CN115716929A - Method for thermal-sensitizing radiation crosslinking polyethylene - Google Patents
Method for thermal-sensitizing radiation crosslinking polyethylene Download PDFInfo
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- CN115716929A CN115716929A CN202211466017.7A CN202211466017A CN115716929A CN 115716929 A CN115716929 A CN 115716929A CN 202211466017 A CN202211466017 A CN 202211466017A CN 115716929 A CN115716929 A CN 115716929A
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- polyethylene film
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- polyethylene
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- 239000004698 Polyethylene Substances 0.000 title claims abstract description 48
- -1 polyethylene Polymers 0.000 title claims abstract description 48
- 229920000573 polyethylene Polymers 0.000 title claims abstract description 48
- 230000005855 radiation Effects 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000004132 cross linking Methods 0.000 title abstract description 20
- 238000010438 heat treatment Methods 0.000 claims abstract description 37
- 238000010894 electron beam technology Methods 0.000 claims abstract description 16
- 229920003020 cross-linked polyethylene Polymers 0.000 claims abstract description 15
- 239000004703 cross-linked polyethylene Substances 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 12
- 231100000987 absorbed dose Toxicity 0.000 claims abstract description 3
- 230000001678 irradiating effect Effects 0.000 claims abstract description 3
- 230000001235 sensitizing effect Effects 0.000 claims description 9
- 229920006262 high density polyethylene film Polymers 0.000 claims description 6
- 229920001684 low density polyethylene Polymers 0.000 claims description 4
- 239000004702 low-density polyethylene Substances 0.000 claims description 4
- 230000003213 activating effect Effects 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 6
- 239000002131 composite material Substances 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 5
- 230000015556 catabolic process Effects 0.000 abstract description 3
- 238000006731 degradation reaction Methods 0.000 abstract description 3
- 239000002861 polymer material Substances 0.000 abstract description 2
- 239000000499 gel Substances 0.000 description 6
- 238000012986 modification Methods 0.000 description 6
- 230000004048 modification Effects 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 4
- 238000007385 chemical modification Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 206010070834 Sensitisation Diseases 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 239000012752 auxiliary agent Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000008313 sensitization Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012668 chain scission Methods 0.000 description 1
- 238000010382 chemical cross-linking Methods 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 239000011243 crosslinked material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000000017 hydrogel Substances 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
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Abstract
The invention discloses a method for thermal-sensitizing radiation crosslinking polyethylene, and relates to the technical field of high polymer materials. The method comprises the following steps: the method comprises the following steps of (1) flatly attaching a polyethylene film serving as a base material to a constant-temperature heating plate, heating the polyethylene film to a viscoelastic state through the constant-temperature heating plate, and irradiating the polyethylene film on the constant-temperature heating plate by using an electron beam accelerator to obtain a crosslinked polyethylene film; wherein the radiation absorbed dose is 50-100 KGy. The invention realizes the crosslinking reaction through the radiation of the high-energy electron beam, so as to reduce the occurrence of negative effects such as radiation degradation and the like caused by higher radiation dose, improve the temperature resistance level and the mechanical property of the composite material, and further expand the application field of the composite material.
Description
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a method for thermally sensitizing radiation cross-linked polyethylene.
Background
Polyethylene is widely used in industry, agriculture and daily life due to its good mechanical and chemical resistance, easy processing, non-toxicity and low price, and its consumption is on the rapidly increasing trend. However, the main disadvantage is poor temperature resistance, and the performance of the polyethylene is deteriorated due to the influence of the internal molecular structure and external environment, such as ultraviolet aging and thermal oxidative aging, which limits the use of the polyethylene under severe conditions. Therefore, the modification of polyethylene is always the key for the development and application of polyethylene products. The modification method mainly comprises chemical modification, radiation modification and the like. The chemical modification is mainly to add chemical cross-linking agent and other auxiliary agent into the formula to improve the performance, and because the forming and cross-linking are completed in the same process, the product is gelled too early before being formed, thus affecting the processing and use performance of the product. Compared with chemical modification, the radiation modification is mainly characterized by being carried out at room temperature, being capable of initiating a crosslinking or grafting reaction without adding auxiliary agents such as an initiator and the like, having no pollution and being convenient to process. Wherein the improvement of material properties by radiation crosslinking is an important technique. The polyethylene modified by crosslinking not only can greatly improve the comprehensive performance, but also can obviously improve the temperature resistance grade.
