Jingsheng Wang , Jun Wang , Shuang Yang , Guoping Ding , Renxin Xu , Wei Liu , Jiuxiao Sun , Kaiwen Chen , Liu Duan , Jiaqi Wang , Hao Wang , Siqi Huo
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引用次数: 0
Abstract
Single-component epoxy resin (EP) is the premix of EP and latent curing agent, which is highly demanded in industries. However, current single-component EPs struggle to balance storage stability with mechanical properties and flame retardancy. To address this issue, three phosphorus-derived imidazolium salts (MPOx, x = 2, 3, 4) were synthesized using 2-ethyl-4-methylimidazole (EMI) and phosphorus-containing acids with different oxidation states (diphenylphosphinic acid, phenyl hydrogen phenylphosphonate, and diphenyl phosphate). The oxidation state of phosphorus significantly influenced thermal latency of MPOx, with higher oxidation states leading to improved latency. EP/MPO4 achieved the longest shelf life of 42 d at 25 °C. EP/MPO3 and EP/MPO4 exhibited enhanced tensile strength, modulus, and impact resistance compared to EP/EMI, but EP/MPO2 showed poor mechanical properties due to phase separation. All EP/MPOx achieved limiting oxygen index (LOI) exceeding 30 %, with EP/MPO3 showing the highest LOI of 34.0 % and significant reductions in heat release and smoke production. Flame-retardant mechanistic studies revealed a shift from gaseous-phase flame inhibition to condensed-phase promoting carbonization with increasing phosphorus oxidation state. Obviously, MPOx provides a tailored balance of latency, mechanical strength, and flame retardancy, making it a promising solution for advanced single-component EPs in aerospace, electronics, and optical applications.
期刊介绍：
Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology.
Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal.
However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.
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