Wang Yiming,Li Cui,Liu Hui,Ma Lili,Jiang Dayong,Wen Xin,Tang Tao
Abstract As a promising biodegradable polymer, poly(butylene succinate) (PBS) is limited by its inherent flammable and melt-dripping nature. In this study, the effect of molecular sieve 4A (MS4A) as synergist on thermal stability and flame retardancy of PBS/piperazine pyrophosphate (PAPP) composites was investigated. TGA results showed that the addition of MS4A could effectively improve the thermal stability of PBS/PAPP composites both in nitrogen and air atmospheres. Compared to PBS/20PAPP, PBS/17PAPP-3MS4A exhibited the optimal flame retardancy with limited oxygen index of 29.8%, V0 rating in UL-94 vertical burning test, and 86.6% reduction on the peak of heat release rate in cone calorimeter test. According to the analysis for char morphology and microstructure, the combination of PPAP/MS4A mainly imparted its flame retardancy through condensed phase. The enhancement mechanism was ascribed to their catalytic carbonization effect and the migration of MS4A to construct stronger char layer in out interface during combustion. This work provides a new intumescent flame-retardant system with high efficiency and low toxicity, which will greatly promote the widely applications of PBS composites. Graphical abstract
The capture of CO 2 from ambient air (400 ppm) has become a critical issue in combating climate change. In this study, a novel recombinant 13X zeolite (RS13X) with an Faujasite (FAU) structure was synthesized by transforming discarded Linde type A (LTA)-structured 4 A molecular sieves through alkali fusion. This material was subsequently modified with hydrazine (HZ) vapor to produce HZ-RS13X, which significantly enhances the pore structure of RS13X, leading to excellent CO 2 adsorption performance across a range of concentrations. Specifically, HZ-RS13X demonstrates excellent adsorption capacities of 2.16 mmol/g at 400 ppm, 6.14 mmol/g at 10,000 ppm, and 7.89 mmol/g at 100,000 ppm, highlighting its efficacy for industrial CO 2 emissions. Additionally, HZ-RS13X excels in the selective separation of CO 2 from CH 4 and N 2 , exhibiting high ideal adsorbed solution theory (IAST) selectivity values of 335 for a CO 2 /N 2 mixture (10/80) and 260 for a CO 2 /CH 4 mixture (50/50). Characterization results, along with grand canonical Monte Carlo (GCMC) simulations, reveal that HZ vapor modification enhances CO 2 adsorption modes of RS13X beyond those achieved through conventional carbamate generation methods. HZ-RS13X offers substantial CO 2 capture potential across a wide range of concentrations, from atmospheric levels to industrial emissions, presenting a promising strategy for solid-state CO 2 capture.
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