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Excited Triplet States of Organic Molecules and Reactive Free Radicals in Polymers

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                                             JUNIPER PUBLISHERS-   ACADEMIC JOURNAL OF POLYMER SCIENCE Abstract The mini-review is devoted to the recent investigation the role of cage effect during photopolymerization. Benzophenone was selected as a photoinitiator of polymerization. Introduction Free-radical photopolymerization (UV-cure) of organic coatings is a very important process that has been used for more than half a century. Academic and industrial researchers study the basics of this complex process [1-4] In this mini review we will briefly consider the important role of low MW free radicals of photoinitiators (PIs) and the excited triplet states of PIs in photopolymerization. On the contrary, residual PIs in the cured coatings and other low MW photoreactive species in the cured coatings/polymers lead to a negative effect: photodecomposition of polymers outdoors, poor weatherability. We will comment on that as well. Discussion A primary chemical act of free radical photopolyme

Recent Advances in the Synthesis and Analysis of Polyamide 6 and Products therefrom: From Polymerization Chemistry of εcaprolactam to Thermoplastic Resin Transfer Moulding (t-rtm)

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                                   JUNIPER PUBLISHERS-   ACADEMIC JOURNAL OF POLYMER SCIENCE Abstract Significant research and developments are taking place in the field of synthetic polyamides (Nylons). One of the most investigated members of this family of polymers is poly (ε-caprolactam) (PCL, Polyamide 6, PA6, Nylon 6). Herein, a brief overview will be presented on the major recent advancements in the anionic ringopening polymerization (AROP) of ε-caprolactam (CL) by the initiating combinations of metal lactamates and carbamoylcaprolactams and by some other initiating systems, e.g. protected N-heterocyclic carbenes , NaHMDI and σ-borane-barium complexes. The in situ polymerization of CL in the presence of additives, such as flame retardants, reinforcing agents and fillers, is also discussed. Examples are presented on the determination of the molecular weight distributions (MWD) and average molecular weights of Polyamide 6 by GPC (SEC) measurements with 1,1,1-trifluoroethanol as elu