| With rapid development of materials science and technology, addition-cure liquidsilicone rubber(ALSR) has received a great deal of attention because of its excellentresistance to moisture, water, ultraviolet light, radiation, weather and ozone, etc., whichmakes it widely applied in electronic devices and injection molding industries, etc. However,due to its low surface free energy, ALSR cannot be adhered to many substrates, which greatlylimits its wide application. In order to overcome the disadvantage of ALSR, a novel type ofsilicone adhesion promoter containing acrylate group(PHMS-g-HDDA) was synthesized andapplied to enhance the adhesive performance between ALSR and polyethylene terephthalate(PET) substrate. The main research contents and achievements are as followings:Firstly, the effect of the amount of HDDA on adhesive property, viscosity, vulcanizationand mechanical properties of ALSR was investigated. Besides, the boiling water resistance ofadhesion and storage stability of ALSR were also studied. The results showed that the180°peel strength and tensile strength of ALSR containing0.9phr HDDA were6.1kN/m and7.1MPa, while the180°peel strength and tensile strength of ALSR without addition of HDDAwere0.76kN/m and6.0MPa, respectively. Furthermore, HDDA remarkably influenced thevulcanization of ALSR. It could accelerate vulcanization obviously when the addition ofHDDA was less than0.9phr, but the inhibition effect would take place when HDDAexceeded0.9phr. Besides, the storage period was3h under50℃.Secondly, by grafting1,6-hexanediol diacrylate (HDDA) onto poly(methylhydrosiloxane)(PHMS) via hydrosilylation reaction, PHMS-g-HDDA was synthesized and applied to ALSRfor enhancing the adhesive performance between ALSR and PET substrate. The chemicalstructure of PHMS-g-HDDA was characterized by Fourier transform infraredspectroscopy(FT-IR) and1H nuclear magnetic resonance(1H-NMR). The effects of thesynthesis conditions, including molar ratio of vinyl group in HDDA and silicon hydrogengroup in PHMS (nC=C/nSi-H), Pt catalyst concentration, dropping time, dropping temperature,reaction temperature and reaction time, on the structure and adhesion promoting performanceof PHMS-g-HDDA were investigated. The research results showed the optimal molar ratio of nC=C/nSi-H, catalyst concentration, dropping temperature, dropping time, reaction temperatureand reaction time were1.0,0.15ppm,80℃,1h,80℃and2h, respectively. On the condition,the PHMS-g-HDDA had the optimum adhesion promoting property, whose180°peelstrength of ALSR containing PHMS-g-HDDA was6.9kN/m.Finally, the effect of the amount of PHMS-g-HDDA on adhesive property, viscosity,vulcanization and mechanical properties of ALSR was studied. Moreover, the boiling waterresistance of adhesion and storage stability of ALSR were also investigated. The resultsshowed that the ALSR containing0.9phr PHMS-g-HDDA had excellent adhesive property,whose180°peel strength was7.0kN/m. Furthermore, PHMS-g-HDDA remarkablyinfluenced the vulcanization of ALSR. PHMS-g-HDDA could accelerate vulcanizationobviously when PHMS-g-HDDA was less than0.9phr, while it would inhibit vulcanizationwhen it exceeded0.9phr. Moreover, PHMS-g-HDDA could improve the mechanicalproperties and storage stability of ALSR. The tensile strength of ALSR containing1.2phrPHMS-g-HDDA could reach7.0MPa and the storage period was5h under50℃. |
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