Epoxy resins chain propagation

Figure 3.2 (a) Epoxy resin synthesis generalized reaction (b) reaction of hydroxyl group of NaOH with proton (c) displacement of the chlorine atom by the hydroxyl group (d) chain propagation (e) termination step. 

Alinear-chained epoxy resin was formulated from phenyl glycidyl ether and nadic methyl anhydride catalysed by benzyldimethylamine. Intermolecular polymerisations were modelled as a parallel set of propagation reactions. FTIR spectroscopy was used to determine the concentrations of the oxirane, anhydride and ester moieties within the resin as a function of time for two isothermal cures. Data analyses yielded the propagation rate constant as a function of temp, and the concentration of initiator, including contributions fl om impurities within the resin. Results obtained compared favourably with measurements on fractionated resins, using GPC. Population density distributions are described by Poisson molar distributions for this resin. 25 refs. 

Polytetrafluoroethene (Teflon) is etched, giving an active surface which can then be bonded strongly to an epoxy resin. With a source of acidic hydrogen such as water or an alcohol, sodium naphthalene affords 1,4-dihydronaphthalene. Polymers with functional groups at each end of the chain ( telechelic polymers) can be made by polymerization of styrene with sodium naphthalene. The anionic radical which is produced in the initiation step dimerizes to a dianion containing two propagating centres. 

---