Graphene oxide (GO) with a two-dimensional lamellar structure and single-atom thickness has exhibited advantages in water purification by stacking to a continuous membrane. However, a proper method to further increase the separation property of the GO membrane is still urgently needed. Besides, damage to the membrane during the fullscale application processes and the resulted consequential loss are prevalent problems need to be solved. Here, a hierarchically assembled GO composite membrane was developed that can achieve high-efficiency water purification performance and self-healing property via the synergistic effect of the metal− organic framework (MOF) and the coated hydrophilic layer of chitosan. The intercalated MOF effectively expanded the channel space of GO and endowed the channels with molecular-sieving property. Meanwhile, the coated chitosan layer can selectively adsorb water and achieve self-healing through the cross-linking reaction. The prepared GO composite membrane shows largely improved water flux (14.62 L m −2 h −1 bar −1 ), increased 344% than the water flux of the GO membrane, high rejection ratio (>99% for dyes), and good antifouling performance. In addition, the damaged GO composite membrane can recover its water flux (95%) and rejection ratio (96%) through a facile self-healing process.

A titanium dioxide modified expendable graphite (EGT) was prepared and characterized. The synergistic effect between EGT and ammonium polyphosphate (APP) on the combustion characteristics and thermal stability of rigid polyurethane foam (RPUF) were investigated through limiting oxygen index (LOI), vertical‐combustion, microscale combustion calorimeter tests, and thermogravimetric/differential thermal gravimetric (TG/DTG) analysis. Results showed that EGT modified RPUF presented better thermal stability and flame retardancy than the normal expandable graphite (EG) modified RPUF. Addition of EGT improved the LOI value of 80RPUF/20EGT from 19.0% to 26.9%. Furthermore, the combination of EGT and APP caused the 80RPUF/10APP/10EGT to exhibit a LOI value of 27.8%, a vertical burning level of V‐0 and a total heat release of 16.5 kJ g−1. The research gave a body of evidence for synergistic performance between EGT and APP, and the effect of condensed phase mechanism was believed to be the main reason for such synergistic effect. POLYM. ENG. SCI., 58:2008–2018, 2018. © 2018 Society of Plastics Engineers

Metal–organic frameworks (MOFs) exhibit highly designable properties and have been used in wide applications. To further improve their performance, the modification of MOFs is an effective method. However, the modification process is usually complicated. Besides, the sustainable use of MOFs is difficult to achieve due to the complicated recycling treatment. Herein, we designed a polyethyleneimine (PEI)-modified NH 2 -MIL-101(Al) composite (PEI@NH 2 -MIL-101(Al)). This composite showed excellent dye removal performance of methyl orange (MO, 89.4%) and Direct Red 80 (DR80, 99.8%). Remarkably, the dye removal application of PEI@NH 2 -MIL-101(Al) also acted as a modification process toward flame retardant application. Thus, the dye-adsorbed PEI@NH 2 -MIL-101(Al) composite (MO-PEI@NH 2 -MIL-101(Al) and DR80-PEI@NH 2 -MIL-101(Al)) was sustainably used as an effective flame retardant for an epoxy resin (EP) at low additions (4.0 wt %). The limiting oxygen values of EP/MO-PEI@NH 2 -MIL-101(Al) and EP/DR80-PEI@NH 2 -MIL-101(Al) increased to 26.5 and 26.7%, respectively. The heat release and the smoke production of dyes-PEI@NH 2 -MIL-101(Al)/EP were greatly reduced compared with those of EP. This strategy provides a simple and effective modification method for MOFs. Meanwhile, the modified MOF composite can achieve sustainable application, giving full play to the advantages of MOFs.

Delicately regulating the distribution morphology of a filler is an effective strategy to promote the separation performance of mixed matrix membranes (MMMs). Herein, we describe a highly permeable metal−organic framework (MOF)-based MMM comprising vertically aligned ZIF-8 (V-ZIF-8) and polysulfone (PSF). The V-ZIF-8 is distributed uniformly within the PSF matrix. With this unique distribution morphology of ZIF-8, the shortest gas transport pathways are formed in the membrane. Meanwhile, the molecular-sieving pores of ZIF-8 can allow CO 2 to pass through and crowding out N 2 . The obtained V-ZIF-8/PSF membrane shows a high CO 2 permeability of 89.7 Barrer and a CO 2 /N 2 selectivity of 30.0 that is stable over a period of 50 h. The CO 2 permeability is enhanced about 11.8 times than that of the pure PSF membrane. The results prove that the vertically aligned distribution morphology of an MOF in a polymer matrix is an effective method to improve the separation performance of a membrane, providing a new concept for designing more advanced membranes.

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