Polyethylene films are typical radiation cross-linked materials, but the absorption dose required to obtain sufficient cross-link density is high, typically in the range of 110 to 300KGy. However, the radiation dose is too large, so that the chain scission degree of the active free radicals is high, and the material is easy to degrade in a large amount, so that the mechanical property of the material is reduced, and the product performance of the final product is influenced, therefore, the control of the radiation dose is an important condition for obtaining the ideal performance of the polyethylene. The addition of a vinyl active monomer with a sensitizing effect in the material is an effective means for reducing the radiation crosslinking absorbed dose, but the introduction of a sensitizer tends to increase the processing cost of the material, and adverse effects are caused on the popularization and application of the material.
Disclosure of Invention
The invention aims to solve the defects in the background technology, and provides a method for cross-linking polyethylene by thermal sensitization and radiation, which has high production efficiency and good physical properties and can be widely applied.
The invention aims to provide a method for thermally sensitizing radiation crosslinked polyethylene, which comprises the following steps:
the method comprises the following steps of (1) flatly attaching a polyethylene film serving as a base material to a constant-temperature heating plate, heating the polyethylene film to a viscoelastic state through the constant-temperature heating plate, and irradiating the polyethylene film on the constant-temperature heating plate by using an electron beam accelerator to obtain a crosslinked polyethylene film; wherein the radiation absorption dose is 50-100 KGy.
Preferably, in the process of irradiation by the electron beam accelerator, the polyethylene film and the constant temperature heating plate are fixed on a beam lower conveying device of the electron accelerator together, after the polyethylene film is heated to a viscoelastic state, the beam lower conveying device of the electron accelerator is started, so that the polyethylene film and the constant temperature heating plate continuously pass through an electron beam irradiation area to be irradiated, and after the polyethylene film and the constant temperature heating plate pass through the irradiation area, the irradiation is finished.
More preferably, the polyethylene film is heated to a temperature of 110 to 130 ℃ in the viscoelastic state.
Preferably, the polyethylene film comprises a low density polyethylene film or a high density polyethylene film, and the thickness of the film is 10-300 um.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a method for thermal-sensitizing radiation crosslinking polyethylene, which realizes crosslinking reaction by high-energy electron beam radiation under the temperature condition close to the melting point of polyethylene, so as to reduce the occurrence of negative effects such as radiation degradation and the like caused by higher radiation dose, improve the temperature resistance level and mechanical property of the polyethylene, and further expand the application field of the polyethylene.
The method provided by the invention has high production efficiency, and the obtained crosslinked polyethylene has good physical properties and can be widely applied.
Detailed Description
In order to make the technical solutions of the present invention better understood and enable those skilled in the art to practice the present invention, the following embodiments are further described, but the present invention is not limited to the following embodiments.
In the research process, the invention discovers that when the high molecular material is irradiated near the melting point, the high molecular chain is basically in a melt state and is easy to move, and the macromolecular free radicals are easier to polymerize to form a cross-linking structure to realize cross-linking. It has also been found that polymers in the molten state also exhibit radiation crosslinking. In practice, the medical hydrogel material is also obtained by radiation crosslinking. It can be concluded from this that the crosslinking reaction can take place by irradiation with high-energy radiation on the polymer in the viscoelastic state, in the molten state, a phenomenon known as "heat-sensitizing radiation crosslinking". The reaction conditions are very favorable for improving the temperature resistance grade and the mechanical property of the polyethylene material.
The electron accelerator model 0.5MEV60mA adopted by the invention is purchased from Wuxi Aibang radiation technology Co.
