Frontal polymerization involves the conversion of monomer to polymer in a localized reaction zone that propagates due to the interplay of thermal conduction and temperature-dependent reaction rates. The localization of reactions and the fast increase in temperature are the key features that allow for the rapid synthesis of a wealth of polymer systems with spatially controlled microstructures an...

antibacterial, antifungal and antioxidant activities of methanolic crude extracts from aerial parts of four arnebia species namely arnebia fimbriopetala, arnebia linearifolia, arnebia garandiflora, arnebia tubata were screened. total phenolic contents were determined by folin-ciocalteu procedure and ranged from 2.2 ± 0.13 (a. fimbriopetala) to 1.6 ± 1.0 mg (arnebia tubata) gallic acid µmol equi...

Introduction Polysulfides play a critical role in the optimization of many chemical processes. Dimethyl disulfide (DMDS), for example, is used as coke inhibiting additive in steam cracking furnaces and can also be used as photolytic initiator during free radical polymerization.[1, 2] Also tetrasulfides are frequently used in chemistry, mostly as inhibitors during polymerization reactions. Despi...

The effects of polymerization kinetics and chemical miscibility on the crosslinking structure and mechanical properties of polymers cured by visible-light initiated free-radical/cationic ring-opening hybrid photopolymerization are determined. A three-component initiator system is used and the monomer system contains methacrylates and epoxides. The photopolymerization kinetics is monitored in si...

A series of bicationic monochromophoric hemicyanine dyes based on benzothiazolestyrylium residues were synthesized. The dyeing photoinitiating systems consisting of N-[3-(4-methylpyridino)propyl]-2-(p-substituted styryl)benzothiazolium dihalides as chromophores and n-butyltriphenylborate anion as electron donor were also prepared to achieve an efficient photoinitiators for free-radical polymeri...

in current work a comprehensive mechanism based on intermediate radical termination theory is assumed for raft polymerization of styrene over cumyl dithiobenzoate as raft agent. rate constants for addition (ka) and fragmentation reactions (kf) are set to 6×106 and 5×104 respectively, which lead to an equilibrium constant value of k = ka/kf = 1.2 x 102. moment equations method was used to model ...

The first detailed study on free-radical polymerization, copolymerization and controlled radical polymerization of the cyclic push-pull-type monomer methylenelactide in comparison to the non-cyclic monomer α-acetoxyacrylate is described. The experimental results revealed that methylenelactide undergoes a self-initiated polymerization. The copolymerization parameters of methylenelactide and styr...

A brief overview of the principles and associated instrumentation used to monitor polymerization reactions by automatic continuous online monitoring of polymerization reactions (ACOMP) is presented. ACOMP can be used as an analytical method in R&D, as a tool for reaction optimization at the bench and pilot plant level and, eventually, for feedback control of full-scale reactors. ACOMP measures ...

Efficiency of photoinitiators (PI) depends upon quantum yield of photogeneration of reactive free radicals and upon cage effect value. Only radicals that escape the cage can initiate free radical polymerization. The modern concept of the cage effect is presented. Dependencies of the cage effect upon increasing of solvent viscosity in the course of polymerization are discussed. Cage effect dynam...