromolecular material serviceable life.
Embodiment
With the life-span equation of deriving of the isothermal experiment method in the nitrogen atmosphere:
Selecting lignin is experiment material, purge gas N
2, flow velocity 150mL/min is as experiment condition.Lignin 100 ℃, 110 ℃, 120 ℃, 150 ℃, is located respectively constant temperature 120min for 200 ℃ at 90 ℃.The record experimental data is at table 1.
Table 1N
2Purging the parameter of lignin under different temperatures changes
| T(℃) | T(K) | τ(min) | 1/T(K -1) | lgτ(min) |
| 90 | 363.15 | 1895.8904 | 0.002754 | 3.2778 |
| 100 | 373.15 | 1249.5069 | 0.002680 | 3.0967 |
| 110 | 383.15 | 1204.1641 | 0.002610 | 3.0807 |
| 120 | 393.15 | 757.4903 | 0.002544 | 2.8794 |
| 150 | 423.15 | 233.6026 | 0.002363 | 2.3685 |
| 200 | 473.15 | 4.1324 | 0.002113 | 0.6160 |
According to numerical value, so obtain ultimate life equation: lgt=4050.315/T-7.6185
The isothermal contrast experiment of lignin in air atmosphere:
In order to make experiment condition closer to physical environment, we select lignin as experiment material again, the purge gas air, and flow velocity 150mL/min is as experiment condition.Lignin 100 ℃, 110 ℃, 120 ℃, 150 ℃, is located respectively constant temperature 120min for 200 ℃ at 90 ℃.The record experimental data is listed in table 2.
The parameter of table 2 air purge lignin under different temperatures changes
| T(℃) | T(K) | τ(min) | 1/T(K -1) | lgτ(min) |
| 90 | 363.15 | 1887.3878 | 0.002754 | 3.2759 |
| 100 | 373.15 | 1239.3829 | 0.002680 | 3.0932 |
| 110 | 383.15 | 780.4809 | 0.002610 | 2.8924 |
| 120 | 393.15 | 481.0021 | 0.002544 | 2.6821 |
| 150 | 423.15 | 129.3281 | 0.002363 | 2.1116 |
| 200 | 473.15 | 2.3321 | 0.002113 | 0.3677 |
According to numerical value, so obtain ultimate life equation: lgt=4446.073/T-8.7588
Ask for activation energy by the Ozawa method
As experiment material, carry out respectively 5K/mic with lignin, 10K/min, 15K/min, 20K/min, 30K/min, the experiment of pyrolysis under nitrogen atmosphere, the temperature terminal temperature in the time of delignification weightless 10%, data list 3.
Under pyrolysis experiment, the temperature terminal temperature in the time of delignification weightless 10%, data list 3.
Table 3 nitrogen atmosphere changes lignin Thermal Decomposition Parameters under condition of different temperatures
| T(℃) | T(K) | 1000/T | β | lgβ |
| 202.16 | 475.31 | 2.1039 | 5 | 0.6990 |
| 212.78 | 485.93 | 2.0579 | 10 | 1.0000 |
| 222.61 | 495.76 | 2.0171 | 15 | 1.1761 |
| 227.97 | 501.12 | 1.9955 | 20 | 1.3010 |
| 239.67 | 514.82 | 1.9500 | 30 | 1.4771 |
According to numerical value, final life-span equation is: lgt=4781.11/T-8.01426
Ask for the activation energy that lignin decomposes with the Ozawa method in air atmosphere
As experiment material, carry out respectively 5K/mic with lignin, 10K/min, 15K/min, 20K/min, 30K/min, the experiment of pyrolysis under air atmosphere, the temperature of attaching most importance to of the temperature in the time of delignification weightless 10%, data list 4.
Table 4 air atmosphere changes lignin Thermal Decomposition Parameters under condition of different temperatures
| T(℃) | T(K) | 1000/T | β | lgβ |
| 201.24 | 474.39 | 2.1080 | 5 | 0.6990 |
| 208.30 | 481.45 | 2.0771 | 10 | 1.0000 |
| 222.02 | 495.17 | 2.0195 | 15 | 1.1761 |
| 225.33 | 498.48 | 2.0061 | 20 | 1.3010 |
| 227.10 | 500.25 | 1.9990 | 30 | 1.4771 |
According to numerical value, final life-span equation is: lgt=5675.57/T-9.5675
The present invention by respectively lignin is carried out in the nitrogen atmosphere and air atmosphere in the isothermal experiment of linear temperature increase experiment and different temperatures of different rates, then ask for respectively the life-span equation of lignin with dynamic method and isothermal experiment method, and calculate the life-span of weightlessness 10% under the lignin different temperatures according to the life-span equation.
