A novel hyperbranched polyphosphate ester (HPPE) and a high‐performance hybrid flame‐retarding material HPPE/diglycidyl ether of bisphenol‐A (DGEBA) epoxy resin are prepared. The effect of HPPE content and molecular weight on the mechanical performance, thermal performance, and flame‐retarding property of the hybrid material is studied. The results show that the overall performance of the hybrid material first increases and then decreases with the increase of HPPE content as well as the molecular weight and reaches maximum with 8–12 wt% of HPPE. When compared with the performance of pure DGEBA, the tensile strength, flexural strength, impact strength, fracture toughness, and limited oxygen index of the HPPE‐2/DGEBA hybrid material are enhanced by about 114%, 50%, 48%, 95%, and 20%, respectively. The toughening and reinforcing mechanism of the hybrid system is a novel in situ effect as revealed by the micrographs of the fracture surfaces using scanning electron microscopy. POLYM. COMPOS., 32:36–43, 2011. © 2010 Society of Plastics Engineers

In this work, a flame retardant curing agent (DOPO-MAC) composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and methyl acrylamide (MAC) was synthesized successfully, and the structure of the compound was characterized by FT-IR and 1H-NMR. The non-isothermal kinetics of the epoxy resin/DOPO-MAC system with 1% phosphorus was studied by non-isothermal DSC method. The activation energy of the reaction (Ea), about 46 kJ/mol, was calculated by Kissinger and Ozawa method, indicating that the curing reaction was easy to carry out. The flame retardancy of the epoxy resin system was analyzed by vertical combustion test (UL94) and limiting oxygen index (LOI) test. The results showed that epoxy resin (EP) with 1% phosphorus successfully passed a UL-94 V-0 rating, and the LOI value increased along with the increasing of phosphorus content. It confirmed that DOPO-MAC possessed excellent flame retardance and higher curing reactivity. Moreover, the thermal stability of EP materials was also investigated by TGA. With the DOPO-MAC added, the residual mass of EP materials increased remarkably although the initial decomposition temperature decreased slightly.

In nonequilibrium chemical reaction systems, a fundamental relationship between unbalanced kinetic one-way fluxes and thermodynamic chemical driving forces is believed to exist. However, in fact, the formula for this fundamental relation, in general, and the very definition of kinetic one-way fluxes in nonlinear chemical reaction networks, are still missing. In terms of its stochastic kinetic representation, we formulate the one-way fluxes for a general chemical reaction far from equilibrium, with arbitrary complex mechanisms, multiple intermediates, and internal kinetic cycles. For each kinetic cycle, the logarithm of the ratio of the steady-state forward and backward one-way fluxes is equal to the free energy difference between the reactants and products along the cycle. This fundamental relation is further established for general chemical reaction networks with multiple input and output complexes. This work provides a concrete mathematical/physical basis for a long-hold belief in chemical kinetics. It gives an equivalent definition of the free energy difference in nonequilibrium chemical reaction networks and unifies the stochastic and macroscopic nonequilibrium chemical thermodynamics in a very broad setting.

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