Example 1
A method of thermally sensitizing radiation crosslinked polyethylene comprising the steps of:
the method comprises the steps of flatly pasting a high-density polyethylene film with the thickness of 300 mu m on a constant-temperature heating plate, fixing the high-density polyethylene film on a beam lower conveying device of an electron accelerator, starting the electron beam accelerator, setting the irradiation absorption dose to be 75KGy until the beam current rises to a set value, simultaneously starting a heating plate power supply, setting the temperature of a heating plate to be 130 ℃, starting the beam lower conveying device of the electron accelerator to enable the film and the heating plate to continuously pass through an electron beam irradiation area to be irradiated when the temperature of the heating plate reaches 130 ℃, and finishing irradiation after the polyethylene film and the heating plate penetrate through the irradiation area to obtain the crosslinked polyethylene. And (3) carrying out gel content test according to GB/T18474, and detecting the mechanical strength and temperature resistance of the composite material by means of an electronic tensile testing machine, a thermal shrinkage performance test and the like. When the irradiation dose is 75KGy, the gel content of the polyethylene film is 97%, the highest high temperature resistant temperature is 180 ℃, the thermal shrinkage rate of the film is as low as 1.5%, and the mechanical strength is reduced by 5.8% compared with that before irradiation.
Example 2
A method of thermally sensitizing radiation crosslinked polyethylene comprising the steps of:
the method comprises the steps of flatly pasting a low-density polyethylene film with the thickness of 150 mu m on a constant-temperature heating plate, fixing the low-density polyethylene film on a beam-down conveying device of an electron accelerator, starting the electron beam accelerator, setting the irradiation absorption dose to be 50KGy until the beam current rises to a set value, simultaneously starting a heating plate power supply, setting the temperature of the heating plate to be 110 ℃, starting the beam-down conveying device of the electron accelerator to enable the film and the heating plate to continuously pass through an electron beam irradiation area to receive irradiation when the temperature of the heating plate reaches 110 ℃, and ending the irradiation after the polyethylene film and the heating plate pass through the irradiation area to obtain the crosslinked polyethylene. And (3) testing the gel content according to GB/T18474, and detecting the mechanical strength and the temperature resistance of the composite material by means of an electronic tensile testing machine, a thermal shrinkage performance test and the like. When the irradiation dose is 50KGy, the gel content of the polyethylene film is 92 percent, the highest high temperature resistant temperature is 176 ℃, the thermal shrinkage rate of the film is as low as 1.2 percent, and the mechanical strength is reduced by 4.8 percent compared with that before irradiation.
Example 3
A method of thermally sensitizing radiation crosslinked polyethylene comprising the steps of:
flatly attaching a high-density polyethylene film with the thickness of 10 mu m on a constant-temperature heating plate, fixing the high-density polyethylene film on a beam-down conveying device of an electron accelerator, starting the electron beam accelerator, setting the irradiation absorption dose to be 100KGy until the beam current rises to a set value, simultaneously starting a heating plate power supply, setting the temperature of the heating plate to be 130 ℃, starting the beam-down conveying device of the electron accelerator when the temperature of the heating plate reaches 130 ℃, enabling the film and the heating plate to continuously pass through an electron beam irradiation area to be irradiated, and finishing irradiation after the polyethylene film and the heating plate pass through the irradiation area to obtain crosslinked polyethylene. And (3) carrying out gel content test according to GB/T18474, and detecting the mechanical strength and temperature resistance of the composite material by means of an electronic tensile testing machine, a thermal shrinkage performance test and the like. When the irradiation dose is 100KGy, the gel content of the polyethylene film is 96.2%, the highest high temperature resistant temperature is 184 ℃, the heat shrinkage rate of the film is as low as 1.8%, and the mechanical strength is reduced by 6.4% compared with that before irradiation.
In summary, the method for cross-linking polyethylene by thermal sensitization and radiation provided by the invention realizes cross-linking reaction by high-energy electron beam radiation under the temperature condition close to the melting point of polyethylene, so as to reduce the occurrence of negative effects such as radiation degradation caused by higher radiation dose, improve the temperature resistance level and mechanical property of the polyethylene, and further expand the application field of the polyethylene.
