نتایج جستجو برای: Free Radical Initiator

تعداد نتایج: 591774  

Journal: :علوم و تکنولوژی پلیمر 0
فرشید ضیایی مونا بصیری مهدی نکومنش اردشیر خزایی

polymerization of styrene in presence of two monofunctional initiators is studied kinetically in an ampoule scale. polymerizations were ceased at different conversions for each ampoule while the temperature was increased almost linearly during the reaction. three different initiator mixtures were used. the first mixtures were composed of benzoil peroxide (bpo) and t-butyl perbenzoate (tbpb) wit...

Journal: :iranian journal of medical physics 0
zeynab sanjabi m.sc. of radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran mohammad hassan zahmatkesh associate professor, shahid beheshti university, evin, tehran, iran saeid bagheri m.sc. in medical physics, shahid beheshti university, tehran, iran

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...

Titanium dioxide (TiO2) nanoparticles, with an average size of about 45 nm, were encapsulated by polystyrene using in situ nitroxide mediated radical polymerization   in the presence of 3-aminopropyl triethoxy silane (APTES) as a coupling agent and 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy  as a initiator. First, the initiator for NMRP was covalently bonded onto the surface of Titanium dioxide na...

Journal: :Journal of biomedical materials research. Part A 2014
Mary M Caruso Dailey Alexander W Silvia Patrick J McIntire Gerald O Wilson Jeffrey S Moore Scott R White

Self-healing chemistry used for damage repair have not previously been demonstrated for free-radical polymerization pathways. However, this chemistry is important for addition polymers such as poly(methyl methacrylate) used in bone cement and epoxy vinyl ester used in dental resins. Self-healing biomaterials offer the potential for safer and longer lasting implants and restoratives by slowing o...

Journal: :journal of nanostructures 2016
m. abbasian n. khakpour aali

titanium dioxide (tio2) nanoparticles, with an average size of about 45 nm, were encapsulated by polystyrene using in situ nitroxide mediated radical polymerization   in the presence of 3-aminopropyl triethoxy silane (aptes) as a coupling agent and 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy  as a initiator. first, the initiator for nmrp was covalently bonded onto the surface of titanium dioxide na...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1997
rouhallah bagheri faranak naimian nassrin sheikh

acrylamide was grafted in low density polyethylene during melt processing in the presence of a free radical initiator using a torque rheometer in a closed system. effects of processing time, acrylamide and benzoyl peroxide concentrations were studied. ftir studies revealed that the degree of grafting increased by an increase in acrylamide concentration. maximum grafting was obtained at 7 minute...

2012
Yoshimi Sueishi Misa Ishikawa Daisuke Yoshioka Nobuyuki Endoh Shigeru Oowada Masashi Shimmei Hirotada Fujii Yashige Kotake

Recently, we proposed an oxygen radical absorbance capacity method that directly quantifies the antioxidant's scavenging capacity against free radicals and evaluated the radical scavenging abilities for water soluble antioxidant compounds. In this study, we determined the radical scavenging abilities of lipophilic antioxidants which were solubilized by cyclodextrin in water. Commonly employed f...

Journal: :The Journal of organic chemistry 2014
Cody Ross Pitts Bill Ling Ryan Woltornist Ran Liu Thomas Lectka

We offer a mild, metal-free sp(3) C-H fluorination alternative using Selectfluor and a substoichiometric amount of triethylborane--an established radical initiator in the presence of O2. This radical-chain-based synthetic method is particularly noteworthy as an offspring of the insight gained from a mechanistic study of copper-promoted aliphatic fluorination, constructively turning O2 from an e...

Journal: :Angewandte Chemie 2023

Mechanochemical approaches are widely used for the efficient, solvent-free synthesis of organic molecules, however their applicability to functional polymers has remained underexplored. In Research Article (e202305783), Carsten Bolm, Andrij Pich, and co-workers developed a free-radical polymerization approach mechanochemically synthesize structurally morphologically well-defined complex macromo...

2017
Gholamreza Mahdavinia Ali Afzali Hossein Etemadi Hossein Hosseinzadeh

* Corresponding Author Email: [email protected] Objective(s): The main aim of current research was to develop a novel magnetically responsive hydrogel by radical polymerization of carboxymethyl cellulose (CMC) on acryl amide (Am) using N,N'-methylene bis acrylamide (MBA) as a crosslinking agent, potassium persulfate (KPS) as a free radical initiator, and magnetic montmorillonite ( mMT)...

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