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Organic matrices
Published in A.R. Bunsell, S. Joannès, A. Thionnet, Fundamentals of Fibre Reinforced Composite Materials, 2021
R. Bunsell, S. Joannes, A. Thionnet
The polyaddition process occurs when the addition of another monomer leads to the repeated linking of molecular chains to create macromolecules. When only one type of monomer is involved a homopolymer is produced giving, for the monomer, the following chain (C3.3).
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Published in Eli Ruckenstein, Hangquan Li, Chong Cheng, Solution and Surface Polymerization, 2019
Hongmin Zhang, Eli Ruckenstein
2E, 4B, 6H were polymerized in THF in the presence of PTS as a catalyst. The polymerization proceeded by a step-growth self-polyaddition mechanism and not by a chain reaction. A hydroxyl group of one molecule reacted with a vinyloxyl group of another molecule to generate a polymer with an acetal main-chain structure and not a carbon–carbon backbone. Under selected conditions, the copolymerization of two monomers, 6H/4B, 6H/2E, or 4B/2E, also proceeded smoothly, generating the corresponding copolymers with acetal chain structure.
Curing processes of binary epoxy-amine systems for manufacturing epoxy-silica films
Published in Materials and Manufacturing Processes, 2020
Elham Naeemikhah, Aziz Ahmadi Khaneghah, Zeinab Shamsi-Jamkhaneh, Hossein Behniafar
Two epoxy resins including bisphenol A diglycidyl ether (BADGE) and polyoxybutylene diglycidyl ether (POBDGE) were considered for curing processes. Isophorone diamine (IPDA) and polyoxybutylene diamine (POBDA) were used as the curing agents of the resins. Two of these four monomers, i.e., POBDGE and POBDA, were based on polyoxybutylene flexible units, and both were synthesized from polytetramethylene glycol (PTMG). The one-step synthesis reaction of POBDGE resin from PTMG and epichlorohydrin (ECH) is shown in Scheme 1(a). POBDA hardener was synthesized via a three-step reaction with PTMG starting material according to our previous report.[40] The structures of the used hardeners are illustrated in Scheme 1(b). Trace amounts of oligomerization arisen from the ring opening of the epoxide rings may also occur alongside the substitution reaction. These polyaddition reactions can lead to an inaccuracy in the measurement of the stoichiometric ratios of the monomers. To minimize the oligomerization phenomenon during the synthesis of POBDGE resin, a large excess amount of ECH was used. In this condition, “m” value was found to be lower than 0.1. Two other monomers, BADGE epoxy resin and IPDA curing agent, were among the most popular monomers, which have been widely used for preparing epoxy materials.