Biodegradable Microcapsules of Poly(Butylene Adipate-co-Terephthalate) (PBAT) as Isocyanate Carriers and the Effect of the Process Parameters

Poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable flexible, and tough polymer is herein used, for the first time, to encapsulate and protect isocyanate derivatives. Isocyanates are essential building blocks widely employed in the chemical industry for the production of high-performing materials. Microencapsulation of isocyanates eliminates the risks associated with their direct handling and protects them from moisture. In light of this, and having in mind eco-innovative products and sustainability, we present a straightforward process to encapsulate isophorone diisocyanate (IPDI) using this biodegradable polymer. Spherical and core-shell microcapsules (MCs) were produced by an emulsion system combined with the solvent evaporation method. The MCs present a regular surface, without holes or cracks, with a thin shell and high isocyanate loadings, up to 79 wt%. Additionally, the MCs showed very good isocyanate protection if not dispersed in organic or aqueous solutions. Effects of various process parameters were systematically studied, showing that a higher stirring speed (1000 rpm) and emulsifier amount (2.5 g), as well as a smaller PBAT amount (1.60 g), lead to smaller MCs and narrower size distribution.

Preparation of Superhydrophilic Adsorbents with 3DOM Structure by Water-Soluble Colloidal Crystal Templates for Boron Removal from Natural Seawater

Three-dimensionally ordered macroporous cross-linked poly(glycidyl methacrylate) (3DOM) was constructed by water-soluble colloidal crystal templates and further functionalized with N-methyl-d-glucamine (NMDG) to prepare superhydrophilic adsorbents for boron removal from natural seawater. 3DOM adsorbents possess features of interconnected macropore structure, ultrathin pore wall, and superhydrophilicity, making efficient adsorption possible. The effect of cross-linking degree on the adsorption capacity toward boron was investigated. The NMDG-modified 3DOM adsorbent with rich vicinal diol functional groups showed superhydrophilicity and outstanding performance of adsorption. Significantly, its adsorption effect in boron removal from natural seawater indicated that the concentration of boron in natural seawater could decline to 0.16 from 4.24 mg·L^-1 when the adsorbent dosage was 1 g·L^-1, whereas the boron rejection reached 96.2%. After 10 regeneration-adsorption cycles, the adsorption capacity of 3DOM adsorbent remained over 85% of the initial value and the ordered structure was hardly changed. Additionally, 3DOM adsorbent could be directly and quickly separated from the seawater by a filter mesh of 16 mesh number. Research shows that the 3DOM adsorbent exhibits an adsorption performance for practical applications in boron removal from natural seawater.