Silicone Modified Polyesters Vulcanizable at Room Temperature for Anti-corrosion Coatings on Tinplate

Trimethoxysilyl Polyester(TMOS-PET)was prepared via hydrosilylation of trimethylsilane with acryl-terminated polyester.Copolymerization of TMOS-PET with trimethylmethoxysilane,tetramethoxysilane,and/or dimethyldimethoxysilane give silicone modified polyesters(Si-PET)containing=(SiO_(2))=,-(CH_(3)SiO_(3/2))=,and/or-((CH_(3))_(2)SiO)-units.Coatings from Si-PET were formed on tinplate surface via room temperature vulcanization with applicable curing time(the quickest tact free time and completely drying time are 2 h and 15 h,respectively).Mechanical properties,thermal stability,chemical resistance,and anti-corrosion of coatings were detected.Although the flexibility of the coatings were lowered by=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units,adhesion and thermal stability of coatings were both improved.On the contrary,(CH_(3))_(2)SiOunits seem to improve the flexibility,while decrease the adhesive force for less crosslink points.Generally,the silicone modified polyesters act as an effective shielding for tinplate.According to electrochemical impedance spectroscopy(EIS),the electric resistance of coatings(Rc)were improved about 25 times and open circuit potential(OCP)increased about 0.10 V compared to the control.The chemical resistance and anti-corrosion of the coatings were decreased slightly after=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units were added,but they could be greatly improved by-(CH_(3)SiO_(3/2))=units.Specially,after adding-(CH_(3)SiO_(3/2))=units,coatings give doubled Rc,and its OCP is about 0.20 V higher than the control.

Morphologies and Mechanical Properties of Unsaturated Polyester Resin Modified with TDI

The morphology, mechanical properties of unsaturated polyester（UP） resin modified with TDI were studied via dynamic FT-1R spectra, SEM, DMA and mechanical property testing. Results show that companying with the cured cross-linking reaction of UP resin, TDI can firstly react with UP and produce polyurethane（PU）, and then UP and PU form the cross-linking nets together. The impact fracture section morphology of modified UP resin manifested the typical sea- islands structure. Testing of mechanical properties showes that for introducing of PU, the TDI has an obvious effect on the toughness and strength of UP resin. When the ratio of TDI/UP （w/w） was 7.5%, the modified UP resin exhibited the best mechanical properties with flexural strength of 125 MPa, impact strength of 18 kJ·m^-2 and tensile strength of 72 MPa.