Experiment shows that Ozawa method and isothermal experiment method are more applicable, the new method that both combine and obtain---the life-span that lignin that the thermogravimetric point slope method the is obtained life-span that weightless 10% life-span and dynamic method are obtained under the different temperatures in different atmosphere and isothermal experiment method are obtained also is to approach very much; So the thermogravimetric point slope method is feasible, further obtain a thereby namely obtain activation energy by the Ozawa method in the dynamic method; Do linear regression by the isothermal experiment method, obtain intercept, thereby obtain b; So the thermogravimetric point slope method that the present invention inquires into asks the life-span equation of lignin can be summarized as following two equations:
(1) in the nitrogen atmosphere, tries to achieve activation energy=91.54kJ/mol with the Ozawa method, try to achieve a=4781.1, ask b=-7.61581 with the isothermal experiment method, thereby obtain life-span equation: lgt=4781/T-7.6185;
(2) in the air atmosphere, try to achieve activation energy=108.67kJ/mol with the Ozawa method, try to achieve a=5675.57, ask b=-8.75879 with the isothermal experiment method, thereby obtain life-span equation: lgt=5675.57/T-8.758.
In conjunction with actual conditions, we can find out the Kissinger method and not be suitable for asking for the activation energy of lignin thermal decomposition in air or nitrogen atmosphere, the Ozawa method is then no matter in air atmosphere or in nitrogen atmosphere, and the activation energy that is used for asking for lignin all has more confidence level.
Claims (2)
1. evaluate the macromolecular material method in serviceable life for one kind, it is characterized in that:
(1) chooses lignin as experiment material, carry out the thermal decomposition experiment;
(2) utilize respectively dynamic method and isothermal experiment method in nitrogen atmosphere and air atmosphere, to compare experiment;
(3) asking for lignin with Ozawa is E=91.54kJ/mol at the energy of activation of nitrogen atmosphere thermal decomposition, activation energy=108.67kJ/mol in air atmosphere;
(4) ask for the b=-7.61581 of lignin thermal decomposition in nitrogen atmosphere with the isothermal test method, b=-8.75879 in air atmosphere;
(5) determine that the life-span equation of lignin in nitrogen atmosphere is that lgt=4781/T-7.6185 and the life-span equation in air atmosphere are lgt=5675.57/T-8.7588.
2. a kind of macromolecular material method in serviceable life of evaluating according to claim 1, it is characterized in that: described lignin, claim again lignin (Lignin), it is the synthetic a kind of natural organic high-molecular material of plant secondary metabolism, the multiple functional group of containing in the lignin structure such as aromatic proton, hydroxyl, carboxyl, methoxyl etc. have many-sided ability when synthetic macromolecular compound, so the structure of lignin makes it become the potential valuable source of a series of organic chemicalss.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105203579A (en) * | 2015-09-14 | 2015-12-30 | 中国环境科学研究院 | Thermal analysis determination method for plant biomass lignin content |
| CN105973745A (en) * | 2016-04-29 | 2016-09-28 | 山东大学 | Experiment and analysis method of insulation life of power supply cable polymer material |
| CN109085115A (en) * | 2018-09-27 | 2018-12-25 | 中际联合（北京）科技股份有限公司 | A method of the assessment brake friction material natural aging service life |
| CN113188942A (en) * | 2021-04-07 | 2021-07-30 | 青岛科技大学 | Activation energy calculation method for thermal cracking process of PVC-containing mixed plastic |
Citations (1)
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| CN102661906A (en) * | 2012-05-31 | 2012-09-12 | 中国西电集团公司 | Test method for quickly evaluating thermal ageing performance of electrical laminated board |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102661906A (en) * | 2012-05-31 | 2012-09-12 | 中国西电集团公司 | Test method for quickly evaluating thermal ageing performance of electrical laminated board |
Non-Patent Citations (1)
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| 魏莉萍等: "热重点斜法估算硫化橡胶的热老化寿命", 《橡胶工业》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105203579A (en) * | 2015-09-14 | 2015-12-30 | 中国环境科学研究院 | Thermal analysis determination method for plant biomass lignin content |
| CN105203579B (en) * | 2015-09-14 | 2018-07-31 | 中国环境科学研究院 | The heat analysis assay method of plant biomass content of lignin |
| CN105973745A (en) * | 2016-04-29 | 2016-09-28 | 山东大学 | Experiment and analysis method of insulation life of power supply cable polymer material |
| CN109085115A (en) * | 2018-09-27 | 2018-12-25 | 中际联合（北京）科技股份有限公司 | A method of the assessment brake friction material natural aging service life |
| CN113188942A (en) * | 2021-04-07 | 2021-07-30 | 青岛科技大学 | Activation energy calculation method for thermal cracking process of PVC-containing mixed plastic |
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Application publication date: 20130313 |