Of Amps Modified Epoxy Resin And Emulsifying Properties

The epoxy resin emulsion derived from chemical method received much attention duo to absence of surfactant. It is characteristic of self-emulsification, dispersoid particle was small to nano level. The modifier reported in the literature to prepare anionic epoxy resin was mostly acrylic monomers. Epoxy resin can obtain water-dispersibility after carboxyl group was introduced and neutralized. The emulsion prepared by this approach only could keep stable under the alkalescent circumstance. If pH value vary, the systerm tend to agglomerate or gelate, which is bad to preservation and untilization.In this article epoxy resin was modified by waterborne monomer 2-acrylamido-2-methyl-l-propanesulfonic acid (AMPS). The copolymer could acquire good water dispersibility needless of neutralization. The reaction route was schemed out independently. By a series of orthogonal and contrastive experiments, the optimal materials ratio , reaction temperature and dosage of the initiator were discovered. Furthermore some other factors that could affect polymeric ability were researched. Due to the extreme high reactive capability, some peculiar adding techniques were adopted so as to insure the process of the whole reaction. As a result, under the condition of the materials ratio 1: 2, the temperature 110℃ and the dosage of BPO 1.5%, the productive rate could achieve 69.1 %. The change of intrinsic viscosity [η], the acid value and the productive rate along with reaction time were measured. IR spectrum analysis indicated the structure of the copolymer. The kinds of stabilities were tested and the apparent properties of the copolymerization were described.From the descent of the acid value we can speculate that there would be the chain extension derived from sulfonic acid and epoxy group and the graft copolymerization in the chain of the epoxy resin with presence of BPO. Therefore three parallel experiments were carried through to probe into the mechanism of the reaction. It could be concluded that during the whole process graft and ring-open reaction went along, both of which respectively took dominant status in the early and after stage. DSCand TG curves were determined, and the appearance of the two glass transition temperatures made sure the speculation of the mechanism. Furthermore the active energy and velocity constant were measured. We took the concentration change of the epoxy resin as the object and differential coefficient method was adopted. It was found that the key step was the producing velocity of free radical which controlled the speed of graft and chain extension reaction.The particle size distribution of the derived emulsion was related to the reaction time. With the time extending, the size turned gradually large and broad. It could be explained that in the early phase ring-opening reaction consumed many sulfonic groups which made the dispersibility of the copolymer decline. It was also discovered that the particle size was affected by the dosage of the monomer. With the increasing of the dosage of AMPS the size of the emulsion was getting larger. The modified resin was directly emulsified without the neutralizer, which affected little the particle size distribution of the water-dispersoid. This point embodied fundamental difference comparing to the epoxy resin modified by the other waterborne monomers which would obtain good dispersibility only after neutralization.In this paper, the author studied the properties of the epoxy resin modified by both MAA and AMPS. It was found that the viscosity of such system went down a little, the glass transition temperatures and the thermal decomposing temperature was ascending to some extent. But the particle size distribution became larger and boarder than that of the copolymer modified by AMPS alone. Therefore the copolymer with different properties could be acquired by modulating the proportion of the monomer.