Mahdi Yadollahi Maghsoudlou,Guojun Cao,Zonghua Wang
This article describes the preparation of structural acrylic adhesives (SAA) with low odor and high strength. Isobornyl methacrylate and methacrylic acid were used as the main monomers. Cumene hydroperoxide was used as a radical polymerization initiator. The effects of tougheners, coupling agents, elastomers, monomers, and peroxide on the performance of acrylic adhesives were studied sequentially. The toughness of acrylic structural adhesives was discovered to be enhanced by the addition of carboxyl-terminated butadiene-acrylonitrile liquid rubber (CTBN) to the acrylic matrix. Coupling agents were added to improve SAA’s ability to adhere to steel. The results demonstrated that the SAA performs best when the methacrylic acid’s content is 7 wt%, cumene hydroperoxide’s content is about 1.5 wt%, CTBN’s content is 3 wt%, and the coupling agent’s content is 1 wt%. Adhesive modified using 2-hydroxyethylmethacrylate phosphate and CTBN as the toughener provided excellent adhesion to the steel substrate. Its lap shear strength was found to be above 24 MPa, its T-peel strength was up to 8.29 N/mm, and its impact strength was up to 12 kJ/m2. The resulting SAA is capable of meeting structural adhesive bonding strength criteria for steel-to-steel joints.
In order to remove VOCs in paints and coatings as more as possible, photo-curable waterborne polyurethane acrylates (WPUAs) were synthesized and an easy process to obtain low VOCs and low odor by the devolatilization technology was investigated. It was found that VOCs contents and WPUAs odors were significantly reduced by using the deionized water as the devolatilization aid chemical. With the conditions that the temperature was 75 °C, vacuum degree was 0.085 MPa, and the added deionized water content was 3 wt%, the VOCs content of WPUA was 33.6 mg/g with odor level 2 after devolatilization. Moreover, in the process of devolatilization, the increasing temperature strengthened the mass transfer process, thus the removal efficiency of VOCs was improved. Comparison with the WPUA coatings without devolatilization, the photo-cured films of deodorized WPUA coatings showed good thermal stability and excellent mechanical properties due to most of the solvents and small molecular impurities were removed. The WPUA coatings with low VOCs not only reduced environmental pollution, but also improved their coatings quality. At the same time, the devolatilization technology had the characteristics of simplicity and efficiency. Therefore, it was suitable for industrial production of organic photo-curable coatings in order to protect both environment and people's health as much as possible.
Xanthate, a high-consumption functional surfactant, poses health and environmental risks due to the presence of volatile sulfides and pungent odors. In this study, we designed a novel ether group enhanced xanthate collector, O-(2-( tert -butoxy)ethyl) xanthate (TBOEX), which exhibits low odor and excellent flotation performance. The high matching between the calculated and the experimental infrared spectrum confirms the existence of water-bridged self-assembly behaviour. Odor evaluation results show that TBOEX reduced the content of volatile sulfur organic compounds and volatile hydrocarbons by 54.2% and 88.6%, respectively, compared to isobutyl xanthate (IBX), effectively reducing odor production. Flotation experiments and Zeta potential measurements demonstrate that TBOEX adsorbs densely on the surface of chalcopyrite, while the rich hydroxide on the surface of pyrite hinders the self-assembly of the collector, resulting in good selectivity for chalcopyrite. DFT calculations further reveal that TBOEX can form a stable and tightly arranged adsorption layer bridged by water molecules on the surface of chalcopyrite through two paths, and interact with d orbitals of copper atoms in the form of Cu-S tetrahedra through π* orbitals, finally improving the flotation recovery of chalcopyrite. The discovery of the water-bridge self-assembly mechanism and interfacial adsorption behavior of TBOEX is expected to drive the targeted design of collectors.
危险品化学品经营许可证（带存储）