Abstract
Rubber as a material of choice is used in an increasingly higher number of applications. With new applications it is anticipated that the rubber industry will continue to innovate. In the past twenty years, natural rubber and synthetic polymers experienced an extensive growth.
Consumption of natural rubber grew by 145%, from 5.1 million metric tons (MMT) used in 1990, to 12.7 MMT used in 2020. By comparison, synthetic rubber usage grew by approximately 48%, from 9.6 MMT in 1990 to 14.2 MMT in 2020. [1] With an increased number of rubber applications, there also is a need for new materials or sometimes blends of existing materials combined in such ways that they exhibit new properties.
The goal of this research project was to propose mechanisms of crosslinking for new binary polymer blends designed for rubber applications. The blends are comprising of either a nonpolar polymer or a polar polymer and cyclic tetrasulfide (CTS), a new development from the class of polysulfides. The blends comprised of a non-polar polymer and CTS, also contain a dual cure system. Most of the current rubber compounds contain a single cure system: i.e. sulfur cure– in most rubber compounds or organic peroxide cure – for a lower number of applications. The newly developed blend system was tested in detail to prove that it allows the combination of both curing system without deactivating the curatives. For the polar polymer and CTS blends, a segregation based on the type of cure is not possible; the preferred cure system is sulfur.
The new material used in all the blends studied was a cyclic tetrasulfide (CTS). For the binary non-polar polymer and CTS blends, EPDM or EPM were used and for the polar polymer and CTS blends, NBR or HNBR were used. The CTS is undergoing a ring opening reaction during curing. The resulting fragments are participating in the cure process of the other polymer included in the blend or recombine, which leads to an in-situ polymer formation. In-depth analyses were conducted to explain the chemical process the CTS is subjected to during
crosslinking process.
Consumption of natural rubber grew by 145%, from 5.1 million metric tons (MMT) used in 1990, to 12.7 MMT used in 2020. By comparison, synthetic rubber usage grew by approximately 48%, from 9.6 MMT in 1990 to 14.2 MMT in 2020. [1] With an increased number of rubber applications, there also is a need for new materials or sometimes blends of existing materials combined in such ways that they exhibit new properties.
The goal of this research project was to propose mechanisms of crosslinking for new binary polymer blends designed for rubber applications. The blends are comprising of either a nonpolar polymer or a polar polymer and cyclic tetrasulfide (CTS), a new development from the class of polysulfides. The blends comprised of a non-polar polymer and CTS, also contain a dual cure system. Most of the current rubber compounds contain a single cure system: i.e. sulfur cure– in most rubber compounds or organic peroxide cure – for a lower number of applications. The newly developed blend system was tested in detail to prove that it allows the combination of both curing system without deactivating the curatives. For the polar polymer and CTS blends, a segregation based on the type of cure is not possible; the preferred cure system is sulfur.
The new material used in all the blends studied was a cyclic tetrasulfide (CTS). For the binary non-polar polymer and CTS blends, EPDM or EPM were used and for the polar polymer and CTS blends, NBR or HNBR were used. The CTS is undergoing a ring opening reaction during curing. The resulting fragments are participating in the cure process of the other polymer included in the blend or recombine, which leads to an in-situ polymer formation. In-depth analyses were conducted to explain the chemical process the CTS is subjected to during
crosslinking process.
| Original language | English |
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| Qualification | Doctor of Philosophy |
| Awarding Institution |
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| Supervisors/Advisors |
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| Award date | 17 Dec 2021 |
| Place of Publication | Enschede |
| Publisher | |
| Print ISBNs | 978-90-365-5315-5 |
| DOIs | |
| Publication status | Published - 17 Dec 2021 |