Study On Synthesis And Properties Of Poly(Ethanediol Itaconate)

Unsaturated polyester could be synthesized by a variety of different materials.Its properties could be changed in a large range.So unsaturated polyester had broad rage of application.Among them,the unsaturated polyester polyurethane coating,which is made by unsaturated polyester,had the advantages of unsaturated polyester paint coating and polyurethane coating.It was widely used in the field of automotive industry,building decoration and equipment protection and so on.In this paper,the new unsaturated polyester-poly(ethanediol itaconate)(PEI)was prepared with itaconic acid(IA)and ethanediol(EG)as materials,which was terminated by hydroxyl.The effects of the mole ratio,reaction temperature,reaction time and the catalyst type on the performance of PEI were studied.Then,its molecular structure was characterized by FT-IR and 1H-NMR.And then PEI reacted with tolylene isocyanate(TDI),diphenylmethane diisocyanate(MDI)respectively to prepare the unsaturated polyester polyurethane.Then,the structure and thermal stable performance of PBI with TDI and MDI respectively were studied by infrared spectroscopy(FT-IR)and thermo gravimetric analysis(TGA).Finally,unsaturated polyester polyurethane of TDI or MDI was reacted with curing agent.The optimum reaction conditions were confirmed.The results were shown that PEI had the best performance when the esterification temperature was 140℃,the ratio of nEG to nIA was 1.25,the catalyzer was P-toluene sulfonic acid and its dosage was 0.1 percent of IA,the inhibitor was p-benzenediol and its dosage was 0.1 percent of IA,the esterification time was 7 hours,the polymerization temperature was 170 ℃,the polymerization vacuum degree was 0.1Mpa,the polymerization time was 4h.Using FT-IR and 1H-NMR to characterize the structure of the product and the results show that the product was PEI.Polyurethane of TDI had the best performance on the onditions that the molar ratio of nTDI to nPEI was 2.2:1,the reaction time was 2h,the reaction temperature was 80℃.Polyurethane of MDI had the best performance on the conditions that the molar ratio of nTDI to nPEI was 2.1:1,the reaction time was 1.5h,and the reaction temperature was 70℃.The spectra of FT-IR indicated that the-C=C-in the PEI molecule was well preserved during the pre-polymerization reaction.The data of thermo gravimetric analysis(TGA)showed that polyurethane of MDI had better heat resistance than polyurethane of TDI.The coating film performance test showed that the TDI coating film had the best performance on the condition that the curing temperature was 80℃,the curing time was 60 minutes,the dosage of the curing agent was 0.8% of PEI and the best performance was that the film was transparent and colorless,the hardness was 4H,the grade of adhesive force was 2,the impact strength was 45 cm.The coating film performance test showed that the MDI coating film had the best performance on the condition that the curing temperature was 70℃,the curing time was 50 minutes,the dosage of the curing agent is 0.8% PEI and the best performance was that the film was transparent and colorless,the hardness was 5H,the grade of adhesive force was 1,the impact strength was 50 cm.Obviously,the performance of MDI coating film was better.