نتایج جستجو برای: free radical initiator
تعداد نتایج: 591774 فیلتر نتایج به سال:
The radical-mediated transition metal-free approach for the direct C–H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively s...
Commercial initiator – 2,2-dimethoxy-2-phenyl acetophenone (Irgacure 651, Ciba, Switzerland) was introduced to poly(methyl methacrylate) (PMMA) matrix to enhance the polymer degradation. Two types of thin polymeric films (PMMA and PMMA+5% Irgacure) were UV-irradiated in laboratory conditions (Xenon lamp, air atmosphere, room temperature). The photochemical changes in pure PMMA and PMMA doped wi...
Introduction: Different dosimetric modalities (e.g., ionization chambers, semiconductors, TLDs, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. Research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. The ‘PRESAGE’ dosimet...
The Matsuda-Heck reaction, usually performed with palladium catalysts, can be carried out under transition-metal-free conditions in the presence of a KOtBu/DMF couple. This system allows selective and direct synthesis stilbenes from aryldiazonium salts mild temperature (20 °C). Mechanistic studies suggest radical pathway which DMF acts as initiator overall process.
antioxidants are vital substances which possess the ability to protect the body from damage caused by free radical induced oxidative stress. a variety of free radical scavenging antioxidants exist within the body which many of them are derived from dietary sources like fruits, vegetables and teas. in this study the antioxidant activity and radical scavenging activity of methanolic extracts of s...
A series of ABA triblock copolymers, consisting of double-bond-containing poly(phenoxyallene) (PPOA), poly(methyl methacrylate) (PMMA), or poly(butyl acrylate) (PBA) segments, were synthesized by sequential free radical polymerization and atom transfer radical polymerization (ATRP). A new bifunctional initiator bearing azo and halogen-containing ATRP initiating groups was first prepared followe...
In free-radical polymerization, a monomer-initiator mixture is converted into a polymer. Depending on initial and boundary conditions, free-radical polymerization can occur either in a bulk mode (BP) or in a frontal mode (FP) via a propagating selfsustaining reaction front. The main goal of this paper is to study the role that bulk polymerization plays in frontal polymerization processes for va...
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