The present invention describes preferred embodiments and effects thereof. Additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. A method of thermally sensitizing radiation crosslinked polyethylene comprising the steps of:
the method comprises the following steps of (1) flatly attaching a polyethylene film serving as a base material to a constant-temperature heating plate, heating the polyethylene film to a viscoelastic state through the constant-temperature heating plate, and irradiating the polyethylene film on the constant-temperature heating plate by using an electron beam accelerator to obtain a crosslinked polyethylene film; wherein the radiation absorbed dose is 50-100 KGy.
2. The method of claim 1, wherein the irradiation with the electron beam accelerator comprises fixing the polyethylene film together with the constant temperature heating plate on a lower beam transport device of the electron accelerator, heating the polyethylene film to a viscoelastic state, activating the lower beam transport device of the electron accelerator to allow the polyethylene film and the constant temperature heating plate to pass through the electron beam irradiation region continuously to receive irradiation, and ending the irradiation after the polyethylene film and the constant temperature heating plate pass through the irradiation region.
3. The method of thermally sensitizing radiation crosslinked polyethylene of claim 2, wherein said polyethylene film is heated to a temperature of 110 to 130 ℃ in a viscoelastic state.
4. The method of thermally sensitizing radiation crosslinked polyethylene of claim 1, wherein said polyethylene film comprises a low density polyethylene film or a high density polyethylene film, and the thickness of the film is 10 to 300um.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211466017.7A CN115716929A (en) | 2022-11-22 | 2022-11-22 | Method for thermal-sensitizing radiation crosslinking polyethylene |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211466017.7A CN115716929A (en) | 2022-11-22 | 2022-11-22 | Method for thermal-sensitizing radiation crosslinking polyethylene |
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| CN115716929A true CN115716929A (en) | 2023-02-28 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030149125A1 (en) * | 2002-01-04 | 2003-08-07 | Muratoglu Orhun K. | High modulus crosslinked polyethylene with reduced residual free radical concentration prepared below the melt |
| US20040132854A1 (en) * | 2002-04-19 | 2004-07-08 | Du Plessis Tjaart Andries | Radiation treated ethylene polymers and articles made from said polymers |
| CN101716809A (en) * | 2009-11-26 | 2010-06-02 | 上海大学 | Preparation method of electron beam irradiation modified super-high molecular weight polyethylene board |
| US20110244215A1 (en) * | 2009-01-16 | 2011-10-06 | Sartorius Stedim Biotech Gmbh | Electron beam induced modification of membranes by polymers |
| CN108611006A (en) * | 2016-12-19 | 2018-10-02 | 上海海优威新材料股份有限公司 | Caking property protective film of cross-linking radiation and preparation method thereof |
| CN113956528A (en) * | 2021-10-09 | 2022-01-21 | 中国科学院上海应用物理研究所 | High-crosslinking ultrahigh molecular weight polyethylene and preparation method and application thereof |
-
2022
- 2022-11-22 CN CN202211466017.7A patent/CN115716929A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030149125A1 (en) * | 2002-01-04 | 2003-08-07 | Muratoglu Orhun K. | High modulus crosslinked polyethylene with reduced residual free radical concentration prepared below the melt |
| US20040132854A1 (en) * | 2002-04-19 | 2004-07-08 | Du Plessis Tjaart Andries | Radiation treated ethylene polymers and articles made from said polymers |
| US20110244215A1 (en) * | 2009-01-16 | 2011-10-06 | Sartorius Stedim Biotech Gmbh | Electron beam induced modification of membranes by polymers |
| CN101716809A (en) * | 2009-11-26 | 2010-06-02 | 上海大学 | Preparation method of electron beam irradiation modified super-high molecular weight polyethylene board |
| CN108611006A (en) * | 2016-12-19 | 2018-10-02 | 上海海优威新材料股份有限公司 | Caking property protective film of cross-linking radiation and preparation method thereof |
| CN113956528A (en) * | 2021-10-09 | 2022-01-21 | 中国科学院上海应用物理研究所 | High-crosslinking ultrahigh molecular weight polyethylene and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| 高俊娜等: "超高分子量聚乙烯微孔膜在不同温度下辐射交联及其性能", 辐射研究与辐射工艺学报, vol. 39, no. 3, 30 June 2021 (2021-06-30), pages 28 - 34 * |
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