A highly efficient flame-retardant melamine salt (DPPMA) was synthesized from diphenylphosphinic acid (DPPA) and melamine (MA). The chemical structure of DPPMA was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis, and the thermal degradation behavior was investigated by thermogravimetric analysis (TGA). Subsequently, flexible polyurethane foams (FPUFs) were prepared with DPPMA. Limiting oxygen index (LOI) tests, vertical burning tests, and cone calorimetric tests were carried out to investigate the combustion of the materials. The results showed that the FPUF with only 5 php DPPMA passed the vertical burning test and had an increased LOI value of 22%. The corresponding flame-retardant mechanism was systematically investigated by FTIR spectroscopy, TGA, and energy-dispersive X-ray (EDX) spectrometry. The results revealed that DPPMA released NH3 and H2O to dilute the combustible gas and phosphorus-containing radicals during combustion, which consumed the active free radicals produced by the FPUF.

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A novel, slow‐release polymer containing phosphorous fertilizer was synthesized by the rapid coordination of iron ions with polymers after the microwave radiation polymerization of collagen, 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid, and acrylic acid. We obtained an optimized collagen‐g‐poly(acrylic acid‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) collagen‐g‐p(AA‐co‐AMPS)–Fe(III) polymer with great equilibrium swelling capacities of 2595 g/g in distilled water and 121 g/g in 0.9 wt % NaCl solution and an excellent sustained fertilizer release of about 30 days. In addition, for the collagen‐g‐p(AA‐co‐AMPS)–Fe(III) polymer, the effect of cations on its swelling followed the order K+ > Na+ > Mg2+ > Ca2+. The structure and morphology were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Moreover, the collagen‐g‐p(AA‐co‐AMPS)–Fe(III) polymers emancipated the nutrients in a more controlled manner than collagen‐g‐p(AA‐co‐AMPS). The thermal stability, water absorbency, and good slow‐release of fertilizer provide the collagen‐g‐p(AA‐co‐AMPS)–Fe(III) polymer with great potential as a fertilizer‐carrying vehicle and an aquasorb to be applied in agriculture and horticulture. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47178.

As release formulations, superabsorbent polymers have attracted considerable attentions to reduce herbicide leaching and mitigate contamination. For this purpose, this study dealt with preparation, characterization, and performance test of a novel amphoteric superabsorbent polymer in adsorption and release of 2, 4-Dichlorophenoxyacetic acid (2, 4-D) herbicide. LW-g-p(AA-co-DMDAAC) was successfully synthesized by using leather waste (LW) as raw material and acrylic acid (AA), and dimethyldiallylammonium chloride (DMDAAC) as monomers. Then, the resulting LW-g-p(AA-co-DMDAAC) was characterized before and after 2, 4-D sorption by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). In addition, LW-g-p(AA-co-DMDAAC) with great equilibrium swelling capacity of 3203 g/g in distilled water, 181 g/g in 0.9 wt % NaCl exhibited excellent performance of swelling. Two absorption peaks appeared at pH = 4 and 7 solely when swelling occurred, and the swelling behavior in pH = 7 satisfied the pseudo first-order kinetic equation. Moreover, the sorbed 2, 4-D reached at 68 mg/g and showed sustained release cycle of 45 days under acidic or alkaline conditions. Therefore, the sustained release pattern of 2, 4-D as well as water absorbency made LW-g-p (AA-co-DMDAAC) suitable and potential candidate for controlling the release of herbicides to improve utilization and reduce environmental pollution.

Shape memory hydrogels (SMHs) have been the subject of great interest in recent years. However, there were few reports on the simultaneous multiple shape memory and high mechanical performance. Therefore, a novel nanocomposite (NC) hydrogel poly (acrylic acid)/Chitosan/ Laponite (PAA/CS/ Laponite) was developed by using Laponite as physical cross-linker. In order to achieve three temporary shapes, the PAA/CS/Laponite was soaked in iron chloride hexahydrate (FeCl 3), sodium hydroxide (NaCl) and sodium hydroxide (NaOH) respectively to (a) form metal coordination; (b) gain the chains entanglement of chitosan; (c) get the microcrystalline structure of chitosan. The maximum shape fixity ratio of PAA/CS/Laponite can reach 100% in 1 minute and it can be restored its original shape within 5 minutes. Moreover, PAA/CS/Laponite showed excellent mechanical performance. The maximum tensile and compressive strengths were 0.73 MPa and 13.1 MPa. By comparison with PAA/CS obtained from our previous work, the tensile strength, elongation at break and compressive strength increased by 2.21 times, 1.46 times, and 3.26 times respectively. Scanning electron microscopy (SEM) showed that the obtained sample has uniform honeycomb network structures which can effectively explain why the gel has strong mechanical performance. These characteristics make PAA/CS/Laponite have huge application potential in reality.