Tea not only has a beloved taste, but also has rich biological activity, so it has become one of the best-selling beverages in the world. In the existing studies on tea, it is found that TPs account for highest proportion, which is the main bioactive ingredient. Generally, green tea polyphenols (GTP S ) are the main research materials, which are high in catechins. GTP S have significant health benefits (Xing et al., 2019) and are considered to be safe by the US Food and Drug Administration (Chang et al., 2019). Since the 1950s, scholars have begun to study the biological activity of TPs and their mechanism of action, and found that TPs are not only beneficial to human health, but also have an impact on food, medical, chemical and other fields.According to the research on the components of TPs (Khan & Mukhtar, 2018;Li et al., 2019), it is found that TPs contain catechins, flavonoids, anthocyanins, phenolic acids and other substances, among which catechins account for the largest proportion, up to 60%-80%. Catechin is divided into epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG; the molecular structure is shown in the Figure 1). The content relationship is EGCG > EGC > ECG > EC, of which EGCG accounts for about 70%. Therefore, EGCG is the main catechin and the research on the biological activity of TPs mainly starts from EGCG.The research conclude that TPs can exert a variety of biological activities such as anti-oxidation, anti-tumor, anti-inflammation,

Two kinds of novel poly(arylene ether nitrile)s (CPDP-DCBN and CHDP-DCBN) containing pendant aliphtatic ring were synthesized by 4,4′-cyclopentane-1,1′-diyldiphenol (CPDP) or 4,4′-cyclohexane-1,1′-diyldiphenol (CHDP) and 2,6-dichlorobenzonitrile (DCBN) in this work. The inherent viscosities of poly(arylene ether nitrile)s (PENs) were in the range of 0.701–0.806 dL g−1. The polymers showed high glass transition temperatures ( T g) of 185.4–196.4°C and weight-loss temperatures ( T5%) of 447.8–454.3°C. The obtained CPDP-DCBN and CHDP-DCBN could be hot pressed into the films, which showed the tensile strengths of 82.6 MPa and 86.8 MPa, respectively. And the storage modulus of CPDP-DCBN and CHDP-DCBN were about 1.0 GPa and 1.5 GPa at 150°C, respectively. Additionally, the PENs could be dissolved in many solutions at room temperature, such as NMP and concentrated H2SO4, indicating that they had good solubility; they can be processed by the solution method. Meanwhile, the optical transmittance of CPDP-DCBN was 78.1% at 450 nm; it has potential to be applied to the heat-resistant optical film.