Rubber Chemistry and Technology最新文献

Styrene–butadiene–styrene (SBS) rubbers are one of the most frequently used thermoplastic elastomers globally. The upper operating temperature of SBS is limited by the glass transition temperature (T_g) of poly(styrene) (PS), circa 100 °C. This study demonstrates a noteworthy enhancement in the properties of SBSs by introducing a diblock copolymer consisting of styrene and α-methylene-γ-butyrolactone (α-MBL). Polymers derived from α-MBL exhibit exceptional thermal stability, attributable to a T_g of 195 °C. Notably, α-MBL, also recognized as Tulipalin A, is a biorenewable compound naturally found in tulips. This investigation encompasses both crosslinked and noncrosslinked blends of poly(styrene)-block-poly(α-methylene-γ-butyrolactone) diblock copolymer (PS-b-PMBL) and poly(styrene)-block-poly(butadiene)-block-poly(styrene) triblock copolymer, within the 0–20 wt% PS-b-PMBL range. Thorough examination using thermal analysis and linear shear rheology reveals that all blends surpass the properties of their pure SBS counterparts. Specifically, blending at 200 °C induces crosslinking between the polymers, yielding heightened Young’s modulus and complex viscosity, thereby resulting in a robust and rigid material compared with noncrosslinked blends. For noncrosslinked blends, an increase in strength is observed while maintaining commendable rubbery properties. Notably, the noncrosslinked blends permit the recycling of components (SBS and PS-b-PMBL) through the redissolving of rubber in tetrahydrofuran. These findings present a promising avenue for the enhancement of rubbers through the incorporation of biorenewable compounds.

The recycling of waste rubber is very important for environmental protection, but the compatibility problem restricts the recycling and application of waste rubber powder (WRP). Devulcanization of WRP has been proven to be an effective method to improve the solubilization effect. The use of environmentally friendly nontoxic solvents can not only improve the devulcanization effect but also avoid secondary pollution. Thus, in this article, an environmentally friendly deep eutectic solvent (DES) is first prepared and then applied to the devulcanization treatment of WRP. The results show that the prepared DES has a positive devulcanization effect, and the devulcanization rate can reach 50%. The devulcanization mechanism can be divided into two aspects: (1) adsorption and removal of sulfur-containing low-molecular compounds and (2) destruction of the crosslinking structure and improvement of fluidity. Observation of the microstructure showed that the rougher the surface of the desulfurized rubber powder, the more conducive to the crosslinking reaction with the matrix material to form a uniform whole. The devulcanization mechanism of DES is divided into destroying the sulfur-containing cross-linked structure and adsorbing the sulfur-containing low-molecular compounds. The surface of WRP after DES treatment is rougher and more porous, which is beneficial to the crosslinking reaction with the matrix material. Finally, the optimum process conditions for the de-crosslinking effect are determined by orthogonal test as follows: liquid-solid ratio 15∶1, temperature 120°C, time 0.5 h.

Rubbers and elastomers have a rich history that spans many eras of human civilization dating back to 1600 AD. Upon their introduction into Europe, they became common materials in shoes and fabrics. With the invention of vulcanization by Charles Goodyear in 1839, rubbers became widely used in many new applications, ranging from tires to industrial machine parts. Today, rubbers and elastomers are essential in the development of innovative, emerging technologies. This review exemplifies how rubbers and elastomers have been used to advance the emerging fields of soft robotics through soft grippers and dielectric elastomer actuators, stretchable and wearable devices through conductive elastomers and smart elastomers used in thermal camouflage and sensors, biomedical applications through tissue scaffolding and stretch-triggered drug delivery, and energy harvesting through piezoelectric elastomers and wave harvesting triboelectric nanogenerators. This review also briefly summarizes other developments in these fields as well as glimpses into other emerging fields that are advancing through the incorporation of rubbers and elastomers.