2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene: Enhancing Fluorescent Stability in LDPE Films and Optical Brighteners

General Description

2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene has applications in LDPE films and optical brighteners. It enhances the fluorescent stability of LDPE films by improving their light stability and fluorescence intensity. The compound can be incorporated into LDPE films using a multi-layer system, resulting in a significant increase in light stability. In the textile industry, it is used as a fluorescent whitening agent to give fabrics a bright, white appearance. It is also employed in plastics and paper industries to enhance their visual appeal. The compound exhibits low toxicity in oral and inhalation exposure and shows low toxicity to aquatic organisms.

Figure 1. 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene

Applications in LDPE films

2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene is a compound that has shown significant applications in enhancing the fluorescent stability of LDPE films. In a study investigating the photostability of 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene in LDPE films, it was found that the range of 250 to 300 nm irradiation spectra was responsible for light sensitivity, while the range of 300 to 400 nm was responsible for fluorescence. Various methods were employed to improve the fluorescent stability of 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene in LDPE films. Simple lamination with titanium dioxide-containing films did not provide effective protection, as both photostability and fluorescence intensity decreased simultaneously due to 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene migration into the TiO2-containing film. To address this issue, a five-component system was developed to enhance the light stability of the product. In this system, LDPE film was attached to one side of a 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene-containing film using a cross-linked adhesive, while the other side was linked to either another LDPE film or a TiO2-particle-filled LDPE film using the same adhesive. This arrangement resulted in a 15 to 40% drop in initial fluorescence intensity but led to a significant increase in light stability, up to 400% of the original value. Overall, the incorporation of 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene in LDPE films through this multi-layer system demonstrates promising potential for improving fluorescent stability in various applications. ¹

Applications in optical brightener

2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene is a versatile compound widely used in various applications related to optical brighteners. Optical brighteners are chemical additives that enhance the brightness and whiteness of materials, such as textiles, plastics, papers, and detergents, by absorbing ultraviolet light and re-emitting it as blue light. 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene finds extensive use in the textile industry, where it is employed as a fluorescent whitening agent. It imparts a bright, white appearance to fabrics by absorbing UV radiation and converting it into visible blue light, thus masking any yellowish or dull tones. Additionally, 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene's excellent light stability ensures that the fabric maintains its enhanced brightness even after prolonged exposure to sunlight. Furthermore, 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene is utilized in the production of brightening agents for plastics, such as PVC, polystyrene, and polyethylene. The compound effectively improves the optical properties of these materials, enhancing their visual appeal and making them appear more vibrant and attractive. In the paper industry, 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene is employed as a fluorescent whitening agent to improve the brightness and color of papers, making them appear whiter and more visually appealing. Overall, 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene plays a crucial role in the development of optical brighteners, enhancing the visual aesthetics of various materials and products across industries. ²

Toxicity

2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene exhibits low acute toxicity in oral and inhalation exposure. In oral tests with rats, the LD50 of 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene was found to be greater than 10,000 mg/kg bw, with no mortality observed. Inhalation tests on rats resulted in an LC50 greater than 1,820 mg/m3 air. However, there is no available data regarding dermal toxicity. In aquatic environments, the compound demonstrated low toxicity to fish, daphnia, other aquatic invertebrates, algae, and microorganisms, with LC50/EC50 values all exceeding 100 mg/L within various exposure periods. Notably, in the case of microorganisms, 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene's presence even led to an increase in respiration rate. ³

Reference

1. TÚRY G. Enhancement of fluorescent stability of 2,5-bis-2-(5-tert-butyl)-benzoxazolyl-thiophene (BBOT) containing LDPE films. Journal of Photochemistry and Photobiology A-chemistry. 1998. 114(1): 51-58.

2. 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene. National Center for Biotechnology Information (2024). PubChem Compound Summary for CID 292429.

3. Chemical Safety Data Sheet MSDS / SDS: 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene. Chemical Book. 2023. CBnumber: CB3434574.

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