Triazine-based Organic Framework Research Articles

The preparation of layered double hydroxide wrapped with triazine-based organic framework to enhance the flame retardancy for polypropylene

Layered double hydroxide (LDH) can be used as a flame retardant (FR) for polypropylene (PP) because of its excellent flame retardancy and smoke-suppression effects. However, the agglomeration of LDH seriously affects its dispersity in the PP matrix, thus limiting its application as a FR polymer. This study aimed to enhance the dispersion of LDH in the PP matrix for improving its flame retardancy performance. Herein, a reactive triazine-based organic framework (TOF) was designed and formed by the in situ polymerisation of cyanuric chloride and melamine, and then the LDH surface was covered with TOF to obtain a novel core–shell FR (LDH@TOF), with TOF as the ‘shell’ and LDH as the ‘core’. Subsequently, LDH@TOF was melted into the PP matrix as nanofillers to prepare PP and LDH@TOF composites (PP/LDH@TOF). As expected, the PP/LDH@TOF composites exhibited superior flame-retarding performance (limiting oxygen index of 29.2% and UL-94 V-0 rating) and favourable smoke-suppression performance at 20 wt% of LDH@TOF loading. Moreover, the peak heat release rate, total heat release and total smoke production of PP/LDH@TOF composites decreased by 29.9%, 12.1% and 12.4%, respectively, compared with those of PP and LDH composites. The outstanding flame retardancy properties of the PP/LDH@TOF composites were attributed to the better dispersibility of LDH@TOF in the PP matrix, the synergy of the physical barrier effect of nanosheets and the dense carbonisation acceleration of LDH@TOF. The findings of this study provide a highly efficient approach for functionalising LDH for expanding its application value of PP composites.

A covalent triazine-based framework containing hydrogen-bonding for highly drug loading and pH-responsive release

A porous covalent triazine-based organic framework (CTF) containing amide hydrogen-bonding was synthesized using Pigment Orange 71 under Lewis acidic (ZnCl2) conditions at 400 °C. The novel CTF material shows excellent chemical and thermal stability with 10% weight loss temperature up to 465 °C and owns a high surface area (960 m2 g−1) and a total pore volume of 0.48 cm3 g−1. The pore size distribution calculated by the non-local density functional theory shows the single micropores center at about 1.5 nm. The CTF particles have an average size of 374 nm and display excellent size-selective adsorption performance, high anticancer drug Irinotecan (CPT-11) loading (27.9 wt%) capacity and outstanding pH-responsive release.