Eugenol-Based Siloxane Acrylates for Ultraviolet-Curable Coatings and 3D Printing

To explore more sustainable, safer UV-curable acrylates, a series of bio-based acrylates (SIEEA, SIPEEA, and SIDPEEA) are synthesized from eugenol and siloxanes under mild conditions without any solvent. The molecular structures of the acrylates are characterized, and the acrylates exhibit much lower viscosities than a commercial bisphenol A glycol dimethacrylate (BisGMA) does. The synthesized acrylates can be well cured under UV radiation to form thin films and thick 3D objects. The cured acrylates display significantly improved thermal properties and hydrophobicity and a decreased dielectric constant as low as 3.0 (1 kHz) due to the siloxane backbones. Moreover, they are low in toxicity with the cytotoxicity value above 80%, which is far lower than that of BisGMAs. More interestingly, SIEEA is used as a UV-curable ink and successfully shaped into objects such as chess pieces and a dental model with a high resolution by 3D printing. To summarize, these eugenol-based siloxane acrylates can be readily synthesized, showing a good promise for UV-curable coatings and 3D printing with high thermal stability, low dielectric constant, and low toxicity

Synthesis of Poly(butylene adipate terephthalate)-<i>co</i>-poly(glycolic acid) with Enhanced Degradability in Water

As one of the most promising biodegradable polymers, poly(butylene adipate-co-terephthalate) (PBAT) has attracted immense attention in packaging and mulching film applications. However, their slow degradation performance in aqueous environments remains a great challenge. In this work, we focused on tailoring the chain structure of PBAT by introducing poly(glycolic acid) (PGA) into the copolyester backbone. The PBAT-co-PGA copolyesters with molar percentages of butylene terephthalate of 36.2–50.3 mol % and GA of 8.0–20.2 mol % and number-average sequence lengths of poly(butylene terephthalate) of 1.55–1.97 and PGA of 1.06–1.11 were synthesized using a melt copolycondensation. The number-average sequence length of the PBAT-co-PGAs can be tailored while maintaining the same monomer composition. The PBAT-co-PGAs exhibit higher Young’s modulus (88 MPa) and tensile strength (35 MPa) owing to their better crystallization ability compared with PBAT at the same terephthalic acid fraction. The incorporation of more terephthalic acid and glycolic acid results in an increase of glass transition temperature and the formation of a more rigid chain structure, which is beneficial to improving the water vapor barrier properties of the copolyesters. Importantly, the PBAT-co-PGA copolyesters show enhanced degradation properties in water environments without sacrificing their aging resistance. The synthetic strategy proposed here endows the PBAT-co-PGA copolyesters with a broad chain structure tailoring window, which renders them to exhibit excellent mechanical properties, water barrier, aging resistance, and, most importantly, accelerated hydrolysis performances in aqueous environments