Du Chenglong,Huang Zhibo,Wu Xiaohui,Jing Shuailin,Wang Feifei,Liu Xiao,Shi Yan,Zhang Liqun
The increasing demand for brominated butyl rubber (BIIR) has intensified the use of conventional ZnO/sulfur-based curing systems, raising significant environmental concerns. Herein, we present a sustainable, ZnO- and sulfur-free cross-linking strategy enabled by a primary amine, octadecylamine (ODA), which serves as an efficient cross-linker for BIIR. Upon thermal activation at 160 °C, ODA reacts with the benzylic bromide groups of BIIR via dual nucleophilic substitution, forming stable covalent networks. The cross-link density and resultant mechanical properties exhibit a positive correlation with ODA loading, reaching an optimum at 3 phr. In contrast, octadecyltrimethylammonium bromide (OTAB) and diethylamine hydrochloride—lacking N–H protons—show negligible reactivity, highlighting the essential role of the primary amine functionality in the cross-linking mechanism. This work establishes a quantitative structure–efficiency relationship for amine-based cross-linkers, providing both experimental validation and mechanistic insight for the rational design of environmentally benign vulcanization processes in halogenated elastomers.
Heavy metal cations and anions contaminated groundwater was a big challenge to water resource safety. Herein, a green sulfidated micro zero-valent iron-based hydrogel (SA-S-mZVI) was synthesized using sodium alginate biomass for the simultaneous removal of heavy metal cations (Cu(II), Pb(II), Cd(II)) and anions (Cr(VI)). The sulfur modification and incorporation of sodium alginate hydrogel facilitated the efficient and sustainable removal of both single and multi-heavy metals. The co-existing heavy metal cations benefited the removal of Cr(VI), and heavy metals were mostly transformed into stable precipitates. The presence of organic substance and ions slightly affected the removal of heavy metals. Long-term column experiments (240 days) showed that SA-S-mZVI maintained over 99.9 % removal efficiency for heavy metal cations and anions, without adverse impacts on the groundwater environment. This study provided new insights into the development of eco-friendly, long-lasting zero-valent iron-based hydrogels for in-situ remediation of heavy metals-contaminated groundwater.
Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties, and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system. In this contribution, a novel modified product of isobutylene isoprene rubber (IIR), epoxy-functionalized IIR (EIIR) was successfully prepared by in situ epoxidation technique for the first time, and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride (MAH) without additional additives. The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process. Under optimal condition, the degree of epoxidation of the rubber reached around 99% without side reactions. The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites. More importantly, compared with IIR composites, the air-tightness of the EIIR composites was improved by about 50%, and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times. The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.
危险品化学品经营许可证（带存储）