Lenzi Luca, Mas-Giner Itziar, Degli Esposti Micaela, Morselli Davide, Hernández Santana Marianella, Fabbri Paola
Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), Universitá di Bologna, Via Terracini 28, 40131 Bologna, Italy.
National Interuniversity Consortium of Materials Science and Technology (INSTM), 50121 Firenze, Italy.
ACS Polym Au. 2025 Apr 24;5(3):298-310. doi: 10.1021/acspolymersau.5c00009. eCollection 2025 Jun 11.
Plasticizers are essential for improving the processability and flexibility of rubber compounds by reducing viscosity, aiding filler dispersion, and softening the rubber matrix. Traditionally, petroleum-based phthalate esters like dioctyl phthalate (DOP) and dibutyl phthalate (DBP) have been widely used for these purposes. However, these plasticizers pose significant challenges, including migration from the rubber over time, which can lower performance and raise environmental and health concerns. This study investigates the competing effects of plasticization and miscibility on the structure and dynamics of natural rubber (NR) and epoxidized natural rubber (ENR) when plasticized with glycerol trilevulinate (GT), a biobased plasticizer, and tris-(2-ethylhexyl) trimellitate (TOTM), a petroleum-derived plasticizer. Results show that GT accelerates vulcanization and reduces reversion risks, promoting faster curing and greater flexibility in the rubber network. In contrast, TOTM delays vulcanization and increases reversion, while forming a more rigid cross-linked network. Structurally, GT promotes longer sulfur bridges and strain-induced crystallization in NR, while TOTM favors the formation of shorter sulfur bonds and a more homogeneous network structure. In terms of miscibility, GT is fully miscible with ENR, improving segmental mobility, but shows partial miscibility in NR, restricting chain dynamics as evidenced by Broadband Dielectric Spectroscopy. These findings highlight GT as a potential sustainable alternative to petroleum-derived commercial plasticizers, offering promising advantages for high-performance, biobased rubber applications.
增塑剂对于通过降低粘度、促进填料分散和软化橡胶基体来提高橡胶混合物的加工性能和柔韧性至关重要。传统上，基于石油的邻苯二甲酸酯，如邻苯二甲酸二辛酯（DOP）和邻苯二甲酸二丁酯（DBP），已被广泛用于这些目的。然而，这些增塑剂带来了重大挑战，包括随着时间推移从橡胶中迁移，这可能会降低性能并引发环境和健康问题。本研究调查了用生物基增塑剂三乙酰丙酮甘油酯（GT）和石油衍生增塑剂偏苯三酸三（2-乙基己基）酯（TOTM）对天然橡胶（NR）和环氧化天然橡胶（ENR）进行增塑时，增塑和混溶性对其结构和动力学的竞争影响。结果表明，GT加速硫化并降低返原风险，促进橡胶网络更快硫化和更大的柔韧性。相比之下，TOTM延迟硫化并增加返原，同时形成更刚性的交联网络。在结构上，GT促进NR中更长的硫桥和应变诱导结晶，而TOTM有利于形成更短的硫键和更均匀的网络结构。在混溶性方面，GT与ENR完全混溶，改善了链段流动性，但在NR中表现出部分混溶，如宽带介电谱所示，限制了链动力学。这些发现突出了GT作为石油衍生商业增塑剂潜在的可持续替代品，为高性能生物基橡胶应用提供了有前景的优势。
