Synthesis, Characterization And Irradiation Modification Of Hyperbranched Unsaturated Polyesteramides And Application As Rheological Modificator

The research in this dissertation involves synthesis and characterization of hyperbranched unsaturated polyesteramides and their irradiation effect and application as rheological modificator.In this research, hyper- branched unsaturated polyesteramides were successfully synthesized from maleic anhydride and diethanolamine with ethylene glycol as a core monomer through a one-step and a two-step polycondensation reactions, respectively. The one-step synthesis was achieved with by-product water removed by strong N₂ stream （the resulting polymer labeled by HUPEA）, and thetwostep with by-product water removed by xy!ene refluxing （the resulting polymer labeled by Hupea）. At the initial stage of polymerization in the one-step and the two-step methods, the amine group in diethanolamine reacted fast with maleic anhydride, predominantly generating an AB2-type intermediate, i.e. N, N-diethanol maleamic acid monoamide. Further polymerization of the compound formed in situ gave a soluble polymerrather than a gel, which is different from the polymerization of diethanolamine with other cyclic anhydrides in which a strongly discolored, partially crosslinked, or even gelled product was obtained, and also which indicates that these polymerization processes in this research are effective methods for preparing hyperbranched polyesteramide.The obtained polymers were characterized by using FTIR and NMR spectroscopies as well as GPC. FTIR and NMR spectra indicated the presence of esterification of N, N-diethanol maleamic acid monoamide in the processes of polymerization, but fast esterification without any catalysts indirectly indicated the presence of an oxazolinium intermediate as discovered in other hyperbranched polyesteramides. But ¹³C dept135 NMR spectra indicated the presence of methane （CH） carbon which suggested that the hyperbranched polyesteramides formed via a mechanism in a combination of esterification and addition reactions. The addition of the hydroxyl group to the -CH=CH- in maleic anhydride unit results in a formation of CH methine group. The ratio of-CH=CH- to CH in the polymers increased as the decreasing content of ethylene glycol charged, which was estimated from ¹H NMR spectrum. The molecular weights of HUPEA and their polydispersities showed reverse dependences on the feed ratio of ethylene glycol to diethanolamine, which is in disagreement with other works in which the presence of a core molecule decreases the molecular weight of hyperbranched polymers with a concurrent reduction in the molecular weight distributions.In the investigated M_w range in this research, HUPEA polymers exhibited a steady increase of [η] with increasing M_w, and the Mark-Houwink exponent for these polymers was 0.26, which is much lower than 0.5 and suggested that the polymers possess a highly branched architecture. R_h～M_w^0.42 for HUPEA was determined from [η] by using Einstein’s equation for a hard sphee.Hyperbranched unsaturated polyesteramides solutions showed a Newtonian behavior with steady shear viscosities independent of shear rate, which indicated the absence of physical entanglement. Solution viscosity dependence on the temperature was also investigated over a temperature range 20- 60℃for HUPEA and 15-50^C for Hupea. The general trend seemed to indicate that solution viscosities of HUPEA at 40℃yield lower values, and that solution viscosities of Hupea at 25℃yield lower values. The above-mentioned rheological behavior also strongly suggested that these polymers possess a highly branched architecture.For the first time, ionizing irradiation effect on hyperbranched polymers was studied. The results showed that the gel was absent in irradiated HUPEA polymers at the investigated absorbed dose range and that the chemical structure of the polymers changed byγray radiation. The [η] of the polymers irradiated in solution form showed no dependence on radiation dose, but the [η] of the polymers irradiated in solid decreased with the increasing dosage. The temperatures of thermal transition and weight loss of HUPEA polymers irradiated in solid increased with the increasing dosage. The mechanical properties of the blends of HUPEA and their irradiated copies respectively with polycarbonate had been studied in this research. The results showed that the properties of PC/HUPEA were lower than that of PC, but that the properties of the blends of HUPEA irradiated at 100 kGy with polycarbonate were more higher than PC and PC/HUPEA, especially the tensile modulus, the flexural modulus and the maximum flexural strength increased 31%, 7 % and 6.3 % respectively.